All human organ systems and their functions (Part 1)

Lymphatic System Collects and returns some tissue fluid to the bloodstream; defends the body against infection and tissue damage. Respiratory System Rapidly delivers oxy- gen to the tissue fluid that bathes all living cells; removes carbon dioxide wastes of cells; helps regulate pH. Digestive System lngests food and water; mechanically, chemically breaks down food and absorbs small molecules into internal environment; eliminates food residues. Urinary System Maintains the volume and composition of internal environment; excretes excess fluid and bloodborne wastes. Reproductive System Female: Produces eggs; provides a protected, nutritive environment for the development of new individuals. Male: Produces and transfers sperm to the female. Hormones of both systems also influence other organ systems.