Male Physiology

Question 1

Hormones secreted by anterior pituitary?

Answer 1

TSH – thyroid stimulating hormone
FSH – follicle stimulating hormone
LH  - luteinizing hormone
GH – growth hormone
ACTH – adrenocorticotrophic hormone
Prolactin

Question 2

Anterior pituitary is linked to hypothalamus via the _______________.

Answer 2

hypothalamic-hypophyseal portal blood vessels

Question 3

How is LH and FSH release controlled?

Answer 3

hypothalamus releases GnRH to stimulate LH and FSH secretion from anterior pituitary

Sertoli cells release inhibin to decrease LH and FSH release

Question 4

What is the significance of having testes suspended in scrotum?

Answer 4

sperm development in testes requires a temp cooler than core body

Question 5

Testes are composed primarily of ___________ packed together.

Answer 5

seminiferous tubules

Question 6

Contents of spermatic cord

Answer 6

testicular artery and vein, lymphatics, nerves, and vas deferens

Question 7

What are roles of FSH and LH on testes?

Answer 7

FSH stimulates Sertoli cells to produce inhibit and germ cells that mature into spermatozoa

LH stimulates Leydig cells to produce testosterone

Question 8

Describe process of a sperm to mature

Answer 8

• 3 step process (Mitosis; Meiosis; Spermiogenesis), taking approximately 74 days
• spermatozoon released into tubule lumen and pass through efferent ducts into epididymis. Sperm continuing maturing for another 21 days in epididymis
• Spermatogenesis first occurs at puberty and continues throughout life

Question 9

Where do sperm acquire their motility?

Answer 9

epididymis

Question 10

Where does sperm go after maturing in epididymis?

Answer 10

vas deferens -> seminal vesicles -> ejaculation duct -> prostatic urethra

Question 11

typical prostate size for 50 year old

Answer 11

40 g

Question 12

Location of prostate

Answer 12

base of bladder, surrounds urethra

Question 13

Pathophysiology behind BPH causing urinary symptoms

Answer 13

prostate surrounded by tough, fibrous capsule so growth goes inward and constricts urethra

Question 14

What makes smooth muscle contract?

Answer 14

alpha sympathetic nervous system

Question 15

______ is produced by epithelial cells in prostate and can be measured in serum.

Answer 15

PSA

Question 16

Females only source of testosterone and 5% of male testosterone production occurs where?

Answer 16

adrenal gland and peripheral tissue

Question 17

What enzyme converts testosterone to DHT?

Answer 17

5 alpha-reductase

Question 18

sperm : seminiferous tubules

testosterone : _______

Answer 18

interstitial space of testes

Question 19

backbone of all steroid hormones is

Answer 19

cholesterol

Question 20

A healthy male produces about ______ testosterone daily.

Answer 20

5 mg

Question 21

Where is testosterone converted to DHT in body?

Answer 21

prostate and hair follicles

Question 22

Med that can treat both male pattern baldness and BPH

Answer 22

5-alpha-reductase inhibitors (increases testosterone)

Question 23

Beneficial effect of DHT

Answer 23

development of secondary sex characteristics; critical for external genitalia development in boys

Question 24

A female hormone produced in small amounts in males from conversion of testosterone

Answer 24

estradiol

Question 25

Sign of elevated estradiol in males

Answer 25

hepatic impairment -> spider angioma

Question 26

Testicular feminization syndrome

Answer 26

Male hormone levels are normal, but tissues lack adequately androgen receptor

Prevents masculinization of male genitalia in the developing fetus, as well as development of male secondary sexual characteristics at puberty

May result in ambiguous genitalia in new born, or a female body habitus in a genetic male

Question 27

Parasympathetic controls ______ of penis.

Answer 27

erection

Question 28

Sympathetic controls ______ of penis.

Answer 28

ejaculation;

contracts epididymis, vas deferens, seminal vesicles, and prostate

Question 29

Nitric oxide effects on smooth muscles

Answer 29

induces relaxation of vascular smooth muscle

NO stimulates cGMP to activate protein kinase -> vasodilation

Question 30

MOA of Viagra

Answer 30

inhibit phosphodiesterase activity, leaving more cGMP in tissue and hence longer vasodilation (erection)

Question 31

Sympathetic fibers to penis travel from ______ via the hypogastric plexus.

Answer 31

T11-L2

Question 32

Parasympathetic fibers to penis travel from ____ in sacral spinal nerves.

Answer 32

S2-S4

Question 33

Enzyme that converts testosterone to DHT

Answer 33

5-alpha-reductase

Question 34

Sensory innervation of penis skin? where does it originate?

Answer 34

dorsal nerve of penis

originates from S2-S4 of pudenal nerve

Question 35

Physiology behind priapism

Answer 35

clogging of venous drainage from penis

Question 36

3 physiological problems that can cause erectile dysfunction

Answer 36

1. Failure to initiate (psychogenic, endocrine, neurogenic)
2. Failure to Fill (arteriogenic)
3. Failure to store (veno-occulusive problem)

Question 37

Testosterone is bound to what in blood stream?

Answer 37

• sex hormone binding globulin (SHBG)
• albumin

~2% unbound

Question 38

Tissue compartments of penis that fill with blood during erection?

Answer 38

3 erectile columns: 2 corpora cavernosa and the corpus spongiosum