Human Reproductive System

• The human reproductive system is responsible for sexual reproduction
• Gametes (sperm and egg) fuse to form a zygote, which develops into a new individual
• The system includes organs that produce gametes and facilitate their union

Male Reproductive Anatomy

• The primary organs are the testes, which produce sperm and testosterone

Testes

• Located in the scrotum, an external sac that maintains a cooler temperature for optimal sperm production
• Seminiferous tubules produce sperm through spermatogenesis
• Interstitial cells (Leydig cells) produce testosterone, the primary male sex hormone

Ducts

• Epididymis: A coiled tube where sperm mature and are stored
• Vas deferens: A duct that transports sperm from the epididymis to the ejaculatory duct
• Ejaculatory duct: Formed by the union of the vas deferens and the seminal vesicle duct, it passes through the prostate gland and empties into the urethra
• Urethra: A tube that carries both urine and semen out of the body through the penis

Accessory Glands

• Seminal vesicles: Secrete a fluid rich in fructose, prostaglandins, and other substances that nourish and protect sperm
• Prostate gland: Secretes a milky fluid containing citrate, calcium, and enzymes that contribute to sperm motility and viability
• Bulbourethral glands (Cowper's glands): Secrete a clear, alkaline mucus that lubricates the urethra and neutralizes acidic urine

Penis

• The male copulatory organ, containing erectile tissue that fills with blood during sexual arousal, causing an erection
• The glans penis is covered by the prepuce (foreskin), which may be removed by circumcision

Female Reproductive Anatomy

• Includes the ovaries, fallopian tubes, uterus, vagina, and external genitalia
• These structures facilitate ovulation, fertilization, implantation, gestation, and childbirth

Ovaries

• The primary female reproductive organs, located in the pelvic cavity
• Produce eggs (ova) through oogenesis and secrete estrogen and progesterone

Fallopian Tubes (Oviducts)

• Extend from the ovaries to the uterus
• The site of fertilization, where sperm typically meet the egg
• Fimbriae are finger-like projections that sweep the released egg into the fallopian tube

Uterus

• A muscular organ where a fertilized egg implants and develops
• The endometrium is the inner lining of the uterus, which thickens and sheds during the menstrual cycle
• The myometrium is the muscular outer layer of the uterus, which contracts during labor

Cervix

• The lower, narrow portion of the uterus that connects to the vagina
• Produces mucus that can either facilitate or inhibit sperm passage

Vagina

• A muscular canal that extends from the cervix to the external environment
• Serves as the receptacle for the penis during sexual intercourse and the birth canal during childbirth

External Genitalia (Vulva)

• Labia majora: Outer folds of skin that protect the other external genitalia
• Labia minora: Inner folds of skin that surround the clitoris and vaginal opening
• Clitoris: A highly sensitive erectile organ involved in sexual arousal
• Vestibule: The area enclosed by the labia minora, containing the urethral and vaginal openings

Mammary Glands

• Accessory organs of the female reproductive system, responsible for milk production (lactation) after childbirth
• Contain glandular tissue and fat deposits
• Milk is secreted through ducts that lead to the nipple