4_5MaleReproductive Flashcards
How much of semen is contributed by the prostate?
30%
How much of semen is contributed by the seminal vesicles?
60%
Describe the characteristics of prostate gland secretions?
thin, milky, and slightly alkaline
What are the contents of prostate gland secretions?
1) clotting factors; 2) profibrinolysin; 3) ca, citrate, po4
pH of vas deferens
3.5-4
pH of vagina
3.5-4
pH at which sperm motility is active?
6+
What is the function of prostate gland secretion?
activating sperm motility
What are the components of seminal vesicle secretions?
1) fibrinogen, 2) alkali, 3) fructose, citric acid, nutrients; 4) PGs
What is the function of PGs of semen?
1) receptive cervical mucous for good motility; 2) reverse peristalsis in uterus and fallopian tubes
How much of semen is contributed by the bulbourethral glands?
5%
What are the components of the bulbourethral secretions?
mucous (right before ejaculation) for neutrilizing pH of urethra/vagina
What are the accessory glands of the male repro system?
1) prostate, 2) seminal vesicles, 3) bulbourethral glands
Where does spermatogenesis occur?
seminiferous tubule
Where does spermiogenesis occur?
rete testis
What are the 3 phases of the male sex act?
1) erection, 2) lubrication, 3) emission and ejaculation
Describe the structure of sperm
head, neck, body, tail
What is the function of the acrosome?
supply of hyaluronidase and proteolytic enzymes
What is the function of the sperm body?
rich in mitochondria for motility
What is the function of the tail?
corkscrew movement for propulsion
Describe the composition of the sperm tail.
microtubules
Where do sperm mature?
epididymis
Where are mature sperm stored?
vas deferens
How long do sperm live in the female tract?
1-2 days
How fast do sperm move?
1-4 mm/min
What is the zona pellucida?
granulosa cells surrounding the ovum
When and for how long does male puberty occur?
9-14 yo lasting 2-4.5 years
What is the first sign of male puberty?
testes enlargement (2.5+ cm)
Where is inhibit secreted?
sertoli cells
How long does spermiogenesis take?
21 days
Describe the timeframe and production rate of spermatogenesis.
constant 74 day process making 10^8 spermatids per day
What is spermiogenesis?
the change from spermatid to spermatozoa
How long does it take for a spermatozoa to mature in the epididymis and gain motility?
18-24 hours
What is the corpus spongiosum?
spongy tissue surrounding the urethra
What is the corpus cavernosum?
there are 2 cavernosa that surround central arteries
What occurs during the erection phase?
parasympathetic system dilates erectile tissue
What occurs during the lubrication phase?
parasympathetic system stimulates urethral and bulbourethral mucous secretions
What occurs during emission?
sympathetic stimulation causes 1) vas deferens contracts to propel sperm into urethra; 2) seminal glands and prostate empty and mix with mucous
Where does capacitation occur and why does it occur?
in vagina; required for mature sperm to be able to fertilize
How is the zona pellucida held together?
hyaluronic acid
Describe the steps in the acrosomal reaction.
1) sperm binds specific zona pellucida receptors; 2) acrosome membrane dissolves to release enzymes; 3) pathway for fertilization opened; 4) blockage to polyspermy
Describe the steps in capacitation.
1) fibrinogen clot near cervix digested by slow-acting fibrinolysin; 2) loss of inhibitory factors from male; 3) depletion of acrosomal cholesterol; 4) increased membrane Pe to Ca++ increases flagellum activity and initiates acrosome reaction
What happens when the sperm’s membrane becomes more permeable to Ca++ during capacitation?
increased tail activity and initiation of acrosome reaction
How long does it take for fibrinolysin to act?
15-30 min
What causes the clot near the cervix?
fibrinogen + prostate’s clotting factors
Where is gonadal testosterone synthesized?
leydig cells
How does testosterone circulate in the plasma?
bound to sex steroid binding globulin
Describe the circulating [testosterone] over lifetime.
high in fetal/neonatal patients for 1 year; then peak in puberty and decline at 50 yo
What is the most active form of testosterone?
dihydrotestosterone (DHT)
How is testosterone excreted?
converted to weak androgens or glucuronidated/sulfated then peed out
What is the fate of testosterone in tissues?
converted to DHT by 5-alpha-reductase
What causes testical enlargement in puberty?
trophic effects of FSH and LH on seminiferous tubules and Leydig cells
When is inhibin secreted?
when spermatogenesis rate is fast
What is the effect of FSH?
acts on sertoli cell to stimulate spermatogenesis
What is the effect of LH?
acts on Leydig cell to stimulate testosterone synthesis
What kinds of hormones are LH/FSH?
glycoproteins
What are the effects of testosterone?
binds androgen receptor to: 1) cause primary sex characteristics and testical descent (3rd trimester) in fetus; 2) cause secondary sex characteristics; 3) increase BMR; 4) increase BMR
What is the concentration of RBCs in males?
700,000/mL
What do Sertoli cells do?
nursemaid cells that support spermatogonia (spermatogenesis) and secrete inhibin
Describe feedback regulation of the HT-Pituitary-Testicular axis.
1) testosterone: -AP, -HT, +Sertoli (inhibin); 2) inhibin: -AP, -HT
To which receptors to LH/FSH bind?
G-alpha-s
What is andropause?
a slow decline in 2ndary sex characteristics beginning in 40s and 50s; LH constant but FSH increases with aging
What are causes of premature ejaculation?
anxiety and learned behavior
What are treatments for premature ejaculation?
BMOD, SSRIs
In what population is ED most prevalent?
40-70 years (52%)
What are causes of ED?
1) vascular disease, 2) radiation/surgery for prostate cancer, 3) spinal cord injury, 4) stress, 5) drugs
What drugs can cause ED?
diuretics, antidepressants, antilipidemics, antihypertensives, tranquilizers, hormones, EtOH, cocaine, marijuana
What drugs treat ED?
sildenafil, tadalafil, vardenifil
When are PD5-I’s C/I?
recent MI or stroke since PDE-5 is in heart
What are ADRs of PDE5-I’s?
congestion, flushing, dizziness, dyspepsia
What is eunichism?
loss of testes before puberty
What is hypogonadism?
when a non-functional testes during fetal life gives no primary sex characteristics
What are causes of hypogonadism?
1) eunichism, 2) castration after puberty, 3) hypothalamic eunichism
What is benign prostatic fibroadenoma?
BPH leading to urinary obstruction NOT caused by testosterone
What are the two types of testicular cancers?
1) interstitial cell tumor, 2) germinal epithelial tumor
Describe the development of prostate cancer.
Initiation somehow, then testosterone causes rapid growth
Which testicular cancer is more common?
germinal epithelial tumor
How is an interstitial cell tumor diagnosed?
quick sexual development in children; hard to tell in adults
What is a teratoma?
a tumor of many types of cells (totipotent)
Though uncommon, what hormones can be secreted by a germinal epithelial testicular tumor?
hCG (if placental tissue develops), or estrogen (causing gynecomastia)
What are the reactions behind erection?
1) L-Arg – NO + citrulline (via NOS); 2) GMP – cGMP (via guanylate cyclase); 3) cGMP – GMP (via PDE5)
How does cGMP give an erection?
relaxes smooth muscle in the corpus cavernosa
How is guanylate cyclase activated?
NO
How is male infertility diagnosed?
1) less than 20 million sperm/mL; 2) or, less than 40% motility; 3) or, less than 40% normal morphology
What are the causes of male infertility?
1) anabolic steroid use, 2) STDs, chemo/radiation; 3) viral orchitis/mumps; 4) low testosterone (hypogonadism or hypopituitarism)
What are the various methods for male birth control?
1) vasectomy, 2) hormonal, 3) immunocontraception
Is vasectomy reversible?
yes, unless interstitial fibrosis of the testes occurs
Describe hormonal contraception.
In europe, testosterone and progestagin yielded azospermia in 6-8 weeks
What are the various types of immunocontraception?
1) vaccines that target gamete production via hormones; 2) vaccines that target gamete function via zona pellucida and sperm; 3) vaccines that target gamete outcome via hCG
When do the seminal vesicles empty?
right after the sperm go through
What is needed to stimulate spermatogenesis?
GH stimulates; but LH also required
What happens at birth regarding spermatogenesis?
primordial germ cell enters testis to become spermatogonia
What happens at puberty regarding spermatogenesis?
spermatogonia migrate toward lumen among Sertoli cells and spermatogenesis is triggered
How can prostate cancer be inhibited?
estrogens or testicle removal (both indicate carcinoma of the prostate)
What factors give a false positive for PSA?
inflammation of the prostate
When does PSA no work?
if PSA less than 2 and no lesions by digital exam - 30% still had carcinoma
