Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ENRE > Male Reproductive Physiology > Flashcards

Male Reproductive Physiology Flashcards

1
Q

What is the general timeline of gonadal development in gestation?

A

weeks 1-5: bipotential

6-7: testes begin to develop

week 9: the ovaries begin to develop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is Gonadotropin secretion like over the lifetime?

A

high in fetus

low in childhood (FSH>LH)

starts to increase in puberty

plateau in men in adulthood, fluctuates in women (LH>FSH)

increases in senescense, moreso in women (FSH>LH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What initiates puberty?

A

pulsatile secretion of GnRH –> gonadal tesroud hormones

secondary sex characteristics bc of T and estrogen

pulses of GnRH are essential - if you administer long-acting, puberty not initiated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What can delay onset of puberty?

A

extreme stress or caloric deprivation in girls

melatonin may be a natural inhibitor of GnRH release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the scrotum essential for?

A

maintaining lower temperature essential for spermatogenesis (1-2C below body temp)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the primary function of the epididymis?

A

location for the maturation and storage of sperm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where do spermatogonia mature into spermatozoa?

A

seminiferous tubules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the general composition of an adult testis?

A

80% seminiferous tubules

20% CT w/ leydig cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the androgens secreted by the testes?

A

testosterone (most abundant)

DHT

androstenedione

most T goes to DHT in target tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When enzymes do the testes have and lack?

A

Lack: 21beta-hydroxylase and 11beta-hydroxylase (no glucocorticoids or mineralcorticoids are made)

have: 17beta-hydroxysteroid dehydrogenase (androstenedione –> T)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does 17B-hydroxysteroid dehydrogenase do?

A

converts androstenedione to testosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What occurs to T in the lumen of seminiferous tubules?

A

concentrated by binding to androgen-binding protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When do Leydig cells do?

A

synthesize cholesterol de nove and also aquire it from LDL receptors

store cholesterol esters – HSL –> free cholesterol for androgen production

cholesterol – StAR –> mitochondrial membranes –> pregnolone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is estrogen produced in the male?

A

In sertoli cells: T – aromatase –> estradiol

concentration of E is high in seminiferous tubule fluid - potential role in spermatogenesis

most of E is produced in other tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is 17,20 desmolase?

A

same as 17-alpha hydroxylase

converts 17alpha-hydroxyprogesterone to androstenedione

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the rate limiting step in the synthesis of testosterone?

A

conversion of cholesterol to pregnenolone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does LH do in a male?

A

increases affinity for cholesterol desmolase for cholesterol

stimulates synthesis of cholesterol desmolase

regulates overall rate of T synthesis by leydig cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is P450scc?

A

cholesterol desmolase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When does Testosterone production begin?

A

7-8 weeks gestation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the androgen receptor?

A

nuclear receptor that directs protein synthesis

found in prostate, testis, epididymis and seminal vesicles

also in non-repro tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the significance of DHT?

A

binds to AR w/ greater affinity than T alone

has important role in causing changes at puberty

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How is T found in the blood?

A

60% bound to SHBG

38% bound to albumin

2% free T = bio active form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How is T excreted?

A

primarily in urine

50% of excreted androgens found as urinary 17-ketosteroids

remainder conjugated androgens or diol or triol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the fetal actions of T?

A

present at 2nd month

differentiation of internal male genital tract

causes descent of testes during last 2-3 months of pregnancy

25
Q

What are the specific actions of DHT?

A

fetal differentiation of external male genitalia

hair distribution and baldness

sebaceous gland activity

growth of prostate

26
Q

What are the anabolic actions of androgens?

A

stimulation of EPO

stimulation os sebaceous glands

control of protein anabolic effects (N retention)

linear body growth, bone growth, and closure of epiphyses

ABP synthesis

behavioral effects, including libido

27
Q

How is DHT involved in BPH?

A

concentrations of DHT in prostatic tissue not higher in men w/ BPH –> might have more DHT receptors on prostates

28
Q

How does LH stimulate leydig cells?

A

Gs receptor –> cAMP/PKA –> steroidogenesis and T production

29
Q

How does do FSH and T stimulate sertoli cells?

A

FSH –> Gs –> new protein synthesis and production of inhibin (inhibits FSH release)

Testosterone contributes to this too by diffusing freely from leydig to sertoli cells

30
Q

What stimulates ABP production?

A

FSH –> sertoli cells –> ABP into lumen of S tubules

31
Q

What are the exocrine fxns of sertoli cells?

A

produce fluid

ABP

determination of release of sperm from seminiferous tubules

32
Q

What are the endocrine fxns of sertoli cells?

A

expression of ABP, T, and FSH

production of AMH

aromatization of T –> estradiol-17B

production of inhibin to regulate FSH

32
Q
A
33
Q

How long does spermatogenesis take?

A

64 days

34
Q

What occurs to spermatogenesis at puberty?

A

mitotic divisions (spermatocytogenesis) increase to produce daughter spermatogonia

35
Q

What occurs in the meiosis phase of spermatogenesis?

A

primary spermatocytes undergo 2 meiotic divisions:

1st: 2 secondary spermatocytes, 1n, 2d
2nd: spermatocytes enter 2nd div, producing 2 spermatids, 1n, 1d

36
Q

What is spermiogenesis?

A

spermatid maturation into spermatozoa

37
Q

What is the residual body and how is it removed?

A

excess cytoplasm ejected during spermatid maturation

phagocytized by sertoli cells

38
Q

What are the hormonal factors that stimulate spermatogenesis?

A

LH –> leydig cells make T

FSH –> sertoli cells nurse and form sperm

GH –> necessary for background metabolic fxns of testes; promotes early div of sperm

T –> growth and div of germinal cells

Estrogens –> might be essential

39
Q

What is seen in sperm in pituitary dwarfs?

A

no GH –> spermatogenesis is severely deficient or absent = infertile

40
Q

What occurs when exogenous T is administered?

A

inhibits LH release –> lowered intratesticular T levels –> insufficient spermatogenesis

41
Q

What occurs to sperm in the epididymis?

A

sperm spend about a month here further maturing after release from rete testis

weakly motile upon entering, strongly motile when exiting

decapacitation

storage site for mature sperm for several months

42
Q

What is decapacitation?

A

adding molecules to membranes of sperm to prevent acrosomal reaction before contact w/ an egg

43
Q

What are plasma testosterone and sperm production like throughout a male’s life?

A

no sperm production until puberty; high through adulthood and decreases in old age

T high fetally, dips at birth, high neonatally

low in childhood

increases during puberty and stays high throughout adulthood, decreases in old age

44
Q

What do prostaglandidns do and where are they secreted?

A

from seminal vesicles

react w/ female cervical mucus to make it more receptive to sperm movement (less thick)

cause backward peristaltic contractions in uterus and fallopian tubes to move sperm to ovaries

45
Q

When does the prostate gland secrete, and what is in its secretion?

A

secrete during emission

thin fluid w/ Ca, citrate ion, Pi, clotting enzyme, and profibrinolysin

fxns for pH adjustment

46
Q

How long can sperm live once ejaculated?

How many sperm are in each ejaculation?

A

24-48 hrs at body temp

2-6 mL, 20-200 million sperm (<20 million = infertile)

47
Q

What is emission?

A

movement of semen from epididymis, vas deferens, seminal vesicles, and prostate to ejaculatory ducts

under Sympathetic control

peristaltic contraction of SM of vas deferens –> closes internal sphincter of bladder to prevent retrograde ejaculation

usually precedes ejaculation

48
Q

What is ejaculation?

A

propulsion of semen out of male urethra

rhythmic contraction of bulbospongiosus and ischiocavernosus ms

striated muscles innervated by somatic motor nerves

49
Q

What occurs in capacitation?

A

changes occur when sperm come in contact w/ fluids of female tract

uterine tubes wash away inhibitory factors

loss of cholesterol built-up on acrosome

membrane more permeable to Ca –> increased motility

50
Q

What is the acrosome reaction?

A

large quantities of hyaluronidase and proteolytic enzymes stored in acrosomal head

hyaluronidase –> depolymerizes hyaluronic acid polymers in intercellular cement that hold ovarian granulosa cells together

proteolytic enzymes –> digest proteins in structural elements of tissue cells that adhere to ovum

51
Q

What does T deficiency in 2-3rd mo of gestation cause?

3rd trimester?

A

2-3rd mo: varying degrees of ambiguity in male genitalia, DSD

3rd trimester: problems in testicular descent, micropenis

52
Q

What does T deficiency in puberty cause?

A

poor secondary sexual dev and overal eunuchoid features (prepubertal characteristics)

53
Q

What does T deficiency in post-puberty cause?

A

decreased libido, erectile dysfunction, decreased facial and body hair growth, low energy, infertility

54
Q

What is Kallman’s syndrome?

A

genetic disorder

GnRH neurons fail to migrate into hypothalamus during embryo

delayed/absent puberty and impaired sense of smell

hypogonadotropic hypogonadism

55
Q

What is Klinefelter syndrome?

A

male w/ extra X chromosome

at puberty, increased gonadotropins fail to induce normal testicular growth and spermatogenesis

androgen production is low = primary hypogonadism

seminiferous tubules destroyed –> infertility

56
Q

What can treat benign prostatic hypertrophy?

A

5alpha-reductase inhibitor

57
Q

What do tumors of testis often cause?

A

interstitial tumors: large amounts of testosterone

germinal epithelial tumors: produce no hormones

58
Q

What occurs in “andropause”?

A

as men age, gonadal sensitivity to LG decreases and androgen production drops

serm LH and FSH rise (FSH>LH)

T production decreases slowly after age 40

sperm production drops after age 50, but many men can maintain repro fxn and spermatogenesis throughout life

ENRE (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions