Mechanisms of Cell Degeneration and Death Flashcards
What is cellular adaptation?
Response to excessive physiological stresses or pathological stimuli, cell achieves a new altered state, but remains visible
Affects growth/differentiation
What is atrophy?
Reduction in number or size of cells
What is hypertrophy?
Increase in size of cells or organ size, no new cells
What is involution?
Physiological atrophy- such as the thymus or uterus after pregnancy
What are the causes and examples of pathological atrophy?
Disuse- skeletal muscle Denervation atrophy- skeletal muscle Reduced organ blood perfusion Inadequate nutrition Loss of endocrine stimulation (neutered animals) Senile atrophy (brain and heart) Pressure atrophy
What is the effect of cellular atrophy?
Reduced metabolism = reduction of structural components = reduction of cell volume
Occurrence of autophagic vacuoles
What are examples of physiological hypertrophy?
Smooth muscle cells in pregnant uterus
Skeletal muscles with training
What is an example of pathological hypertrophy?
Cardiac myocytes with chronic haemodynamic overload
What is hyperplasia?
Total increase in organ volume as effect of increase in total cell number
What are the two types of physiological hyperplasia?
Hormonal- proliferation of mammary epithelium during pregnancy, proliferation of uterine epithelium
Compensatory- In symmetrical organs with loss of one (kidneys)
What can cause pathological hyperplasia?
Excessive hormonal stimulation
Attempt of regeneration
Viral infections
What is metaplasia?
Reversible change, replacement of one cell adult type by another cell type
What are intracellular accumulations?
Accumulation of various substances in abnormal amounts due to metabolic derangements in cells
What are the three categories of intracellular accumulation?
Normal cellular constituents- water, lipid, proteins
Abnormal substance- exogenous, endogenous
Pigment
