Homeostasis 

Homeostasis 

The stability of the body’s internal environment 

Major Components and Functions of the Body Systems

Body System	Component(s)	Major Function(s)
Cardiovascular	Heart, blood vessels, blood	Transport of materials throughout the body
Digestive	Gastrointestinal tract, liver, pancreas	Assimilation of nutrients; elimination of  some wastes
Endocrine	Endocrine glands	Coordination of body functions through release of regulatory molecules
Immune	Thymus, spleen, lymphatic system, white blood cells	Defense against pathogens
Integumentary	Skin	Protection against external environment
Musculoskeletal	Skeletal muscle and bones	Movement and support
Nervous	Brain, spinal cord, peripheral nerves	Coordination of body functions through electrical signals and release of  regulatory molecules; cognition
Reproductive	Gonads, penis, vagina, uterus	Procreation
Respiratory	Lungs	Oxygen and carbon dioxide exchange with external environment
Urinary	Kidneys, bladder	Homeostasis of ion concentrations in internal environment; elimination of wastes

• There is the integration of the body systems that allows the creation of a stable internal environment in which cells are able to function.

• Such ability to maintain a stable internal environment is referred to as homeostasis.

• The stability of the body’s internal environment is defined by the maintenance of several physiologic controlled variables within narrow normal ranges.

Some Examples of Physiologic Controlled Variables

• Pathological states occur when homeostasis is not maintained.

Conclusions:

• Homeostasis is ability to maintain a stable internal environment.
• Homeostasis is the base of health.
• Homeostasis is the base of life.