Altered Cell - CH. 4

Reversible

Decrease in cell size

Increase in cell size

Reversible replacement of one mature cell type by another, less mature cell type or a change in cell phenotype.

Deranged cellular growth, not considered a true cellular adaptation but rather atypical hyperplasia.

Occurs with early development and is a normal event. ex. thymus in childhood

Result of decrease in workload, pressure, use, blood supply, nutrition, hormonal stimulation, or neural stimulation.

Occurs with prolonged bedrest or immobilization. Also known as pathologic atrophy Ex. arm in a cast

ER, mitochondria, and myofilaments.

Decrease in protein synthesis, increase in protein degradation, or both.

Contain cellular debris and hydrolytic enzymes that degrade substances into simple units. Vacuoles help ensure no uncontrolled destruction.

Yellow-brown pigmented granules; lipid-containing residue that persists after lysosomal destruction. Become age spots in older adults

Muscle enlargement

Result of increased demand, stimulation by hormones, and growth factors.

Result of chronic hemodynamic overload (ex. hypertension or heart valve dysfunction)

Increased interstitial fibrosis, cell death, and abnormal cardiac function.

Enables organs to regenerate

Thickening of the skin, considered compensatory hyperplasia

Occurs in organs that respond to endocrine hormonal stimulation

Abnormal proliferation of normal cells, usually in response to excessive hormonal stimulation or to the action of growth factors on target cells.

The degree of variation from normal.

The new cell type might be better suited to withstand an adverse environment. However, the change is usually not beneficial.

A reprogramming of stem cells present in most epithelia or of undifferentiated mesenchymal (tissue from embryonic mesoderm) cells

Severe vacuolization of the mitochondria and Ca++ moves into the cell.