Study sheet: Male Reproductive System Functions

📋 Course Outline

1. Penis Structure and Erection
2. Male Reproductive System Facts
3. Semen Composition and Functions
4. Male Reproductive Disorders

📖 1. Penis Structure and Erection

★ Must-know

• The penis contains two dorsal corpora cavernosa and one ventral corpus spongiosum, which are richly supplied with blood vessels and contain blood sinuses.

• During sexual stimulation, blood rapidly enters the penile blood sinuses while drainage is prevented, causing the penis to become stiff and rigid.

Further detail

• Penile erection helps deposit semen into the female vagina.

• The penis increases in length from about 2½ to 3 inches to about 4 to 7 inches during erection.

💡 Memory Hook

Sexual stimulation → blood enters sinuses → drainage is prevented → erection

📖 2. Male Reproductive System Facts

★ Must-know

• The male reproductive system is located in the pelvic region.

• More than 50% of the total volume of human semen comes from the seminal vesicles, while 20% comes from the prostate gland.

Further detail

• Fructose provides energy for sperm and also provides a forensic test in rape cases.

• Prostaglandins stimulate vaginal contractions that help sperm move upward through the female genital tract toward the ovum.

• Each epididymis is comma-shaped, and the stereocilia on the free surface of its columnar cells are actually microvilli that absorb degenerated sperm.

📖 3. Semen Composition and Functions

🔑 Key Concepts & Definitions

• Semen : a fluid consisting of sperm and the secretions of the passages and male glands through which sperm pass, including the prostate, seminal vesicles, and Cowper’s gland

★ Must-know

• Semen provides sperm with nutrients, neutralizes vaginal acidity, and induces contractions in the female uterus and fallopian tubes that speed sperm toward the ovum.

• Semen is basically alkaline, clots soon after ejaculation, and liquefies after about 20 minutes.

Further detail

• Fibrinogen causes semen clotting, while plasmin dissolves the clot.

💡 Memory Hook

Sperm and glandular secretions → alkaline semen → clotting → liquefaction

📖 4. Male Reproductive Disorders

🔑 Key Concepts & Definitions

• Impotence : the inability to achieve or maintain a penile erection long enough to complete sexual intercourse
• Sterility : the inability of sperm to fertilize an ovum
• Androgen deficiency in ageing males : also called male menopause, results from reduced testosterone production
• Hydrocele : the collection of fluid, usually in the tunica vaginalis of the testis

★ Must-know

• Cryptorchidism occurs when the testes do not descend into the scrotum and leads to sterility.

Further detail

• Prostate cancer is a common malignancy accounting for 2 to 3% of male deaths.

💡 Memory Hook

Impotence prevents erection, whereas sterility prevents fertilization

📊 Synthesis Tables

Male Reproductive Disorders

Disorder	Defining feature	Consequence or cause
Impotence	Inability to achieve or maintain erection	Prevents completion of intercourse
Sterility	Sperm cannot fertilize an ovum	Prevents fertilization
Androgen deficiency in ageing males	Reduced testosterone production	Also called male menopause
Cryptorchidism	Testes do not descend into scrotum	Leads to sterility
Hydrocele	Fluid collection in the tunica vaginalis	Fluid-related condition
Prostate cancer	Common malignancy	Accounts for 2 to 3% of male deaths