- Protects deeper organs from mechanical, chemical, and bacterial injury, and desiccation (dry out).
- Excretes salts and urea.
- Aids in regulation of body temperature.
- Produces vitamin D.
- Body support and protection of internal organs.
- Provides levers for muscular action.
- Cavities provide a site for blood cell formation.
- Primary function is to contract or shorten; in doing so, skeletal muscles allow locomotion (running, walking, etc.), grasping and manipulation of the environment, and facial expression.
- Generates heat.
- Allows body to detect changes in its internal and external environment and to respond to such information by activating appropriate muscles or glands.
- Helps maintain homeostasis of the body via rapid transmission of electrical signals.
- Helps maintain body homeostasis, promotes growth and development; produces chemical "messengers" (hormones) that travel in the blood to exert their effect(s) on various "target organs" of the body.
- Primarily a transport system that carries blood containing oxygen, carbon dioxide, nutrients, waste, ions, hormones, and other substances to and from the tissue cells where exchanges are made; blood is propelled through the blood vessels by the pumping action of the heart.
- Picks up fluid leaked from the blood vessels and returns it to the blood.
- Cleanses blood of pathogens and other debris.
- Houses lymphocytes that act via the immune response to protect the body from foreign substances (antigen).
- Keeps the blood continuously supplied with oxygen while removing carbon dioxide.
- Contributes to the acid-base balance of the blood via its carbonic acid-bicarbonate buffer system.
- Breaks down ingested foods to minute particles, which can be absorbed into the blood for delivery to the body cells.
- Undigested residue removed from the body as feces.
- Rids the body of nitrogen-containing wastes (urea, uric acid and ammonia), which result from the breakdown of proteins and nucleic acids by body cells.
- Maintain water, electrolyte, and acid-base balance of blood/
- Provides germ cells (sperm in male) for perpetuation of the species.
- Provides germ cells (eggs in females); the female uterus houses the developing fetus until birth , mammary gland provide nutrition for the infant.