Flashcards in Yan Male Deck (135)
How many seminiferous tubules are there in a man?
900 seminiferous tubules
How long is the epididymis?
When does spermatogenesis begin?
@ puberty-->like @ ages 12-14.
What are the 3 phases of spermatogenesis?
1.Mitotic spermatogonial proliferation & differentiation
2. meiotic division of spermatocytes into spermatids
3. Haploid differentiation & morphogenesis of spermatids into spermatozoa
Roughly describe the process of spermatogenesis.
Basal membrane w/ developing primordial germ cells
PGM becomes spermatogonia
Spermatogonia multiply in number via mitosis
Spermatogonia become primary spermatocytes.
Primary spermatocytes enter meiosis I so that they can become haploid...become secondary spermatocytes.
Secondary spermatocytes via meiosis II become spermatids.
Spermatids differentiate into mature sperm.
How long does spermatogenesis take in humans?
Where does estrogen come from in men?
aromatized from testosterone in Sertoli cells
Why is reabsorption of luminal fluid in the epididymis important?
b/c then sperm can enter the epididymis concentrated, rather than dilute.
T/F ERß on spermatogonia, spermatocytes & Sertoli cells may mediate the actions of xenoestrogens (‘estrogenic endocrine disruptors’)
True. I have no idea why.
What are xenoestrogens?
estrogenic endocrine disruptors
Where are growth factors released from in the male? What is their effect?
secreted from Sertoli or germ cells
act on germ cells or somatic cells via their receptors
When FSH binds to Sertoli cells...what happens in terms of GH?
GH is released
this drives the development of germ cells
Stem cell-->meiotic cell-->haploid cell-->sperm
Describe negative feedback w/ testosterone production & w/ inhibin.
Testosterone produced by Leydig cells. When there is too much-->negative feedback to anterior pituitary & hypothalamus.
Inhibin is produced by Sertoli cells. It exerts negative feedback on anterior pituitary & hypothalamus.
Describe the maturation of the sperm in the epididymis.
120 million sperm are developed each day.
No motility when the sperm is in the head of the epididymis.
Some motility when the sperm is in the body of the epididymis.
Moderate motility when the sperm is in the tail of the epididymis.
What is the name for the head, body, & tail of the epididymis?
What happens to the sperm when it is in the vas deferens?
this is a place where it can be stored for over a month w/ suppressed motility
Describe the difference in the sperm's swimming pattern in the male v. in the female.
male: elegant swimming w/ equal peaks & valleys
female: goes crazy! more forceful, can penetrate mucus & make it to the secondary oocyte
T/F The sperm are more motile in the male right before ejaculation than in the female.
there is an initial ejaculation motility
then there is hyper activated motility in the female.
What is better for a sperm to swim in: neutral/alkaline environment or acidic environment?
Alkaline environment, greater motility
How long can the sperm typically survive in the female reproductive tract?
What is the function of the seminal vesicles?
secrete mucus that empties into the ejaculatory duct...rich in:
fructose (nutrition for the sperm)
prostaglandins (aid fertilization)
How does female orgasm help w/ fertilization?
it causes contraction & prostaglandin release...negative pressure that sucks sperm in
How does the prostate gland add fluid to the semen?
during emission it contracts w/ the vas deferens
What is roughly the pH of the prostate gland secretions? Why is this important?
They are roughly acidic, this is to neutralize the basic secretions of the seminal vesicles
What types of substances are contained in the prostate gland secretions?
What are the 4 sources that contribute to semen fluid? What percentage does each contribute?
vas deferens (10%)
seminal vesicles (60%)
prostate gland (30%)
bulbourethral glands (small amt)
How long can sperm last if they are properly preserved?
years via cryopreservation
What is the pH of semen fluid?
What is the appearance of semen?
coagulum that dissolves in 15-30 minutes