1. Cellular Adaptation

NUR 565 UNIT 1

• Cellular Adaptation

Answer

• Diseases begin with cellular alterations

• Extent of injury depends on

*Type, state, adaptive processes of cell

*Type, severity, and duration of injurious stimulus

• Can be reversible

• All diseases exert their effects on the smallest living unit

the cell

• Cells adapt to changes in the internal environment just as the total organism adapts to changes in

the external environment

• When the stress is overwhelming or adaptation is ineffective

injury, maladaptive changes, and cell death occur

• Pathological

abnormal, disease 1 / 4

• Physiological

normal

• Atrophy

Answer

• Decrease in cell size

• Occurs when cells have a decrease in work demand or adverse environmental conditions;

adapt to survive

• Atrophied cells use less oxygen and reduce other cellular functions by decreasing the number

and size of organelles an other structures

• When enough cells experience atrophy, the entire tissue atrophies.

• Five groups of causes

• disuse 2. denervation 3. loss of endocrine stimulation, 4. inadequate nutrition, and 5. ischemia

or decreased blood flow

• Hypertrophy

• Increase in cell size
• Increased cell size results in increased amount of functioning tissue mass -- involves an

increase in the functional components of the cell that allows equilibrium between demand and functional capacity -- can result from normal physiologic or abnormal pathologic conditions

• Physiologic (normal functioning)

increased muscle mass with exercise

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• Pathologic (abnormality/disease state)

result of disease -- Can be adaptive or compensatory

*Adaptive

myocardial hypertrophy from valvular heart disease or HTN

*Compensatory

enlargement of remaining kidney after one is surgically re- moved-compensation.

• Hyperplasia

Answer

• Increase in number of cells

• Occurs in tissues with cells capable of mitotic division (epidermis, intestinal epithelium,

glandular tissue)

Physiologic (2) types

• Hormonal

Uterus during pregnancy

• Compensatory

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Liver regeneration after partial hepatectomy

• Also important in wound healing (fibroblasts and blood vessels)

Nonphysiologic

Results from excessive hormonal stimulation or effects of growth factors on target tissues (Ex.Skin warts secondary to HPV)

• Stress cells may fill up with these (intracellular accumulations)

Answer

• Substances may accumulate in the cytoplasm or nucleus

• Normal body substances

Lipids, proteins, pigments. produced faster than metabolism or removal (ex

fatty liver)

• Abnormal endogenous substances

Metabolic products—glycogen, lipids, May result from genetic disorders hindering degradation of a substance or interrupting transfer of a substance to another site (ex

Tay sachs)

• Abnormal exogenous substances

Pigments -May be transient or permanent, might be harmless or toxic. The significance of intracellular accumulations depends on the cause and severity of the condition. For example

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