Male Reproductive System

Gonads (Testes)

• produce gametes (sperm cell)

• secrete sex hormones (testosterone)

Ducts

• stores & transports gametes

Accessory Glands

• creates substances that help protect & move the gametes

Scrotum

sac of loose skin that houses the Testes

Function of SCROTUM

• protects the Testes

• keeps it 2-3 degrees cooler = healthy sperm

Scrotal Septum

• Wall of flexible C.T.

• smooth muscle (Dartos)

Function of SCROTAL SEPTUM

• separates the Testes

• prevents friction

Dartos Muscle

wrinkles the skin (Scrotum)

= keeps warm

Cremaster Muscle

elevates/lowers the Testes closer/away from the body
= temperature regulation + protection

Testes

paired, oval glands inside the Scrotum

Function of TESTES

• sperm production

• secretes Testosterone

Spermatogenic Cells

lines the Seminiferous Tubules

• forms sperm

Sustentacular (Sertoli) cells

secretes Inhibin → inhibits FSH

• protects/supports the Spermatogenic cells

Blood-Testis Barrier

tight junctions between Sertoli cells (near the base of Seminiferous Tubules)

• isolates Spermatogenic cells w/ diff. DNA (→ “foreign”) that Immune System might attack

Interstitial (Leydig) cells

between Seminiferous Tubules

• produces Testosterone (LH)

Seminiferous Tubules

main pathway of the Sperm as fluid flows through the Testes

→ Straight Tubules → Rete Testis → Efferent Ducts

Epididymis

site of sperm maturation + storage

• acquires motility/ability to fertilize Ovum

• takes months

Ductus (Vas) Deferens

muscular wall that expels Sperm during Ejaculation (via contractions)

→ goes up Spermatic Cord → loops over Ureter → goes down posterior Bladder → empties into Ejaculatory Duct

Ejaculatory Ducts

receives the Sperm from Ductus Deferens

• mixes with fluids from Seminal Vesicles + Prostate gland = Semen

• ejects Semen into Urethra

Urethra

carries Semen out of the body

Prostatic → Membranous → Spongy → EXTERNAL URETHRAL ORIFICE

Seminal Vesicles (60% of semen)

paired, pouch-like

→ secretes alkaline (females are acidic), vicious fluid with…

• Fructose = ATP production

• Prostaglandins = sperm motility/viability

• Coagulation Proteins = prevents leaking

Prostate Gland (25% of semen)

single, golf ball-sized

→ secretes slightly acidic, milky fluid with…

• Citric Acid = ATP production

• Seminal Plasmin = antibiotic

• Enzymes (PSA) = enlargement increases chance of infections/cancer

Bulbourethral (Cowper’s) Gland

paired, pea-sized

→ secretes alkaline fluid into Urethra during sexual arousal

• neutralizes acidity of urine

• creates mucus for lubrication

Penis is also known as…

“Genitourinary” = works with both Reproductive & Urinary

Corpus Cavernosa (2)

sexual stimulation = smooth muscle relaxes (Penis)

• increased blood flow in arteries = hard/rigid ERECTION

Corpus Spongiosum (1)

• ensures Urethra stays open for Ejaculation

• expands at the end for cushioning = Glans Penis (tip)

Erection

caused by Mechanical stimuli

→ Parasympathetic reflex = Nitric Oxide

• Arterioles dilate = increased blood flow but compressed veins

Ejaculation

Sympathetic reflex: forces ducts & pelvic floor muscles to contract

= releases Semen