Immune System - Natural Killer Cell. Alzheimer's Disease. Homeostasis. The body's balance Introduction to homeostasis homeo = same; stasis = standing Homeostasis = relative constancy of the internal fluid environment The concept was first articulated by [Frenchman] Claude Bernard in 1860s "I think I was the first to urge the belief that animals have really two environments: a milieu extérieur in which the organism is situated, and a milieu intérieur in which the tissue elements live.
Anatomy and Disease: The Human Body. The human body is remarkably well designed.
Most of its organs have a great deal of extra capacity or reserve: They can still function adequately even when damaged. For example, more than two thirds of the liver must be destroyed before serious consequences occur, and a person can usually live with only one lung or kidney. Other organs can tolerate little damage before they malfunction and symptoms occur. For example, if a an artery in the brain becomes blocked or ruptures (stroke) and even a small amount of tissue in a vital part of the brain is destroyed, a person may be unable to speak, move a limb, or maintain balance. If a heart attack destroys a small amount of tissue in the part of the heart that creates or carries the signals to beat, the heart rate may become dangerously slow and the person may even die.
Alzheimer's: Is the Cure in the Genes?