Cellular Responses to Stress Flashcards
Molecular targets of cellular injury
Cell membrane integrity
Mitochondrial function
Functional and structural proteins
Inability of the cell to adapt leads to
Limits of adaptive response exceeded
Adaptation is not possible
Reversible / irreversible
Cell injury / cell death
- necrosis
- apoptosis
Highly reactive atoms with a single unpaired electron in an outer orbital
Chemically unstable
Generated by normal cellular metabolism
Formed by ionizing radiation
Free radicals
Oxygen deprivation
From loss of blood supply
From toxins that could prevent phosphorylation like cyanide toxicity
Hypoxia / anoxia
High susceptibility Neurons
Low susceptibility Skeletal Muscle
Loss of blood flow
Ischemia
If cells are reversibly injured due to ischemia…
Reperfusion injury
Decreased cell size or number of cells
Decreased nourishment
Atrophy
Type of atrophy
Programmed “normal” atrophy
Ageing
Increase/decrease in size of uterus,in response to hormonal stimulation
Physiological atrophy
Type of atrophy associated with disease Decreased workload Loss of innervation Diminished blood supply Loss of endocrine stimulation
Pathological atrophy
Increase in cell size (cellular mass)
Hypertrophy
Hypertension, aortic stenosis
Hypertrophy of viable tissue with a healed myocardial infarction
Compensatory hypertrophy
Failure to grow
Caused by defdtive genetic instructions
Aplasia
Increased growth
Increase in the number of cells in response to a particular stress
Hyperplasia
Physiologic (during wound healing, hyperplasia of mammary gland, regeneration of liver after hepatectomy)
Pathologic (callous, goiter)
Reversible change in cell structure from one fully differentiated form to another in response to a noxious stimulus
Change to a different cell type
Usually reversible
Smokers
Metaplasia
Abnormal cell growth
Results in cells that vary in size, shape and appearance
Reversible if abnormal stimuli is removed
Dysplasia
