Male Reproductive Physiology

Question 1

sexual excitement causes CNS activation of ___ neurons innervating internal pudendal arteries, causing release of nitric oxide (NO)

Answer 1

parasympathetic

Question 2

During ejaculation, spinal reflex is initiated over sympathetic nerves serving genital organs, resulting in: (1)

Answer 2

ductus deferens, prostate, and seminal glands contract and empty contents into prostatic urethra; bladder internal sphincter muscle constricts, preventing expulsion of urine or reflux of semen into bladder

Question 3

During ejaculation, spinal reflex is initiated over sympathetic nerves serving genital organs, resulting in: (2)

Answer 3

Semen in urethra triggers spinal reflex through
somatic neurons; bulbospongiosus muscles undergo rapid series of
contractions that cause expulsion of semen

Question 4

latent (refractory) period

Answer 4

time during which man is unable to achieve another orgasm

Question 5

erectile dysfunction

Answer 5

parasympathetic nerves of penis release too little NO, leading to inability to attain erection

Question 6

spermatogenesis

Answer 6

process of forming male gametes; occurs in seminiferous tubules

Question 7

Seminiferous tubules

Answer 7

consist of a thick stratified epithelium surrounding a central fluid-filled lumen containing four important types of cells

Question 8

Seminiferous tubules contain four important types of cells:

Answer 8

sustenocytes, spermatogenic cells, myoid cells, interstitial endocrine cells

Question 9

sustenocytes

Answer 9

large columnar cells act as supporting cells and play role in sperm formation

Question 10

spermatogenic cells

Answer 10

cells that are surrounded by sustentocytes and give rise to sperm

Question 11

myoid cells

Answer 11

smooth muscle-like cells surrounding seminiferous tubule that contract to squeeze sperm and testicular fluid through tubules

Question 12

interstitial endocrine cells (Leydig cells)

Answer 12

produce androgens and some estrogen

Question 13

three steps of spermatogenesis

Answer 13

mitosis of spermatogonia, meiosis, spermiogenesis

Question 14

mitosis of spermatogonia (stem cell)

Answer 14

forms two spermatocytes

Question 15

meiosis

Answer 15

spermatocytes form secondary spermatocytes, which form spermatids

Question 16

spermiogenesis

Answer 16

spermatids become sperm

Question 17

spermatogonia

Answer 17

stem cells that are in direct contact with epithelial basal lamina that divide more or less continuously by mitosis

Question 18

After puberty, each division of stem cells produces:

Answer 18

Type A daughter cells (remain at basal lamina to maintain pool of dividing germ cells); Type B daughter cells (move toward lumen and develop into primary spermatocytes)

Question 19

meiosis

Answer 19

spermatocytes to spermatids

Question 20

spermiogenesis

Answer 20

spermatids to sperm

Question 21

contains hydrolytic enzymes that enable sperm to penetrate egg

Answer 21

acrosome (found in head of sperm)

Question 22

sperm midpiece

Answer 22

metabolic region containing mitochondria that produce ATP to move tail

Question 23

role of sustenocytes

Answer 23

large supporting cells extend from basal lamina to tubule lumen and surround developing spermatogonium

Question 24

sustentocytes contain tight junctions that divide tubule into two compartments

Answer 24

basal and adluminal

Question 25

basal compartment

Answer 25

basal lamina to tight junctions; spermatogonia and primary spermatocytes located here

Question 26

adluminal compartment

Answer 26

internal to tight junction; area where meiotically active cells and tubule lumen are located

Question 27

tight junctions form the blood testis barrier

Answer 27

prevents sperm antigens from escaping into blood and causing activation of immune system

Question 28

testicular fluid

Answer 28

rich in androgens and metabolic acid; secreted by sustenocytes

Question 29

androgen-binding protein (ABP)

Answer 29

keeps testosterone levels high to stimulate spermatogenesis

Question 30

referred to as the hypothalamic-pituitary-gonadal (HPG) axis

Answer 30

sequence of hormonal events involving hypothalamus, anterior pituitary gland, and testes that regulates the production of gametes and sex hormones

Question 31

testosterone is converted to what in the prostate

Answer 31

digydrotestosterone (DHT)

Question 32

testosterone is converted to what in some brain neurons

Answer 32

estradiol