1. Mechanisms of Disease Part 2 Aging and Death

2. Aging Retirement age of 65 considered aging Actually aging begins when puberty ends around age 18 Degenerative diseases are those related to aging (Ex: joint and disk disease) Thought to include heredity, lifestyle, stress, diet, and environment Body replaces and repairs itself through life, but slows as we age

3. Death Cellular Injury and Death ◦ Caused by  hypoxia (not enough oxygen)  Anoxia (no oxygen)  Trauma  Drug or bacterial toxins  Viruses ◦ Survival depends on  Type of cell  Amount of time cell suffers  Type of injury

4. Death Cellular Adaptation- some go back to normal cells but sometimes permanently changed ◦ Atrophy (a = without, trophy = growth)  often due to aging process  decrease in cell size  decrease in use and function

5. Death ◦ Hypertrophy (hyper = excessive, trophy = growth)  increase in size of tissue cells ◦ Hyperplasia (hyper = excessive, plasia = growth)  Increase in cell number  Often due to hormonal stimulation

6. Death ◦ Dysplasia (dys = bad, plasia = growth)  Alteration in shape, size, and organization of cells  May change back to normal cells if irritant is removed, if not, may change to neoplasm ◦ Metaplasia (meta = changed, plasia = growth)  Cell changes to another type of cell ◦ Neoplasia (neo = new, plasia = growth)  Uncontrolled growth pattern

7. Death Types of Cellular Adaptation

8. Death Cell and Tissue Death ◦ Cell hypoxia caused by decreased blood flow is called ischemia ◦ Without blood, there is no oxygen and without oxygen the cell cannot produce needed energy and dies ◦ Cellular death is called necrosis (Coagulation most common-due to cellular anoxia) ◦ When necrosis occurs due to ischemia, it is called an infarct

9. Death ◦ When saprophytic (dead tissue loving) bacteria become involved, the tissue has gangrene  Wet- caused by sudden stoppage of blood (Ex: burning, freezing, embolism)  Dry- blood slowed over long period of time (Ex: arteriosclerosis and advanced diabetes)  Gas- caused from dirty, infected wounds that become infected with anaerobic bacteria

10. Death Organism Death ◦ According to the CDC the leading causes of death are  Heart disease  Cancer  Strokes (Cerebrovascular Accident- CVA) ◦ If no death, but disabled, it is called morbidity

11. Death ◦ Determining death  Major organs stop functioning  Death usually determined by brain death  Lack of response to stimuli  Loss of all reflexes  Absence of respirations  Lack of brain activity as determined by EEG (Electroencephalogram)