NATS 1675 16.2 LN's

Male Reproductive System (Ducts and Glands)

Sperm pathway through the duct system

Seminiferous tubules → Efferent ductules → Epidiymis → Vas deferens → Ejaculatory duct → Urethra → Ejaclation

What controls the concentration of testosterone?

A negative feedback loop. Involves the hypothalamus, anterior pituitary, testes and many hormones.

What is spermatogenesis?

The process through which sperm is formed.

Efferent Ductulus

• 12 ciliated ducts

• Collect sperm from seminiferous tubules within testes

Ducts of epididymis

• single 6m long tight coil

• adheres to posterior of testis

• site of maturation and storage

• sperm mature as they move thought he duct

• extends from testis to vans deferens

What happens when sperm not ejaculated?

They disintegrate and are reabsorbed by epididymis

How does sperm move through the epididymis?

1. contracts of smooth muscle

2. pressure from fluid and spermatozoa entering the duct

How is sperm protected and kept healthy?

1. Molecules secreted by the duct lumen maintain pH and antioxidants

2. Blood-Epididymis Barrier

3. White blood cells protect from blood born pathogens

Ductus (Vans) deferens

• muscular 45 cm tube

• extends from epididymis to urinary bladder

Ejaculatory duct

• 2 cm long duct

• formed from union of vans deference with seminal vesicle

• passes through prostate gland

• empties into urethra

Urethra

• 18 cm long duct

• shared by reproductive and urinary systems

What are the 3 regions of the urethra?

Prostatic, Membranous, and Spongy (penile).

What are 3 male accessory glands?

Include the prostate gland, seminal vesicles, and bulbourethral glands

Seminal vesicles

• pair of glands posterior to bladder

• attached other vas deferens near base of urinary bladder

• secret alkaline fluid (fructose and prostaglandins)

• empties into ejaculatory duct

• forms 60% of semen

Prostate glands

• surrounds urethra and ejaculatory duct

• secrets milky fluid → forms 30% of semen

• alkaline secretion activates sperm and reduces acidity of repo. tracts

Bulbourethral (cowper) glands

• pair of glands near bulb of penis

• produces clear slippery fluid when aroused

Semen components

1. sperm cells

2. secretions from seminal vesicles, prostate and bulbourethral glands

3. prostaglandins

Semen alkaline solution

• Vol 2-5ml per ejaculation

• Avrg 120 mill sperm cells per ml of semen

Semen

seminal fluid that passes though the urethra to the outside during ejaculation

Penis

• 3 cylindrical bodies of erectile tissue that are sponge-like

• Two Corpora cavernosa and One Corpus spongiosum

• fill with blood during arousal

Vasectomy

Surgical procedure for male sterilization of permanent contraception

Vasectomy process

1. cut vas deferens and seal ends

2. no sperm in semen

3. testes continue to produce sperm

4. sperm flow doesn’t reach urethra/penis

5. sperm reabsorbed into body

Mitochondria is maternal

All paternal mitochondria used in sperm for movement

Decline of sperm count and quality

Past 50+ years. Linked to plastics in environment. Observed in other animals.

Viagra

• OG for cardiac medication to dilate blood vessels

• effective in reversing erectile dysfunction

• enhances nitric oxide (more dilation of blood vessels)