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30 Cards in this Set
- Front
- Back
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Major types of cellular death include:
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Apoptosis
Liquefactive Caseous Fat |
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Apoptosis
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Genetically programmed cell death.
Accounts for cell turnover in skin's outer keratin layer & the lens of the eye. It is distinct & differs from necrosis. |
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Liquefactive necrosis occurs when?
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a lytic enzyme liquefies necrotic cells.
It is common in the brain, which has a rich supply of lytic enzymes. Is observed in abcesses & brain infarcts. |
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In caseous necrosis-
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the necrotic cells disintegrate but the cellular pieces remain undigested for months/years.
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Fat Necrosis
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1. Lipase breaks down intracellular triglycarides into free fatty acids.
2. These free fatty acids combine with sodium, magnesium or calcium ions to form soaps. 3. Tissue becomes opaque and chalky white. |
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Coagulative Necrosis
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Occurs primarily in the kidneys, heart, & adrenal glands. Lytic enzyme activity in the cells is inhibited. Necrotic cells temporarily maintain their shape.
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During the normal process of aging, cells lose both-
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Structure and function.
Atrophy is indicative of loss of cell structure. Hypertrophy or hyperplasia is characteristic of lost cell function. |
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Aging causes what changes?
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Physical
Psychological Social These increase as a person ages. |
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Maximal life span
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80-100 years
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How do biological theories attempt to explain physical aging?
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As an involuntary process that eventually leads to cummulative changes in cells, tissues, and fluids.
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Senescence
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Act of growing old.
State of being old. |
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How do genetic theories attempt to explain physical aging?
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It suggests that aging occurs secondary to cellular damage through gene mutation, accumulation of toxic substances, protein degradation, and free radical damage.
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What causes gene mutation?
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Exposure to free radicals, radiation and other environmental toxins.
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What causes protein degradation?
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Biochemical degenerative processes that hamper DNA's ability to repair.
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Cellular adaptation
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An alteration that enables the cell to maintain a steady state despite adverse conditions
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Atrophy
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A decrease in cellular size caused by aging, disuse or lack of blood supply, hormonal stimulation or neural stimulation.
Amounts of ER, mitochondria & microfilaments, are decreased. |
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Hypertrophy
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A increase in the size of cells caused by increased work demands or hormonal stimulation. Amts. of protein in the p membrane, ER, microfilaments, & mitochrondia are increased.
May be physiologic, compensatory, or pathologic. |
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Hyperplasia
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Increase in the # of cells caused by a increased rate of cellular division. Normanl hyperplasia is stimulated by hormones or the need to replace lost tissues.
May be physiologic, compensatory or pathologic. |
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Dysplasia
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(atypical hyperplasia) Abnormal change in the size, shape & organization of mature tissue cells.
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Metaplasia
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The reversible replacement of one mature cell type by another less mature cell type.
Can be physiologic & pathologic. |
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The physiologic mechanisms of aging:
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1.Cellular changes produced by genetic and environmental factors.
2.Changes in cellular regulatory or control mechanisms. 3.Degenerative extracellular & vascular alterations. |
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Immunologic processes that contribute to aging include:
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A decrease in T-cell function.
Production of abnormal monoclonal antibodies. |
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Humoral immunity
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The protective activities of antibodies against infection or reinfection by common organisms.
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An aging immune system is less able to distinguish between body and foreign cells. This leads to the greater chance that it will:
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Attack itself.
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Hayflick's study in the cellular senescence in cultured human fibroblasts demonstrated?
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That fibroblasts are limited to a finite # of generations (40-60 doublings).
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If cells are transformed with a virus or a chemical, cellular senescence is:
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not seen, & the cells are "immortalized" & continue to divide indefinitely.
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Wear and tear theory states that?
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Body cells, structure, & functions wear out or are overused through exposure to internal & external stressors.
Effects of residual damage accumulate & the body can no longer resist stress & death occurs. |
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Cellular death theory states that?
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Cellular death is a normal, genetically determined process.
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Cellular death theory regarding stem cells.
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Stem cells have a limited proliferative capability and a finite end to their replicating ability.
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Mitotic capability in people with progeria?
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Mitotic capability is only half of that in a normal human.
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