Organ Systems

Integumentary System

The external covering of the body (skin) that waterproofs, protects deeper tissues, excretes salts and urea, helps regulate body temperature, and contains sensory receptors.

Skeletal System

Consists of bones, cartilages, ligaments, and joints; it supports the body, provides a framework for muscles to cause movement, protects organs, forms blood cells (hematopoiesis), and stores minerals.

Muscular System

Its function is to contract or shorten to cause movement; it allows locomotion, maintains posture, and produces heat.

Nervous System

The body's fast-acting control system, consisting of the brain, spinal cord, nerves, and sensory receptors; it responds to internal and external changes by activating muscles or glands.

Endocrine System

Controls body activities slowly by producing hormones that regulate processes such as growth, reproduction, and nutrient use by cells.

Cardiovascular System

Consists of the heart and blood vessels; it uses blood to transport oxygen, nutrients, hormones, and other substances to and from tissue cells.

Lymphatic System

Complements the cardiovascular system; its organs (lymphatic vessels, lymph nodes, spleen, tonsils) return leaked fluid to the blood, cleanse the blood, and house cells involved in immunity.

Respiratory System

Keeps the body constantly supplied with oxygen and removes carbon dioxide through gaseous exchange in the lungs; consists of nasal passages, pharynx, larynx, trachea, bronchi, and lungs.

Digestive System

A tube running from mouth to anus that breaks down food into absorbable units, delivers products to the blood, and eliminates indigestible food as feces.

Urinary System

Removes nitrogen-containing wastes from the blood and flushes them from the body in urine; also maintains water, electrolyte, and acid-base balance.

Reproductive System

Exists primarily to produce offspring; testes produce sperm in males, and ovaries produce eggs in females