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Male Reproduction I & II
Pasley 5/4/11 1.5 hrs
111
Physiology
Undergraduate 4
05/04/2011

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Cards

Term
chromosomal sex -> gonadal sex -> phenotypic sex
Definition
what are the 3 types of sex determination?
Term
yes, both gonads produces hormones of the opposite sex
Definition
do female gonads make testosterone? do males make estrogen?
Term
Sry antigen on the y chromosomes tell the fetus's undifferentiated gonad to from the medulla into seminiferous tubules
Definition
what tells the undifferentiated gonad to make the medulla testis?
Term
Sertoli cells
Definition
when the testicle medulla starts developing, what cells form and start making Mullerian inhibitory factor (MIS), causing regression of the Mullerian ducts
Term
Leydig cells
Definition
when the testicle medulla starts developing, what cells form and start making testosterone & inducing further differentiation?
Term
sex determining region of the y chromosome
Definition
what does Sry mean?
Term
sry gene
Definition
what directs the fate of gonadal primordia towards testis development?
Term
female
Definition
what is the default gender?
Term
Sertoli cells
Definition
what are the first cells to differentiate under control by Sry (AMH)?
Term
fetal Leydig cells
Definition
what cells make androgen required for masculinization of fetuses?
Term
Wolffian ducts: seminal vesseicles, epididymis, vas deferens
Definition
what male repro- structures develop from testosterone presence?
Term
external genitalia + prostate, (penis & scrotum)
Definition
what male repro- structures develop from dihydrotestosterone presence?
Term
12-15
Definition
at what age in fetal development do the testis migrate from the posterior abdominal wall?
Term
25 wks
Definition
at what age in fetal development do the testis migrate into the scrotum?
Term
cryptorchidism
Definition
most frequent congenital birth defect in male infants
Term
2-4% occurrence
Definition
how often does cryptorchidism occur in full-term male births?
Term
cryptorchidism
Definition
failure of one or both testes to descend into the scrotal sac
Term
uni- 2/3 of cases
bi - 1/3 of cases
Definition
what fraction of cases of cryptorchidism are unilateral? bilateral?
Term
testes need a lower temp than body temp for spermatogenesis
Definition
why can cryptorchidism make you infertile?
Term
= tight short syndrome, leads to infertility
Definition
what is TSS and what does it cause?
Term
1) mechanical inhibition
2) hormonal insufficiency (lack of testosterone)
Definition
what things can inhibit the testicles descent?
Term
LH & FSH
Definition
name the gonadotropes
Term
FSH
Definition
what stimulates Sertoli cells to start spermatogenesis?
Term
Sertoli cells
Definition
what secretes inhibin to provide a negative feedback loop and prevents the anterior petuitary from making FSH?
Term
TSH
Definition
name a thyrotrope
Term
HCG
Definition
placental trophoblast cells in primates and equids only make this
Term
alpha (glycoprotein), beta is unique to each protein
Definition
what subunit is common between TSH, LH, and FSH?
Term
adrenal glands in small amounts
Definition
where besides Leydig cells are male horomones secreted?
Term
Leydig -> testosterone -> virilizing
Sertoli -> spermatogenesis
Definition
___ cells uptimately have virilizing effects, while ___ cells induce spermatogenesis.
Term
cholesterol
Definition
what are all androgens derrived from?
Term
testosterone
Definition
what is the most abundant but relatively inactive androgen in males?
Term
DHT
Definition
what is the active form of testosterone in the target tissue?
Term
androstenedione
Definition
what male hormone is responsible for muscle strength and growth in males and is an anabolic hormone?
Term
in the early morning, remember that secretion is pulsatile and varies with the circadian rhythm
Definition
when are testosterone levels highest?
Term
97%, bound to beta globulin
Definition
what percent of testosterone is bound in plasma? to what?
Term
30 min - 1 hr
Definition
what is the half life of testosterone?
Term
aromatase in the sertoli cells
Definition
what converts testosterone to estrogen in males and where is it found?
Term
stallion testes
Definition
what is a high natural source of estrogen?
Term
sertoli cells convert testosterone to estrogen
Definition
why can male animals with sertoli tumors become feminized?
Term
DHT
Definition
does the androgen receptor (a ligan-activated transcription facotr) have a higher affinity for DHT or testosterone?
Term
failure to regulate gene expression programs, and disorders of androgen sensitivity (like AIS)
Definition
what do mutations in the androgen receptors cause?
Term
1) converted to estradiol by aromatase
2) convered to DHT by 5 alpha reductase
3) excreted as 17-keto-steroids (converted by 12 beta dehydrogenase)
4) conjugated with conjugating enzymes(for excretion)
5) used in testes, petuitary, or muscle
Definition
how is testosterone metabolized (5 ways)
Term
albumin 60%
Sex hormone binding globulin 40%
Definition
what two plasma proteins carry testosterone? which one does more?
Term
sulfur or glucuronides
Definition
what is used to conjugate testosterone before it is secreted?
Term
2-5%
Definition
how much testosterone is free (unbound)?
Term
the liver
Definition
where does testosterone get degraded?
Term
spermatogonium
Definition
what male cell is stimulated to divide at puberty?
Term
toward the tubule lumen
Definition
which direction do germ cells move as they mature?
Term
1) spermatogoium
2) primary spermatocyte
3) secondary spermatocyte (first division)
4) spermatid (second division)
5) spermatozoa
Definition
name the spermatogonium as they mature to a spermatozoa, where does the cell divide?
Term
testosterone
Definition
secreted by interstitial Leydig cells in testis, essential for growth and development of germ cells
Term
Androgen Binding Protein (ABP)
Definition
secreted by Sertoli cells, binds and concentrates testosterone in seminiferous tubules
Term
Leutenizing Hormone (LH)
Definition
secreted by anterior petuitary, in the male this stimulates Leydig cells to secrete testosterone
Term
Growth Hormone (GH)
Definition
secreted by the anterior petuitary, controls metabolic rate in testes, promotes division of spermatogonia
Term
FSH
Definition
secreted by the anterior petuitary in the male, stimulates Sertoli cells during Spermatogenesis
Term
estrogen
Definition
formed from testosterone by Sertoli cells under influence of FSH
Term
LH, GH, FSH
Definition
what sex hormones are secreted by the anterior petuitary?
Term
lack: FSH receptor, Androgen receptor
have: estrogen receptor
Definition
what receptors do germ cells have/lack?
Term
have: FSH receptor, Androgen receptor, estrogen from them facilitates spermatogenesis
Definition
what receptors do Sertoli cells have?
Term
Leydig cells
Definition
what cells have LH receptors and make testosterone required for spermatogenesis?
Term
both FSH and LH
Definition
what is required for maximal sperm production?
Term
1) destruction of seminiferous tubule epithelium due to orchitis from mumps
2) high temperatures
3) cryptorchidism
Definition
what can cause abnormal spermatogenesis?
Term
2 degrees celcius below normal body temp
Definition
what is the ideal temp for sperm?
Term
25% abnormal morphology, additional 25% abnormal motility
Definition
what percent of sperm have abnormal morphology? abnormal motility?
Term
epididymis
Definition
where does final maturation of sperm occur where sperm gain their motility?
Term
the epididymis & ampulla of the vas deferens
Definition
where are sperm stored?
Term
120 million
Definition
how many sperm are formed/day in young adult males
Term
over a month
Definition
how long can sperm be stored without losing their motility?
Term
inhibitory substances are secreted
Definition
what keeps sperm inactive in the epididymis and vas deferens?
Term
enhanced flagellum movement and the head enzymes changes so the sperm can penetrate the ovum
Definition
what changes occur in the sperm with capacitation?
Term
the adluminal compartment
Definition
where does the second mitotic division of sperm occur?
Term
the occluding Sertoli cell junction, this also provides the immunologic barrier
Definition
what keeps toxic materials from reaching sperm cells? (and prevents damage to the seminiferous tubule)
Term
Sertoli cells
Definition
what cells make up the blood testes barrier?
Term
Sertoli cells
Definition
what cells synth & secrete androgen binding protein?
Term
Sertoli cells
Definition
what cells phagocytize defective sperm?
Term
1) luminal fluid
2) ABP
3) factors that mediate sperm proliferation and differentiation
4) inhibin
5) molecules that target Leydig cells
6) Mullerian inhibiting substance(MIS)
Definition
list all the substances secreted by Sertoli cells
Term
fructose, citric acid, prostaglandins & fibrinogen
Definition
what do the secretions of the seminal vessicles contain?
Term
helps semen coagulate and adhere to the cervix
Definition
what does fibrinogen do to semen?
Term
1) stimulate reverse peristalsis of the uterus and fallopian tubes
2) increase fluidity of cervical mucus
3) increase sperm motility
Definition
what do prostaglandins in semen do?
Term
citrate, Ca++, phosphatase, fibrinolysin
Definition
what is found in the fluid secreted by the prostate?
Term
increases sperm motility by dissolving fibrinogen, secreted by the prostate
Definition
what does fibrinolysin do and what accessory sex gland secretes it?
Term
fibrinogen: seminal vessicles
fibrinolysin: prostate
Definition
where is fibrinogen secreted into semen? where is fibrinolysin secreted into the semen?
Term
LH and FSH
Definition
what hormones increase when testosterone increases?
Term
testosterone
Definition
what causes testicular descent into the scrotum, formation of the external genetalia/acessory glands, pubic & axillary body hair growth, and growth/remodeling of the larynx?
Term
the temporal region
Definition
what region of the scalp does testosterone cause hair loss?
Term
beard growth
Definition
what is one of the last secondary sex characteristics to develop?
Term
1) pubertal growth spurt 2) directs pelvic bone formation 3) increase in muscle mass 4) positive nitrogen and electrolyte balance 5) increases red cell pdxn 6) increase BMR 7) renal/salivary gland enlargement 8) decreased sub Q fat deposition
Definition
what are the anabolic effects of testosterone in men?
Term
1) closes epihyseal plates in long bones 2) bone remodeling (anti-osteoporosis) 3) increases insulin sensitivity 4) increase HDL, decreases LDL and TAGs 5) contributes to feedback inhibition on the HPG axis
Definition
what does estrogen to do men?
Term
unknown
Definition
what does progesterone do in men?
Term
1)thoughts, emotions, sensory inputs: sight and smell -psychogenic 2) mechanoreceptors

parasympathetic
Definition
what things trigger erection? what branch of the ANS?
Term
1)increased activity of neurons releases NO
2) decreased sympathetic activity
Definition
once stimulated by mechanical or psychogenic factors, what happens to the neurons in the penis?
Term
dilation of the arteries in the penis, erection, and compression of the veins
Definition
during erection, once NO is released and sympathetic neurons activity decreases in the penis, what happens?
Term
erection
Definition
what is tumescence?
Term
erection
Definition
what process happens when nitric oxide from parasympathetic fibers leads to vasodilation and engorgement of the erectile tissues
Term
1) erection
2) lubrication
3) orgasm (emission and ejaculation)
4) detumescence
Definition
what are the 4 stages of arousal?
Term
parasympathetics (cause lubrication)
Definition
what branch of the ANS causes mucus to be secreted by the urethra and bulbourethral glands
Term
sympathetics
Definition
what branch of the ANS causes orgasm?
Term
L1 & L2
Definition
where is the sympathetics reflex in the spinal cord that causes orgasm?
Term
emission
Definition
contraction of the vas deferens & ampulla which releases sperm into the urethra
Term
ejaculation
Definition
contraction of the prostate and seminal vessicles, fills and stretches urethra
Term
resolution (of the male sexual response)
Definition
what is detumescence?
Term
causes increase in guanylate cyclase activity in VSM of helicine arteries leading to an increase in cGMP, causeing relaxation of VSM and increase blood flow to vascular sinuses
Definition
what does NO do to cause erection (cellularly)?
Term
nitrous oxide synthase
Definition
what enzyme is NEEDED for erection?
Term
1) arterial
2) neurogenic
3) psychogenic
4) traumatic
5) endocrinologic probs
6) drugs
Definition
what factors can cause ED?
Term
diabetic neuropathy
Definition
what can lead to impariment of nitrergic innervation of the endothelium and thus ED?
Term
a decrease in bioavailability of NO
Definition
endothelial dysfunction from inflammation and oxidative stress can cause _____ leading to ED
Term
5 phosphodiesterase, converts cGMP to 5'-GMP (so erection is maintained)
Definition
what enzyme is inhibited by viagra, and what does it do?
Term
there are phosphodiesterase 6 receptors in the retina
Definition
why does too much viagra cause blue vision?
Term
infertility
Definition
what can exogenous Testosterone administration result in?
Term
intra-testicular testosterone must be 100 x greater than the blood to support spermatogenesis
Definition
what testicular: blood ratio supports spermatogenesis?
Term
the circulating T feedback inhibits LH, failing to make the Leydig cells make testosterone
Definition
why does raising circulating testosterone fail to elevate testicular testosterone to physiological levels?
Term
sperm antibodies build up
Definition
why does a vasectomy reversal cause lower fertility rates?
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