Reproductive system Flashcards
1
Q
What are Gonads (1)
A
Are the primary sex organs (testes in males and ovaries in females) that produce the gametes (sex cells) and secrete hormones
2
Q
What are the functions of the male reproductive system (3)
A
- Production of male sex cells (gametes) - sperm cells or spermatozoa
- Sustaining and transferring the sperm cells to the female
- Production of male sex hormones (androgens, e.g. testosterone)
3
Q
What are the functions of the female reproductive system (4)
A
- Production of female sex cells (gametes) – ova or egg cells (oocytes when immature)
- Reception of sperm cells from the male
- Protects and supports developing embryo, maintains growing foetus and nourishes newborn infant
- Production of female sex hormones
4
Q
What is the external genitalia of the male reproductive system comprised of (3)
A
- Penis – has erectile tissue, deposits sperm into the vagina of the female.
- Urethra – conducts semen to the exterior (remember: also conducts urine to the exterior)
- Scrotum – surrounds testes and maintains testes at three °C lower than normal body temperature to protect sperm viability.
5
Q
What is the internal genitalia of the male reproductive system comprised of (6)
A
- Ductus (vas) deferens – conducts sperm between epididymis and prostate, transports sperm from epididymis to ejaculatory duct.
- Seminal gland/vesicle **– secretes fluid, making up much volume of semen.
- Prostate – secretes fluid and enzymes.
- Bulbourethral gland (Cowper’s gland) **– secretes fluid that lubricates the tip of the penis and helps neutralise acids in the urethra.
- Epididymis **– site of sperm maturation and storage
- Testis – produces sperm (in the seminiferous tubules) and hormones.
6
Q
How is sperm produced (6)
A
- Starts at puberty and continues throughout life
- Occurs in the seminiferous tubules in the testes
- Involves three processes
- Mitosis and cell division (cytokinesis) – produces two identical daughter cells (diploid)
- Meiosis – cell division involved in gamete production; two cycles of cell division (meiosis I and II) produce four haploid cells; four chromatids (a tetrad) are then formed.
- Spermiogenesis - differentiation of immature male gametes into physically mature spermatozoa
7
Q
What is the process of spermatogenesis (4)
A
- Mitosis of a spermatogonium -primary spermatocyte (diploid, 2n)
- Meiosis i - DNA replication, primary spermatocyte, synapsis and tetrad formation, secondary spermatocytes
- Meiosis ii - spermatids (haploid, n)
- Spermiogenesis (physical mutation) - sperm (haploid, n)
8
Q
What is the structure of a sperm (5)
A
- Acrosome **– membranous compartment, contains enzymes essential to fertilisation
- Head – contains a nucleus (DNA) with densely packed chromosomes.
- Neck – **contains both centrioles of the original spermatid.
- Middle piece – **contains mitochondria to provide ATP for tail movement)
- Tail (flagellum) **– whiplike, moves sperm
9
Q
How is sperm activated (5)
A
- While sperm released from the testis is physically mature, it is immobile and incapable of fertilising an oocyte.
- Other parts of the male reproductive system help in functional maturation, nourishment, storage, and transport.
- Capacitation enables sperm to become motile and fully functional.
- It becomes motile when mixed with seminal gland secretions.
- It becomes capable of fertilisation when exposed to the female reproductive tract.
10
Q
How is testosterone produced, and what is its impact (6)
A
- Produced in the interstitial cells of Leydig (in the testes)
- Plays a key role in establishing and maintaining sexual function
- Maintains accessory glands and stimulates reproductive organ development
- Underlies sex drive (libido) and related behaviours
- Causes secondary sex characteristics (e.g., deepening of voice, increased hair growth, enlargement of skeletal muscles, thickening of bones)
- It is converted to dihydrotestosterone (DHT) in some tissues, to which some tissues respond (external genitalia) or are more sensitive (e.g., prostate). DHT binds to the same receptor as testosterone
11
Q
What are the hormonal interactions for the production of the male sex hormones (5)
A
- Hypothalamus secretes gonadotropin-releasing hormone (GnRH)
- GnRH targets the anterior lobe of the pituitary gland.
- The anterior pituitary responds by producing two gonadotropins:
- Luteinising hormone (LH)
- Follicle-stimulating hormone (FSH)
12
Q
What are the peripheral effects of testosterone (6)
A
- CNS effects
- Bone and muscle growth stimulation
- Establishment and maintenance of male secondary sex characteristics
- Maintenance of accessory glands and organs of the male reproductive system
- Controlling the local environment around spermatocytes and spermatids
- Androgen-binding protein (ABP) binds androgens and stimulates the physical maturation of spermatids.
13
Q
What are the functions of the Luteinising hormone (LH) in males (2)
A
- Targets the interstitial cells of the testes, which secrete testosterone and other androgens
- Testosterone levels are regulated by negative feedback - high testosterone level inhibits the release of GnRH.
14
Q
What are the functions of the Luteinising hormone (LH) in males (5)
A
- Targets nurse cells of seminiferous tubules
- Nurse (Sertoli) cells
- promote spermatogenesis and spermiogenesis
- secrete androgen-binding protein (ABP), which stimulates maturation of spermatids
- secrete inhibin, which **inhibits FSH and provides feedback control of spermatogenesis
15
Q
What are the parts of the female external genitalia (6)
A
- Vulva (pudendum) contains outer genitals
- mons pubis
- labia
- vestibule
- clitoris
- urethra
16
Q
What are the parts of the female internal genitalia (5)
A
- Ovaries
- uterine tubes (fallopian tubes or oviducts)
- uterus
- vagina
- cervix
17
Q
What are the functions of the external female genitalia (4)
A
- Mons pubis: fatty area overlying pubic symphysis, covered with pubic hair after puberty
- Labia majora (outer or large folds/lips) and labia minora (inner folds/lips): **the skin folds protect the opening of the urethra and vagina; they contain glands that lubricate the entrance to the vagina (prepuce or hood **is an extension of the labia minora encircling the body of the clitoris)
- Vestibule: enclosed by labia majora, contains opening of the urethra and the greater vestibular glands (produce mucus)
- Clitoris: contains erectile tissue, stimulation produces pleasurable sensations (female orgasm); corresponds to the male penis
18
Q
What are the functions of the vagina (5)
A
- Extends from the cervix to the exterior of the body, behind the bladder, and in front of the rectum.
- Site of sperm deposition (receives the penis during intercourse)
- Birth canal during childbirth/delivery
- Passageway for fluids during menstruation
- Partially closed by hymen until hymen ruptures
19
Q
What are the functions of the ovaries (6)
A
- Two almond-shaped structures on either side of the uterus, near the lateral wall of the pelvic cavity
- Produce immature female gametes (oocytes)
- Are composed of ovarian follicles (sac-like structures – oocyte and follicular cells)
- Secrete inhibin, which inhibits FSH production in the anterior pituitary gland)
- Support for ovaries: suspensory, ovarian and broad ligaments
- Layers: germinal epithelium, tunica albuginea, interior (cortex and medulla)
20
Q
What are the ovarian follicle stages (3)
A
- Primary follicle – contains an immature oocyte.
- Graafian (vesicular) follicle – growing follicle with a maturing oocyte
- Ovulation – when the egg matures, the follicle ruptures (occurs approximately every 28 days), and the ruptured follicle is transformed into a corpus luteum
21
Q
What are the functions of the uterine (Fallopian) tubes (7)
A
- Attaches to the uterus but not physically to the ovary
- The expanded funnel (infundibulum) opens into the pelvic cavity along the surface of the ovary; the other end opens into the uterine cavity.
- Supported by broad ligament
- Receives the ovulated oocyte
- Is the site for fertilisation?
- Fimbriae: finger-like projections at the distal end that receive the ovulated oocyte and sweep it into the tube towards the uterus
- Cilia inside uterine tubes move the oocyte slowly towards the uterus.
22
Q
What are the features of the uterus (womb) (7)
A
- Located between the urinary bladder and rectum
- (Anatomically) inferior to the ovaries, angled anteriorly above the urinary bladder
- Hollow organ with thick muscular walls that retain and nourish the fertilised egg.
- Supported by broad, round and uterosacral ligaments
- Regions: body (main portion), fundus (where the uterine tube enters) and cervix or neck of the uterus (a narrow outlet that protrudes into the vagina)
- Provides mechanical protection, nutritional support, and waste removal for the embryo (weeks 1–8) and foetus (>8 weeks)
- Contractions in the muscular wall are important in delivering the foetus at birth.
23
Q
What are the uterine wall (layer) (6)
A
- Endometrium: the inner layer that allows for implantation of a fertilised egg; sloughs off if no pregnancy occurs (menses)
- Myometrium: the middle layer of smooth muscle
Serous layer (perimetrium): outer visceral peritoneum - Uterine cavity, or uterine lumen - Large, superior cavity continuous with isthmus of uterine tube
- Internal os: **(os, opening or mouth)- opening connecting the uterine cavity to the cervical canal
- Cervical canal: **Constricted passageway at the inferior end of the uterine cavity; begins at internal os; ends at external os
- External os: **Curving vaginal opening into the uterus
24
Q
What is oogenesis (10)
A
- Formation and development of the oocyte
- Begins before birth the total supply of eggs present at birth, but the ability to release eggs begins at puberty.
- Occurs in the ovaries (ovulation occurs during the 28-day ovarian cycle)
- Oogenesis (and hence reproductive ability) ends at menopause.
- Nuclear events are the same as with spermatogenesis.
- Oocytes mature in developing ovarian follicles.
- Oogonia: female stem cells found in a developing foetus, which undergo mitosis to produce primary oocytes that are surrounded by cells that form primary follicles in the ovary
- Oogonia no longer exist by the time of birth.
- Primary oocytes are inactive until puberty.
- FSH causes some primary follicles to mature (rising FSH levels trigger the start of the ovarian cycle)
25
Q
What are the stages of the ovarian cycle (7)
A
- Primordial ovarian follicles in egg nest
- Formation of primary ovarian follicle
- Formation of secondary ovarian follicle
- Formation of a tertiary ovarian follicle
- Ovulation
- Formation of corpus luteum
- Formation of corpus Albicans
26
Q
What are the stages in the ovarian cycle of hormonal regulation (3)
A
- Release of GnRH: from the hypothalamus, which causes the production and secretion of FSH and production of LH
- The follicular phase of the ovarian cycle
- Luteal phase
27
Q
What is the menstrual (uterine cycle) (5)
A
- Cyclic changes of endometrium, regulated by cyclic production of oestrogens and progesterone
- Averages 28 days in length (range 21–35 days); first cycle (menarche) begins ~11–12 years of age; cycles continue until menopause (~45–55 years of age)
- Menses stage – functional layer of endometrium sloughed
- Proliferative stage: regeneration of functional layer
- Secretory stage: endometrium increases in size and readies for implantation
28
Q
What are the endometrial changes during the uterine cycle (3)
A
- Menstrual phase - the destruction of the functional layer
- Proliferative phase - repair and regeneration of functional layer
- Secretory phase - secretion by uterine glands
29
Q
What are the follicle stages during the ovarian cycle (5)
A
- Primary follicle
- Vesicular follicle
- Ovulation
- Corpus luteum
- Degenerating corpus luteum
30
Q
What are the key events of the ovarian and uterine cycles?
A
31
Q
What hormones are produced by the ovaries (4)
A
- Oestrogens: **Produced by follicle cells
- Oestrogens causes secondary sex characteristics (accessory organs enlargement, development of breasts, appearance of pubic hair, increase in fat beneath the skin, widening and lightening of the pelvis, onset of menses)
- Progesterone: **Produced by the corpus luteum
- Progesterone production continues until LH diminishes in the blood and helps maintain pregnancy
32
Q
What are the mammary glands (9)
A
- Present in both sexes but only functions in females
- Embedded in the subcutaneous tissue of the pectoral fat pad deep to the skin
- Has suspensory ligaments
- Glandular tissue divided into lobes (each lobe has several secretory lobules and each lobule is composed of secretory alveoli)
- Stimulated by sex hormones (mostly oestrogens) to increase in size
- Provide nourishment (milk) for developing infant
- Milk production (lactation) controlled by hormones released by the reproductive system and the placenta
- Located on the anterior chest, directly over the pectoralis major muscle
- Prolactin and oxytocin are the major hormones that promote lactation, although some other hormones could contribute. Prolactin is responsible for alveoli making milk, oxytocin promotes milk ejection and breast emptying
33
Q
What is the anatomy of the mammary glands (5)
A
- Areola: central pigmented areas
- Nipple: protruding central area of areola
- Lobes: internal structures that radiate around nipple
- Alveolar glands: clusters of milk-producing glands within lobules
- Lactiferous ducts: connect alveolar glands to nipple
34
Q
What are the stages of fertilisation (4)
A
- occurs when the genetic material of a sperm combines with that of an oocyte to form a zygote
- The oocyte is viable for 12 to 24 hours after ovulation; sperm is viable for 12 to 48 hours after ejaculation
- Membrane receptors on an oocyte pulls in the head of the first sperm cell to make contact; the membrane of the oocyte does not permit a second sperm head to enter
- Zygote: first cell of a new individual, results from fusion of DNA from sperm and egg; begins rapid mitotic cell divisions; zygote stage is in the uterine tube, moving towards the uterus
35
Q
What are the stages of embryonic development (5)
A
- Developmental stage from the start of cleavage until the ninth week
- The embryo first undergoes division without growth
- The embryo enters the uterus at the 16-cell state
- The embryo floats free in the uterus temporarily
- Uterine secretions are used for nourishment
36
Q
What are the initial stages of pregnancy (6)
A
- Blastocysts - Ball-like circle of cells
- Begins at about the 100 cell stage
- Secretes human chorionic gonadotropin (hCG) to produce the corpus luteum to continue producing hormones
- Contains trophoblast (large, fluid-filled sphere) and inner cell mass
- Primary germ layers formed – ectoderm, mesoderm, endoderm
- Late blastocyst implants in the wall of the uterus by day 14
37
Q
What are the stages of development after implantation (3)
A
- Chorionic villi (projections of the blastocyst) develop
- The embryo is surrounded by the amnion (a fluid-filled sac)
- An umbilical cord forms to attach the embryo to the placenta (placenta forms a barrier between mother and embryo, delivers nutrients and oxygen, removes wastes from embryonic blood, becomes an endocrine organ (produces hormones – oestrogen, progesterone, other hormones that maintain pregnancy))
38
Q
What are the stages of development of the foetus (beginning of the ninth week) (3)
A
- All organ systems are formed by the end of the eighth (8th) week
- Activities of the foetus are growth and organ specialisation
- A stage of tremendous growth and change in appearance
39
Q
What happens to the body from conception to birth (7)
A
- Enlargement of the uterus
- Relaxation of the pelvic ligaments and pubic symphysis due to production of relaxin
- An umbilical cord forms to attach the embryo to the placenta
- Kidneys have additional burden and produce more urine
- The uterus compresses the bladder
- Vital capacity and respiratory rate increase
- Body water rises, blood volume increases by 25-40%, blood pressure and pulse increase, varicose veins are common
40
Q
What are the stages of labour (9)
A
- oestrogen levels rise
- uterine contractions begin
- placenta releases prostaglandins
- oxytocin is released by the pituitary, combination of the hormones produces contractions
- Cervix becomes dilated
- Uterine contractions begin and increase
- The amnion ruptures
- Expulsion - Infant passes through the cervix and vagina
- Placental stage: delivery of the placenta
41
Q
How is positive feedback used in labour (7)
A
- baby moves deeper into the mothers birth canal
- Pressoreceptors in cervix of uterus excited
- Afferent impulses to hypothalamus
- Hypothalamus sends efferent impulses to prosterior pituitary where oxytocin is stored
- Prosterior pituitary releases oxytocin targets mothers uterine muscle
- Uterus responds by contracting more vigourously
- Positive feedback mechanism continues to cycle until interrupted by birth of baby.
