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Block 3 Week 7 > Yan: Male > Flashcards

Yan: Male Flashcards

(63 cards)

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1
Q

When does spermatogenesis begin?

A

Puberty, age 12-14

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2
Q

What are the three phases of spermatogenesis?

A
  1. mitotic: spermatogonial proliferation and differentiation
  2. meiotic: division of spermatocytes into spermatids
  3. haploid: differentiation and morphogenesis of spermatids to spermatozoa
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3
Q

PGCs enter the testis and become (blank). They then proliferate by mitotic cell division in the testis and form (blank). After the first meiotic division, they become (blank). After the second meiotic division, they become (blank). After differentiation, they finally become (blank).

A

spermatogonia; primary spermatocytes; secondary spermatocytes; spermatids; mature sperm

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4
Q

5 hormonal factors that stimulate spermatogenesis

A
  1. testosterone
  2. LH
  3. FSH
  4. estrogen
  5. growth factors
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5
Q

Secreted by the interstitial Leydig cells

Essential for spermatogenesis, especially for meiotic and haploid phases

A

testosterone

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6
Q

Secreted by the anterior pituitary gland

Stimulate the Leydig cells to secrete testosterone

A

LH

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7
Q

Secreted by the anterior pituitary gland

Stimulate the Sertoli cells to secrete factors to maintain quantitative spermatogenesis

A

FSH

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8
Q

Aromatized from testosterone in Sertoli cells
Re-absorption of luminal fluid in the head of the epididymis, allowing sperm to enter the epididymis concentrated rather than dilute.
ERß on spermatogonia, spermatocytes & Sertoli cells may mediate the actions of xenoestrogens (‘estrogenic endocrine disruptors’)

A

estrogen

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9
Q

Secreted from the Sertoli cells or germ cells
Act on germ cells or somatic cells via their receptors
Effectors of major hormonal signals
Paracrine and autocrine regulation under the control of endocrine signals

A

growth factors

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10
Q

Hypothalamus releases (blank) which causes the anterior pituitary to release (blank) and (blank). What stimulates Leydig cells of the testis to secrete testosterone and activates virilizing effects? What stimulates Sertoli cells to secrete inhibin and activates spematogenesis?

A

GnRH; LH and FSH; LH; FSH

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11
Q

Both testosterone and inhibin can provide (blank) feedback on the anterior pituitary.

A

negative

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12
Q

Maturation of sperm occurs in the (blank). About how many sperm are generated per day?

A

epididymis; 120 million/day

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13
Q

Do sperm have motility in the head of the epididymis? When do they gain motility? Where do they have moderate motility?

A

No; in the transition from the head to the corpus epididymis; moderate motility in the tail

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14
Q

Where is most sperm stored? How long do sperm remain motile there?

A

vas deferens; >1month

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15
Q

Sperm motility is suppressed in the vas deferens. When do they initially become motile? Where are they most motile?

A

upon ejaculation; most motile in the female reproductive tract –> HYPERACTIVE MOTILITY

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16
Q

How long do sperm survive in the female reproductive tract? What kind of environment is ok? What kind of environment causes them to lose motility?

A

1-2 days; neutral/slightly alkaline OK; acidic = loss of motility

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17
Q

Secrete an alkaline mucoid material enriched in fructose, citric acid, prostaglandins, fibrinogen, and other nutrient substances

A

seminal vesicles

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18
Q

Where do the seminal vesicles empty their contents?

A

ejaculatory duct

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19
Q

One function of the seminal vesicles is to provide (blank) to the sperm in the semen. What is the function of prostaglandins in the seminal fluid?

A

nutrition; aid fertilization

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20
Q

Secrete fluid containing Ca2+, citrate ion, a clotting enzyme, and a profibrinolysin

A

Prostate gland

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21
Q

During emission, the prostate gland contracts together with the (blank) to add fluid to the semen

A

vas deferens

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22
Q

The stuff emitted from the prostate gland is (blank) to neutralize the basic seminal vesicle fluid

A

acidic

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23
Q

What four things contribute to semen?

A

60% seminal vesicle
30% prostate
10% sperm and fluid from vas deferens
<1% bulbourethral glands

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24
Q

What’s the pH of semen?

In semen, (blank) dissolves in 15-30 minutes due to fibrinolysin derived from profibrinolysin.

A

7.2-8.0

coagulum

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25
Compare how long semen lasts in the vas deferens and epididymis vs the female tract
1 month in vas deferens, 1-2 days in female
26
This can keep sperm alive for years!
cryopreservation
27
Making sperm capable of fertilizing the egg | Occurs naturally in the female genital tract
capacitation
28
How long does capacitation take?
1-10 hours
29
Washing off inhibitory factors that suppress sperm activity Removing lipid/cholesterol vesicles and exposing the acrosome so that acrosomal enzymes can be released Sperm membrane becomes more permeable and Ca2+ enters the sperm, triggering hyperactivated motility, which is essential for penetrating zona pellucida
Changes that occur with capacitation
30
Washing the semen with (blank) or capacitating medium can capacitate the sperm. This is the first step in IUI.
HTF: human tubular fluid
31
What is the content of acrosome?
Hyaluronidase: dissolves connective tissues among multiple layers of granulose cells Proteolytic enzymes: dissolve zona pellucida
32
What is the acrosome derived from? Why is it essential?
from the golgi apparatus during spermiogenesis; essential for sperm to fertilize eggs
33
Spermatogenesis in the testis requires a temp of (blank) degrees below body temp. What things keep the scrotum cool?
2; sweat glands; countercurrent heat exchange, reflex regulation of scrotal surface area, reflex regulation of distance from abdomen (retraction/ lengthening)
34
Failure of one or both of the testis to descend
cryptorchidism
35
1-3 months before birth, testis descend through the inguinal canal into the scrotum. What triggers this? If the testis do not descend before birth, they usually do so within months after birth. If not, what can done?
testosterone from the fetal Leydig cells; testosterone treatment or surgery after one year
36
Testes that remain in the abdomen can cause spermatogenic block leading to depletion of germ cells and (blank). Can also lead to tumorigenesis.
sterility
37
Average sperm count/ml vs infertile sperm count
120 mill/ml | <20 mill/ml
38
Things that can cause low sperm count
sperm deformation | abnormal sperm motility (structural or metabolic)
39
Neural stimulus for performance of the male sexual act: sexual stimulations from the sex organs Impulses->(blank) nerve->sacral plexus->sacral portion of spinal cord Psychic stimulation from the brain: thinking, dreaming (nocturnal emissions) Impulses from brain and/or sex organs are integrated in the sacral and lumbar spinal cord
pudendal
40
What is the parasympathetic nerve flow to the penis?
sacral portion of spinal cord-->pelvic nerves-->penis
41
relaxes penile arteries and trabecular meshwork of smooth muscle fibers in the erectile tissue of the corpora cavernosa and corpus spongiosum in the shaft of the penis
NO
42
Testosterone is synthesized from (blank). What is its origin? What is in bound to in the circulation?
cholesterol; leydig cells of the testis; sex hormone binding globulin or albumin
43
Testosterone can be converted to (blank) by 5-alpha reductase in the liver and target tissues. This is in low abundance, but has high affinity for androgen receptors. Testosterone can also be aromatized to form (blank)
DHT; estradiol
44
T/F: Testosterone has a bell shaped curve during gestation, and then drops low at birth. During neonatal life, there is a spike in testosterone, and then it declines until puberty. Then, it remains relatively high until old age.
True
45
When does testosterone production start in fetal development?
~week 7
46
Development of adult primary and secondary sexual characteristics: Further development of external and internal genitalia Development of 20 sexual characteristics Distribution of body hair Baldness: genetic background + large amount of androgen Voice Increased skin thickness: acne Increased muscle development: abuse by athletes Increased bone matrix and calcium retention Increases basal metabolism
Functions of testosterone
47
In the adult: gonadal steroid actions are no longer concerned with establishing the individual as a male or female; rather, they ensure that the (blank) functions effectively.
reproductive system
48
In men, (blank) regulates the re-absorption of luminal fluid in the head of the epididymis, allowing sperm to enter the epididymis concentrated rather than diluted.
estrogen
49
At what levels is estrogen found in men? Where is it produced?
at early follicular phase levels; from Leydig cells, Sertoli cells, and developing germ cells--> 2/3 from peripheral conversion
50
At what levels does testosterone provide negative feedback in the hypothalamo-pituitary-gonadal axis?
At the level of the pituitary gland (decreases pulse amplitude) and at the hypothalamic GnRH pulse generator (decreases LH pulse frequency)
51
What is the mechanism of action of LH?
LH-->LHR-->cAMP-->PKA
52
What is the action of LH?
testosterone production spermatogenesis (testosterone absolutely required) LHR Leydig cell growth and differentiation
53
What is the mechanism of action of FSH?
FSH-->FSHR-->cAMP-->PKA
54
What is the action of FSH?
spermatogenesis growth, differentiation and maintenance of Sertoli cells increased LHR on Leydig cells
55
What is the target of LH? What is the target of FSH?
Leydig cells; Sertoli cells
56
T/F: both testosterone and inhibin control FSH levels
true
57
At what age do males' T levels begin to decline (called "andropause")? What are some associated symptoms?
at ~age 40; hot flashes, suffocation, psychic disorders
58
What is necessary for control of FSH secretion (proven in monkey castrate experiment)
Inhibin
59
What two things produce negative feedback from the testes to the hypothal?
inhibin and testosterone
60
Is DHT more important for male internal or external genital development?
external
61
What happens if you remove testes?
Accessory sex organs will regress - epithelia shrink and diminished secretory activity Muscular mass decreases Decreased (not lost) libido Prevention of male baldness, decrease in kidney and liver weight and RBC synth
62
Also called Fröhlich's syndrome, or hypothalamic eunuchism Hypothalamus: deficiency in GnRH production Abnormalities in the feeding center of the hypothalamus: overeat->obesity
adiposogenital syndrome
63
Overproduction of androgens
hirsutism and virilization | can cause facial hair, body hair, and enlarged clitoris

Block 3 Week 7 (10 decks)

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