1. Physiology and Aging Aging is a normal process accompanied by a progressive alteration of the body's adaptive responses due to genetically programmed changes? due to accumulated oxidative damage?

2. SKIN skin loses its elasticity dermal fat deposit loss sweat glands atrophy reduced tolerance to temperature changes sebum production is reduced vitamin D production falls hair and fat distribution slowly changes skin repair is slower

3. SKELETAL MUSCLE skeletal muscle fibers become smaller in diameter muscle becomes inelastic ability to recover from muscular injuries decreases some muscle tissue is replaced by fat deposits. tolerance for exercise decreases

4. HEART reduction in cardiac output changes in electrical conducting system reduced elasticity of the supporting framework replacement of damaged tissue by scar tissue vessel wall become inelastic reduced blood flow as the heart muscle atrophies stamina declines with less oxygenation.

5. NERVOUS SYSTEM the brain shrinks reduction in the number of neurons synaptic connections are lost neurotransmitter production declines decrease in blood flow to the brain accumulation of plaques, tangles, lipofuscin

6. SKELETAL SYSTEM bone becomes less dense reduction in mineral content reduction in size of intevertebral discs loss of features of bone markings

7. GASTROINTESTINAL acid production in the stomach declines digestive enzyme levels decline vitamin deficiencies may occur smooth muscle tone decreases regeneration of the GI lining declines rates of stomach and colon cancer rise

8. URINARY decline in number of nephrons (filtering units) decrease in filtration rate reduce sensitivity to anti-diuretic hormone problems with continence

9. Changes in SENSORY functions include: decrease in pupil diameter and response time to light decrease in pitch and tone discrimination fewer taste buds insensitivity to touch

10. The ENDOCRINE system shows few functional changes reproductive hormone levels are an exception loss of tissue responsiveness to hormones has been documented overall metabolic rate decreases about 1% each year from about age 25 total body water content declines

11. REPRODUCTIVE Sexual activity may become more limited but capacity is not lost Vaginal fluid production may decline some decrease in uterine, ovarian, and vaginal tissue may occur With advancing age the IMMUNE system becomes less capable of combating infectious disease Aging is a normal process