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Reproduction > Male reproductive physiology- Lopez > Flashcards

Male reproductive physiology- Lopez Flashcards

1
Q

what week do the testes begin to develop in genetic males

A

week 6-7

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2
Q

what week do ovaries begin to develop in females

A

week 9

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3
Q

female gonads consist of what cells and function

A

germ cells: produce oogonia
granulosa cells: surround an protect oogonia with stroma
theca cells: produce progesterone and with granulosa cells synthesize estradiol

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4
Q

secretion of GnRH begins week ____ but levels remain low until puberty. FSH and LH begins ___ and ___ weeks which remain low until puberty. During childhood ___ is higher than __

A

4
10 and 12
FSH than LH

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5
Q

during adult reproductive period the secretion becomes ___ and ___ is secreted in higher amounts than ___

A

pulsatile, LH>FSH

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6
Q

during the senescence stage what is secreted more FSH or LH

A

FSH

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7
Q

what is one of the earliest events of puberty

A

appearance of large nocturnal pulses of LH during REM sleep

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8
Q

the increased circulating levels of the sex steroid hormones are responsible for the appearance of what

A

secondary sex characterisitcs at puberty

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9
Q

GnRH analogue administered in intermittent pulses =

-long activing GnRH analogue administered =

A
  • puberty is initiated and reproductive fnct is established

- puberty is not initiated

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10
Q

what is a physiologic cause of the increased secretion of FSH and LH

A

GnRH receptor in the anterior pituitary becomes more sensitive so this causes greater stimulation of secretion

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11
Q

what may be a natural inhibitor of GnRH release

A

melatonin

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12
Q

what are the two main functions of testes

A

spermatogenesis and secretion of testosterone

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13
Q

where is the primary location for the maturation and storage of sperm

A

epididymis

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14
Q

function of vas deferens

A

provides another storage area for sperm
-secretes fluid rich in citrate and fructose

FC Vas Deferens

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15
Q

seminal vesicles secrete what

A

FF PC

fibrinogen, fructose, prostaglandins, citrate

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16
Q

prostate gland secretes what

A

milky aqueous sltn rich in citrate, enzymes, and calcium

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17
Q

what is the blood testes barrier

A

formed by sertoli cell tight junctions

  • selective permeability
    • testosterone can cross but not noxious substances
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18
Q

what are the 3 androgens secreted by the testis

A

testosterone, DHT, androstenedione

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19
Q

fetal leydig cell function

A

masculinization of the male urogenital tract and inducing testis descent
-cells atrophy shortly after birth and don’t contribute to adult leydig cell pop

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20
Q

adult leydig cells formation

A

derive from undifferentiated precursors present after birth, become fully steroidogenic at puberty

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21
Q

how do leydig cells make cholesterol

A

de novo

  • also get from circulation via LDL receptors and sometimes HDL
  • they have it stored as cholesterol esters and release it to free cholesterol with HSL
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22
Q

what enzymes do the testis lack that prevents glucocort or mineralcort syn

A

21-B hydroxylase

11-B hydroxylase

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23
Q

in the lumen of the seminiferous tubules testosterone is concentrated by binding

A

androgen-binding protein

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24
Q

in what tissue is DHT the active androgen

A

SLEP

skin, liver, external genitalia of the male fetus, prostate gland

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25
Q

what is most of the circulating testosterone bound to

A

plasma proteins such as SHBG and albumin

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26
Q

___ stimulates syn of SHBG ___ inhibits

A

estrogens stim

androgens inhib

27
Q

where in the male is the estrogen levels high and what may be the source

A

in the seminiferous tubules it is high

  • sertoli cells may convert testosterone to estradiol via aromatose
  • could play role in spermiogenesis bc sperm cells have isoform of estrogen receptor
28
Q

where is 80% of estrogens formed from in the male

A

the liver

29
Q

what is another name for P450SCC

A

cholesterol desmolase

30
Q

leydig cells make testosterone then what happens

A

Testosterone diffuses both into the neighboring seminiferous tubules and into the peritubular capillary network to be carried to peripheral circulation

  • in tubules T concentrated by binding ABP
  • T carried to periphery by SHBG
31
Q

the leydig cells makes limited amount of ___ and ___ which is made much more by ___

A

DHT and estradiol-17B

-these are usually made more by peripheral conversion

32
Q

how does LH promote pregnenolone synthesis

A
  • increases affinity of desmolase enzyme for cholesterol

- long term action stimulates synthesis of desmolase enzyme

33
Q

what kind of receptor is the androgen receptor

A

nuclear receptor

34
Q

deficiency of 5a-reductase causes what

A

ambiguous external genitalia

35
Q

50% of excreted androgens are found as what

A

urinary 17-ketosteroids

36
Q

testosterone action during fetal development

A 
\+test = penis, scrotum
-test = clit, vag
  • internal male genital tract = seminal vesicales, epididymis, vas deferens
  • causes descent of testes into scrotum during last 2-3 months of pregnancy
37
Q

specific actions of DHT

A

fetal differentiation of external male genitalia (penis, scrotum, prostate)

  • male hair distribution and male pattern baldness
  • sebaceous gland activity
  • growth of prostate
38
Q

LH binds LH receptor on leydig cell: molecular mech

A

coupled to Gs

  • cAMP and PKA, leads to testosterone production
  • testosterone diffuses into seminiferous tubules and peripheral circulation
39
Q

sertoli cell stimulated by what and pathway

A

FSH and testosterone

  • binds, linked to Gs, cAMP and PKA, produces inhibin which inhibits FSH release
  • FSH also stimulates sertoli cells to secrete ABP into lumen of sem tub which binds testosterone and provides local supply of testosterone for developing spermatogonia
40
Q

sertoli cell can also convert ___ to ___ bc it produces what

A

testosterone to estradiol bc it makes aromatase

41
Q

functions of sertoli cells

A

supportive, exocrine, and endocrine

42
Q

fnct of sertoli cells; supportive

A

-maintain blood-testis barrier
-phagocytosis
-transfer of nutrients from blood to sperm
receptors for hormones and paracrines

43
Q

fnct of sertoli cells: exocrine

A

produce fluid and ABP

-determine release of sperm from seminiferous tubule

44
Q

fnct of sertoli cells: endocrine

A
  • express testost, ABP and FSH receptors
  • produce AMH
  • aromatization of test to estradiol 17B
  • produce inhibin to regulate FSH levels
45
Q

inhibin from sertoli cells feeds back on what?

A

anterior pituitary gland

46
Q

seminiferous tubules have 2 sets of cells

A

spermatogenic cells that develop into spermatozoa

-sertoli cells which have supportive and nutrient function

47
Q

hormonal factors that stimulate spermatogenesis

A
  • LH: leydig cells secrete test
  • Testosterone: growth and division of testicular germ cells
  • FSH: sertoli cells nurse and form sperm
  • estrogens: may be essential for spermatogenesis
  • GH: promotes early division of sperm
48
Q

functions of seminal vesicles

prostaglandins

A

secretions add nutrients to sperm

  • prostaglandins aid in fetilization by reacting with femal cervial mucus to make it more receptive to sperm movement (make it less thick)
  • cause backward reverse peristatltic contraction in uterus and fallopian tubes to help move ejaculated sperm towards ovaries
49
Q

function of prostate gland

A

secretes thin, milky fluid that contains Ca2+, citrate, and enzymes
-alkaline fluid helps neutralize acidity of other seminal fluids during ejac

50
Q

what is the pH of semen

A

7.5

51
Q

steps in erection

A

parasymp nerves innervating vascular SM of helicine arteries that supply blood to cavernous spaces release NO

  • NO activates guanylyl cyclase, increases cGMP and decresases intracell Ca2+ = relaxation of SM
  • vasodilation allows blood in and causes engorgement and erection
  • engorged tissue presses veins against no compliant fascia to prevent drainage
  • somatic stimulation increases contraction of muscles at base of penis, further promoting erection
52
Q

emission of semen

A

under symp control (adrenergic transmitter)

  • causes sequential peristaltic contraction of SM of vas deferens, while closing internal sphincter of bladder
    • prevents retrograde ejac into bladder
  • emission normaly precedes ejaculation but also continues during ejaculation
53
Q

ejaculation

A

propulsion of semen out of male urethra
-rhythmic contraction of bulbospongiousus and ischiocavernousus muslces
both innervated by somatic motor nerves

54
Q

capacitation of spermatozoa

A

when sperm first expelled in semen can’t fertilize ovum

-change occurs when they come in contact with fluids of female tract

55
Q

changes of sperm during capacatiation

A
  • uterine and fallop tubes wash away inhib factors
  • loss of cholesterol which was built up on acrosome, which now make head of sperm weaker
  • membrane of sperm more permeable to calcium, increases motility
56
Q

sperm acrosome reaction

A

stored in acrosomal head of sperm are large quant of hyaluronidase which breaks hyaluronic acid polymers that hold ovarian granulosa cells together
-enzymes digest proteins in the strucutural elements of tissue cells that adhere to ovum

57
Q

gonadal dysfunction in male 2nd to 3rd month gestation

A

ambiguity in male genitalia and male pseudohermaphrodism

58
Q

GD in male 3rd trimester of pregnancy

A

leads to problems in test descent and micropenis

59
Q

GD during puberty

A

poor 2ndary sex development and eunuchoid features

-prepubertal charact, and often by presence of charact typical of opp sex

60
Q

GD post puberty

A

decreased libido, ED, decreased facial and body hair growth, low energy, infertility

61
Q

klinefelter syndrome

A

men with extra X chrom

  • androgen production low (variable)
  • levels of gonadotropins are elevated, indicate primary hypogonadism
  • seminif tubes destroyed, infertility
62
Q

andropause

A

as men age gonadal sensitivity to LH decreases and androgen production drops
-FSH and LH levels rise

63
Q

secondary hypogonadism: pituit dys

A

decreased LH and FSH = decreased T

64
Q

secondary hypogonadism: hypothal dys

A

decreased GnRH leads to decreased LH and FSH and therfore decreased T

Reproduction (15 decks)

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