Alterations in Cellular and Tissue Biology Flashcards
Adaptation
Reversible response involving structural or functional modifications to accommidate both physiologic (normal) and pathologic (abnormal) conditions
Adaptations can affect
size, number, phenotype, metabolic activity, or function of cells
Types of cellular adaption
Atrophy
Hypertrophy
Hyperplasia
Metaplasia
Atrophy
Decrease in cell size
Disuse atrophy
Occurs after limb has been placed in a cast for an extended period w/ prolonged bed rest/immobilization.
Pressure can cause tissue atrophy and lead to
pressure ulcers
Chronic ischemia in the brain can result in
Senile atrophy- decreased blood supply to the brain
Hypertrophy
Increase in cell size
Common triggers for hypertrophy include
repetitive stretching, chronic pressure and volume overload
What two organs are more prone to enlargement
Heart and Kidneys
Example of physiologic hypertrophy
Enlargement secondary to aerobic exercise (runners heart)
Ex of pathologic hypertrophy
Chronic increased hemodynamic overload
-HTN
-Heart valve dysfunction
Hyperplasia
Increase in cell number
Metaplasia
Reversible replacement of one differentiated cell type by another cell type
Persistent damage can become malignant.
Dysplasia (Atypical hyperplasia)
Deragned cellular growth (nuclei looks different)
NOT considered true cellular adaptation
Most common cause of cellular injury
Ischemic and hypoxic injury (insufficient oxygen)
Progressive vs sudden hypoxia
Gradual ischemia-adaptation
Acute/sudden obstruction-if blood supply is not restored within a few minutes can cause tissue death
Ischemia-reperfusion injury
Rapid restoration of blood flow can reslut in additional injury and even cell death
Reoxygenation/reperfusion can lead to
Oxidative stress
Free radicals
Intracellular calcium concentration
Inflammation and complement system activation
