Physiology: Male Reproductive System

Question 1

Components of Male Reproductive System

Answer 1

Testis: sperm, steroid hormones
Epididymis: sperm maturation and storage
Vas Deferens: sperm carrier
Seminal Vesicle: seminal secretion
Prostate Gland: acid phosphatase, proteases, PSA

Question 2

Onset of Puberty

Answer 2

Begin 10-11 yrs; Ends 15-17 yrs
Activation of GnRH neurons
FSH rises followed by LH
Increase in testicular volume
Rise of testosterone - induces pubic hair, penile growth, sperm production, linear body growth
2 years after adult levels of testosterone results in ceasing of linear growth

Question 3

Functions of Testis

Answer 3

Spermatogenesis

Steroidogenesis

Question 4

Testis Anatomy

Answer 4

80% of testis comprised of seminiferous tubule
Wall contains germ cells and Sertoli cells, surrounded by basement membrane (peritubular myoid cells)
Sperm production occurs in seminiferous tubules
Intertubular space - contains Leydig cells

Question 5

Interstitial Cells of Leydig

Answer 5

LH sensitive, androgen producing cells

Question 6

Sperm Production

Answer 6

Ends with death

100-200 million per day

Question 7

Stages of Spermatogenesis

Answer 7

1. Primary Spermatogonium
2. Secondary Spermatogonium
3. Primary Spermatocyte
4. Secondary Spermatocyte
5. Spermatid
6. Spermatozoon

Question 8

Spermatogenesis

Answer 8

Occurs between 2 adjacent Sertoli cells - which form a tight junction creating Blood Testis Barrier
Germ cells move from basal to luminal side
Spermatids attach to Sertoli cells, penetrate into cytoplasm, undergo Spermiogenesis
Cytoplasms shrinks, chromosome condenses, arcosome sac appears, flagellum develops
Spermatozoa are transported into the epididymis by Spermiation

Question 9

Changes in Spermiogenesis

Answer 9

Cytoplasms shrinks, chromosome condenses, arcosome sac appears, flagellum develops

Question 10

Spermiation

Answer 10

transport of spermatozoa into epididymis

Question 11

Regulation of Spermatogenesis

Answer 11

FSH maintains Sertoli cell functions

Testosterone vital for completion of meiosis of primary spermatocytes

Question 12

Steroidgenesis

Answer 12

Testosterone is synthesized in Leydig cells from cholesterol, regulated by LH

Question 13

Leydig Cells

Answer 13

synthesize testosterone, estradiol-17B, and growth factors

Question 14

Testosterone Physiology

Answer 14

Reduced in target tissue to 5a-DHT

Binds to sex steroid binding globulin and albumin

Question 15

Functions of DHT - Intrauterine Differentiation

Answer 15

Penis
Scrotum
Urethra
Prostate
Male Type Imprint (E2, T, and DHT)

Question 16

Functions of Testosterone - Intrauterine Differentiation

Answer 16

Epididymis
Vas Deferens
Seminal Vesicles
Male Type Imprint (E2, T and DHT)

Question 17

Functions of Estradiol - Intrauterine Differentiation

Answer 17

Male Type Imprint (E2, T and DHT)

Question 18

Functions of DHT - Pubertal Development

Answer 18

Sebum formation
Development of prostate gland
Penis
Sperm production (E2, DHT, and T)

Question 19

Functions of Testosterone - Pubertal Development

Answer 19

Beard growth
Seminal vesicles
Sperm production (E2, DHT, and T)
Increased: VLDL, LDL; decreased: HDL
RBC
Muscle mass
Upper body fat
Larynx - muscle growth, male voice