Short Male Reproductive

Primary function of male reproductive system?

Produce and deliver sperm

Male gonads?

Testes

What do testes produce?

Sperm and testosterone

Where does spermatogenesis occur?

Seminiferous tubules

What cells support developing sperm?

Sertoli cells

Function of Sertoli cells?

Nourish sperm and produce inhibin

What cells produce testosterone?

Leydig cells

Where are Leydig cells located?

Between seminiferous tubules

Optimal temperature for testes?

~3°C below body temperature

Why are testes in scrotum?

To maintain lower temperature for sperm production

What is spermatogenesis?

Production of sperm via meiosis

Final product of spermatogenesis?

Spermatozoa

Where do sperm mature and gain motility?

Epididymis

Function of epididymis?

Sperm maturation and storage

Function of vas deferens?

Transport sperm to urethra

What is vasectomy?

Cutting vas deferens for sterilization

Accessory glands?

Seminal vesicles, prostate, bulbourethral glands

Seminal vesicles contribute what?

60–70% of semen (fructose-rich fluid)

Function of fructose in semen?

Energy source for sperm

Prostate gland function?

Secretes alkaline fluid that activates sperm

Bulbourethral gland function?

Secretes mucus to neutralize urethra

What is semen?

Sperm + gland secretions

Why is semen alkaline?

Neutralizes acidic female environment

Typical semen volume?

2–5 mL

Normal sperm count?

~50–130 million/mL

Sperm structure consists of what three parts?

Head, midpiece, tail

Head contains what?

DNA and acrosome

Function of acrosome?

Enzymes to penetrate egg

Midpiece contains what?

Mitochondria for ATP

Tail function?

Motility (flagellum)

What is erection?

Blood filling erectile tissue

Erection controlled by what system?

Parasympathetic nervous system

Key molecule in erection?

Nitric oxide (NO)

NO causes what?

Vasodilation via cGMP → smooth muscle relaxation

What maintains erection?

Compression of veins (reduced outflow)

What is ejaculation?

Release of semen

Ejaculation controlled by what system?

Sympathetic nervous system

What prevents urine during ejaculation?

Bladder sphincter contraction

HPG axis stands for what?

Hypothalamic-pituitary-gonadal axis

Hypothalamus releases what?

GnRH

GnRH stimulates release of what?

FSH and LH

FSH acts on what cells?

Sertoli cells

FSH function?

Stimulates spermatogenesis

LH acts on what cells?

Leydig cells

LH function?

Stimulates testosterone production

Testosterone function?

Maintains spermatogenesis and male traits

What is inhibin?

Hormone from Sertoli cells that inhibits FSH

Testosterone provides what type of feedback?

Negative feedback on GnRH and LH

Testosterone is derived from what?

Cholesterol

Testosterone converts to what for external genitalia?

DHT (dihydrotestosterone)

What enzyme converts testosterone to DHT?

5-alpha reductase

DHT function?

Development of male external genitalia

Male secondary sex characteristics include what?

Facial hair, deep voice, muscle mass

Testosterone effect on voice?

Deepening

Testosterone effect on muscles?

Increased mass

Testosterone effect on libido?

Increases sex drive

What is cryptorchidism?

Undescended testes

Why is cryptorchidism a problem?

Can cause infertility and cancer risk

Normal sperm pathway?

Testes → epididymis → vas deferens → ejaculatory duct → urethra

Where do sperm and gland fluids mix?

Ejaculatory duct

Urethra carries what?

Urine and semen