Exam 5 - Anatomy and Gamete Production

What are some of the primary functions of the reproductive system?

• Make/store gametes

• Provide protection and nutrients for the developing zygote

Sertoli cells

“Nurse cells”; supporting cells

• Supporting sperm development

  • Seminiferous tubules

Leydig Cell

Making testosterone

• in seminiferous tubules

Describe the steps of spermatogenesis

1. Spermatogonia (sperm stem cells)

2. primary spermatocytes

3. secondary spermatocytes

4. spermatids

5. spermatozoa

What is the difference between spermatogenesis, spermiogenesis, and spermiation?

Spermatogenesis: The entire process of producing sperm

Spermiogenesis: Spermatids becoming spermatozoa

Spermiation: Release of sperm into the lumen

Acrosome

Tip of the sperm used to degrade the secondary oocyte’s barrier

Mitochondrial Sheath

Sheath of the sperm used to produce ATP for movement

Tail

Flagella used for propulsion

What is capacitation and why is it important for fertilization?

Hyper-activation of the sperm tail

• helps sperm to penetrate the secondary oocyte

What causes capacitation?

Progesterone binds to sperm cells → Calcium channels open + influx of Na+

What does luteinizing hormone target?

Targets Leydig cells to produce testosterone

What does testosterone do for the male reproductive tract?

• Stimulates final steps of spermatogenesis

• Inhibits LH

• Develops secondary sex characteristics

What does follicle-stimulating hormone target?

Targets Sertoli cells to promote spermatogenesis

What hormones do Sertoli cells release and what do they do?

• Inhibin: inhibits FSH

• ABP (androgen-binding protein): keeps local testosterone high

What are stimuli for the Erection Reflex?

1. Touch (mechanoreceptors of the glans penis)

2. Cerebrum (thoughts of sex)

Which effectors are involved in the Erection Reflex?

1. Bulbourethral gland

2. Bulbospongiosal muscle

3. Cavernous trabecular arteries

What does the bulbourethral gland do in the erection reflex?

Secrete bicarb (HCO₃^-) and mucous

• Mucous for sperm protection (mechanical and chemical)

What does the bulbospongiosal muscle do in the erection reflex?

Contraction to compress the penile venules

• Prevent blood flow from leaving

What do the cavernous trabecular arteries do in the erection reflex?

Nitric oxide release → vasodilation

Increase in blood flow, increase in hydrostatic pressure