Male Repro Lab

3 parts of male reproductive system

• gonads (testes) → sperm and hormones

• Accessory glands → semen fluid

• Penis/ducts → transport and delivery

Path of sperm

Seminiferous tubules → rete testis → efferent ducts → epididymis (caput, corpus, cauda) → vas deferens → pelvic urethra → accessory glands → penis

Where do sperm form?

Seminiferous tubules

Where do sperm mature?

Epididymis

Where are sperm stored?

Cauda epididymis

Where do sperm gain fluid?

Accessory glands

What happens in seminiferous tubules?

• site of spermatogenesis

• Contain germ cells + Sertoli cells

• Surrounded by basal lamina

Order of spermatogenic cells (outer → inner)

Spermatogonia → primary spermatocytes → secondary spermatocytes → spermatids → sperm

Trend: smaller and closer to lumen = more mature

Key features of primary spermatocytes

• largest germ cells

• Undergo meiosis I

• Prominent round nucleus

Why are secondary spermatocytes rarely seen?

Divide quickly → become spermatids

Sertoli cell functions

• nourish sperm

• Form blood-testis barrier

• Move sperm to lumen

• Phagocytose residual bodies

• Controlled by FSH

How to identify Sertoli cells

• large, pale nucleus

• Irregular shape

• Not round

• Borders unclear

Leydig cell function and location

• between tubules (interstitial)

• Produce testosterone

• Controlled by LH

3 phases of spermatogenesis

1. Spermatocytogenesis (mitosis)

2. Meiosis

3. Spermiogenesis (shape change)

When do cells become haploid?

During meiosis → spermatids are haploid

Parts of epididymis

Caput → corpus → cauda

Function of each epididymis region

• caput → fluid removal

• corpus → maturation

• Cauda → storage

How do sperm move in epididymis?

• fluid flow

• Smooth muscle contractions

Why must testes be cooler?

Required for normal sperm production

Function of pampiniform plexus

• heat exchanger

• Cools arterial blood

Function of tunica dartos

• adjusts scrotal temperature

• Smooth muscle

Function of cremaster muscle

Raises/lowers testes

Main role of accessory glands

Produce most of semen fluid

List of accessory gland types

• seminal vesicles

• Prostate

• Bulbourethral glands

• Ampullae

Where is the prostate located?

Near pelvic urethra

Two types of penis

• fibroelastic

• Musculocavernous

Key traits of fibroelastic penis

• rigid

• Sigmoid flexure

• Erection = straightening

Key traits of musculocavernous penis

• fills with blood

• Increases diameter

Blood-testis barrier

Protects sperm from immune system

How long does sperm production take?

about 55-80 days total