Yan Male Flashcards
1
Q
How many seminiferous tubules are there in a man?
A
900 seminiferous tubules
2
Q
How long is the epididymis?
A
6 meters
3
Q
When does spermatogenesis begin?
A
@ puberty–>like @ ages 12-14.
4
Q
What are the 3 phases of spermatogenesis?
A
- Mitotic spermatogonial proliferation & differentiation
- meiotic division of spermatocytes into spermatids
- Haploid differentiation & morphogenesis of spermatids into spermatozoa
5
Q
Roughly describe the process of spermatogenesis.
A
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.
6
Q
How long does spermatogenesis take in humans?
A
72 days
7
Q
Where does estrogen come from in men?
A
aromatized from testosterone in Sertoli cells
8
Q
Why is reabsorption of luminal fluid in the epididymis important?
A
b/c then sperm can enter the epididymis concentrated, rather than dilute.
9
Q
T/F ERß on spermatogonia, spermatocytes & Sertoli cells may mediate the actions of xenoestrogens (‘estrogenic endocrine disruptors’)
A
True. I have no idea why.
10
Q
What are xenoestrogens?
A
estrogenic endocrine disruptors
11
Q
Where are growth factors released from in the male? What is their effect?
A
secreted from Sertoli or germ cells
act on germ cells or somatic cells via their receptors
12
Q
When FSH binds to Sertoli cells…what happens in terms of GH?
A
GH is released
this drives the development of germ cells
Stem cell–>meiotic cell–>haploid cell–>sperm
13
Q
Describe negative feedback w/ testosterone production & w/ inhibin.
A
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.
14
Q
Describe the maturation of the sperm in the epididymis.
A
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.
15
Q
What is the name for the head, body, & tail of the epididymis?
A
Head: caput
Body: corpus
Tail: cauda
16
Q
What happens to the sperm when it is in the vas deferens?
A
this is a place where it can be stored for over a month w/ suppressed motility
17
Q
Describe the difference in the sperm’s swimming pattern in the male v. in the female.
A
male: elegant swimming w/ equal peaks & valleys
female: goes crazy! more forceful, can penetrate mucus & make it to the secondary oocyte
18
Q
T/F The sperm are more motile in the male right before ejaculation than in the female.
A
False.
there is an initial ejaculation motility
then there is hyper activated motility in the female.
19
Q
What is better for a sperm to swim in: neutral/alkaline environment or acidic environment?
A
Alkaline environment, greater motility
20
Q
How long can the sperm typically survive in the female reproductive tract?
A
1-2 days
21
Q
What is the function of the seminal vesicles?
A
secrete mucus that empties into the ejaculatory duct...rich in: fructose (nutrition for the sperm) citric acid prostaglandins (aid fertilization) fibrinogen
22
Q
How does female orgasm help w/ fertilization?
A
it causes contraction & prostaglandin release…negative pressure that sucks sperm in
23
Q
How does the prostate gland add fluid to the semen?
A
during emission it contracts w/ the vas deferens
24
Q
What is roughly the pH of the prostate gland secretions? Why is this important?
A
They are roughly acidic, this is to neutralize the basic secretions of the seminal vesicles
25
What types of substances are contained in the prostate gland secretions?
calcium
citrate ion
clotting enzyme
profibrinolysin
26
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)
```
27
How long can sperm last if they are properly preserved?
years via cryopreservation
28
What is the pH of semen fluid?
pH=7.2-8
29
What is the appearance of semen?
milky appearance
| coagulum that dissolves in 15-30 minutes
30
What is the coagulum in the semen? Why does it dissolve after 30 minutes?
coagulum--clotting enzyme
| dissolves b/c of fibrinolysin in the semen derived from profibrinolysin
31
What does capacitation of sperm do? How can you capacitate sperm?
it makes the sperm capable of fertilizing an egg
* *occurs naturally in the female genital tract w/i 1-10 hours
* *can artificially do it by washing the sperm in human tubular fluid or a capacitation medium
32
What changes occur to the sperm during capacitation?
* *inhibitory factors that suppress sperm activity are washed off...
* *lipid vesicles are removed from the acrosome & the acrosomal enzymes are released
* *sperm membrane becomes permeable to calcium-->hyperactivates motility-->ability to penetrate ZP
33
The acrosome is essential for the sperm to be able to fertilize the egg. What is it derived from? What does it contain?
* *Derived from Golgi apparatus during spermiogenesis
* *hyaluronidase: to get thru CT layers & the granulosa cells
* *proteases: to get thru the ZP
34
What are 2 reflexes that have to do w/ the scrotum?
reflex regulation of scrotal surface area
| reflex regulation of distance from abdomen
35
Aside from being outside of the body, what is another way that the scrotum is kept cool?
countercurrent heat exchange
36
T/F There are NOT sweat glands in the scrotum.
False. There are.
37
What is cryptorchidism?
* *this is a cause of male infertility
* *the testes don't descend even 3 months after birth as they should in response to fetal Leydig cells' release of testosterone
* *can cause spermatogenic block w/ testes in abdomen, depletion of germ cells, sterility, & tumor formation.
38
What is the treatment for cryptorchidism?
testosterone administration
| after 1 year if they still haven't descended-->surgical intervention.
39
T/F Globally, sperm count is getting lower & lower.
True. Now, a normal sperm count is 10 million per mL.
40
What is a sperm count that is considered infertile?
| What is considered normal?
Normal: 25-200 million sperm/mL
Infertile: less than 20 million sperm/mL
41
What are impulses from the brain for the male sexual act?
psychic stimulation from thinking or dreaming (nocturnal emissions)
42
What are the impulses from the sex organs for the male sexual act?
glans penis or areas adjacent to the penis
43
Where are the brain & sex organ impulses integrated w/ the male sexual act?
sacral & lumbar spinal cord
44
How do the impulses from the male sex organs travel to the sacral & lumbar spinal cord?
Impulses-->pudendal nerve-->sacral plexus-->sacral portion of the spinal cord
45
Penile Erection:
| What is the path of parasympathetic impulses to the penis? Which substances are released to make this happen?
Parasympathetic Impulses-->Sacral portion of the spinal cord-->pelvic nerves-->penis
**Releases: NO, Vasoactive Intestinal Peptide, ACh
46
What is the function of NO in a penile erection?
* *relaxes penile arteries
* *relaxes trabecular meshwork of smooth muscle fibers in erectile tissue of corpus cavernosum & corpus spongiosum in the penis
47
How does lubrication happen as a part of the male sexual act?
parasympathetic response
| secretion of mucus from urethral glands & bulbourethral glands!
48
Emission & ejaculation are both _____ responses. Describe the reflex that makes emission happen.
sympathetic responses
reflex center @ T12-L2 of spinal cord-->sympathetic impulses-->hypogastric & pelvic sympathetic nerve plexuses-->genital organs-->emission.
49
Describe the contraction part of ejaculation.
Vas Deferens-->expulsion of sperm into internal urethra
prostatic & seminal fluids get into urethra
mucus from bulbourethral & urethral glands contributes
50
What happens when the internal urethra is filled?
sensory signals are given off...causes rhythmic contractions of the internal genital organs & pelvic muscles; causes thrusting of the pelvis & penis & propulsion of the sperm.
51
When does resolution of the male sexual act happen?
1-2 minutes after ejaculation
52
What percentage of testosterone in the man comes from the adrenal glands?
5% of testosterone comes from the adrenal glands.
53
What percentage of testosterone is found in the blood? When it is in the blood-->which carrier proteins is it bound to?
5% of testosterone is found in the blood
carried on ABP (from Sertoli cells)
albumin
54
What is testosterone converted to in the liver? in target tissues? How?
Liver: converted to DHT by 5 alpha reductase Type I.
| Target tissues: converted to DHT by 5 alpha reductase Type II.
55
If testosterone is aromatized...what does it become?
estrogen
56
How is testosterone metabolized & excreted?
reduced & conjugated in the liver
| excreted by the kidneys & the gut...
57
What is the function of testosterone during fetal development?
formation of external & internal male sex organs
descent of the testis (if fails: cryptorchidism)
testosterone production starts the 7th week.
57
What is the function of testosterone during fetal development?
formation of external & internal male sex organs
descent of the testis (if fails: cryptorchidism)
testosterone production starts the 7th week.
58
What are the functions of testosterone during puberty or adulthood?
further development of internal & external genitalia
| secondary sexual characteristics
58
What are the functions of testosterone during puberty or adulthood?
further development of internal & external genitalia
| secondary sexual characteristics
59
What are some of the secondary sexual characteristics caused by testosterone?
```
body hair distribution
baldness
voice changes
increased skin thickness (acne)
increased muscle development
increased bone matrix & Ca++ retention
increased basal metabolism
```
59
What are some of the secondary sexual characteristics caused by testosterone?
```
body hair distribution
baldness
voice changes
increased skin thickness (acne)
increased muscle development
increased bone matrix & Ca++ retention
increased basal metabolism
```
60
What are the sources of estrogen in men?
Leydig cells
Sertoli cells
developing germ cells
60
What are the sources of estrogen in men?
Leydig cells
Sertoli cells
developing germ cells
61
2/3 of the estrogen in men comes from peripheral conversion in which tissues?
skin
brain
fat
liver
61
2/3 of the estrogen in men comes from peripheral conversion in which tissues?
skin
brain
fat
liver
62
What are some of the important roles of estrogen in men?
* *regulates luminal fluid reabsorption in the head of the epididymis so that sperm can be concentrated.
* *helps w/ negative feedback on hormone release
* *pubertal growth spurt
* *epiphyseal closure
* *maintenance of bone mineralization & integrity
* *maintenance of insulin sensitivity
62
What are some of the important roles of estrogen in men?
* *regulates luminal fluid reabsorption in the head of the epididymis so that sperm can be concentrated.
* *helps w/ negative feedback on hormone release
* *pubertal growth spurt
* *epiphyseal closure
* *maintenance of bone mineralization & integrity
* *maintenance of insulin sensitivity
63
T/F ERß on spermatogonia, spermatocytes & Sertoli cells may mediate the actions of xenoestrogens (‘estrogenic endocrine disruptors’)
True. I have no idea why.
63
T/F ERß on spermatogonia, spermatocytes & Sertoli cells may mediate the actions of xenoestrogens (‘estrogenic endocrine disruptors’)
True. I have no idea why.
64
Testosterone feeds back on the pituitary gland & hypothalamus to decrease LH release. What are the 2 ways it does this?
@ the level of the pituitary gland: decreases LH pulse amplitude
@ the level of the hypothalamus: decreases LH pulse frequency
65
Where are FSH & LH secreted from specifically?
anterior pituitary
| gonadotropes
66
What is the mechanism of action that FSH & LH use on their targets? What are their targets?
FSH: uses FSH receptors on Sertoli cells; causes cAMP to increase & PKA to be activated
LH: uses LH receptors on Leydig cells; causes cAMP to increase & PKA to be activated
67
What is the effect of LH on Leydig cells?
```
testosterone production (necessary for spermatogenesis)
Leydig cell growth & differentiation
```
68
What is the effect of FSH on Sertoli cells?
spermatogenesis
growth, differentiation & maintenance of Sertoli cells
**indirectly: increase in LH receptors on Leydig cells.
69
FSH causes Sertoli cells to do their thing w/ spermatogenesis mainly via what types of factors?
paracrine factors
70
What is andropause?
sorta a male menopause
happens around the 40s when testosterone levels decline
can be accompanied w/ hot flashes, suffocation, psychic disorders
71
What is male hypogonadism?
small gonads in a male.
72
What is the nocturnal penile tumescence test?
this is a test that measures the number of erections a male has during REM sleep each night...in a normal male should be 3-5 full erections.
If a man is having a hard time having erections, could be psychological or physical. If pass NPT probably not physical.
73
What is orchidectomy?
surgical removal of a man's testicles
74
What does an orchidectomy do to accessory sex organs?
* *prostate, epididymis, seminal vesicles all involute & their epithelial shrink
* *secretory activity declines
* *no seminal plasma
75
What does an orchidectomy do to muscle mass?
decreases
| can reverse w/ testosterone administration
76
What does an orchidectomy do to the brain?
decreased libido
77
What are some random things that happen to the body as a result of an orchidectomy?
prevention of male baldness
decrease in kidney & liver weight
decrease in erythropoiesis
increase in thymus weight
78
What is adiposogenital syndrome? What are 2 other names for it?
AKA hypothalamic eunuchism
Frohlich's Syndrome
deficiency of GnRH production @ the level of the hypothalamus
**abnormalities in the feeding center of the hypothalamus-->overweight or obese
79
What is hirsutism or virilization? What are some possible causes of this?
**could include such things as facial hair, temporal balding, muscle development, male type pubic hair, clitoromegaly
**possible causes: gonadal dysfunction
adrenocortical dysfunction
androgenic therapy
80
When is sex determined?
@ fertilization. Whether or not the dad gave the kid an X or Y chromosome.
81
When does male or female morphology show up in a fetus?
around the 7th week
82
When do germ cells appear?
around the 6th week
83
What are the genital ridges derived from?
derived from proliferation of epithelium & condensation of the underlying mesenchyme
84
Without primordial germ cells there is no differentiation of the ovaries & testes. Tell the story of their journey.
Start off as endodermal cells in the wall of the secondary yolk sac located close to the allantois
they migrate via ameboid movement along the dorsal mesentery of the hind gut
Beginning of 5th week: arrive @ primitive gonads
6th week: invade gonadal ridges
then develop ovaries & testes
85
What exactly happens once the PGCs arrive the gonadal ridges?
the epithelium of the genital ridge proliferates
it penetrates the underlying mesenchyme
forms primitive sex cords
general gonads
86
How are primitive sex cords formed during testis formation?
primordial germ cells carry the y chromosome (including the SRY gene, testis determining factor)...this decides oh we will form some primitive sex cords.
87
How do the primitive sex cords change and develop after that?
primitive sex cords become testis medullary cords. They then converge @ the rete testis & eventually are covered in tunica albuginea
88
In the 4th month, what are the testis cords composed of?
composed of primordial germ cells & Sertoli cells
89
When does testosterone production begin? Explain the circumstances behind that.
8th week
| at this point the interstitial Leydig cells lie in the space b/w the testis cords
90
What are the interstitial Leydig cells derived from?
derived from the original mesenchyme of the gonadal ridges
91
Why is it so important developmentally to have sufficient testosterone?
for the development of genital ducts & external genitalia
92
What happens to the testis cords at puberty?
originally: solid cross-sectionally up to this point
Now: canalization, get a lumen, & develop seminiferous tubules that join at the rete testis.
they are then connected to the efferent ductules & the mesonephric duct & finally vas deferens.
93
Where do the efferent ductules come from?
these are the remaining parts of the excretory tubules of the mesonephric system.
94
What happens when the primordial germ cells carry no Y chromosome?
sex cords dissociate into irregular cell clusters & degenerate.
but cortical cords form from surface epithelium, penetrate mesenchyme, split into cell clusters, surround PGCs.
95
What happens when the cortical cord cell clusters surround the PGCs?
the PGCs become oogonia & the surrounding cell clusters become follicular cells. Together they constitute a primordial follicle.
96
When are the gonads formed no longer indifferent?
At week 6. then we start to see the male & female differentiation based off of the presence of absence of a Y chromosome. But remember that sex is determined @ fertilization.
97
If you have a Y chromosome your indifferent gonads become what? What happens to the following?
Medullary Cords
Cortical Cords
Tunica Albuginea
Testes!
Medullary cords develop
no cortical cords
thick tunica albuginea
98
If you have no Y chromosome your indifferent gonads become what? What happens to the following?
Medullary Cords
Cortical Cords
Tunica Albuginea
Ovaries!
Medullary cords degenerate
Cortical cords develop
No tunica albuginea
99
What are the 2 main ducts of sexual development?
paramesonephric ducts: Mullerian
| mesonephric ducts: Wolffian
100
If you have a Y chromosome you have Sertoli cells. What does this do to the sexual formation ducts?
Sertoli cells produce Anti-mullerian hormone. Mullerian ducts degenerate. Wolffian ducts stay. Get epididymis formation.
101
If the Y chromosome is absent, what happens to the ducts?
Mullerian ducts stay.
Mesonephric ducts degenerate
Upper Mullerian duct: fallopian tubes
Lower Mullerian ducts: fuse & form the uterus
102
Where are Mullerian ducts derived from?
derived from the genital ridge
103
Where are Wolffian ducts derived from?
mesonephros & genital ridge
104
What happens when the SRY gene is turned on?
Testis form & you get interstitial cells & sustentacular (Sertoli) cells.
Sustentacular cells form anti-mullerian hormone & mullein ducts degenerate
Leydig cells produce testosterone from blood cholesterol.
Some testosterone forms internal male structures by diffusing into tissues.
Some testosterone is converted to stronger DHT to form external male structures.
105
Which enzyme is required to convert testosterone into DHT?
a reductase
106
Testosterone leads to the formation of mainly internal male structures. Which structures specifically?
epididymis
vas deferens
seminal vesicles
ejaculatory ducts
107
DHT leads to formation of mainly external male structures. Which structures specifically?
Urethra
Penis
Scrotum
**internal structure: prostate gland
108
In molecular sex differentiation...you start off with a genital ridge. This becomes what? Which 3 factors are necessary for this transformation to occur?
```
Genital Ridge-->Bipotential Gonad
Requires:
SF1
WT1
LHX9
```
109
The bipotential gonad can become which 2 things? Which factors cause this process to happen?
```
Ovary:
DAX1
WNT4
Testis:
SRY
SOX9
```
110
What is the next important things that ovaries form?
Follicles that secrete estrogen!
111
What is the next important thing that testes form?
Leydig cells-->testosterone w/ SF1
112
When a female has estrogen in her system now...what forms next?
the estrogen transforms the Mullerian ducts into female internal genitalia: uterus, uterine tube, cervix, upper vagina
113
When a male has testosterone in his system...what happens next?
the testosterone causes the transformation of the Wolffian duct into internal male genitalia: epididymis, vas deferens, seminal vesicles
some testosterone is converted into DHT.
The DHT transforms the genital tubercle & urogenital sinus into the penis, prostate, & scrotum
114
Discuss the formation of genital ducts in a female.
Mesonephric ducts regress. Leave behind Gartner's cyst & epoophoron and paroophron
Paramesonephric ducts are open to the abdominal cavity @ cranial side & fuse @ caudal side to form the uterine canal.
115
The broad ligament divides the pelvic space into 2 pouches. Which 2 pouches?
uterovesical pouch
| uterorectal pouch
116
What forms the upper & lower portions of the vagina?
Upper portion: paramesonephric duct (uterine canal)
| Lower portion: urogenital sinus
117
What are 3 common uterine defects?
uterus didelphys: double uterus w/ 2 vaginas
uterus arcuatus: slightly indented in the middle.
uterus bicornis: 2 uterine horns from a common vagina
118
Describe the beginning of the formation of external genitalia...beginning in the 3rd week of development.
3rd week
mesenchyme cells from the primitive streak migrate around the cloacal membrane & make cloacal folds.
Cranial portion of cloacal folds unite=genital tubercle.
Anterior portion of cloacal folds=urethral folds
Posterior portion of cloacal folds=anal folds
Also, there is a genital swelling outside of the cloacal folds.
119
Cranial portion of cloacal folds unite=genital tubercle. What does this form in men & women?
Men: penis
Women: clitoris
120
Anterior portion of cloacal folds=urethral folds
| What does this form in men & women?
Men: urethra (fuse)
Women: labia minora (no fusion)
121
Genital swelling outside of the cloacal folds. What does this form in men & women?
Men: scrotum (fuse)
Women: labia majora (no fusion)
122
How can you tell on a 5 month ultrasound whether you are looking at a boy or girl?
fusion of urethral folds=boy; no fusion of urethral folds=girl
genital tubercle might be slightly larger on a boy by this point
123
What is hypospadia?
defect in male genitalia
incomplete fusion of urethral folds
openings along the ventral surface of the penis
124
What are epispadias?
defect in male genitalia
urine comes out of the dorsum of the penis
associated always w/ exstrophy of the bladder
125
What causes a bifid penis? What causes a micropenis?
bifid penis: genital tubercle splits
| micropenis: lack of androgen stimulation
126
What is -Pseudohermaphroditism?
sometimes caused by congenital adrenal hyperplasia
46 XX female w/ male looking external genitalia b/c of the growth of the genital tubercle & the partial fusion of the labia majora to look like a scrotum
127
What is androgen insensitivity syndrome?
unresponsive to testosterone b/c of androgen receptor mutations
testicular feminization
46XY but looks like a female
testes still present, could become dangerous
short & blind vagina
128
What is Cryptorchidism?
one or both of the testes don't descend
