Injuries To Cells Flashcards
What three things are cells lost or changed by during irreversible cell damage?
Apoptosis - cell suicide
Necrosis - cell death
Neoplasia - cancer
What four things do cells adapt by during reversible cellular repair and recovery?
Hyperplasia
Hypertrophy
Metaplasia
Atrophy
What is hypertrophy?
Increase in the size of cells
Hypertrophy can be….
Physiological or pathological
What type of drug can cause hypertrophy?
Steroids
What is hyperplasia?
Increase in cell number resulting in larger organ
What can hyperplasia occur along side by?
Hypertrophy
Hyperplasia can be
Physiological
Pathological
What is atrophy?
Shrinkage of the size of the cell by loss of cell substance
Atrophy is due to what 5 things?
Decreased workload, reduced blood supply, inadequate nutrition, loss of hormonal stimulation, ageing.
What is metaplasia?
One adult cell type is replaced by another adult cell type.
Is metaplasia reversible?
Yes
In metaplasia what might the new type of cell be more able to withstand?
Stress
Give an example of metaplasia
Chronic gastro - oesophageal reflux
List 8 causes of cell injury
Hypoxia Ischaemia Chemical exposure eg cigarette smoke, alcohol... Infection Radiation Lack of nutrients Immunologic reactions Ageing
Give three features of cell necrosis
Damage to membranes allows enzymes to digest cell.
Local inflammation.
Always pathological.
Give three features of apoptosis
Programmed cell death.
Irreparable damage to cells protein/DNA. Deprived of growth factors.
Can be pathological or physiological
Describe the three stages of apoptosis
Cells activate enzymes that degrade the cells own DNA and proteins resulting in death.
Fragments of the apotopic cell break off.
Dead cell rapidly removed by phagocytosis.
Describe four features of physiological apoptosis
Embryogenesis
Involution of hormone dependent tissues upon hormone deprivation.
Elimination of cells which have served their purpose.
Elimination of potentially harmful self reactive lymphocytes.
List five pathological conditions of apoptosis
DNA damage.
Accumulation of misfolded proteins eg prions in Alzheimer’s.
Infections eg hepatitis
Pathological atrophy in parenchymal organs after duct obstruction.
Cell death induced by cytotoxic T cells.
What does apoptosis result from?
The activation of enzymes called caspases - mitochondrial (intrinsic) pathway and fas receptor (extrinsic) pathway.
What are the 4 types of necrosis?
Coagulation necrosis
Liquefactive necrosis
Caseous necrosis
Fat necrosis
Causeous necrosis is caused by what illness?
TB
Liquifactive necrosis is caused by..
Stroke
Fat necrosis happens when
Fat is damaged by lipases due to trauma, released by damaged pancreas, fat is released into the blood stream causing a generalised septic response that damages other tissues
List the 6 mechanisms of cell injury
Depletion of ATP Mitochondrial damage Influx of calcium Oxidative stress Damage to the cell membrane DNA damage
Why is there a depletion of ATP in cell damage?
Reduced oxygen and nutrient supply, leads to mitochondrial damage, cells can’t regain sodium content and lactic acid and toxins are released into the blood stream.
