Reproductive System Flashcards
Define gonads and give examples for both sexes.
Organs where gametes a produced.
- testes produce spermatozoa
- ovaries produce oocytes
Define coitus and its function.
Sexual intercourse- enabling gametes to fuse and form an embryo.
What are the differences between the pelvic inlet and outlet (2)?
The inlet is open, while the outlet is closed by muscles. The inlet is larger than the outlet.
Name the two pelvic subdivisions, their location, and what they contain.
False/ greater pelvis- above pelvic inlet, containing GI organs
True/ lesser pelvis- below pelvic inlet, containing reproductive organs
Name three ways in which female and male pelvises differ.
Females have a broader subpubic angle.
Female- oval inlet, male- heart inlet
Females have a straighter coccyx, pointing more inferiorly, while males have a curved coccyx which points more anteriorly.
Describe the pelvic floor/ diaphragm.
Two muscles- levator ani and coccygeus- that close over the pelvic outlet.
Describe the male perineum.
An anatomical region inferior to the pelvic floor, between upper region of the thighs. Two divisions:
- urogenital triangle- includes urethral opening and external genitalia
- anal triangle- includes anal canal and fat
Name the two functions of the male reproductive system.
To produce spermatozoa, and to transport them into the female reproductive tract.
What structures does the scrotum enclose?
Two testes, two epididymides, and two spermatic cords (containing part of the ductus deferens).
What do testes produce (3)?
Spermatozoa
Testosterone
Inhibin
What are the testes surrounded by?
Tunica albuginea- dense fibrous capsule
In which structures of the testes are sperm produced?
Seminiferous tubules (1-4 within each lobule of the testes)
Where do sperm undergo maturation? Name the three parts of this structure.
Epididymis
Head, body, tail
Through which structures does sperm travel to get to the epididymis?
Seminiferous tubules join to form rete testis (series of canals), which join to form efferent ductules leading to the epididymis.
Name three cell types within the seminiferous tubules, and their functions.
Interstitial endocrine cells (in tissue surrounding tubules)- produce testosterone
Nurse cells- produce inhibin and support developing spermatozoa
Spermatogenic cells- spermatozoa at various developmental stages (get pushed into the lumen)
Which structure continues from the tail of the epididymis?
Ductus deferens
Where does the ductus deferens run?
- up and out of the scrotum
- through the inguinal cavity in the abdominal wall
- continues superior and posterior to the bladder
- dilates to form the ampulla
What covers the ductus deferens?
Smooth muscle Spermatic cord (until inguinal canal)
Which duct joins the ampulla to form the ejaculatory duct? And where does the ejaculatory duct open?
Duct from the seminal vesicle
Into the prostatic urethra
What is the function of the bulbourethral gland?
Produces a component of seminal fluid- along with the prostate gland and seminal vesicle
What causes retrograde ejaculation?
The internal urethral sphincter doesn’t close during ejaculation, so sperm ends up in the bladder.
Where do the epididymides join to the testes?
At their posterior borders
Why is the scrotum located outside the body?
Because it holds the testes which need to maintain a temperature of 34 degrees celsius- slightly lower than internal body temperature.
Which muscle lines the scrotum, and what is its function?
Dartos muscle
Contracts to wrinkle the skin and reduce the SA for heat exchange
Which muscle surrounds the testes and spermatic cord? What occurs when it contracts?
Cremaster muscle
Brings testes closer to the body for heat conservation
Where does the spermatic cord run, and what does it contain?
From the testes to the abdomen.
Ductus deferens, testicular arteries and veins (venous plexus), nerves, lymphatics
Where does the spermatic cord run, and what does it contain?
From the testes to the abdomen.
Ductus deferens, testicular artery, venous plexus, nerves, lymphatics
What are the two functions of the penis?
Urination
Copulation- transporting sperm into female reproductive tract
Name the three parts of the penis.
Root/ bulb (attaches penis to the body wall)
Body (motile)
Glans
What covers the glans of the penis?
Prepuce/ foreskin
Which region separates the body and the glans of the penis?
Neck of glans
Which state of the penis are the ventral and dorsal terms based on?
Erect state
Describe the three erectile tissues of the penis.
2 corpora cavernosa (one on each side)
- main erectile tissue, on dorsal aspect
1 corpus spongiosum
- contains urethra, forms bulb and glans, on ventral aspect
Why are the corpora cavernosa the main erectile tissue of the penis?
Because the corpus spongiosum contains the urethra, and further erectile movement may block it off.
Which three accessory glands produce seminal fluid? Name the components they produce and their functions.
Seminal vesicles- alkaline viscous secretion (60% of semen) protects sperm against acidic environment in urethra and vagina
Prostate gland- slightly acidic, milky fluid (30% of semen) contributes to sperm activation, viability and motility
Bulbourethral glands- secretion (5% of semen) lubricates and neutralises acidity in urethra prior to ejaculation
Where are the seminal vesicles located?
Posterior to the bladder, lateral to the ampulla.
Where is the prostate gland located?
Inferior to bladder, wraps around prostatic urethra.
Which protein is secreted by the prostate gland?
PSA prostate-specific antigen
Where are the bulbourethral glands located?
In the urogenital diaphragm, opening into the penile urethra.
Describe a vasectomy.
A surgical method of sterilisation in males which involves cutting the ductus deferens- has no effect on volume of seminal fluid (-5% on volume of semen).
Define gametogenesis. What is it called in each sex?
Formation of gametes.
Females- oogenesis
Males- spermatogenesis
What is the basis of spermatogenesis?
Spermatogonia maturing into spermatozoa via mitosis and meiosis.
When and where does spermatogenesis occur?
From puberty onwards, in the seminiferous tubules.
Describe spermatogenesis 1.
Mitosis divides spermatogonia (stem cell) into 2 diploid daughter cells. One stays at the basement membrane of the seminiferous tubule (type A) while the other moves away (type B).
Describe spermatogenesis 2.
Type B spermatogonia differentiates into a diploid primary spermatocyte which undergoes meiosis I to form 2 haploid secondary spermatocytes.
Describe spermatogenesis 3.
Secondary spermatocytes undergo meiosis II to form 4 haploid spermatids, which differentiate into spermatozoa by spermiogenesis. Spermatozoa are released into the lumen.
What changes to the spermatids as they undergo spermiogenesis to become spermatozoa?
- nucleus condenses into head of spermatozoon
- (enzyme-containing) acrosomal vesicle becomes acrosome
- lots of mitochondria form to produce ATP for tail production
- excess cytoplasm is discarded
Define gonadotropin.
A hormone that acts on the gonads.
Describe two male gonadotropins, and their stimulus.
LH luteinizing hormone- AP
FSH follicle stimulating hormone- AP
GnRH gonadotropin releasing hormone- hypothalamus
What does luteinizing hormone stimulate?
Production of testosterone in interstitial endocrine cells (connective tissue surrounding seminiferous tubules).
Which two hormones control spermatogenesis?
Testosterone and follicle stimulating hormone.
What does FSH stimulate?
Production of inhibin in nurse cells (within seminiferous tubules).
Describe negative feedback of gonadotropins (male).
Inhibin suppresses follicle stimulating hormone.
Testosterone suppresses luteinizing hormone and gonadotropin releasing hormone.
Name four functions of the female reproductive system.
- produce oocytes
- transport ova (ovulated oocytes) and spermatozoa to the fertilisation site
- provide a protective and nourishing site for the developing embryo and foetus to grow
- deliver the foetus
How does the female perineum differ to the male perineum?
In the urogenital region, instead of the penis and scrotum, it has the vulva- includes vaginal and urethral orifices.
Which structures does the vulva incorporate (5)?
- mons pubis
- labia majora and minora
- vestibule
- vestibular glands
- clitoris
Define the mons pubis.
A fatty tissue layer covered in thick pubic hair that sits anterior to the pubic symphisis.
What’s the difference between the labia minora and majora?
The labia minora sit more medially and are smaller.
Define the vestibule of the vulva.
Space between the labia minora, contains the vaginal orifice.
Name the position of the vestibular glands, the two types, and their functions.
Deep to the labia.
- lesser vestibular glands- lubricate and moisten the anterior area of the vestibule
- greater vestibular glands- lubricate the vagina when female is aroused, can be seen next to vaginal orifice
Define the clitoris and name its four parts.
A complex erectile organ. Consists of:
- glans
- body (erectile)
- 2 crura (erectile)
- 2 bulbs (erectile)- sit adjacent to the greater vestibular glands
Name the five structures of the female reproductive tract.
- ovaries
- uterine tubes
- uterus
- cervix
- vagina
Name the three portions of the uterine tube, and describe their shapes and locations.
- infundibulum (funnel shape with finger like projections): most lateral
- ampulla (dilated area where fertilisation occurs): mid-portion
- isthmus: most medial portion, opens into lumen of uterus
Define the terms fundus, body, cervix, and fornix.
The uterus is split into two parts: the body and the cervix. The fundus is the dome-shaped region at the most superior part of the body. The cervix, most inferior, protrudes into the vagina. The fornices are arches in the vagina adjacent to the protrusion of the cervix.
What is the position of the uterus in reference to the bladder?
Anti-flexed- curves up and over the superior portion of the bladder.
Name the three layers of the uterus, and describe their composition.
Perimetrium- connective tissue
Myometrium- smooth muscle
Endometrium- columnar epithelium, uterine glands, and arteries
Name the two layers of the endometrium.
Functional layer (grows and is shed every menstrual cycle) Basal layer
Name three components of the cervix.
Internal os- opening of cervix into body of uterus
Cervical canal
External os- opening of cervix into vagina
Name two functions of the cervix.
Produces cervical mucus
Regulates sperm transport
How does the texture of cervical mucus change around ovulation?
During ovulation: more watery to allow sperm into the uterus
After ovulation: more viscous to prevent infection and entry of sperm
Which organs surround the vagina?
Anteriorly- bladder
Posteriorly- rectum
Superiorly- cervix (uterus)
Inferiorly- perineum
Which feature of the vagina allows it to be distensible?
Rugae- folds that can flatten out to increase volume of vaginal canal to allow the penis to enter during insemination
Describe the path of blood supply from the aorta to the endometrium.
Internal iliac –> uterine artery –> arcuate arteries –> radial arteries –> straight arteries (supply basal layer) and spiral arteries (supply functional layer)
Which arteries supply the ovaries and vagina?
Ovarian arteries, arising from the abdominal aorta.
Vaginal artery, arising from the internal iliac
Describe the location of the ovaries.
Lateral and posterior to the uterus, in the lateral portion of the true/ lesser pelvic cavity.
Name the two components of the ovary, and their composition.
Cortex (outer)- follicles
Medulla (inner)- connective tissue, blood/ lymphatic vessels, nerves
Which two processes occur in the ovaries?
Hormone production and oogenesis.
Describe the stages of the follicle during oogenesis.
Oocytes develop within follicles (in the cortex) in the ovary. The follicle is a layer of cells that grows and develops with the oocyte.
Primordial ovarian follicle –> primary ovarian follicle –> secondary ovarian follicle –> tertiary ovarian follicle
The tertiary ovarian follicle releases the oocyte, and differentiates into a corpus luteum, and finally degrades into a corpus albicans if fertilisation doesn’t take place.
Name the four ligaments of the female reproductive system, and their locations.
Broad ligament
Ovarian ligament- extends from ovary to the uterus
Suspensory ligament- extends from lateral surface of the ovary to the pelvic wall (includes ovarian artery)
Round ligament- starts adjacent to uterine tube entry of the uterus, and extends laterally and inferiorly through the inguinal canal to the labia majora
Describe the three parts of the broad ligament.
- mesometrium- where the two peritoneum layers fold and meet adjacent to the uterus
- mesosalpinx- where the two peritoneum layers fold and meet inferior to the uterine tube
- mesovarium- where the two peritoneum layers fold and meet superior to the ovary
Name the two pouches next to the uterus where the peritoneum does not reach. What is their function?
Anterior (between bladder and uterus)- vesicouterine pouch
Posterior (between uterus and rectum)- rectouterine pouch
To provide extra space for the uterus to expand when the foetus is developing.
Describe the location and function of the breasts. Which hormones stimulate their development?
Superficial to the pectoralis major muscles. Nourish infants. Estradiol and progesterone (during pregnancy and puberty).
Describe the structure of the breast.
15-20 lobes which are separated by suspensory ligaments and adipose tissue. Each lobe is made up of lobules which consist of secretory alveoli. Milk secreted from the alveoli is released into the lactiferous ducts –> lactiferous sinuses which open at nipple pores.
Describe the part of oogenesis that occurs before birth.
- oogonia (female germ cells) undergo mitosis to increase oogonium population
- they differentiate into primary oocytes encased into primordial follicles
- primary oocytes start meiosis I, halting at prophase I until puberty
Describe oogenesis between menarche and menopause.
- small number of follicles recruited each menstrual/ ovarian cycle (only dominant follicle oocyte will be ovulated)
- primary oocyte completes meiosis I, forming a secondary oocyte and a polar body
- secondary oocyte starts meiosis II, halting at metaphase II
- sperm penetrates plasma membrane of secondary oocyte and meiosis II resumes, forming an ovum (fertilised) and a second polar body
Describe a polar body.
Second cell formed during meiosis in oogenesis. Three form for each ovum produced.
- division of cytoplasm isn’t equal, and polar body doesn’t contain the organelles it needs to survive (undergoes atresia)
Name the two cell types in the developing follicle containing the oocyte. Which is the corona radiata made of? Name the hormone they produce.
Granulosa cells- estradiol
Theca cells
Corona radiata are the granulosa cells surrounding the oocyte within the antrum of the follicle.
Name the hormones involved in female reproduction (6), where they are released, and what they stimulate.
GnRH- hypothalamus, release of gonadotropins (LH and FSH)
LH- anterior pituitary, formation of corpus luteum + ovulation
FSH- anterior pituitary, growth of ovarian follicles
Estradiol- developing follicles, assists follicle growth, bone and muscle growth, endometrial growth, secondary sex characteristics (breasts), AP feedback
Inhibin- granulosa cells, suppress FSH via negative feedback to AP
Progesterone- corpus luteum, endometrial maturation, maintaining pregnancy, suppress GnRH via negative feedback
Name the phases of the ovarian cycle, and their days.
Follicular/ preovulatory phase- 1 to 14
Luteal/ postovulatory phase- 15 to 28
Describe the follicular/ preovulatory phase of the ovarian cycle.
- increased FSH stimulates follicle growth
- decreased FSH due to negative feedback from inhibin and low levels of estradiol- produced from growing follicles
- all but dominant follicle undergo atresia
- dominant follicle secretes
Describe the follicular/ preovulatory phase of the ovarian cycle.
- increased FSH stimulates follicle growth
- decreased FSH due to negative feedback from inhibin and low levels of estradiol- produced from growing follicles
- all but dominant follicle undergo atresia
- dominant follicle secretes large amounts of estradiol, stimulating surge in LH –> stimulates final stages of oogenesis (meiosis II and ovulation)
Describe the luteal/ postovulatory phase of the ovarian cycle.
- LH stimulates differentiation of follicular cells into the corpus luteum
- Corpus luteum secretes progesterone, estradiol, and inhibin which inhibit FSH and LH via negative feedback to hypothalamus and AP (preventing folliculogenesis)
- if fertilisation does not occur, corpus luteum undergoes luteolysis, causing a fall in progesterone and estradiol, so FSH and LH levels rise back up
Name the phases of the menstrual/ endometrial cycle, and their days.
Menstrual- 1 to 14, before proliferative
Proliferative- 1 to 14, after menstrual
Secretory (incl. premenstrual)- 15 to 28
Describe the menstrual and proliferative phases of the menstrual/ endometrial cycle.
- endometrium breaks down and bleeds from spiral arterioles (menstrual)
- increasing estradiol levels (from dominant follicle) stimulate rapid endometrial growth including glands and blood vessels
Describe the secretory phase of the menstrual/ endometrial cycle.
- progesterone secreted by corpus luteum promotes endometrial maturation- glands become secretory and spiral arterioles grow and coil
- if fertilisation does not occur, progesterone levels fall (corpus luteum atrophies) so endometrium breaks down and bleeds- menstruation
Define intromission and insemination.
Intromission = introduction of erect penis into the vagina Insemination = release of sperm into the upper part of the vagina, so they can travel to the appropriate fertilisation site
Define smegma.
Secretion of sebaceous glands on the prepuce and glans of the penis that lubricates and allows movement of the prepuce over the glans.
Describe the cellular structure of the erectile tissues of the penis.
Trabeculae consisting of smooth muscle fibres, surrounding lacunae (cavernous spaces).
Name the layers of fascia surrounding the erectile tissues.
Tunica albuginea- one surrounds the corpora cavernosa, one surrounds the corpus spongiosum
Deep fascia
Superficial fascia
What’s different about the tunica albuginea surrounding the corpus spongiosum?
Isn’t as compact- so doesn’t place too much pressure on the urethra during erection.
Describe what happens within the erectile tissues during erection, and how the erection is maintained.
Deep artery dilates, blood fills lacunae, smooth muscle of trabeculae relaxes, and pressure is placed on the surrounding fascia. Erection is maintained because the venous plexus is blocked by pressure, decreasing blood being drained.
Which artery feeds the male perineum and external genitalia, and where does it arise from?
Internal pudendal artery
Abdominal aorta –> common iliac –> internal iliac –> internal pudendal
Why does the testicular artery arise so high in the abdominal aorta?
The testicles start development up in the abdomen before descending through the inguinal canal to the scrotum.
Name the branches of the internal pudendal artery to the penis, and their locations.
Artery supplying the bulb Urethral artery (in corpus spongiosum) Dorsal artery (dorsal to the erectile tissues) Deep artery (in corpora cavernosa)
Describe the nervous supply of the penis (2).
- pudendal nerve supplies sensory and somatic motor innervation to perineum and external genitalia (dorsal nerve to penis)
- autonomic (both SNS and PNS) innervation from pelvic plexus to penis
Name the stages of the male sexual act, and the nervous system regulating them.
Erection- PNS Ejaculation: - emission- SNS - expulsion- SNS + motor Resolution- SNS
What stimulates the PNS response of erection?
Visual and tactile stimuli, memories etc.
What other response does the PNS stimulate during erection?
Secretion of bulbourethral fluid from the bulbourethral gland- mucus secretion to help clear out the urine and neutralise acidity prior to ejaculation.
Describe the SNS response during emission of the male sexual act.
Smooth muscle of ductus deferens contracts (peristalsis) to move sperm into ampulla. Smooth muscle of ampulla, seminal vesicles and prostate gland contract to move the sperm and seminal fluid into the urethra.
Describe the SNS and somatic responses during expulsion of the male sexual act.
SNS: contraction of internal urethral sphincter, additional secretions from prostate gland and seminal vesicles
Somatic: bulbospongiosus muscle contracts and rhythmically compresses root of penis, expelling semen
Describe the SNS response during resolution of the male sexual act.
Internal pudendal artery constricts, trabecular muscles contract to squeeze blood from erectile tissues, penis becomes flacid/ detumescent.
Describe the stages of the female sexual response.
- engorgement of clitoris, labia, and vagina (autonomic stimulation)
- lubricating fluid secreted through vaginal wall, mucus secreted into vestibule by greater vestibular glands
- vagina increases in width and length, uterus elevates upwards
- rhythmic contraction of vaginal, uterine, and perineal muscles
Define zygote.
Fertilised oocyte/ ovum.
Name three natural methods of contraception.
Rhythm method/ periodic abstinence
Withdrawal method/ coitus interruptus
Lactational infertility
Name two barrier methods of contraception.
Caps/ diaphragms
Condoms
Name four steroidal contraceptives for women.
Oral contraceptive pill (estrogen and progestin)
Progesterone-only pill
Subdermal implant
Intrauterine device
How does the oral contraceptive pill prevent pregnancy?
Suppresses ovulation by affecting negative feedback loops to hypothalamus and pituitary –> no LH and FSH secretion –> no follicle development
Stimulates more viscous mucus production from cervix
What are the effects of progesterone-only pills and subdermal implants?
Progesterone-only pill: more viscous cervical mucus
Subdermal implant: disrupts follicular growth and ovulation via feedback loops
Describe the effects of IUD types.
Copper- causes low-grade inflammation that reduces sperm transport, is toxic to oocytes and zygotes
Hormonal- contains progestins that affect cervical mucus to reduce sperm transport, and may prevent ovulation
Name the sterilisation method in females.
Tubal ligation
