Block IX - Reproductive Flashcards
23. Male reproductive physiology 24. Female reproductive physiology
What gene is responsible for regression of Mullerian ducts during sex differentiation in males?
The sry gene
When does capacitation occur normally?
Upon exposure to the fluid environment of the female reproductive tract
What is the pharmacological mechanism of currently available medication for treatment of ED?
Inhibiting the action of phosphodiesterase type 5
What is the target of LH secreted by anterior pituitary?
Leydig cells
What enzyme catalyzes the reaction in which testosterone is converted into dihydrotestosterone?
5-alpha reductase
How many haploid oocytes and polar bodies are formed upon the completion of meiosis in women?
One haploid oocyte and 2 polar bodies
In each menstrual cycle a cohort of follicles will be stimulated to develop but usually only one follicle will ovulate. Why does this follicle become dominant?
It is the first follicle in this cycle to convert androgens secreted by theca cells to estrogens, which have a negative feedback on gonadotropins
What is the proper sequence of events in the menstrual cycle?
Estrogen peak, LH peak, first polar body, ovulation
What determines the length of time between from ovulation to menses in a non-pregnant cycle?
The life span of the corpus luteum
Which hormonal changes take place during pregnancy?
hCGpeaks around 70 days then declines, progesterone and estradiol increase
What will happen if the Sertoli blood barrier in the testis is damaged?
There most likely will be an immune reaction and sperm antibodies will form which may interfere with sperm function
What is the function of Wolffian duct?
In the developing fetus, the continued presence of Wolffian ducts will lead to male sexual development
What does the first meiotic division result in during spermatogenesis?
Secondary spermocytes
What does the transport of sperm into the vas deferens depend on?
The pressure exerted by the Sertoli cells which are continuously secreting fluid
What is the mechanism of erection in the penis?
Arteries releasing NO, which relax the arterial smooth muscle, thereby facilitating blood flow into the corpora cavernosa
How do hormones control spermatogenesis in males?
Pulsatile secretion of GnRH by the hypothalamus stimulates FSH and LH release from the anterior pituitary. LH acts on Leydig cells to stimulate secretion of testosterone, while FSH acts on Sertoli cells to stimulate spermatogenesis
What is the correct sequence of stages during oogenesis?
Oogonium, primary oocyte, secondary oocyte, ovum
What is responsible for completion of the first meiotic division in the female?
Midcycle LH surge
Which hormones are produced by the corpus luteum after the ovum is expelled from the follicle?
Estrogen, progesterone, inhibin
Which hormone prevents the regression of the corpus luteum during the early stages of pregnancy?
hCG produced by the conceptus
What is the major hormone responsible for inducing contractions during parturition?
Oxytocin
Which hormone is released at the highest level at the delivery time?
Estrogen
How many copies of chromosomes per cell are in primary oocytes stage?
2
During the menstrual cycle (if fertilization does not occur), which day marks the transition from follicular phase to luteal phase?
14
What is the function of inhibit?
Acts on the pituitary to inhibit the secretion of FSH
Which hormone does the leydig cells in the testis primarily secrete?
Testosterone
What is the physiological event that characterizes menopause?
Primary ovarian failure
Is the ovulatory phase among the changes in the uterus during the menstrual cycle?
No
What is the function of Sertoli cells in the testes?
Secretion of luminal fluid, providing nutrients to developing sperm cells, secretion of that anti-Muellerian hormone, secretion of androgen-binding protein, secretion of inhibin
From where is gonadotropin releasing hormone GnRH secreted?
Hypothalamus
What is the earliest hormonal indicator of pregnancy?
Increase in chorionic gonadotropin, hCG peaks at around day 70 then declines, progesterone and estradiol increase
Which enzyme facilitates the reaction that converts testosterone to estrogen in the brain?
Aromatase
Why is the lifespan of the corpus luteum expanded during early pregnancy?
The conceptus produces human chorionic gonadotropin
Which hormone controls the milk ejection reflex?
Oxytocin
Which hormone controls milk synthesis?
Prolactin
What is the sequence of developmental stages during spermatogenesis?
Spermatogonia, primary spermatocyte, secondary spermatocyte, spermatids, spermatozoa
Is spermiation part of the developmental stages during spermatogenesis?
No. Spermiation refers to the release of mature spermatozoa from the Sertoli cells
