Anatomy and Physiology Flashcards

Question

Survival need: Survival of the species - Reproduction (1)

Answer 1

Survival of the fittest Ova, menstrual cycle Sperm Coitus Fertilisation Pregnancy Rearing young / maturation Slide 45

Answer 2

The GI tract is the largest organ of the body. – False, skin Snot is a really important part of the adaptive immune system – False, part of the innate immune system acting as a non-specific barrier that carries pathogens out of the body. The musculoskeletal system is important for survival as it enables hunting, escaping, fighting and reproduction. - True slide 46

Answer 3

Atoms Molecules Macromolecules Cells Tissues Organs Systems Organism slide 6 (2)

Answer 4

1) Epithelial 2) Connective 3) Muscle 4) Nervous Slide 6 (2)

Answer 5

Epithelial tissue – lining structures, covers the body and lines cavities, hollow organs and tubes Connective tissue – most abundant tissue in the body Most abundant tissue in the body! Cells more spread out, more extracellular matrix Slide 6 (2)

Answer 6

1) Structural support (bone, tendons, ligaments). 2) Protection 3) Transport 4) Insulation Slide 6(2)

Answer 7

Muscle tissue – Contractile tissue providing movement of the body and structures within the body Nervous tissue – both excitable (neurones) and non-excitable cells (that support the neurones). Slide 6 (2)

Answer 8

provides O2 needed for oxidation (energy provision) Slide 7 (2)

Answer 9

breaks down nutrients, pass to liver via portal vein Slide 7 (2)

Answer 10

co-ordinates organ system activity by hormones or electrical signals Slide 7 (2)

Answer 11

pumps blood around the body (delivers O2/ nutrients removes CO2/ waste) Slide 7 (2)

Answer 12

controls the contents of the extracellular fluid Slide 7 (2)

Answer 13

locomotion, maintenance of posture, breathing, protection Slide 7 (2)

Answer 14

1) The liver is the largest organ of the body. – False, skin is the largest organ of the body. 2) The nervous system consists only of nervous tissue. – False, the nervous system also includes epithelial tissue, and connective tissue. 3) The digestive system is only made of the stomach, small intestine and large intestine. – False, also includes the accessory organs of salivary glands, liver, gall bladder and pancreas. Slide 9 (2)

Answer 15

Head / cranial / cephalic Facial Cervical Thorax / thoracic Abdomen Pelvis Lumbar Limbs – UEx /LEx** Left = your right Right - your left Slide 10 (2)

Answer 16

Slide 11 - Look at anatomy diagrams powerpoint Standard anatomical position is standing with the palms facing forward. Left and right are from the patient’s perspective. Areas of the body have anatomical names and also common (or layman) names eg. orbit = eye

Answer 17

Slide 12 (2) - look at anatomy powerpoint

Answer 18

means under slide 12 (2)

Answer 19

means ribs slide 12 (2)

Answer 20

means above Slide 12 (2)

Answer 21

means stomach Slide 12 (2)

Answer 22

The term hypochondriac (to mean an imaginary illness) comes from a time when physicians were often unable to tell exactly what the cause of a symptom was, but the symptoms were felt in the soft region under the ribs. The phrase changed meaning over time from an unspecified cause under the ribs to an unspecified cause that may be imagined…. Slide 12 (2)

Answer 23

Sub- Under, beneath, smaller Slide 13 (2)

Answer 24

Hypo- Under, beneath Slide 13 (2)

Answer 25

Infra- Under, within, below Slide 13 (2)

Answer 26

Super- or Supra- Above, on top of Slide 13 (2)

Answer 27

Epi- Above, upon, on top of Slide 13 (2)

Answer 28

Fossa- Depression, hollow Slide 13 (2)

Answer 29

Inter- Between Slide 13 (2)

Answer 30

Ad- Towards Slide 13 (2)

Answer 31

Ab- Away from Slide 13 (2)

Answer 32

Contra- Opposite Slide 13 (2)

Answer 33

Ipsi- Same Slide 13 (2)

Answer 34

Bi- Two Slide 13 (2)

Answer 35

Uni- One Slide 13 (2)

Answer 36

Definition: A vertical plane that divides the body into front (anterior) and back (posterior) portions. Also known as the coronal plane.

Answer 37

Definition: Relating to the belly side (ventral) and the back side (dorsal) of an organism.

Answer 38

Definition: A horizontal plane that divides the body into upper (superior) and lower (inferior) portions. Also known as the horizontal plane or cross-sectional plane.

Answer 39

Definition: Referring to the front (anterior or cranial) and back (posterior or caudal) aspects of an organism.

Answer 40

Definition: A vertical plane that divides the body into left and right halves, running from head to tail. When it bisects the body into equal halves, it's called the median plane. When it's offset from the midline, it's termed a parasagittal plane.

Answer 41

Definition: Relating to the midline (medial) and away from the midline (lateral) of an organism or structure.

Answer 42

Definition: Referring to positions near the point of attachment (proximal) or close to the center of the body, and away from the point of attachment (distal) or farther from the center of the body.

Answer 43

Frontal plane Definition: A vertical plane that divides the body into front (anterior) and back (posterior) portions. Also known as the coronal plane. Flashcard 2: Term: Ventral-dorsal = Anterior-posterior Definition: This refers to the belly side (ventral) and the back side (dorsal) of an organism, equivalent to anterior and posterior in humans.

Answer 44

Term: Transverse plane Definition: A horizontal plane that divides the body into upper (superior) and lower (inferior) portions. Also known as the horizontal plane or cross-sectional plane. Flashcard 4: Term: Cranial-caudal = Superior-inferior Definition: Referring to positions towards the head (cranial or superior) or towards the feet (caudal or inferior) of an organism, respectively.

Answer 45

Term: Median or sagittal plane Definition: A vertical plane that divides the body into left and right halves, running from head to tail. When it bisects the body into equal halves, it's called the median plane. When it's offset from the midline, it's termed a parasagittal plane. Flashcard 6: Term: Medial-lateral Definition: Relating to the midline (medial) and away from the midline (lateral) of an organism or structure.

Answer 46

Stomach, small intestine, most of large intestine Liver, gall bladder, bile ducts, pancreas Spleen 2 kidneys and upper parts of ureters 2 adrenal glands Numerous blood vessels, lymph vessels/nodes, nerves

Answer 47

Term: Proximal-distal Definition: Referring to positions near the point of attachment (proximal) or close to the center of the body, and away from the point of attachment (distal) or farther from the center of the body.

Answer 48

Follicle Stimulating Hormone (FSH): - A gonadotropic hormone (a type of hormone that primarily acts on the gonads, which are the reproductive organs responsible for producing gametes (sperm in males and eggs in females) and sex hormones (such as testosterone in males and estrogen and progesterone in females). Gonadotropic hormones are secreted by the anterior pituitary gland and include follicle-stimulating hormone (FSH) and luteinizing hormone (LH).) Secreted by: Anterior pituitary gland. Function: In females, FSH stimulates/promotes the growth and development of ovarian follicles in the ovary before ovulation. In males, FSH stimulates/promotes the production of sperm in the testes.

Answer 49

Luteinizing Hormone (LH): Secreted by: Anterior pituitary gland. Function: In females, LH stimulates ovulation and promotes the development of the corpus luteum. The CL forms after ovulation; it produces estrogen and progesterone. In males, LH stimulates the production of testosterone in the testes.

Answer 50

Growth Hormone (GH): Secreted by: Anterior pituitary gland. Function: Stimulates growth, cell reproduction, and regeneration in humans and other animals. It also plays a role in regulating metabolism.

Answer 51

Adrenocorticotropic Hormone (ACTH): Secreted by: Anterior pituitary gland. Function: Stimulates the adrenal glands to release cortisol, a hormone involved in stress response and regulation of metabolism.

Answer 52

Thyroid Stimulating Hormone (TSH): Secreted by: Anterior pituitary gland. Function: Stimulates the thyroid gland to produce and release thyroid hormones (T3 and T4), which regulate metabolism, growth, and development.

Answer 53

Prolactin (PRL): Secreted by: Anterior pituitary gland. Function: Stimulates milk production (lactation) in mammary glands following childbirth. It also has roles in reproductive function and behavior.

Answer 54

Melanocyte-Stimulating Hormone (MSH): Secreted by: Anterior pituitary gland (pars intermedia). Function: Regulates pigmentation by stimulating the production and distribution of melanin in the skin, hair, and eyes. It also plays a role in appetite and energy balance regulation.

Answer 55

Antidiuretic Hormone (ADH), also known as Vasopressin: Secreted by: Posterior pituitary gland. Function: Regulates water balance in the body by promoting water reabsorption in the kidneys. It also plays a role in regulating blood pressure by constricting blood vessels.

Answer 56

Oxytocin: Secreted by: Posterior pituitary gland. Function: Stimulates uterine contractions during childbirth and promotes milk ejection (letdown reflex) during breastfeeding. Additionally, oxytocin is involved in social bonding, trust, and emotional regulation.

Answer 57

a hormonal system responsible for regulating the male reproductive system. It involves interactions between the hypothalamus, the anterior pituitary gland, and the testes. Process -

Answer 58

prepare the uterus for pregnancy - Estrogen and progesterone work together to regulate the menstrual cycle and prepare the uterine lining (endometrium) for potential implantation of a fertilized egg. Estrogen stimulates the growth of the endometrium during the first half of the menstrual cycle, while progesterone maintains its thickened state during the second half, making it conducive for embryo implantation. promote the development of mammary glands - Estrogen and progesterone are involved in the development and maintenance of the mammary glands, preparing them for potential lactation during pregnancy. play a role in sex drive = Estrogen and progesterone contribute to sexual desire and arousal by influencing various physiological processes, including the regulation of reproductive hormones and the maintenance of reproductive organs' health. Promote development of secondary sexual characteristics = Estrogen is primarily responsible for the development of secondary sexual characteristics in females, such as breast development, widening of the hips, and distribution of body fat. Progesterone also plays a role in maintaining these characteristics. Regulate LH and FSH secretion = Estrogen and progesterone exert negative feedback on the hypothalamus and anterior pituitary gland, regulating the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). During the menstrual cycle, rising levels of estrogen and progesterone inhibit the release of LH and FSH, helping to regulate ovulation and the menstrual cycle.

Answer 59

- Simulates the development and growth of the mammary glands and milk synthesis during pregnancy Lactation: Prolactin is stimulating milk production in mammary glands after childbirth. It promotes the growth and development of mammary tissue and stimulates the synthesis of milk components, including lactose, lipids, and proteins. Regulation of Milk Secretion: Prolactin acts on mammary glands to initiate and maintain lactation. It works in conjunction with other hormones, such as oxytocin, which is responsible for milk ejection (the "letdown reflex") during breastfeeding. Role in Reproductive Function: Prolactin also plays a role in regulating reproductive function beyond lactation (Sucking action of the offspring stimulates prolactin secretion from Anterior Pituitary)

Answer 60

Stimulates the uterus to contract during childbirth. = Oxytocin is perhaps best known for its role in initiating and coordinating uterine contractions during childbirth. As labor progresses, oxytocin levels increase, stimulating rhythmic contractions of the uterine muscles, which help to dilate the cervix and push the baby through the birth canal. These contractions continue during the delivery of the placenta. A synthetic analogue of oxytocin can be used to induce childbirth Induce child birth = Synthetic forms of oxytocin, known as oxytocin analogues or oxytocin agonists, can be administered medically to induce or augment labor when necessary. This synthetic oxytocin is commonly used in clinical settings to help start or speed up labor if there are concerns about the progression of labor or if the health of the mother or baby is at risk. Also stimulates the mammary glands to release milk in response to suckling

Answer 61

from pubic area down to rectum

Answer 62

(“greater lips”) – outer lips enclosing vestibule

Answer 63

(“lesser lips”) thin, hairless ridges at the entrance of the vestibule which join behind and in front. In front they split to enclose the clitoris

Answer 64

area enclosed by labia minora that leads to opening of vagina and urethra; clitoris at anterior end.

Answer 65

8-10 cm long thin-walled, muscular canal leading from the vestibule (between labia minora) to cervix. The urethra also opens into vestibule between clitoris and vaginal opening

Answer 66

small pea-shaped structure. Plays important role in sexual arousal

Answer 67

pair of pea-sized glands; drain into the vestibule at either side of the vaginal opening; secrete lubricating fluid during sexual arousal

Answer 68

from vestibule to cervix

Answer 69

connects vagina to ‘neck’ of uterus; secretes mucus

Answer 70

– pair-shaped; myometrium and endometrium; secretes fluid

Answer 71

with funnel shaped openings (fimbriae) near ovaries

Answer 72

with ovarian follicles and corpora lutea

Answer 73

Follicle growth and selection of ovulatory follicle in which oocyte matures During this phase, multiple follicles in the ovaries begin to grow and develop under the influence of follicle-stimulating hormone (FSH). Eventually, one dominant follicle becomes the ovulatory follicle, while the others degenerate. The ovulatory follicle contains a mature oocyte (egg) ready for ovulation.

Answer 74

Follicle ruptures - oocyte released Ovulation marks the release of the mature oocyte from the ovary into the fallopian tube. This event is triggered by a surge in luteinizing hormone (LH) and is typically mid-cycle.

Answer 75

Corpus luteum forms Endometrium prepared for blastocyst implantation After ovulation, the ruptured follicle transforms into a structure called the corpus luteum, which secretes progesterone and some estrogen. Progesterone prepares the endometrium (lining of the uterus) for potential implantation of a fertilized egg.

Answer 76

Menstruation Cycle repeats If No Pregnancy Occurs: If fertilization does not occur, the corpus luteum degenerates, leading to a decline in progesterone and estrogen levels. This decline triggers the shedding of the uterine lining, known as menstruation. Menstruation: During menstruation, the unfertilized egg, along with the uterine lining and blood, is shed through the vagina. This marks the end of one estrous cycle, and the cycle repeats with the onset of the next follicular phase.

Answer 77

The proliferative phase is driven by rising levels of estrogen, which are produced by the growing ovarian follicles. Increased Thickness of Endometrium: **Estrogen stimulates the *proliferation and growth of the endometrial lining* (uterine lining), leading to an increase in its thickness.** Angiogenesis: **Estrogen also promotes angiogenesis, the formation of new blood vessels within the endometrial tissue. T**his ensures an adequate blood supply to support the growing endometrium. Growth of Endometrial Glands: Under the influence of estrogen,** the endometrial glands undergo growth and development, preparing them for potential implantation of a fertilized egg.** **Secretion of Thin, Stringy Mucus in Cervical Canal ("Sperm-Friendly"): ** The cervix secretes thin, clear, and stringy mucus during the proliferative phase, which is more conducive to sperm migration through the cervical canal. This type of mucus, often referred to as "sperm-friendly" mucus, provides an optimal environment for sperm survival and facilitates their passage through the cervix and into the uterus and fallopian tubes for potential fertilization

Answer 78

The secretory phase is driven by high levels of progesterone, which are produced by the corpus luteum. Estrogen also continues to play a role during this phase. Further Endometrial Gland Development and More Secretory Activity: Progesterone promotes further development and enlargement of the endometrial glands. These glands become more secretory, producing nutrients and substances to support potential implantation of a fertilized egg. Further Increase in Blood Supply: Further increase in blood supply The endometrium experiences a further increase in blood supply during the secretory phase, ensuring adequate oxygen and nutrient delivery to support potential embryo development. Lipid and Glycogen Deposition: Lipid and glycogen deposition - Progesterone stimulates the deposition of lipids (fats) and glycogen in the endometrial tissue, providing a source of energy for the developing embryo. Favorable Environment for Embryo Implantation and Sustenance: Favourable environment for embryo implantation and sustenance The secretory phase creates a favourable environment within the uterus for embryo implantation and early pregnancy. The thickened, nutrient-rich endometrium provides an ideal site for the embryo to implant and receive nourishment. Stickier, More Viscous Mucus from Cervical Glands ("Sperm Hostile"): Stickier, more viscous mucus from cervical glands (sperm hostile) - The cervical glands secrete a stickier, more viscous type of mucus during the secretory phase, which is less conducive to sperm migration. This "sperm-hostile" mucus acts as a barrier to prevent additional sperm from entering the uterus and fallopian tubes after ovulation has occurred.

Answer 79

caused by sudden decrease of progesterone and oestrogen at luteolysis - loss of hormonal stimulation initiates necrosis in the endometrium ---> new cycle Caused by Sudden Decrease of Progesterone and Oestrogen: Menstruation is triggered by a sudden decrease in the levels of progesterone and estrogen, the two hormones primarily produced by the corpus luteum during the luteal phase. The decline in hormone levels occurs due to the degeneration of the corpus luteum, a process known as luteolysis. Luteolysis: Luteolysis refers to the breakdown and degeneration of the corpus luteum, which occurs if fertilization and implantation of an embryo do not occur. As the corpus luteum regresses, it stops producing progesterone and estrogen, leading to a decline in their circulating levels. Loss of Hormonal Stimulation Initiates Necrosis in the Endometrium: The sudden decrease in progesterone and estrogen levels leads to a loss of hormonal stimulation of the endometrium. Without hormonal support, the endometrial tissue undergoes necrosis (cell death) and begins to slough off from the uterine wall. Initiation of a New Cycle: (The shedding of the endometrium marks the beginning of a new menstrual cycle. Following menstruation, the hypothalamus-pituitary-ovarian axis is activated again, leading to the recruitment and growth of new ovarian follicles and the initiation of a new cycle of ovulation.)

Answer 80

A rich nutritive environment for implantation of early embryo

Answer 81

- Placenta serves as an endocrine gland - Produces chorionic gonadotropin hormone (hCG) - Estrogen and Progesterone hCG hormone Production: hCG is produced by the syncytiotrophoblast cells of the placenta shortly after implantation of the fertilized egg into the uterine wall. Detection in Pregnancy Tests: hCG is the hormone detected by home pregnancy tests. It is present in the urine and blood of pregnant women, and its levels rise rapidly in early pregnancy. Functions: hCG plays several important roles during pregnancy: It supports the corpus luteum in the ovary, which continues to produce progesterone during the early stages of pregnancy. Progesterone is essential for maintaining the uterine lining and supporting the developing embryo until the placenta takes over hormone production. It stimulates the production of estrogen and progesterone by the corpus luteum, which helps maintain the pregnancy. It promotes the development of the placenta and fetal organs. It prevents the mother's immune system from rejecting the developing embryo by suppressing immune responses. Diagnostic Use: hCG levels are monitored in clinical settings as a marker of pregnancy health. Abnormal hCG levels can indicate potential issues such as ectopic pregnancy, miscarriage, or molar pregnancy. hCG levels also play a role in assessing the progression of pregnancy, particularly in cases of suspected miscarriage or ectopic pregnancy.

Answer 82

Collection of Urine Sample: A woman collects a urine sample, usually by urinating directly onto a test stick or into a container provided with the test kit. hCG Detection: The test kit contains antibodies that are specific to hCG. These antibodies react with hCG present in the urine sample. Indicator of Pregnancy: If hCG is present in the urine sample (indicating pregnancy), it binds to the antibodies on the test strip, causing a color change or other visible signal (such as a line appearing on the test strip). The appearance of the color change or indicator line typically indicates a positive result, indicating that the woman is pregnant. Interpretation of Results: The woman reads and interprets the test results according to the instructions provided with the test kit. A positive result indicates pregnancy, while a negative result indicates the absence of detectable levels of hCG in the urine (indicating no pregnancy).

Answer 83

Testes and Spermatogenesis: Spermatogenesis is the process by which spermatozoa (sperm cells), the male haploid gametes, are produced within the seminiferous tubules of the testes. The testes are the male reproductive organs responsible for the production of sperm and the synthesis of male sex hormones, such as testosterone. Temperature Regulation in the Scrotum: The testes are located outside the body cavity, in a sac-like structure called the scrotum. The scrotum serves to house and protect the testes. One of the critical functions of the scrotum is temperature regulation. The testes require a slightly lower temperature than the core body temperature (around 2-3 degrees Celsius cooler) for optimal sperm production. The cremaster muscle and dartos muscle in the scrotum contract or relax in response to environmental temperature changes or stress, adjusting the position of the testes to regulate their temperature. This mechanism helps maintain the testes within the optimal temperature range for spermatogenesis, thereby ensuring efficient sperm production. Impact of Elevated Temperature on Spermatogenesis: Spermatogenesis is sensitive to temperature fluctuations. Elevated temperatures, such as those experienced within the core body (37°C in humans), can disrupt the process of sperm production. Factors such as tight-fitting clothing, excessive heat exposure, or certain medical conditions can lead to increased scrotal temperature and potentially impact fertility by affecting spermatogenesis Failure of Testicular Descent:During fetal development, the testes initially develop near the kidneys and gradually descend into the scrotum before birth. This process is known as testicular descent or testicular migration. Failure of testicular descent, where one or both testes do not descend fully into the scrotum, is a congenital condition known as cryptorchidism. Cryptorchidism can lead to infertility due to impaired spermatogenesis caused by the higher temperature within the body cavity compared to the scrotum. It also increases the risk of testicular cancer and other health issues if left untreated.

Answer 84

Seminiferous Tubules: The seminiferous tubules are tightly coiled tubes located within the testes, and they are the primary sites of spermatogenesis—the process of sperm production. Sites for Spermatogenesis: Within the seminiferous tubules, spermatogenesis occurs. Initiation of Spermatogenesis: Spermatogenesis begins with spermatogonia, which are located around the periphery of the seminiferous tubules. At puberty, under the influence of hormones such as follicle-stimulating hormone (FSH) and testosterone, spermatogonia begin to proliferate and differentiate. Proliferation and Meiosis: Spermatogonia undergo mitotic division to produce primary spermatocytes, which then enter meiosis. During meiosis, primary spermatocytes undergo two rounds of cell division (meiosis I and meiosis II) to produce haploid spermatids. Movement of Spermatids: As spermatids are formed, they move towards the lumen (center) of the seminiferous tubule. The process of spermiogenesis then occurs, during which spermatids undergo further structural and functional changes to become mature, fully formed spermatozoa. Release of Spermatozoa: Fully formed spermatozoa are released into the lumen of the seminiferous tubules. From there, they are transported to the epididymis, where they undergo further maturation and are stored until ejaculation.

Answer 85

Germ cells are the reproductive cells responsible for producing spermatozoa (sperm cells) through the process of spermatogenesis. They begin as spermatogonia, which are located around the periphery of the seminiferous tubules, where spermatogenesis occurs. Germ cells undergo mitosis, meiosis, and spermiogenesis to differentiate into mature spermatozoa. Spermatozoa are released into the lumen of the seminiferous tubules and eventually pass through the epididymis for further maturation.

Answer 86

Sertoli Cells (Sustentacular Cells): Sertoli cells are somatic cells that provide structural and nutritional support to developing germ c**ells within the seminiferous tubules. They form the epithelial lining of the seminiferous tubules and create a specialized microenvironment for spermatogenesis. **Sertoli cells are involved in regulating the process of spermatogenesis by providing physical support, secreting growth factors and hormones, and phagocytosing defective germ cells. They also form tight junctions to create the blood-testis barrier, which separates the developing germ cells from the bloodstream and protects them from immune attac**k.

Answer 87

Leydig Cells (Interstitial Cells): Leydig cells are located in the interstitial spaces between the seminiferous tubules. They are responsible for producing and secreting testosterone, the primary male sex hormone. Testosterone produced by Leydig cells plays a crucial role in the development and maintenance of male reproductive organs and secondary sexual characteristics, as well as in regulating spermatogenesis. Leydig cells are stimulated by luteinizing hormone (LH) from the anterior pituitary gland to produce testosterone.

Answer 88

After spermatozoa are released into the seminiferous tubule lumen, they are delivered via the rete testis to a long, highly coiled tube called the epididymis (~6 meters long in human!) the sperm cell is not motile when it first arrives at the epididymis and must ‘mature’ there for > 1 day before motility develops from the epididymis, the sperm is delivered to another long, straight muscular-walled tube, the vas deferens (~30 cm long x 4mm wide in human) During ejaculation, sperm travel from each vas deferens to the paired ejaculatory ducts (where duct from each seminal vesicle joins) to enter the urethra Sperm mixed with secretions from accessory glands (seminal vesicles, prostate, bulbo-urethral gland) during ejaculation Semen (typically 2-5ml with >100 million sperm) deposited in female tract (usually vagina but directly into uterus in some species e.g. pig) Epididymis: After spermatozoa are released into the lumen of the seminiferous tubules, they travel through the rete testis and into the epididymis. The epididymis is a long, highly coiled tube located on the surface of each testis. Spermatozoa remain in the epididymis for over a day, undergoing maturation processes such as capacitation and acquiring motility. Vas Deferens: From the epididymis, mature and motile spermatozoa are delivered to the vas deferens. The vas deferens is a long, straight muscular-walled tube that extends from the epididymis into the pelvic cavity. Its function is to transport spermatozoa from the epididymis to the ejaculatory ducts during ejaculation. Ejaculatory Ducts and Urethra: During ejaculation, spermatozoa travel from each vas deferens to the paired ejaculatory ducts. The ejaculatory ducts merge with the urethra within the prostate gland. Spermatozoa are then expelled from the body through the urethra during ejaculation. Accessory Glands and Semen Production: Seminal vesicles, prostate gland, and bulbourethral glands are accessory glands that contribute secretions to semen. These secretions provide nutrients, buffer pH, and enhance sperm motility and survival. During ejaculation, spermatozoa mix with secretions from these glands to form semen. Deposition of Semen in Female Tract: Semen, containing spermatozoa and secretions from accessory glands, is typically deposited in the female reproductive tract during sexual intercourse. In most mammals, including humans, semen is deposited into the vagina. However, in some species like pigs, semen can be deposited directly into the uterus. Spermatozoa then swim through the female reproductive tract in search of an egg for fertilization.

Answer 89

Essential for normal growth, development and function of the male genitalia. Promotes muscle development, male pattern hair growth Promotes libido Regulates LH and FSH secretion (-ve feedback)

Answer 90

The corpora cavernosa are a pair of parallel spongy columns of erectile tissue located on the dorsal aspect (upper side) of the penis. They are the main erectile tissue structures responsible for the majority of penile rigidity during an erection. Each corpus cavernosum is composed of highly vascularized, sponge-like tissue containing numerous cavernous sinuses, which are small blood-filled spaces.

Answer 91

The corpus spongiosum is a single, midline structure located ventrally (underside) in the penis. It surrounds the urethra, the tube that carries urine and semen out of the body during urination and ejaculation. The corpus spongiosum also contains erectile tissue and contributes to penile rigidity during erection, although to a lesser extent than the corpora cavernosa.

Answer 92

****Erectile tissue rich in tiny pool-shaped blood vessels called cavernous sinuses - that fill with blood during an erection. Surrounded by cylindrical connective tissue sheath The erectile tissue within th**e corpora cavernosa and corpus spongiosum i**s rich in **tiny pool-shaped blood vessels known as cavernous sinuses.** During sexual arousal, **these cavernous sinuses fill with blood, causing the erectile tissue to become engorged** and the penis to become erect. The in**crease in blood flow and pressure within the cavernous sinuses **is essential for achieving and maintaining an erection.

Answer 93

The erectile tissue of the corpora cavernosa and corpus spongiosum is surrounded by a cylindrical connective tissue sheath known as the tunica albuginea. The tunica albuginea provides structural support and helps maintain the shape and integrity of the erectile tissue during erection. It also plays a role in regulating blood flow into and out of the cavernous sinuses during the erectile process.

Answer 94

Examples include humans, stallions, dogs, and tomcats. Contains abundant erectile tissue and relatively little connective tissue. During erection, there is an increase in both length and diameter of the penis due to the expansion of the cavernous tissue. The cavernous tissue contains large blood spaces divided by thin septa, requiring a relatively larger volume of blood to achieve erection. Many species in this category also possess a penis bone called a baculum or os penis, which provides structural support during copulation.

Answer 95

Examples include bulls, boars, rams, and deer. Characterized by a sigmoid flexure, a curved or S-shaped structure in the non-erect state. Contains large amounts of connective tissue and elastic fibers but limited erectile tissue. During erection, most of the increase in penile length is due to straightening of the sigmoid flexure, resulting in elongation of the penis but no significant increase in diameter. Only a small increase in blood volume is needed for erection due to the limited erectile tissue.

Answer 96

In flaccid state the cavernous sinuses are constricted, so less blood present. During sexual arousal acetylcholine released from parasympathetic nerves => endothelial cells to produce nitric oxide (NO) NO promotes relaxation of the smooth muscle surrounding the arterioles and sinuses of erectile tissues, causing sinusoidal dilation. Tissue engorgement exerts pressure on the cylindrical sheath (tunica albuginea) This flattens the surrounding veins ‘trapping’ blood => erection Flaccid State: In the flaccid state, the cavernous sinuses within the erectile tissue of the penis are constricted, resulting in reduced blood flow and less blood present within the erectile tissue. Sexual Arousal and Nitric Oxide (NO) Release: During sexual arousal, parasympathetic nerves release the neurotransmitter acetylcholine. Acetylcholine stimulates endothelial cells within the erectile tissue to produce nitric oxide (NO). Nitric Oxide-Mediated Vasodilation: Nitric oxide (NO) acts as a vasodilator, promoting relaxation of the smooth muscle surrounding the arterioles and sinuses of the erectile tissues. This relaxation leads to the dilation of the cavernous sinuses, allowing them to fill with blood. Tissue Engorgement and Pressure: The relaxation of the smooth muscle and dilation of the cavernous sinuses result in tissue engorgement, causing the erectile tissue to become filled with blood and increase in size. As the erectile tissue becomes engorged, it exerts pressure on the cylindrical sheath surrounding it, known as the tunica albuginea. Compression of Veins and Erection: The pressure exerted by the engorged erectile tissue on the tunica albuginea compresses the surrounding veins. This compression effectively traps the blood within the erectile tissue, preventing it from flowing out of the penis. The accumulation of blood within the erectile tissue leads to the physiological phenomenon known as an erection.

Answer 97

Neurotransmitters (Ach) released from the cavernous nerve, stimulate production of eNOS within the vascular endothelial cells [NOS = nitric oxide synthase] NO is synthesized and diffuses into surrounding vascular smooth muscle Once inside NO binds to and activates guanylyl cyclase which converts GTP into the second messenger cGMP cGMP activates its dependent protein kinase - protein kinase G (PKG) PKG activation promotes vascular smooth muscle relaxation by: Hyperpolarization (by opening K+ channels) Endoplasmic reticulum sequestration of Ca2+ Inhibition of Ca2+ channels, stopping influx  Reduced free intracellular Ca2+ conc Smooth muscle relaxation => engorgement with blood => ERECTION Flaccid State: In the flaccid state, the cavernous sinuses within the erectile tissue of the penis are constricted, resulting in reduced blood flow and less blood present within the erectile tissue. Sexual Arousal and Nitric Oxide (NO) Release: During sexual arousal, parasympathetic nerves release the neurotransmitter acetylcholine. Acetylcholine stimulates endothelial cells within the erectile tissue to produce nitric oxide (NO). Nitric Oxide-Mediated Vasodilation: Nitric oxide (NO) acts as a vasodilator, promoting relaxation of the smooth muscle surrounding the arterioles and sinuses of the erectile tissues. This relaxation leads to the dilation of the cavernous sinuses, allowing them to fill with blood. Tissue Engorgement and Pressure: The relaxation of the smooth muscle and dilation of the cavernous sinuses result in tissue engorgement, causing the erectile tissue to become filled with blood and increase in size. As the erectile tissue becomes engorged, it exerts pressure on the cylindrical sheath surrounding it, known as the tunica albuginea. Compression of Veins and Erection: The pressure exerted by the engorged erectile tissue on the tunica albuginea compresses the surrounding veins. This compression effectively traps the blood within the erectile tissue, preventing it from flowing out of the penis. The accumulation of blood within the erectile tissue leads to the physiological phenomenon known as an erection.

Answer 98

Nerves are bundles of neurones in the PNS Tracts = bundles of neurones in the CNS Sciatic nerve contains tens-of-thousands of axons!

Answer 99

The sciatic nerve is one of the largest nerves in the body and indeed contains tens of thousands of axons. Endoneurium: surrounds axons This is the innermost layer of connective tissue that surrounds individual axons within a nerve bundle. It provides support and protection to the axons, as well as facilitating the exchange of nutrients and waste products.

Answer 100

Perineurium: surrounds bundles of axons The perineurium is a layer of connective tissue that surrounds bundles of axons within a nerve. It forms a protective barrier and helps maintain the structural integrity of the nerve bundle. Perineurial cells are specialized cells within this layer that regulate the exchange of substances between the blood vessels and the nerve tissue.

Answer 101

**Epineurium: Surrounds bundles of encasing blood vessels** The epineurium is the o**utermost layer of connective tissue that surrounds the entire nerve.** It consists of **dense irregular connective tissue and provides protection and support to the entire nerve structure.** Additionally, the **epineurium contains blood vessels that supply nutrients and oxygen to the nerve tissue.**

Answer 102

Sensory Nerves (Afferent Nerves): Sensory nerves transmit sensory information from peripheral tissues, organs, and sensory receptors to the central nervous system (CNS), specifically to the brain and spinal cord. (They convey various sensory modalities such as touch, pain, temperature, pressure, proprioception (awareness of body position), and information from the special senses (vision, hearing, taste, smell).

Answer 103

Motor Nerves (Efferent Nerves): Motor nerves carry motor signals from the CNS to peripheral effectors, such as muscles, glands, and other tissues. They control voluntary movements of skeletal muscles (somatic motor nerves) as well as involuntary activities of smooth muscles, cardiac muscles, and glandular secretion (visceral motor nerves).

Answer 104

Mixed Nerves: Some nerves in the peripheral nervous system are mixed nerves, meaning they contain both sensory and motor fibers within the same nerve bundle. These mixed nerves can transmit both sensory information from peripheral tissues to the CNS and motor signals from the CNS to peripheral effectors. Examples of mixed nerves include the sciatic nerve, which contains both sensory fibers from the leg and motor fibers to the muscles of the leg and foot.

Answer 105

Autonomic afferents are sensory neurons that carry signals from the peripheral tissues and organs back to the central nervous system (CNS) autonomic afferents transmit information about the internal environment of the body. The autonomic afferents travel via the sympathetic and parasympathetic nerves (like the sensory)

Answer 106

Autonomic efferents are **motor neurons that carry signals from the central nervous system (CNS),** specifically from the autonomic centers located in the brainstem and spinal cord,** to the peripheral tissues and organs innervated** by the autonomic nervous system (ANS) autonomic efferents regulate involuntary bodily functions, including: Cardiovascular System: Autonomic efferents influence heart rate, cardiac contractility, and blood vessel diameter to regulate blood pressure and blood flow distribution throughout the body. autonomic efferents travel via the symp and parasymp (like the motor).

Answer 107

have specialised receptors that respond to different stimuli and carry that info to the spinal cord ( brain or reflex arc) 4 types General somatic sensation (touch, temp, pain) Special somatic sensation (proprioception) Autonomic afferent sensation Special senses (sight, hearing, balance, smell, taste)

Answer 108

Sensory neurons responsible for general somatic sensation detect stimuli related to touch, temperature, and pain from the skin, muscles, joints, and other superficial and deep tissues. These sensations are crucial for basic interactions with the environment and for detecting potential threats or injuries. General somatic sensation, also known as somatic or cutaneous sensation, encompasses various sensory modalities that provide information about the body's external environment and its interaction with external stimuli. These sensations include touch, temperature, and pain

Answer 109

Touch sensation involves the** detection of mechanical stimuli** applied to the skin or other tissues. Different types of touch are mediated by **specialized sensory receptors** located within the skin: **Coarse touch – Merkel’s disks Pressure – Ruffini’s end organs Light touch – Meissner’s corpuscle Vibration – Pacinian corpuscle** Coarse touch is sensed by Merkel's disks, which are specialized nerve endings located in the superficial layers of the skin. Pressure is detected by Ruffini's end organs, which respond to sustained pressure or stretching of the skin. Light touch is sensed by Meissner's corpuscles, which are rapidly adapting receptors found in the dermal papillae of hairless skin. Vibration is detected by Pacinian corpuscles, which are rapidly adapting receptors distributed throughout the skin and deeper tissues.

Answer 110

Temperature: Temperature Warm (34-45C) Cold (5-34C) Pain (<5C or >45C) Temperature sensation involves the detection of thermal stimuli, including warmth and cold. Warmth is sensed when temperatures range between 34-45°C, and cold is sensed when temperatures range between 5-34°C. Extreme temperatures (<5°C or >45°C) can activate pain receptors and elicit a sensation of pain.

Answer 111

Pain: Pain sensation, or nociception, occurs in response to tissue damage or injury and serves as a protective mechanism. Nociceptive pain arises from the activation of pain receptors, known as nociceptors, which respond to mechanical, thermal, or chemical stimuli associated with tissue damage. Neuropathic pain occurs due to injury or dysfunction of the nervous system itself, leading to abnormal processing of pain signals. Neuropathic pain (injury to nerves) Nociceptive pain (injury to tissues – mechanical, thermal or chemical irritation of free nerve endings

Answer 112

Somatic sensory receptors in skin, cell body in posterior root ganglion Enters spinal cord Sensory information from the skin and other peripheral tissues is detected by somatic sensory receptors. These receptors are typically located in the skin and have specialized structures for detecting touch, pressure, temperature, and pain. The cell bodies of primary sensory neurons are located in clusters called posterior root ganglia, which are located adjacent to the spinal cord. Sensory signals are transmitted along the axons of primary sensory neurons and enter the spinal cord through the dorsal roots.

Answer 113

Some 2 sensory nerves synapse and decussate immediately (in cord) Others synapse and decussate in medulla oblongata Travels to thalamus Upon entering the spinal cord, some secondary sensory neurons immediately synapse and decussate (cross over to the opposite side) in the spinal cord itself. Others ascend within the spinal cord to higher levels and synapse and decussate in the medulla oblongata, part of the brainstem. After decussation, the secondary sensory neurons continue their ascent toward the brain.

Answer 114

Synapse in thalamus Travels to somatosensory cortex The axons of secondary sensory neurons synapse in the thalamus, a relay station in the brain. From the thalamus, tertiary sensory neurons transmit the sensory information to the somatosensory cortex, which is located in the parietal lobe of the cerebral cortex. In the somatosensory cortex, sensory information is processed and interpreted, leading to conscious perception of touch, pressure, temperature, and pain. Right cerebral cortex senses left body and vice versa sensory information from the right side of the body is processed in the left hemisphere of the brain, and vice versa. (This crossing over of sensory pathways is known as contralateral organization.)

Answer 115

Decussation – see depends on what sensation as different sensations are carried in different tracts up the spinal cord. Some tracts decussate immediately, others in the medulla. Notice how long some of the primary sensory neurones can be!!! (those that decussate in the medulla). Diabetes and other systemic conditions that cause neuropathy (damage to neurones) tend to affect the longest neurones in the body, possibly they are exposed to the greatest surface area of toxicity. Decussation involves the crossing over of nerve fibers from one side of the body to the other within the central nervous system. It occurs at various levels along neural pathways, depending on the specific sensory or motor information and its location within the nervous system. In sensory pathways, decussation happens at different points along the spinal cord and brainstem. Some sensory pathways decussate immediately upon entering the spinal cord, where signals from one side of the body cross over to the opposite side. Others ascend within the spinal cord and may not decussate until reaching higher brainstem structures like the medulla oblongata. Decussation is significant due to the contralateral organization of sensory and motor pathways. For example, sensory information from the right side of the body is processed in the left hemisphere of the brain, and vice versa.

Answer 116

Perception of body position in space maintaining balance and posture Sensors found in muscles, tendons and ligaments E.g. Muscle spindles Sense stretch AND velocity (intrafusal) Involved in reflexes Two main types of proprioceptive receptors are involved: Muscle Spindles: Muscle spindles are sensory receptors found within muscle fibers. They sense both the stretch and velocity of muscle fibers during contraction and relaxation. Muscle spindles are crucial for reflexive responses to changes in muscle length, such as the stretch reflex, which helps maintain muscle tone and posture. In addition to sensing stretch, muscle spindles can also initiate muscle contractions in response to rapid stretching to prevent overstretching and protect against injury. Golgi Tendon Organs (GTOs): Golgi tendon organs are proprioceptive receptors located at the junction between muscles and tendons. They sense changes in muscle tension or contraction, specifically when muscles pull on tendons. Golgi tendon organs respond to excessive muscle tension by producing a reflexive relaxation of the muscle, helping to prevent excessive force generation and potential damage to tendons or muscle fibers. Golgi tendon organs are particularly important in mechanisms such as muscle energy techniques (METs), where manual therapy techniques aim to enhance muscle relaxation and improve flexibility. Both muscle spindles and Golgi tendon organs play crucial roles in proprioception, but muscle spindles are often considered more important due to their ability to sense both stretch and velocity, as well as their involvement in reflexive muscle responses. these proprioceptive receptors contribute to the body's ability to sense and adapt to changes in position, movement, and muscle tension, ultimately aiding in maintaining balance, posture, and coordination.

Answer 117

involves sensory fibers within both the sympathetic and parasympathetic divisions of the autonomic nervous system (ANS). These transmit impulses for: Sensations (hunger, thirst, nausea, sexual sensation, rectal and bladder distension) Visceral reflexes (cough, blood pressure (baroreceptors), (pressure-sensitive receptors), and control of respiration via chemoreceptors (sensors sensitive to changes in blood chemistry, such as oxygen and carbon dioxide levels). Visceral pain (ischaemia / inflammation, over-contraction, over-distension) ischemia (reduced blood flow), inflammation, over-contraction, or over-distension of internal organs.

Answer 118

In the brain and spinal chord and autonomic ganglia

Answer 119

Skeletal muscle contraction Voluntary OR reflex Upper motor neurones (from brain to level in spinal cord) Lower motor neurones (from spinal cord to muscle) Somatic motor nerves originate from the motor neurons in the brain and spinal cord. These nerves innervate skeletal muscles, controlling voluntary movements such as walking, grasping, and speaking, as well as reflex actions. Somatic motor pathways involve upper motor neurons that originate in the brain and project down to the spinal cord, where they synapse with lower motor neurons. Lower motor neurons, located in the anterior horn of the spinal cord, extend their axons out to the muscles, directly causing muscle contraction.

Answer 120

Skeletal muscle fibres each receive a single, excitatory motor neuron terminal, forming one neuromuscular junction (NMJ) per muscle fibre (called the motor unit) at the vast majority (~98%) of fibres. The neurotransmitter at all NMJs is acetylcholine (ACh) which act on postsynaptic nicotinic ACh receptors (nAChRs). Neuromuscular Junction (NMJ) in Skeletal Muscle: Each skeletal muscle fiber receives input from a single, excitatory motor neuron terminal, forming a neuromuscular junction (NMJ). At the NMJ, the neurotransmitter acetylcholine (ACh) is released from the motor neuron and acts on postsynaptic nicotinic ACh receptors (nAChRs) on the muscle fiber membrane, leading to muscle contraction.

Answer 121

. Smooth muscle contraction is myogenic (i.e. does not rely on neural input) to display intrinsic, rhythmic contraction. Smooth muscle often receive a dual innervation from the sympathetic and parasympathetic NS divisions of the ANS. Smooth Muscle Contraction: Smooth muscle contraction is myogenic, meaning it can contract rhythmically without neural input. However, smooth muscle often receives dual innervation from both the sympathetic and parasympathetic divisions of the autonomic nervous system (ANS), allowing for modulation of its activity. Cardiac and smooth muscle contraction Myogenic (so don’t need neural input), but also innervated by PNS

Answer 122

Cardiac muscle contraction is also myogenic, but different parts of the heart have different intrinsic frequencies of contraction. The pacemaker region receives a dual innervation from the sympathetic and parasympathetic NS. Cardiac Muscle Contraction: Like smooth muscle, cardiac muscle contraction is myogenic and can generate its own rhythmic contractions. Different regions of the heart have intrinsic frequencies of contraction, with the pacemaker region setting the overall heart rate. The pacemaker region receives dual innervation from both the sympathetic and parasympathetic divisions of the ANS, which can modulate heart rate and contraction strength.

Answer 123

Glands (secretion) Sympathetic OR parasympathetic

Answer 124

2 neurones carry motor impulses from the brain to the skeletal muscle: 80-90% of motor nerves decussate at the medulla to run down the contralateral side, but 10% don’t decussate and run down the ipsilateral side.

Answer 125

Upper motor neurone (UMN) - CNS Cell body in motor cortex Decussates (crosses) in the medulla oblongata Descends in spinal cord Location and Cell Body: Upper motor neurons are located within the CNS, specifically in the primary motor cortex of the brain. The cell bodies of upper motor neurons reside in the motor cortex, which is located in the precentral gyrus of the frontal lobe. Decussation (Crossing) in the Medulla Oblongata: One of the defining features of upper motor neurons is their decussation, or crossing over, of fibers from one side of the CNS to the other. After originating in the motor cortex, the axons of upper motor neurons descend through the brain and brainstem. Most upper motor neurons decussate in the medulla oblongata, the lower part of the brainstem, where they cross over to the opposite side of the body. Descent in the Spinal Cord: After decussating in the medulla oblongata, the axons of upper motor neurons continue to descend through the spinal cord. These descending fibers form the corticospinal tract, also known as the pyramidal tract, which is a major pathway for transmitting motor signals from the brain to the spinal cord. The corticospinal tract termi

Answer 126

At appropriate level in spinal cord UMN synapses with LMN Exits spinal cord Terminates at motor end plate of muscle fibre (NMJ) Right cerebral cortex controls movement of left body and vice versa Location and Synapse: Lower motor neurons are located in the anterior horn of the spinal cord and in certain cranial nerve nuclei within the brainstem. Upon receiving input from upper motor neurons (UMNs) originating in the motor cortex, brainstem, or other motor centers, lower motor neurons form synapses with these upper motor neurons at appropriate levels in the spinal cord or brainstem. Exit from Spinal Cord or Brainstem: After receiving input from upper motor neurons, lower motor neurons exit the spinal cord via the ventral roots or exit the brainstem through cranial nerves. These axons then travel through peripheral nerves to reach their target muscles. Termination at Motor End Plate (Neuromuscular Junction - NMJ): Lower motor neurons terminate at the neuromuscular junction (NMJ), where they form synapses with individual muscle fibers. At the NMJ, the axon of the lower motor neuron releases the neurotransmitter acetylcholine (ACh) into the synaptic cleft. ACh binds to receptors on the motor end plate of the muscle fiber, leading to depolarization of the muscle membrane and initiation of muscle contraction.

Answer 127

1) ACh crosses synapse and binds to AChR, opening Na+ channels 2) Influx of Na+ makes it more +ve inside and triggers depolarisation of the muscle cell membrane 3) Depolarisation spreads across muscle cell membrane and down into T-tubules 4) Releases calcium stores from the sarcoplasmic reticulum 5) Calcium binds to troponin C activating sliding filament theory 6) Acetylcholinesterase degrades ACh in synaptic cleft. Acetylcholinesterase in synaptic cleft rapidly degrades released ACh. Depolarisation: making the inside of the cell more positive (as Na+ floods inside down its concentration gradient). 1) Acetylcholine (ACh) Release and Binding: When an action potential reaches the axon terminal of the lower motor neuron, it triggers the release of ACh into the synaptic cleft. ACh diffuses across the synaptic cleft and binds to acetylcholine receptors (AChRs) located on the motor end plate of the muscle fiber. 2) Depolarization of Muscle Cell Membrane: Binding of ACh to AChRs opens sodium (Na^+) channels on the motor end plate. Na^+ ions rush into the muscle fiber, making the interior of the cell more positively charged (depolarized). 3) Propagation of Depolarization: The depolarization of the motor end plate spreads across the muscle cell membrane and travels down into the T-tubules (transverse tubules), which are invaginations of the muscle cell membrane. 4) Release of Calcium (Ca^2+) from Sarcoplasmic Reticulum: The depolarization of the T-tubules triggers the release of calcium ions (Ca^2+) from the sarcoplasmic reticulum (SR), a specialized organelle within the muscle cell. Calcium ions flood into the muscle cell's cytoplasm, increasing the concentration of calcium ions in the vicinity of the myofibrils. 5) Activation of Sliding Filament Theory: Calcium ions bind to troponin C, a regulatory protein associated with the thin filament of the muscle cell. This binding causes a conformational change in the troponin-tropomyosin complex, exposing the active sites on the actin filaments. Myosin heads (from thick filaments) can now bind to these active sites on actin, initiating the cross-bridge cycle and leading to muscle contraction. 6) Degradation of Acetylcholine (ACh): Acetylcholinesterase, an enzyme located in the synaptic cleft, rapidly degrades ACh into acetate and choline. Degradation of ACh prevents continuous stimulation of the AChRs and ensures that muscle contraction is brief and precisely controlled.

Answer 128

the functional element of muscle contraction: = single motor neuron and all the muscle fibers that it activates A single motor unit may have 3-1500 muscle fibres, but individual fibres receive 1 motor neuron input

Answer 129

Coarse Motor Control: Motor units with a large number of muscle fibers innervated by a single motor neuron are responsible for coarse motor control. These motor units are typically found in muscles that are involved in large-scale movements and activities requiring strength, such as the quadriceps in the thighs or the gluteus maximus in the buttocks. Because many muscle fibers are activated simultaneously by a single motor neuron, these muscles are capable of generating powerful contractions but lack fine control over individual muscle fibers.

Answer 130

Motor units with a small number of muscle fibers innervated by a single motor neuron are responsible for fine motor control. These motor units are found in muscles that require precise and delicate movements, such as those controlling the fingers, hands, and face. Because fewer muscle fibers are activated by each motor neuron, these muscles can produce subtle movements and adjustments with high precision and accuracy. Fine motor control allows for tasks requiring dexterity, coordination, and intricate movements, such as writing, typing, or playing a musical instrument.

Answer 131

Each muscle fibre is stimulated by only one synaptic bouton (releasing ACh) but each motor nerve has many synaptic boutons, stimulating numerous muscle fibres (a motor unit). Each motor unit contracts to its full capacity. Strength of a contraction depends upon the number of motor units activated. Motor control depends upon the number of muscle fibres supplied by a single neurone Research drugs / chemicals that act on the NMJ to cause paralysis (used in anaesthetics / ancient poisons (Curare) / Botox) Motor control: More muscle fibres per incoming neurone causes large–scale movements (eg. Quadriceps), whilst less muscle fibres per incoming neurone gives more precise control (eg. fingers). Knots in muscles: Myofascial trigger points – sustained local contraction of a small number of muscle fibres within a muscle tissue (possibly due to high ACh), causing localised ischaemia and pain. Pressure on the trigger point can cause radiating or referred pain distant to the site of compression.

Answer 132

NMJs are blocked by: paralysing poisons such as curare - derived from tree bark and used as an arrow poison by South American Indians, act to block nAChRs agents acting at nAChRs during general anaesthesia to control convulsions/prevent movement during surgery by local injection of botulinum toxin (Botox®), which blocks vesicle release from the presynaptic membrane. Used cosmetically and clinically to treat muscle spasms

Answer 133

In the spinal cord sensory and motor nerves run in separate tracts In the PNS, sensory and motor nerves are enclosed within the same sheath (mixed nerves) Impingement (squashing) of a peripheral nerve can cause both sensory (pain, P&Ns) and motor (weakness, atrophy) symptoms E.g. The sciatic nerve contains both afferent sensory nerve fibres and efferent motor nerve fibres. Squashing of the sciatic nerve can cause pain down the back of the leg, pins and needles to the foot and weakness in dorsi-flexion of the foot and/or big toe (affecting walking). Squashing of the ulnar nerve can cause pain and pins & needles to the 4th and little finger, and weakness in abducting / adducting the fingers (and some wrist flexion weakness).

Answer 134

Nerve conduction is dependent on both diameter AND myelination. Bigger diameter nerves transmit faster eg. Motor neurons, touch. Smaller diameter nerves transmit slower eg. Temperature, pain. Myelinated nerves transmit faster. Some neurons have Schwann cells (to keep them nourished and alive) but do not get myelinated eg. Autonomic postganglionic neurons, slow pain. Concept of fast pain and slow pain.

Answer 135

Pain-Gate Mechanism: The theory suggests that the transmission of pain impulses can be modulated or inhibited by the activation of large-diameter (faster) tactile fibers (Aβ fibers). When these tactile fibers are stimulated, they can "close the gate" in the dorsal horn of the spinal cord, reducing the transmission of pain signals carried by smaller-diameter (slower) pain fibers (Aδ and C fibers). This mechanism helps explain how non-painful stimuli, such as touch, vibration, and temperature, can alleviate pain sensation.

Answer 136

Rubbing (Touch): Rubbing or gentle touch stimulates large-diameter Aβ fibers, which can activate the pain-gate mechanism and reduce the perception of pain. This is why rubbing or massaging an area can provide relief from acute or chronic pain. Vibration (Buzzy): Vibration stimulates Aβ fibers, similar to touch, and can activate the pain-gate mechanism. Buzzy devices, which provide vibrational stimulation, are sometimes used to alleviate pain, such as during procedures like IV access.

Answer 137

Transcutaneous Electrical Nerve Stimulation (TENS): TENS machines deliver electrical impulses through the skin, stimulating Aβ fibers. This stimulation can activate the pain-gate mechanism, leading to pain relief. Temperature (Heat or Cold): Both heat and cold stimuli can stimulate Aδ fibers, which transmit temperature sensations. These sensations can compete with or override the perception of dull achy inflammatory pain carried by C fibers, providing relief. However, they may not be as effective for sharp, burning neuropathic pain, which is carried by Aδ fibers.

Answer 138

anterior is the vertebral body, posterior is the spinous process that you can feel if you run your hand down your back. The spinal cord (CNS) is in the vertebral canal and you can see the classic butterfly pattern of grey matter in the centre (nerve cell bodies), and white matter around the butterfly (myelinated axons running up and down the spinal cord). Going into the spinal cord on either side is an anterior root and a posterior root. All sensory goes in at the back (via the posterior root). All motor exits at the front (via the anterior root). The posterior root ganglion is where all the cell bodies of the primary sensory nerves are collected. The anterior and posterior roots merge to form the spinal nerve (mixed ie. both sensory and motor fibres).

Answer 139

Groups of spinal nerves where the nerve fibres regroup and branch before supplying skin, bones, muscles and joints

Answer 140

Cervical plexus  neck + diaphragm Brachial plexus  arms Lumbar plexus Sacral plexus legs / pelvis Coccygeal plexus (No thoracic plexus – no regrouping and branching)

Answer 141

Median nerve  thumb side of hand Ulnar nerve  little finger side of hand Radial nerve  back of arm

Answer 142

Femoral nerve  front of thigh Obturator nerve  inner thigh Sciatic nerve  back of leg (thickest nerve of the body!) Sciatic nerve contains 10’s of thousands of axons! Sciatic nerve about the same thickness as your thumb

Answer 143

These peripheral nerves contain a mix of lower motor neurones and primary sensory neurones. These peripheral nerves contain a mix of lower motor neurones and primary sensory neurones. The length of the lower motor neurones is from the spinal cord level to the muscle. The length of the primary sensory neurone is from the skin to the first synapse (may be in the medulla!). Decussation: Motor: 80-90% of motor nerves decussate at the medulla to run down the contralateral side, but 10% don’t decussate and run down the ipsilateral side. Sensory: Location of decussation depends on what sensation as different sensations are carried in different tracts up the spinal cord. Some tracts decussate immediately, others in the medulla. Notice how long some of the primary sensory neurones can be!!! (those that decussate in the medulla). Diabetes and other systemic conditions that cause neuropathy (damage to neurones) tend to affect the longest neurones in the body, possibly they are exposed to the greatest surface area of toxicity.

Answer 144

Peripheral nerves for head and neck (mostly) Numbered I to XII from front to back. Functions of cranial nerves - Some sensory - Some motor - Some mixed

Answer 145

Carry sensory (somatic or special senses), motor and/or autonomic innervation e.g. Special senses Smell (CNI) Sight (CNII) Taste (CNVII and IX) Hearing (CNVIII) Balance (CNVIII)

Answer 146

Motor control of: Eye movement (CN III, IV and VI) Mastication (chewing) (CNV) Facial expressions (CNVII) Swallowing (CNIX and X) Speech (CNIX and X) Shrugging shoulder (CNXI) Tongue (CNXII) Sensation: Face, mouth (CNV) Ear (CNVII and X)

Answer 147

Smell (CNI) CNI – Olfactory nerve carries smell

Answer 148

Sight (CNII) CNII – Optic nerve carries sight

Answer 149

Taste (CNVII and IX) CNVII – Facial nerve – and CNIX – glossopharyngeal nerve carry taste

Answer 150

Hearing (CNVIII) CNVIII – Vestibulocochlear nerve (sometimes called the auditory nerve) carries hearing and balance

Answer 151

Balance (CNVIII) CNVIII – Vestibulocochlear nerve (sometimes called the auditory nerve) carries hearing and balance

Answer 152

The Great Vagus Nerve or The Wanderer! Carries parasympathetic motor and sensory innervation to lots of viscera (rest and digest). Smooth muscle contraction Secretory glands Sensory from organs Not in spinal column! IMPORTANT CNX, the Great Vagus Nerve A vagrant is a tramp or a wanderer. So the great wanderer… CNX is a parasympathetic motor and sensory nerve that goes to loads of viscera in the body ie. beyond the head and neck. All sorts of viscera (organs) – digestive system, heart, lungs… Carries motor function causing smooth muscle contraction of gut, and motor to cardiac muscle (slows contraction). Also triggers secretory glands to release digestive juices etc. As well as motor effects, it also carries sensory information from those organs back up to the brain. The Vagus nerve is a parasympathetic nerve (part of the autonomic nervous system) and we’ll learn more about the parasympathetic nervous system in a bit. But basically, the parasympathetics are for the rest and digest functions ie. stimulating the gut to digest dinner (peristalsis, release digestive organs). Also stimulates the “rest” bit ie. slows heart (that sleepy feel after a big meal). Vagus nerve goes beyond the stomach, right down into the pelvis. Picture only shows as far as stomach but it goes much further. It’s amazing that even though this nerve goes all the way down to the pelvis, it’s not found in the spinal cord, it sits outside of the spine Function: The vagus nerve is the tenth cranial nerve (CN X) and carries both motor and sensory fibers. It primarily serves parasympathetic functions, regulating various involuntary processes involved in the "rest and digest" response. Functions include stimulating smooth muscle contraction in organs, controlling secretory glands, and transmitting sensory information from internal organs to the brain. Parasympathetic Motor Innervation: The vagus nerve provides parasympathetic motor innervation to numerous visceral organs, including the heart, lungs, stomach, pancreas, liver, and intestines. Parasympathetic stimulation via the vagus nerve promotes activities such as slowing heart rate, increasing gastrointestinal motility and secretion, and stimulating digestive processes. Sensory Innervation: In addition to motor functions, the vagus nerve also carries sensory fibers that provide sensory innervation from various organs, including the heart, lungs, gastrointestinal tract, liver, and spleen. Sensory information transmitted by the vagus nerve includes signals related to stretch, pressure, and chemical changes within the organs. Not in Spinal Column: Unlike spinal nerves, which emerge from the spinal column, the vagus nerve originates directly from the brainstem, specifically from the medulla oblongata. From its origin in the medulla, the vagus nerve extends downward through the neck, chest, and abdomen, innervating a wide range of organs along its course. Clinical Significance: Dysfunction of the vagus nerve can lead to various health issues, including problems with heart rate regulation, gastrointestinal motility disorders, and impaired digestion. Stimulation of the vagus nerve has also been explored as a therapeutic approach for conditions such as epilepsy, depression, and inflammatory disorders.

Answer 153

Part of PNS Controls involuntary functions Eg. smooth muscle, cardiac muscle, glands 2 divisions: 1) Sympathetic = Fight /flight/freeze 2) Rest and digest (restore /recover) Autonomic efferent neurones have 2 LMNs: Pre-ganglionic and post-ganglionic

Answer 154

**Sympathetic neurones exit the spinal cord at each level from T1 to L2 These form the sympathetic chain either side of the vertebrae Sympathetic neurones exit the spinal cord at each level from T1 to L2 These form the sympathetic chain / trunk either side of the anterior vertebrae. Sympathetic Trunk / Chain: Where some sympathetic nerves synapse, whilst others pass straight through. Blood vessels, sweat glands, piloerector muscles innervated by symp with little/no parasymp influence. SNS causes vasodilation in skeletal muscle but vasoconstriction in gut. Note that the sympathetic NS emerges from T1 to about L2/3. **Autonomic efferent neurones** have 2 LMNs: Pre-ganglionic and post-ganglionic Note the gangion –** 2 lower motor neurones (pre-ganglionic and post-ganglionic).** The pre-ganglionic and post-ganglionic neurones synapse in variable places – some in the sympathetic trunk, some in prevertebral ganglions. **In reality there is a lot of overlap and each organ is supplied by several segmental levels. T1-4: Heart and Lungs T5: Liver T6: Gall bladder T7: Pancreas Stomach Spleen T8: Adrenals T9: Small intestine T10: Kidneys T11: Ovaries and Testes T12: Bladder and Large intestine L1: Uterus and Prostate L2: Rectum I remember the order with this anacronym: Hell Likes Grilling Petite Stumbling Spinning Adults, Small Kiddies, Or Their Blooming Large UPperty Rabbits**

Answer 155

Parasympathetic neurones exit either the brain (cranial outflow) or the spinal cord (sacral outflow) Parasympathetic neurones exit either the brain or the spinal cord Cranial outflow: CN III, VII, IX and X Sacral outflow Pelvic splanchnic nerves are the parasympathetic outflow at S2,3,4 (tiny branches from the sacral spinal nerves at the same levels). O/A = occipito-atlantic joint (base of skull) – where cranial parasympathetic nerves exit. SIJ = sacroiliac joint (sacrum to pelvis). – near the sacral outflow Note that the parasympathetic NS has both a cranial part and a sacral part. Note the ganglions – 2 motor neurones (pre-ganglionic and post-ganglionic)

Answer 156

The musculoskeletal system enables movement for hunting, escaping, fighting, reproduction. Movement can be voluntary / involuntary (reflexes)

Answer 157

Axial Skeleton: This forms the central axis of the body and includes the skull, vertebral column, ribs, and sternum (breastbone). It provides support and protection for the organs within the dorsal and ventral body cavities, including the brain, spinal cord, heart, and lungs.

Answer 158

This consists of the bones of the limbs (arms and legs) and the bones that connect them to the axial skeleton. It includes * **the shoulder girdle (scapula and clavicle), * bones of the arms (humerus, radius, ulna), * bones of the hands (carpals, metacarpals, and phalanges)** * , pelvic girdle (hip bones) * , **bones of the legs (femur, tibia, fibula), * bones of the feet (tarsals, metatarsals, and phalanges), and associated joints.**

Answer 159

The join between 2 bones * Held together by ligaments - ( tough bands of fibrous connective tissue that connect bones to each other across the joint. They provide stability and prevent excessive movement of the joint.) Movement controlled by muscles and their tendons

Answer 160

Suture - Found only in the skull, sutures are immovable fibrous joints that fuse the skull bones together. * Syndesmosis -These joints have slightly more mobility compared to sutures and are connected by ligaments. An example is the distal tibiofibular joint in the lower leg.

Answer 161

joints are connected by cartilage and allow limited movement. There are two main subtypes: Primary – joints at birth but fuse later * Secondary – midline ones Primary (Synchondrosis): These are temporary joints found in infants and children, where the connecting cartilage is eventually replaced by bone. An example is the epiphyseal plate in long bones. Secondary (Symphysis): These joints have a pad of fibrocartilage between the bones, providing shock absorption and slight movement. Examples include the intervertebral discs and the pubic symphysis.

Answer 162

most freely movable joints in the body. They have a joint cavity filled with synovial fluid, allowing for smooth movement between the bones. There are several subtypes: Hinge: These joints allow movement in only one plane, like a door hinge. Examples include the elbow and knee. Ball and Socket: These joints allow for the widest range of motion, with one bone having a spherical end that fits into a cup-like depression on the other bone. Examples include the shoulder and hip. Pivot: These joints allow rotation around a central axis. An example is the joint between the first and second cervical vertebrae (atlantoaxial joint). Saddle: These joints allow movement in two planes, similar to a rider sitting in a saddle. The best example is the carpometacarpal joint of the thumb. Condyloid (Ellipsoidal): These joints allow movement in two planes, like a condyle fitting into an elliptical socket. Examples include the wrist (radiocarpal joint) and the metacarpophalangeal joints. Gliding (Plane): These joints allow sliding or gliding movements between flat or slightly curved surfaces. Examples include the joints between the carpals in the wrist and the tarsals in the ankle.

Answer 163

Respiration: Supplies oxygen to tissues and cells, removes carbon dioxide. Transportation: Carries nutrients, waste products, and hormones. Protection: Defends against infections, aids in tissue repair. Thermoregulation: Regulates body temperature.

Answer 164

Respiration: Red blood cells Transportation: Plasma Protection: White blood cells Tissue Repair: Platelets Thermoregulation: Plasma (regulates heat loss and gain)

Answer 165

liquid that fills the vascular compartment and serves to transport dissolved materials and blood cells throughout the body - Plasma (~55% total blood volume) - White blood cells & platelets (<1% whole blood) - Red blood cells (~45% whole blood) WHITE BLOOD CELLS /PLATELETS/RED BLOOD CELLS = HAEMOCRIT The average human has 4 to 6L of blood

Answer 166

Definition of Blood: Blood is described as a liquid that fills the vascular compartment, transporting dissolved materials and blood cells throughout the body. Unlike some body fluids, blood cells are carried rather than dissolved within the blood.

Answer 167

Hematocrit: Hematocrit refers to the combined volume of red blood cells, white blood cells, and platelets, primarily composed of red blood cells.

Answer 168

Largest Cells in Blood: White blood cells are the largest cells in the blood. They don't settle at the bottom of a tube due to their relatively low density compared to red blood cells.

Answer 169

Thermoregulation: Thermoregulation is the body's ability to regulate temperature. In hot conditions, blood flow is directed to the skin's surface to dissipate heat, while in cold conditions, blood flow is directed to the body's core to conserve heat. Mechanisms such as sweating and shivering aid in temperature regulation by utilizing the latent heat of evaporation and generating heat through muscle contractions, respectively Extreme heat Circulation diverts blood to surface to cool the body Sweating Extreme cold Circulation diverts blood to deep/core to maintain body heat Hair Shivering In hot environments, we're able to redirect blood flow to the body's surface. This involves opening blood vessels leading to the capillary bed near the skin surface while constricting deeper vessels. By doing so, heat can dissipate from the body's surface. Additionally, sweating aids in cooling down the body by utilizing the latent heat of evaporation. Conversely, in cold conditions, we aim to retain heat by constricting blood vessels near the skin surface, directing most of the blood flow to the body's core. Though some blood still circulates near the surface, measures such as having hair stand up and shivering help trap warm air and generate heat through muscle contractions. These mechanisms involve the manipulation of blood flow throughout the body for effective temperature regulation

Answer 170

Plasma is mostly water, serving as a solvent for transporting substances. Dissolved substances in plasma include ions (e.g., sodium), which play a crucial role in osmotic balance. Other electrolytes in plasma have functions like nerve conduction, muscle contractions, and pH buffering. Plasma also carries proteins, notably albumin, fibrinogen, and immunoglobulins. Albumin helps maintain osmotic balance by retaining liquid within blood vessels. Plasma transports nutrients, waste products, gases (e.g., oxygen, carbon dioxide), and hormones.

Answer 171

Red blood cells (erythrocytes) are highly abundant, numbering about 5 to 6 million per microliter. Therefore, a single drop of blood contains approximately 500 million red blood cells. White blood cells (leukocytes) range from 5,000 to 10,000 per microliter, totaling about 500,000 in a drop of blood. Platelets, crucial for clotting, range from 250,000 to 400,000 per microliter, amounting to around 25 million in a drop of blood.

Answer 172

Bone Marrow: Bone marrow is the spongy tissue found inside bones. There are two types: red marrow and yellow marrow. Red marrow is primarily responsible for blood cell production and is found mainly in flat bones. Occurs in bone marrow - spongy tissue inside bones that produces blood cells. RED marrow in flat bones produces most blood cells YELLOW marrow in long bones produces some WBC

Answer 173

Yellow Marrow: Yellow marrow is located in long bones and can also produce some white blood cells, although the bulk of blood cell production occurs in red marrow

Answer 174

Flat Bones: Flat bones include the scapula, pelvis, sternum (or breastbone), and ribs. Despite not being commonly recognized as flat bones, ribs fall into this category. These bones, especially the pelvis, serve as major sites for blood cell production, although blood cells can also be produced in other bones, albeit less significantly.

Answer 175

Drop of Blood: A drop of blood is approximately 100 microliters in volume. It contains roughly 5 million red blood cells, 4,000 to 11,000 white blood cells, and 150,000 to 400,000 platelets per microliter.

Answer 176

Stem Cells: Stem cells are undifferentiated cells with the potential to develop into various specialized cell types. Stroma Composition: Stroma is the supportive tissue in the bone marrow, composed of fibroblasts, macrophages, adipocytes, osteoblasts, osteoclasts, and epithelial cells

Answer 177

Maturation of Blood Cells: Red blood cells mature from stem cells by ejecting their nuclei. White blood cells, like neutrophils, undergo morphological changes during maturation. Platelets are produced from megakaryocytes, with fragments released into circulation. Exceptions in Growth Factor Production: Erythropoietin stimulates red blood cell production and is produced by the kidneys. Thrombopoietin regulates platelet production and is produced by the liver.

Answer 178

Hematopoietic Stem Cell: Hematopoietic stem cells are multipotent, capable of giving rise to various blood cell types. The two daughters of a hematopoietic stem cell are common myeloid progenitors and common lymphoid progenitors.

Answer 179

Maturation of Platelets: Thrombopoiesis is the process of platelet production, regulated by thrombopoietin.

Answer 180

Erythropoiesis: Erythropoiesis is the maturation process of red blood cells from blast cells, regulated by erythropoietin. Red blood cells are also called erythrocytes. Granulopoiesis: Granulopoiesis is the maturation process of granulocytes, including basophils, neutrophils, and eosinophils. Granulocytes are characterized by their granules, hence the name.

Answer 181

Monocytes and Macrophages: Monocytes mature into macrophages or dendritic cells, which play roles in tissue and immune function. Macrophages are scavengers, while dendritic cells present antigens to the immune system. Lymphoid Cells: Lymphoblasts give rise to B and T lymphocytes, which function in immune responses. Natural killer cells are part of the innate immune system and destroy infected or abnormal cells.

Answer 182

What does megakaryopoiesis produce? Platelets. What type of cell does megakaryopoiesis originate from? Megakaryoblasts.

Answer 183

Erythropoiesis: What is the main product of erythropoiesis? Red blood cells (RBCs). What regulates erythropoiesis? Erythropoietin.

Answer 184

Granulopoiesis: What does granulopoiesis produce? Granulocytes. What are the characteristics of granulocytes? They have granules and are part of the innate immune system.

Answer 185

Monocytopoiesis: What does monocytopoiesis produce? Monocytes. What is the function of monocytes and macrophages? They are phagocytes, clearing debris or dead cells.

Answer 186

Lymphopoiesis: What does lymphopoiesis produce? Lymphocytes. What are the two main types of lymphocytes? T-cells and B-cells.

Answer 187

Haemopoietic Growth Factors: Where are haemopoietic growth factors produced? Produced by stromal cells in the bone marrow. Name the exceptions to growth factor production and their sources. Erythropoietin (produced in the kidney) and thrombopoietin (produced in the liver).

Answer 188

Stem Cell Potency: Define "totipotent". Stem cell capable of becoming any cell in the body (e.g., fertilized ovum). Define "pluripotent". Stem cell able to become nearly all cells in the body (from the 3 germ layers). Define "multipotent". Stem cells capable of becoming multiple cells of the same family. Define "oligopotent". Stem cells able to differentiate into a few different cell types.

Answer 189

Describe a common myeloid precursor. Myeloid precursor, capable of becoming any myeloid cell. Describe a common lymphoid precursor. Lymphoid precursor, capable of becoming any lymphoid cell. What distinguishes myeloblasts from lymphoblasts? Myeloblasts can become myeloid cells, while lymphoblasts can become lymphoid cells.

Answer 190

Cell Functions: What is the function of platelets? Involved in blood clotting. What is the role of red blood cells? Carry oxygen around the body. What is the function of granulocytes? Part of innate immune system, dealing with foreign substances. What are the roles of monocytes, macrophages, and dendritic cells? Monocytes/macrophages clear debris, while dendritic cells present antigens.

Answer 191

Lymphocytes and Plasma Cells: What is the function of lymphocytes? Form adaptive immune system. What are the subtypes of lymphocytes? T-cells and B-cells. What is the role of natural killer cells? Kill foreign or cancerous cells lacking MHC-I. Cell Identification: How do mast cells relate to basophils? Mast cells are tissue equivalent cells to basophils. Describe the staining characteristics of different cell types. Notice location, sizes, shapes, nuclei shapes, and colors (on staining) of different cell types.

Answer 192

The spleen is an ovoid organ found in the upper left abdominal cavity (5-13cm). Spleen is the largest “filter” of blood in the body, removing old or damaged blood cells (engulfed by phagocytes).

Answer 193

The windows in the spleen are 3 micrometers in size. Cells are filtered based on their ability to deform and pass through the windows. Cells that cannot deform sufficiently are filtered from the blood and subsequently destroyed. The process involves phagocytes engulfing the cells. The proteins of red blood cells are broken down into amino acids during destruction in the spleen. The iron from red blood cells is transported back to the bone marrow. The porphyrin ring of red blood cells is converted into bilirubin in the spleen. Approximately 4 million blood cells are destroyed every second, with 2.5 million of them being red blood cells. The spleen serves as the primary organ for the destruction of old or damaged blood cells. The spleen accomplishes the removal of blood cells through phagocytosis.

Answer 194

Lack of Nucleus: Ejected to create space for hemoglobin, enhancing oxygen transport, and increasing cell flexibility for passage through capillaries. Absence of Mitochondria: Mitochondria are absent to prevent oxygen consumption, ensuring efficient oxygen transport without competing for oxygen. Production and Lifespan: Approximately 2.5 million red blood cells are produced and destroyed every second out of 4 million, with a lifespan of 120 days. Quantity and Shape: Mammalian blood contains 6-8 million red blood cells per mm3, with a diameter of 7 micrometers. They are biconcave discs, facilitating passage through narrow capillaries. Function: Despite lacking a nucleus and mitochondria, red blood cells play a crucial role in transporting oxygen and carbon dioxide, facilitating respiration.

Answer 195

Biconcave disks 7-12µm in diameter, ~90fL No nucleus (anucleate) No mitochondria 4-6 x 1012/L about 25 trillion in the average human with 5L of blood, varies ♀ ♂ Long life span - 120 days (300 miles) Function Transport of oxygen and carbon dioxide around the body Critical role in respiration

Answer 196

Haemoglobin (Hb) Responsible for the red appearance of RBC’s About 250 million molecules / RBC 4 polypeptide chains each with a cofactor called a haem group, that has an iron atom at the centre. Each iron atom binds one molecule of O2. Co-operativity in O2 binding and release. Binds to O2, CO2 and NO (can also bind CO) and transports these molecules around the body

Answer 197

Cooperative Binding: Eases binding of subsequent oxygen molecules after the first attaches. Harder to offload the first oxygen, progressively easier for the second and third, but harder again for the fourth. Ensures efficient oxygen delivery, holding onto the last oxygen molecule until necessary.

Answer 198

Other Hemoglobin Functions: Binds to carbon dioxide, nitric oxide, and carbon monoxide. Facilitates transport of gases throughout the body. Ensures optimal oxygen delivery to tissues, explored further in respiratory lectures.

Answer 199

The pulmonary system is the blood vessels surrounding the lungs. The pulmonary artery brings blood from the heart to the lungs (but this is deoxygenated), and the pulmonary vein carries the oxygenated blood back to the heart to be pumped around the body. The capillary bed surrounds the alveoli. Air enters via nose / mouth, travels down trachea to the 2 bronchi, then bronchioles, to the alveoli. The red blood cells, the hemoglobin is able to pick up the oxygen from the lungs, so through the pulmonary circulation

Answer 200

Cooperative Binding: Once one molecule of O2 binds, the binding of the 2nd and 3rd molecules becomes easier due to cooperative binding. Oxygen Transport Process: Oxygen is taken into the alveoli of the lungs. It dissolves in the plasma, becoming a dissolved gas. Oxygen binds to hemoglobin in red blood cells, oxygenating them. This process, called oxygenation, forms oxyhemoglobin, which is bright red. Upon losing oxygen, it becomes deoxyhemoglobin, appearing dark red. Oxygen is released from hemoglobin in tissues, dissolving in plasma again. It then moves into the interstitial fluid and enters cells, where it's used in cellular respiration.

Answer 201

Tissue to Interstitial Fluid: CO2 moves from tissues to interstitial fluid. Interstitial Fluid to Plasma: It follows the concentration gradient into the plasma. Travel in Plasma: Around 7% of CO2 travels back dissolved in plasma. Red Blood Cell Uptake: About 90% of CO2 enters red blood cells (RBCs). CO2 Binding to Hemoglobin: Some (~23%) CO2 binds to Hb in RBCs. Formation of Carbonic Acid: Majority (~70%) reacts with water in RBCs, forming carbonic acid. Bicarbonate Ion Formation: Carbonic acid dissociates into bicarbonate ions (HCO3-) and hydrogen ions (H+). Bicarbonate Transport: HCO3- travels in plasma; H+ binds to Hb to maintain blood pH. Lung Exchange: In the lungs, HCO3- and H+ combine to form carbonic acid, which dissociates into CO2 and H2O. Exhalation: CO2 follows the concentration gradient out of the blood into alveolar sacs and is exhaled. (Production: Cells produce carbon dioxide. Dissolution: Carbon dioxide dissolves in the interstitial fluid. Movement: It enters the plasma; about 7% returns to the lungs dissolved in plasma. Red Blood Cell Uptake: Around 90% of carbon dioxide is taken up by red blood cells. Binding to Hemoglobin: Approximately 23% of carbon dioxide binds to hemoglobin, but not at the same site as oxygen. Formation of Carbonic Acid: Most of the carbon dioxide (70%) reacts with water inside red blood cells, forming carbonic acid. Dissociation: Carbonic acid dissociates into bicarbonate ions and hydrogen ions. Bicarbonate Transport: Bicarbonate ions diffuse into the plasma and travel back to the lungs. Hydrogen Ion Capture: Hemoglobin binds to hydrogen ions, preventing changes in blood pH. Return to Lungs: In the lungs, bicarbonate ions re-enter red blood cells, react with hydrogen ions, and form carbonic acid, which then dissociates into water and carbon dioxide. Exhalation: Carbon dioxide diffuses into the airspaces of the lungs and is exhaled.)

Answer 202

A reduced haemoglobin concentration in blood Several classifications  Low haematocrit  Small red cells Most common causes: Poor diet – iron deficiency Chronic blood loss Malabsorption of iron Pregnancy Signs and Symptoms: Fatigue, pallor, tachycardia, shortness of breath

Answer 203

Size: Approximately twice the size of red blood cells Nucleus: Multi-lobed for squeezing through small spaces Granules: Neutral-staining granules containing myeloperoxidase Count: 2.5-7.5 x 10^9/L Lifespan: 6 hours to a few days Function: Vital role in protection from bacterial infections, phagocytosis of bacteria - phagocytose bacteria Name: Derived from their neutral-staining granules

Answer 204

Size: Approximately the same size as neutrophils Nucleus: Bi-lobed nucleus Granules: Large pink-staining granules containing histamine, plasminogen, DNase, RNase, etc. Count: 0.04-0.44 x 10^9/L Lifespan: 8-12 days Functions: Immune-protection, phagocytosis of antibody-coated pathogens, attacks parasites, allergic responses Name: Derived from their eosin-staining granules The granules are a kind of pink color and they contain things like histamine, plasminogen, DNases, RNases. So enzymes that break down DNA and RNA

Answer 205

Size: Slightly smaller than neutrophil Nucleus: Bi-lobed Granules: Large purple-staining granules containing histamine, heparin, proteolytic enzymes Count: 0.01-0.1 x 10^9/L Lifespan: A few hours to a few days Functions: Release of histamine during inflammation, not phagocytes bilobed just like our eosinophils. This time the granules are purple staining containing things like histamine, heparin, proteolytic enzymes. Another key role in things like allergy and inflammation, they release histamine.

Answer 206

Large kidney-shaped nucleus Larger than neutrophil 0.2-0.8 x 109/L Life span - last many months Function Vital role in protection from infections Ingest bacteria, dead cells and cellular debris Phagocytosis Nucleus: Large kidney-shaped nucleus Size: Bigger than neutrophils Count: 0.2 to 0.8 x 10^9/L Lifespan: Many months Functions: Leave blood to become macrophages in tissues, clear debris, dead cells, bacteria, proficient in phagocytosis

Answer 207

Large and relatively round nucleus that fills the cytoplasm Slightly smaller than neutrophil 1.5-3.5 x 109/L Life span - can persist for many years Divided into two types of cell due to function - T & B cells Function Central role in the immune system – protecting from infections, esp viral infections Some lymphocytes attack pathogens directly (T-cells) and some produce antibodies (B-cells) Nucleus: Large and relatively round, filling the cytoplasm Size: Slightly smaller than neutrophils Count: 1.5-3.5 x 10^9/L Lifespan: Can persist for many years Function: Central role in the immune system, protecting from infections, especially viral infections. T-cells attack pathogens directly, while B-cells produce antibodies.

Answer 208

Classification: Group I Innate Lymphocytes (ILCs), part of the innate immune system Origins: Same progenitor as T and B cells Function: Respond quickly to various pathological challenges, including viral infections and cancer Role in Pregnancy: Found in the placenta, may play a crucial role in pregnancy Killing Mechanism: Ability to kill tumor cells and infected cells without prior activation Secretion: Release cytokines such as IFNγ and TNFα to enhance the immune response Receptor Balance: Killing depends on a balance of signals from activating and inhibitory receptors on the NK cell surface Recognition: Activating receptors recognize molecules on cancer cells and infected cells, while inhibitory receptors recognize MHC I receptors on normal healthy cells Killing Process: Once activated, NK cells release cytotoxic granules containing perforin and granzymes, leading to lysis of the target cell.

Answer 209

2.5 – 7.5 [x 10*9/L] Elevated in : Bacterial infection, stress, exercise, myeloproliferative diseases (some leukaemias)

Answer 210

1.5 – 3.5 [x 10*9/L] Elevated in : Viral infection, some lymphoproliferative diseases (some leukaemias)

Answer 211

0.2 – 0.8 [x 10*9/L] Elevated in: Infection, inflammation, tissue damage, monocytic leukaemia

Answer 212

0.04 – 0.44 [x 10*9/L] Elevated in : Allergy, intestinal parasites, some myeloproliferative diseases (some leukaemias)

Answer 213

0.01 – 0.1 [x 10*9/L] Elevated in : Some myeloproliferative diseases (esp. CGL)

Answer 214

Small anucleate fragments of large precursor cells called megakaryocytes 2-4µm diameter Appear in blood films as dark-staining granules 150-400 x 10*9/L Life span - 5-10 days Functions Roles in blood clotting and prevention of blood loss (haemostasis) Definition: Small, anucleate blood cells measuring 2 to 4 micrometers in diameter, produced by megakaryocytes. They circulate for 5 to 10 days and play a key role in hemostasis, transforming upon activation to aid in clot formation.

Answer 215

Term: Platelet Activation Definition: The process by which activated platelets change from a smooth discoid shape to sending out filopodia and forming lamellipodia, crucial for clot formation. Back of Flashcard: Term: Pseudopodia Definition: Projections of membrane formed by activated platelets, including filopodia and lamellipodia, which aid in platelet function during clot formation. Front of Flashcard: Term: Filopodia Definition: Slender projections extended by activated platelets, facilitating platelet-platelet contacts during clot formation. Back of Flashcard: Term: Lamellipodia Definition: Large, flat spreading projections formed by activated platelets, aiding in platelet coverage during clot formation. Front of Flashcard: Term: Fibrin Definition: A protein produced by the coagulation cascade, enhancing the binding of blood cells together and strengthening clot formation.

Answer 216

red blood cells can be stored for up to 35 days at 4degC *platelets can be stored for up to 7 days at room temp *plasma can be stored for up to 3 years at -30degC Leucodepletion: removal of WBCs reduces incidence of febrile transfusion reactions and HLA incompatibility and reduces transmission of some infections. Fresh Frozen Plasma (FFP) is given to people that are bleeding because they have run out of one or more clotting factors eg. after severe bleeding. For patients missing one specific clotting factor often only that factor is replaced using synthetically made clotting factors. Cryoprecipitate is precipitated or thawed FFP that is high in clotting factors, particularly fibrinogen (most clotting factors are now synthetically made to replace genetically malfunctioning / missing clotting factors rather than coming from FFP).

Answer 217

Good health Unpaid volunteers Excluding risk factors (jaundice (?hepatitis), travel in malarial areas, recent tattoo or piercing, risk factors for HIV or CJD). Screening of blood. Screening for compatibility of donor and recipient.

Answer 218

Glycolipids: Examples: ABO antigens. Proteins: Example: Rhesus factor. Glycoproteins: Functions: Channels, receptors, identification markers. Antigens (Ag) and Immune System: Antigens: Location: Present on cell membrane. Importance: Crucial for immune system recognition. Immune System Response: Recognition: Identifies non-self molecules like those on foreign cells, bacteria, or viruses. Tolerance: Ignores self-molecules to prevent attacking healthy cells.

Answer 219

People of blood group A will have A antigens on the surface of their RBCs. Those blood group A people on your red blood cells have the A antigen. So, you have a surface molecule called the A antigen that sits on the surface of your red blood cells. People of blood group B will have B antigens on the surface of their RBCs. blood group B have the B antigen on the surface of their red blood cells. People of blood group AB will have both A antigens and B antigens on the surface of their RBCs. are blood group AB have both the A and the B antigen. They have both molecules on the surface People of blood group O have neither the A antigen nor the B antigen on the surface of their RBCs (but they do have the H antigen (stalk)!). who are blood group O, they don't have either A or B on the surface, but they still have this little stalk

Answer 220

ABO Ag’s are sugar chains attached to the surface of the RBC via the lipid ceramide. The gene for the ABO Ag’s is autosomal dominant (chr9q34) and encodes a specific glycosyl transferase. ABO Antigens Sugar chains composed of glucose, galactose, genac (N-acetylglucosamine), and other molecules, attaching to the red blood cell via ceramide lipid. These chains form the H antigen, present in individuals with blood group O. This H antigen is present on the surface of red blood cells for individuals with blood group O. Blood group A individuals have the H antigen with an additional galnac side branch, If you belong to blood group A, you still have the H antigen, but you also have a side branch consisting of a galnac molecule (N-acetylgalactosamine). while blood group B individuals have the H antigen with a galactose side branch. if you're blood group B, you have the H antigen initially, but your side branch contains a galactose molecule. Individuals with blood group AB have both the A and B antigens on their red blood cell surface. Blood group AB individuals have both A and B antigens on their red blood cell surface.

Answer 221

Definition: A gene on chromosome 9 codes for an enzyme called glycosyl transferase, which instructs sugar molecules to link and form the ABO antigens. The gene follows an autosomal dominant inheritance pattern. Unlike proteins translated from mRNA, sugars are synthesized by enzymes. These enzymes regulate the formation of sugar chains, determining the antigens present on red blood cells. These sugar molecules are encoded by genes, but unlike proteins which are translated from mRNA, sugars are synthesized by enzymes. The gene responsible for determining your blood group codes for an enzyme called glycosyl transferase. This enzyme instructs the sugar molecules to link together in the specified chain.

Answer 222

Proteins that recognise foreign molecules (Ag) in the body Trigger an immune response 5 types with slightly different structures. These include: Immunogoblin G (IgG) Immunogoblin M (IgM) IgG Abs are only made after exposure to a foreign Ag e.g. infections. *Some Abs (naturally occurring IgM) are made without prior exposure to the Ag (ie. From early life). IgM is made of 5 of the IgGs stuck together. This makes IgM much bigger than IgG. This is important as size determines where each type can be found. This way if you have the antigen (ie it is self), the Ab raised against it will be destroyed. If you don’t have the antigen (ie non-self) the Ab raised will be kept, ready to attach to the antigen if it ever appears. (technically it is the Ab producing cells that are either destroyed or kept). Many antibodies are only made after exposure to a foreign antigen eg. against infections. However, some are made without prior exposure eg. naturally occurring Ab. Newborn babies don’t have any Ab against these Ag in their blood.

Answer 223

Immunoglobulin M (IgM) is the largest antibody, formed by five IgG molecules joined together to form a pentamer. IgM is substantially larger than IgG. As the body produces antibodies, it screens them against self to prevent autoimmune reactions. Any antibodies recognizing self are eliminated, as we don't want our immune system attacking our own cells. IgM antibodies are naturally occurring and can be produced without prior exposure to foreign antigens. Naturally occurring antibodies are our IgM antibodies, and we make these without prior exposure to the foreign thing. So, we can make IgM from early in life without prior exposure to that foreign substance

Answer 224

we have immunoglobulin G (IgG), which has a classic Y-shaped structure and is adept at recognizing various substances. IgG antibodies are generated only after exposure to foreign substances like viruses, bacteria, or foreign blood The IgG antibodies, these are only made after you get exposed to something foreign. Whether that's a virus or a bacteria or someone else's blood, you only make the IgG antibody if you see it. So, you see it. That's not me. That's foreign. I'm going to make more antibodies to that. But some antibodies are what's called naturally occurring.

Answer 225

For someone with blood group A, they have the A antigen on their red blood cells' surface. Naturally occurring antibodies produced by their body include anti-A and anti-B. However, the anti-A antibodies react with the self-antigen A, so the body destroys the cells producing them. As a result, there are no anti-A antibodies present in their plasma. Conversely, the body keeps the anti-B antibodies because they don't target self-antigens. Therefore, individuals with blood group A have anti-B antibodies in their plasma.

Answer 226

Similarly, individuals with blood group B have the B antigen on their red blood cells and produce anti-A and anti-B antibodies. However, the anti-B antibodies would target self-antigens, so the body eliminates cells producing them. Therefore, individuals with blood group B have no anti-B antibodies in their plasma but retain the anti-A antibodies.

Answer 227

For blood group AB, which has both A and B antigens, the body recognizes both anti-A and anti-B antibodies as self and destroys cells producing them. Consequently, individuals with blood group AB have neither anti-A nor anti-B antibodies in their plasma.

Answer 228

In contrast, individuals with blood group O lack A and B antigens on their red blood cells. They produce both anti-A and anti-B antibodies, which do not react with their own cells. Therefore, individuals with blood group O have both anti-A and anti-B antibodies circulating in their plasma.

Answer 229

We make all of the antibodies (anti-A and anti-B), but people who are group A (A-antigen on the surface) will destroy any B-cells that make Ab against self (anti-A), but will keep B-cells making antibodies against non-self (anti-B) in their plasma. The antibodies made will be the IgM type (the big ones). IgM is made by natural immunity. This is the production of antibodies without being exposed to the antigen. IgG antibodies are made after exposure to an antigen, such as when you get an infection.

Answer 230

the Rh factor involves a protein located on the surface of red blood cells. This protein, called the Rh antigen, specifically the RhD antigen, is a transmembrane protein, meaning it spans the cell membrane multiple times, creating loops that traverse back and forth across the membrane. Among the various types of Rh antigens, RhD is the most prevalent and significant. It's crucial to remember RhD when discussing blood types. The RhD antigen is inherited through autosomal recessive genetics, with most individuals being Rh positive, meaning they possess the RhD antigen

Answer 231

within each of these blood groups, there's the additional factor of Rh, which can either be present (Rh positive) or absent (Rh negative). For instance, someone could be A positive, indicating they have the A blood group and the RhD antigen on their red blood cell surface. Conversely, an individual could be A negative, meaning they possess the A blood group but lack the RhD antigen. Similarly, one could be B positive (having both the B antigen and the RhD antigen), B negative (having the B antigen but lacking the RhD antigen), AB positive, AB negative, O positive, or O negative. It's important to note that antibodies produced against the Rh factor are of the IgG type, unlike the antibodies against the ABO blood groups, which are primarily IgM. IgG antibodies against the Rh factor are not naturally occurring; they're only developed after exposure to foreign RhD antigens. The antibodies that we can develop to recess are IgG. These are not naturally occurring. We will only produce antibodies against recess if we are recess negative and we see some recess positive. So we have to be negative ourselves and then get exposed to something we're not used to seeing.

Answer 232

Natural immunity: IgM antibodies, no prior exposure, anti-A and anti-B in plasma. Adaptive immunity: IgG antibodies, exposure-dependent. Mismatched transfusions may trigger immune responses, emphasizing the need for proper donor-recipient matching. The natural immunity, those IgM1s, those large antibodies are produced without prior exposure. So we already have the anti-A and the anti-B in our plasma. We don't need to have been exposed to it in advance. We'll recognize things first time. So that's why it gives such a strong reaction. The adaptive immunity that IgG, the small antibodies, these are only produced when we see something foreign. So if you had a blood transfusion, if you were given blood and it was the wrong recess group, it would raise an immune response when you first see it and it's on the second time you see it, you have the big problems. So first time, it's not going to be great, but it's not the end of the world. Second time, big problems. It's important that donors and recipients are matched prior to transfusions to avoid immune reactions.

Answer 233

Let's explore the consequences of incorrect blood matching. Consider a scenario where a person with blood group A receives blood containing the A antigen. If the recipient's blood type is B, meaning they have anti-A antibodies in their plasma, these antibodies will bind to the A antigens on the donated red blood cells. This binding, facilitated by IgM antibodies in pentameric form, leads to clumping or agglutination of the red blood cells, resulting in an acute reaction known as agglutination. Agglutination not only causes the cells to stick together but also activates complement, a protein system that creates pores in cells, leading to their leakage. Consequently, hemoglobin leaks into the bloodstream, resulting in hemoglobinuria, characterized by red-colored urine. Hemoglobin breakdown products like bilirubin become toxic, causing symptoms such as fever, chills, nausea, and potential clot formation in blood vessels. Moreover, it damages kidney cells, contributing to kidney failure and potentially fatal outcomes. Most ABO mismatches occur due to clerical or administrative errors, highlighting the importance of stringent identification procedures in healthcare settings. Measures like barcoding patients and verifying their identity multiple times help mitigate such errors and reduce the risk of acute transfusion reactions caused by ABO mismatching.

Answer 234

Acute Transfusion Reaction caused by ABO mismatch: Within minutes (acute) Agglutination by IgM Complement mediated lysis Release of Hb (haemoglobinuria) Breakdown to bilirubin Toxic (Fever, chills, nausea, clotting within blood vessels, necrosis of kidneys Complement mediated lysis: Agglutination activates the complement system. Complement proteins punch holes in the red blood cell membranes. This leads to lysis or rupture of the red blood cells. Release of Hb (haemoglobinuria): Due to red blood cell lysis, hemoglobin is released into the bloodstream. Hemoglobinuria occurs, where hemoglobin is excreted in the urine. Breakdown to bilirubin: Hemoglobin breakdown products, including bilirubin, are released. Bilirubin is formed as a result of the breakdown of heme, a component of hemoglobin. Toxic effects: Bilirubin is toxic and can lead to various symptoms: Fever, chills, and nausea: systemic inflammatory response. Clotting within blood vessels: can lead to thrombosis or blockage. Necrosis of kidneys: Bilirubin toxicity can cause kidney cell death, leading to kidney failure. Most incompatible blood transfusions arise from clerical errors and mistaken patient identity.

Answer 235

Unlike ABO mismatches, delayed reactions often occur during repeat transfusions. The initial mismatch triggers a less severe immune response, but subsequent exposures lead to more robust reactions. IgG antibodies are produced in delayed transfusion reactions, binding to red blood cells upon repeat exposure and activating complement proteins, causing red blood cell destruction. Symptoms include fever, anemia, and jaundice, but are generally less severe compared to ABO mismatch reactions. Proper cross-matching of blood donors and recipients can prevent these mismatches, ensuring safer transfusions.

Answer 236

In hemolytic disease of the fetus and newborn, the mother produces antibodies that then cross the placenta and attack the baby's red blood cells. And most commonly, this involves rhesus, rhesus D. When mum's antibodies attack baby's red blood cells, what results then is baby ends up with a large liver and spleen because that's clearing up all the debris from all those damaged red blood cells and is trying to produce more red blood cells. The baby has symptoms of anemia, so remember those symptoms, tachycardia, pallor, fatigue, all of those sorts of things. And then we also get high levels of bilirubin. Remember the cells are being broken up and lysed, releasing bilirubin into the circulation. Bilirubin is toxic, and in newborn babies or in the fetus, it can cause brain damage. cause brain damage

Answer 237

Rh incompatibility occurs when the mother is Rh negative. Remember, this only applies to about 15% of females in the population. It's crucial to note that Rh incompatibility arises when the mother carries a baby who is Rh positive, indicating that the father must also be Rh positive. During childbirth, significant blood loss can occur as the placenta separates from the uterine wall. This process releases a substantial amount of blood into the mother's circulation. As a result, some of the baby's Rh-positive red blood cells may enter the mother's bloodstream. Being Rh negative, the mother's immune system recognizes these Rh-positive cells as foreign and mounts an immune response. This response involves the production of IgG antibodies specifically targeting the Rh antigen present on the baby's red blood cells. When the first baby is born, it remains unaffected by these antibodies. However, if the mother has a subsequent Rh-positive baby, she already has circulating anti-Rh antibodies (IgG) from her previous pregnancy. These antibodies can cross the placenta and attack the red blood cells of the Rh-positive baby, potentially causing severe complications. Unlike IgM antibodies against ABO blood groups, which are too large to cross the placenta, IgG antibodies against the Rh factor can pass through. This scenario poses a risk if the mother is carrying an Rh-positive baby in subsequent pregnancies. However, it's essential to recognize that this condition is relatively rare genetically.

Answer 238

As RhD+ is dominant and RhD- is recessive, the likelihood of a mother being RhD –ve is about: RhD-..................23% ie. Minority of pregnant women RhD+..................77% Likelihood of baby being RhD+ also depends on the father: Inheritance of Factor D (RhD) All pregnant women are screened to see what blood group they are (?RhD status). They tend not to screen the fathers because not all children are fathered by the man who thinks he is the father! If the mother is RhD negative they treat her as at risk, if she is RhD positive there is no further action necessary. If a RhD –ve woman has a baby, there is a 50% chance that it will be RhD+ve (depends on the father). – Mendelian genetics.

Answer 239

Anti-D antibody is injected to RhD- mother immediately after birth of first child (if RhD+) * Neutralises RhD+ red cell from foetus * No anti-RhD antibodies raised in mother * Second RhD+ child does not develop haemolytic disease of the newborn Haemolytic disease of the new born can be prevented if the foetal RBCs can all be mopped up before an immune response is raised. Immediately after birth a RhD negative mother is injected with anti-D. The anti-D antibody mops up all the foetal RhD positive RBCs and prevents the immune response happening, so no IgG are made. Anti-D injections are given during pregnancy as well as at birth to mask any foetal RBCs and prevent the mother from raising an immune response.

Answer 240

Add the blood to the cup at the top of the card. In the cup is some of the antibodies. If the antibodies bind to and agglutinate the RBCs they can’t fall to the bottom of the well (can’t get through the gel as they are too big when stuck together). Eg. Group B reacts with anti-B causing agglutination (sticking together), so that the RBCs can’t fall to the bottom of the yellow well and stay as a band at the to

Answer 241

O group is the universal dOnor AB group is the universal recipient A person who is group A has A antigens on the surface of their RBCs. In their plasma they will have anti-B antibodies (IgM). If they are given RBCs with the B antigen on the surface (ie groups B or AB) the anti-B in their plasma will attack the donated cells. They will not attack either group A or group O RBCs. O is the universal dOnor. O- or B- donors more frequent (16 weeks) as O is the universal donor and B is rare. Example B So B on the surfaces So Have anti A in the plasma Incompatible to A and AB However this doesn’t take into Rhesus at all Rhesus D = one part of gene

Answer 242

Antigen: A Antibody: Anti-B Compatible with: A, O Incompatible with: B, AB

Answer 243

Antigen: B Antibody: Anti-A Compatible with: B, O Incompatible with: A, AB

Answer 244

Blood Type AB Antigen: A, B Antibody: Neither anti-A nor anti-B Compatible with: A, B, AB, O Incompatible with: -

Answer 245

Blood Type O Antigen: Neither A nor B Antibody: Anti-A, Anti-B Compatible with: O Incompatible with: A, B, AB

Answer 246

Since there are many blood groups (>44) and allogeneic variants (>400) with varying degrees of antigenicity and rarity, the suitability of blood for transfusion is double checked by cross-matching. *Blood cells from the donation are mixed with plasma from the recipient. *Agglutination indicates that the donor blood is incompatible.

Answer 247

trachea, 2 bronchi, 2 lungs Heart, aorta, superior and inferior vena cava, numerous other blood vessels Oesophagus Lymph vessels and nodes Some important nerves Mediastinum = space between lungs (contains heart, oesophagus, blood vessels)

Answer 248

Formed by pelvis, sacrum/coccyx, pelvic floor, continuous with abdominal cavityontains: Sigmoid colon, rectum, anus Some loops of small intestine Urinary bladder, lower parts of ureters, urethra Reproductive system of males / females