Injury to cells Flashcards
What are the 4 types of cellular adaptation?
Hyperplasia, hypertrophy, metaplasia and atrophy.
What is hypertrophy?
Increase size of cells= increase size of organ.
Physiological example is a body builder.
Pathological example is the heart during hypertension.
What is hyperplasia?
Increase number of cells= increased size of organ.
Physiological example is the menstrual cycle.
Pathological example is the build up of the endometrium if hormone stimulus continues.
What is atrophy?
A decrease size of the cells due to loss of substance.
What is metaplasia?
When once cell type is replaced by another.
This is reversible
E.g Barretts oesophagus.
What is hypoxia?
Cause of injury to a cell.
Due to low oxygen supply.
What is ischaemia?
Cause of injury to a cell.
Loss of blood supply resulting in loss of oxygen and nutrients.
What is chemical exposure?
A cause of cellular injury.
Due to fag smoke, alcohol and paracetamol.
What are common causes of cellular injury?
Infection
Radiation
Lack of nutrients
Ageing
What are two examples of reversible cellular injury?
Cellular swelling and fatty change.
Explain necrosis.
A type of cell death.
Always pathological
Cellular swelling causes membranes to break down. Enzymes enter into the cell and digests cell.
Causes leakage so therefore an inflammatory response.
Explain apoptosis?
Programmed cell death pathway.
Cell activates enzymes that breakdown DNA and proteins causing death.
Membranes remain intact so there is no leakage or inflammatory response.
What is physiological apoptosis?
Embryogenesis.
Hormonal elimination of cells that have served their purpose.
What is pathological apoptosis?
DNA damage.
Occurs in parachymal organs after duct obstruction.
Cell death caused by cytotoxic T cells.
How is apoptosis activated?
A result of the activation of caspases.
