Outline-4, BIO 2320 Male Reproductive System


A. Scrotum (cremaster)

Supports testes, cremaster muscle can move testes closer to or farther from body

B. Testes– Male gonad

1. Tunica albuginea

Dense white connective tissue covering testis

2. Lobules (200-300) – Compartments

3. Seminiferous tubules

Tightly coiled tubules where sperm are produced

Spermatogenesis (5-10 weeks) (300 million/day) – process of making sperm

1. Spermatogonia [mature, grow to become…]

2. Primary spermatocytes [meiosis I…]

3. Secondary spermatocytes [meiosis II…]

4. Spermatids

Haploid, matures to…

5. Spermatozoon

a. Head



b. Midpiece – numerous mitochondria

c. Tail – propels

4. Straight tubules

5. Rete testes – tubular network

6. Interstitial cells (Leydig)

a. Testosterone

1. Sperm production

2. Sexual drive

3. Secondary sex characteristics

C. Puberty

1. Signs

2. Hormones

a. Testosterone made by interstitial cells of testes

b. GnRH = Gonadotropin Releasing Hormone, Stimulates pituitary gland to produce:

c. LH = ICSH – Interstitial cell stimulating hormone

d. FSH-Stimulates spermatogenesis

e. Inhibin

Inhibits FSH

Male sex hormones including GnRH, Inhibin, FSH, Testosterone, and LH which is also known as ICSH.

D. Epididymis

Comma-shaped, posterior to testis

1. Head

Superior, receives sperm from testes

2. Body

3. Tail

Inferior, empties into ductus deferens

E. Ductus deferens (vas)

1. Spermatic cord

Includes ductus deferens plus vessels, nerves…

2. Inguinal canal

Passageway through body wall for spermatic cord

F. Urethra

1. Prostatic

2. Membranous

after prostate, before penis

3. Spongy = Penile

through penis to…

4. External urethral orifice

G. Accessory sex glands

1. Seminal vesicles

2. Prostate

3. Bulbourethral (Cowper’s)

4. Semen

Sperm plus liquids from accessory sex glands which nourishes sperm, buffers acid pH in vagina, helps to propel and activate sperm , 2 1/2 – 5 mls per ejaculate, about 300 million sperm

H. Penis

1. Erectile tissue


2. Corpus cavernosum

Dorsolateral penis, responsible for most of erection

3. Corpus spongiosum

Erectile tissue surrounding urethra

4. Glans penis

Distal end of penis covered by…

5. Prepuce – Foreskin

I. Sexual responses

1. Erection

Penis enlargement and rigidity, vascular phenomenon, parasympathetic nerve impulses cause arteriole dilation

2. Emission

First part of male orgasm mediated by sympathetic nerve impulses resulting in propulsion of sperm to urethra and release of seminal fluids from accessory sex glands

3. Ejaculation

Contractions that result in release of semen from urethra

Spermatogenesis video