Chapter 28: The Reproductive System

General Overview

• Focus on the reproductive systems of male and female without pregnancy.
• Functions in gamete production (sperm in males, eggs in females).
• Gametes are produced, stored, nourished, and transported by the reproductive system.
• Fertilization involves the fusion of male and female gametes to form a zygote.

Male Reproductive System

Key Components

• Gonads: Testes produce spermatozoa (mature sperm cells).
• Ducts: Transport sperm out of the body; includes seminiferous tubules, epididymis, vas deferens, and urethra.
• Accessory Glands: Seminal vesicles, prostate gland, and bulbourethral gland secrete fluids to nourish sperm.
• External Genitalia: Scrotum and penis.

Sperm Pathway (7UP Acronym)

1. S: Seminiferous Tubules - Where sperm production begins.
2. E: Epididymis - Stores and matures sperm.
3. V: Vas Deferens - Transports sperm.
4. Urethra - Ejects sperm through the penis.

Sperm Production (Spermatogenesis)

• Occurs in seminiferous tubules starting with spermatogonia (stem cells).
• Progression: Spermatogonia → Primary Spermatocytes → Secondary Spermatocytes → Spermatids → Spermatozoa.
• Mature sperm have a head (DNA), a midpiece (mitochondria), and a tail (for mobility).

Accessory Organs Functions

• Seminal Vesicles: Provide nutrients (fructose, prostaglandin, fibrinogen) to sperm.
• Prostate Gland: Produces acidic fluid, helps prevent urinary tract infections.
• Bulbourethral Glands: Secrete alkaline mucus to neutralize urinary acids and lubricate.

Testicle Descent & Scrotal Muscles

• Testes descend from the abdomen to the scrotal sac during fetal development.
• Muscles:
  • Dartos Muscle: Wrinkles scrotal skin.
  • Cremaster Muscle: Adjusts testicle position based on temperature.
• Tunica Albuginea: Fibrous membrane surrounding and dividing the testicle.

Male Reproductive Hormones

• FSH: Promotes spermatogenesis.
• LH: Stimulates testosterone production.
• Testosterone: Primary male androgen for sperm production and male characteristics.

Female Reproductive System

Key Components

• Gonads: Ovaries produce oocytes (immature eggs).
• Ducts: Includes uterine tubes (fallopian tubes), leading to the uterus.
• Uterus: Site for embryo development.
• External Genitalia: Vulva, including labia minora/majora, clitoris.

Oogenesis & Ovarian Cycle

• Oogenesis occurs before birth; no new eggs are produced post-birth.
• Ovarian Cycle: Follicular Phase (Pre-ovulation) and Luteal Phase (Post-ovulation).
• Follicular Phase: Formation of primary, secondary, and tertiary follicles.
• Ovulation: Release of secondary oocyte.
• Corpus Luteum: Develops post-ovulation, secretes progesterone.

Uterine Cycle

• Menses: Shedding of the uterine lining if no pregnancy occurs.
• Proliferative Phase: Rebuilding of the endometrium.
• Secretory Phase: Endometrium prepares for potential pregnancy.

Hormones

• FSH: Stimulates follicular development.
• LH: Triggers ovulation.
• Estrogen: Develops secondary sexual characteristics.
• Progesterone: Prepares endometrium for pregnancy.

Female Reproductive Structures

• Uterus: Protects and supports the embryo/fetus.
• Uterine Tubes: Transport oocytes from ovary to uterus.
• Vagina: Passage for menstrual fluid, sexual intercourse, and childbirth.

Sexual Intercourse Physiology

• Male: Arousal (erection), emission, ejaculation (under sympathetic control).
• Female: Clitoral erection, vaginal lubrication, engorgement of blood vessels.

Aging and Reproductive Changes

• Menopause: Cessation of ovulation and menstruation, hormone fluctuation.
• Male Climacteric: Reduced testosterone, gradual reduction in sexual activity.

These notes cover the essential points and details from the lecture on the reproductive systems of male and female, focusing on the anatomy, physiology, and hormonal regulation of both systems.