Cellular Injury Flashcards
Causes of Cellular Injury
Hypoxia (main)
Infectious agents
Chemical agents
Physical agents
Nutritional imbalances
Immunological reactions
Genetics
Ageing
Describe Reversible Cell Injury
Cells are able to recover from injury
Is associated with cellular swelling and accumulation of intracellular lipid content
Describe Irreversible Cell Injury
“Point of no return”
Two types: apoptosis and necrosis
List the mechanisms of cellular injury
- ATP depletion
- Alteration in calcium homeostasis
- Permeability of cell membrane
- Free radical oxygen
Mechanism of Injury:
Describe ATP Depletion
Ischaemia: causes decreased mitochondrial oxygenation = loss of mitochondrial ATP
Mechanism of Injury
Describe: Alteration in calcium homeostasis
Caused by low ATP levels ➡️ ischaemia increases cytosolic Ca concentrations = damage to plasma membrane and cytoskeleton of cell ➡️ activates destructive enzyme which damages the mitochondria
Mechanism of Injury
Discuss: Permeability of cell membrane
Found in all forms of cellular injury
Mechanism of Injury
Discuss: Free radical oxygen
Activated oxygen species (free radicals) destruct cell membrane and structure (re-perfusion injury)
Describe: Altered Cellular Function
The changes in size, shape, organisation and function of a mature cell
Causes of Altered Cellular Function
Adaptation
Injury
Ageing
What is Apoptosis
A form of cellular injury
Programmed cellular death or a process of selective cellular destruction.
Can be:
Physiological: normal program of development
Pathological: elimination of infected cells
What is Necrosis
A form of irreversible cellular injury
Involves autolysis or cellular self-destruction and infiltration of inflammatory cells; macrophages and neutrophils enter to clean dead cells and debris
Describe: Ageing
Cellular ageing: Atrophy: decreased function and loss of cells
Tissue and systematic ageing: progressive stiffness and rigidity
Describe: Somatic Death
Death of an entire person
What is Cellular Adaptation
Cells ability to “adapt” to an environment to protect themselves from injury