Reproductive Physiology Flashcards
What are the phases and days of the ovarian cycle?
Follicular phase (days 1-13) - Ovulation (day 14) - Luteal phase (days 15-28)
Which pituitary and ovarian events occur during the follicular phase?
Several follicles reach secondary stage, but FSH causes the dominant follicle to mature to a tertiary follicle. The dominant follicle produces oestrogen, which causes FSH levels to lower, causing degeneration of the other follicles, which are then reabsorbed.
Which pituitary and ovarian events occur during the ovulatory phase?
Increases levels of oestrogen peak and cause an LH surge. This causes the primary oocyte in the dominant follicle to complete the first meiotic division, forming a secondary oocyte and polar body. Follicle then ruptures and the mature oocyte is then released, alongside nourishing granulosa cells. Ovulation occurs 12 hours after the LH surge
Which pituitary and ovarian events occur during the luteal phase?
After ovulation, the ruptured follicle forms the corpus luteum. Granulosa cells in this secrete progesterone, oestrogen and relaxin - these inhibit FSH release to prevent further follicle development. If pregnancy does not occur, the corpus luteum degenerates and progesterone levels decrease - allowing the follicular phase to then occur again after 14 days. Menstruation (luteolysis) occurs 14 days after ovulation.
The upper 2 thirds, or functional layer, of endometrium is responsive to which hormones?
Oestrogen and progesterone - these cause the structural changes required for pregnancy
What effect does oestrogen have on the endometrium?
Stimulates endometrial growth
What effect does progesterone have on the endometrium?
Matures the endometrium
Which endometrial events occur during proliferative phase (days 5-14)?
Oestrogen from the dominant follicle induced growth of endometrial glands and stroma. Also causes thickening of cervical mucous
Which endometrial events occur during luteal/secretory phase (days 15-28)?
After ovulation, progesterone from the corpus luteum causes decidualisation. This stops the proliferation of endometrial cells, and causes it to differentiate and mature. Also induces glandular secretory activity - glands dilate and become engorged, allowing it to nourish a potential embryo.
Which endometrial events occur during menstruation (days 1-5)?
Decreasing levels of oestrogen and progesterone at the end of the previous cycle, and outgrowing the blood supply leads to apoptosis of the cells in the functional layer. This results in shedding, leaving only the thin basal layer.
What volume of blood is secreted per menstruation?
<80 ml
True or False: clots, ‘flooding’ into clothes, anaemia are normal for menstruation
False
What range of number of days is thought of as normal for a menstrual cycle?
21-35 days
True or False: Intermenstrual Bleeding (IMB) and Post-Coital Bleeding (PCB) is normal
False
How long do sperm live in the female genital tract?
5 days
How long do ovum survive in the female genital tract?
17-24 hrs
What drives the proliferative phase of the uterine cycle?
Oestrogen produced by the granulosa cells
What drives the secretory phase of the uterine cycle?
Progesterone produced by the granulosa cells
What is the point of the secretory phase?
To produce an endometrium that is ready to support fertilised egg.
(*2) What two things grow during the proliferative phase?
(*2) Glands and stroma
How does the endometrium look during the secretory phase?
No mitoses, and quite curvy-looking glands. Become saw-toothed and irregular.
What is the default sex in reproductive development?
Female, as this is what it differentiates into without the SRY gene on the Y chromosome
Which ducts remain in development of the male reproductive system?
Wolffian
Which ducts remain in development of the female reproductive system?
Mullerian
If there is no sensitivity to the action of testosterone, for example in Androgen Insensitivity Syndrome, what happens during development of male reproductive system?
Testes develop but do not descend. Androgen induction of Wolffian duct does not occur, mullein inhibition does occur. Therefore - born phenotypically external genitalia female, absence uterus and ovaries, with short vagina
What are the roles of the sertoli cells?
Generally a support cell: supports sperm and prevents infection
- Form a blood testes barrier (protects sperm from antibody attack)
- Provides nutrient for developing cells
- Phagocytosis
- Secrete seminiferous tubule fluid
- Secrete androgen binding solution (binds testosterone so levels remain high)
- Secrete inhibit and active (regulates FSG secretion and spermatogenesis)
What is the action of luteinising hormone in males?
Acts in leydig cells regulating testosterone secretion
What is the action of FSH in males?
Acts on sertoli cells to enhance spermatogenesis
Which hormone regulates LH and FSH secretion via negative feedback?
Inhibin and testosterone regulate it, and GnRH stimulates it
Which cells produce testosterone?
Leydig cells
What is the action of testosterone before birth?
Masculinises reproductive tract and promotes descent of testes
What is the action of testosterone during puberty?
promotes puberty and male characteristics (growth and maturation male reproductive system)
What is the action of testosterone as an adult?
Controls spermatogenesis, secondary sexual characteristics (male body shape, deep voice, thickens skin), libido, penile erection,? aggressive behaviour
Which cell secretes inhibit and activin?
Sertoli cells
What is the function of the seminal vesicles?
Produces seminal fluid which supports the sperm in semen: fructose, prostaglandins (stimulate motility), fibrinogen (clot precursor)
What is the function of the prostate gland?
Produces alkaline fluid (neutralizes vaginal acidity), and clotting enzymes to clot semen within female
What is the function of the bulbourethral glands?
Secretes mucous to act as a lubricant
what is the route of sperm?
Seminiferous tubules > epidermis > vas deferens > ejaculatory duct > urethra > penis (SEVEN UP)
