The human body is made up of several organ systems that work together as one unit. Each system depends on the others, either directly or indirectly, to keep the body functioning normally.
Central Nervous System
The central nervous system (CNS) is the processing center for the nervous system. The two main organs of the CNS are the brain and spinal cord.
Peripheral Nervous System
Cells of the peripheral nervous system carry signals to and from the central nervous system. It consists of sensory neurons and motor neurons.
The integumentary system consists of the largest organ in the body, the skin. This extraordinary organ system protects the internal structures of the body from damage, prevents dehydration, stores fat and produces vitamines and hormones.
The cardiovascular system is responsible for transporting nutrients and removing gaseous waste from the body. This system is comprised of the heart and the circulatory system.
The circulatory system involves the circulation of blood which serves to move blood to a site or sites where it can be oxygenated, and where wastes can be disposed.
Lymphatic system structures collect, filter, and return lymph to blood circulation.
Find out about the body's natural defense system, the immune system.
Immune System Quiz
Take the Immune System Quiz and find out how much you know about the immune system.
Overview of the Digestive System
This overview of the digestive system provides information on the secretion, absorption and motility of the digestive system.
The skeletal system gives the body shape, form, and mobility while providing protection for sensitive organs.
The reproductive system consists of organs, ducts, and glands that produce or support the development of male and female gametes.
The endocrine system regulates vital processes in the body through the secretion of hormones.