Physio: male repro

Question 1

2 functions in the male reproductive system controlled by the hypothalamic pituitary gonadal axis.

Answer 1

1. Spermatogenesis in the seminiferous tubules

2. Testosterone Synthesis in the Leydig Cells

Question 2

Function of FSH in the male reproductive system.

Answer 2

Binds sertoli cells:

-induces production of Androgen Binding Protein

Question 3

Function of Androgen Binding protein

Answer 3

Binds testosterone to maintain elevated hormone levels locally in the seminiferous tubules to induce the maturation of sperm cells.

Question 4

Function of LH in the male reproductive system.

Answer 4

Binds Leydig cells and induces the production of testosterone.

Question 5

Function of inhibin.

Answer 5

Made by sertoli cells, acts as negative feedback for FSH release from the anterior pituitary

Question 6

Functions of testosterone at puberty.

Answer 6

Spermatogenesis
Hair growth
deepening of the voice
increased libido
growth of internal and external genitalia

Question 7

Functions of testosterone in postpubertal males.

Answer 7

• Maintains everything that occurred during puberty

- increased bone and muscle mass

Question 8

Why do exogenous androgenic steroids cause sterility?

Answer 8

The high serum testosterone (or DHT) levels inhibit the release of FSH and LH from the anterior pituitary.

The decrease in LH decreases Leydig cell testosterone production and decreased testosterone levels locally in the seminiferous tubules.

The decreased FSH prevents Androgen Binding Hormone production in the Sertoli cells. This prevents “trapping” the locally produced testosterone from remaining in the seminiferous tubules.

Question 9

Name the 5 stages of spermatogenesis.

Answer 9

1. Spermatogonia
2. Primary Spermatocytes
3. Secondary Spermatocytes
4. Spermatids
5. Spermatozoa

Question 10

What is spermiogenesis?

Answer 10

Maturation of Spermatids into Spermatozoa

• loss of cytoplasm
• addition of tail

Question 11

What part of the spermatozoa contains the mitochondria for energy production?

Answer 11

Midpiece

Question 12

What forms the blood testis barrier to prevent toxic substances from reaching the developing spermatogonia?

Answer 12

Sertoli cells form tight junctions with one another creating the barrier. The sperm cells mature between the sertoli cells

Question 13

What allows nutrients thru the blood testis barrier?

Answer 13

Gap junctions between the sertoli cells

Question 14

Which 3 glands contribute to semen production?

Answer 14

Seminal Vesicles (fructose, PGs, fibrinogen)
Prostate (alkaline, clotting enzymes)
Bulbourethral Glands (lubrication)

Question 15

Components of the male reproductive tract innervated by the sympathetic nervous system.

Answer 15

Epididymis
Vas Deferens
Seminal Vesicles
Prostate
Internal Urethral Sphincter

Question 16

Components of the male reproductive tract innervated by the parasympathetic nervous system.

Answer 16

Cavernous blood vessels in the penis, causes vasodilation in arteries and venoconstriction in veins.

Question 17

What is the Erection Reflex?

Answer 17

Stimulation of the Mechanoreceptors in the glans penis activates the parasympathetic nervous system to effect blood vessels in the penis. The parasympathetics also stimulate mucus secretion from the bulbourethral glands.

Also activates sympathetics in peripheral blood vessels to move blood into penile vessels.

Question 18

What are the two phases of Ejaculation?

Answer 18

Emission Phase

Expulsion Phase

Question 19

What occurs during the emission phase of ejaculation?

Answer 19

Sympathetic Nervous system moves ejaculate into the prostatic urethra using peristaltic contractions of the vas deferens, seminal vesicles, and prostate.

It also causes contraction of the internal urethral sphincter.

Question 20

What occurs during the expulsion phase of ejaculation?

Answer 20

Once the ejaculate moves into the membranous urethra, the Spinal Reflex is triggered.

The somatic nervous system causes contraction of the ishiocarvernosus and bulbospongiosus muscles forcing expulsion of the ejaculate.