Human Body Systems

Human Body Organization The Human Body is composed of Organ Systems are composed of Organs Tissues Cells

Circulatory System Major Structures heart, blood vessels, blood, lymph nodes and vessels, lymph Functions transports nutrients, wastes, hormones, and gases

Digestive System Major Structures mouth, throat, esophagus, stomach, liver, pancreas, small and large intestines Functions extracts and absorbs nutrients from food; removes wastes; maintains water and chemical balances

Endocrine System Major Structures hypothalamus, pituitary, pancreas, pineal, adrenal, thyroid, parathyroid, testes, and ovaries Functions regulates body temperature, metabolism, development, and reproduction; maintains homeostasis; regulates other organ systems

Excretory System Major Structures kidneys, urinary bladder, ureters, urethra, skin, lungs Functions removes wastes from blood; regulates concentration of body fluids

Immune System Major Structures white blood cells, lymph nodes and vessels, skin Functions defends against pathogens and diseases

Integumentary System Major Structures skin, nails, hair Functions protects against injury, infection, and fluid loss; helps regulate body temperature

Muscular System Major Structures skeletal, smooth, and cardiac muscle tissues Functions moves limbs and trunk; moves substances through body; provides structure and support

Nervous System Major Structures brain, spinal cord, nerves, sense organs Functions regulates behavior; maintains homeostasis; regulates other organ systems; controls sensory and motor functions

Reproductive System Major Structures ovaries, uterus, and breasts (in females); testes and penis (in males) Functions produces gametes and offspring

Respiratory System Major Structures lungs, nose, mouth, trachea Functions moves air into and out of lungs; controls gas exchange between blood and lungs

Skeletal System Major Structures bones and joints Functions protects and supports the body and organs; interacts with skeletal muscles; produces red blood cells, white blood cells, and platelets