Cell Injury And Fate Flashcards
Ischaemia
Where blood flow is restricted or reduced
Infarction
Cell death due to ischaemia
Lethal
Cell death
Sublethal
Produces injury not amounting to cell death
8 causes of cell injuries
- Oxygen deprivation
- Chemical agents
- Infectious agents
- Immunological reactions
- Genetic defects
- Nutritional imbalances
- Physical agents
- Ageing
What 4 intravenous systems are vulnerable to cell injury
- cell membrane integrity
- ATP generation
- Protein synthesis
- the integrity of the genetic apparatus
Atrophy
Shrinkage in size of cell or organ due to loss of cell substance
Dementia
Hypertrophy
Increase is size of cell or organ
Can be caused by increased functional demands or specific hormonal situations,disease,muscle may grow due to exercise
Eg uterus
Hyperplasia
Increase in number of cells in an organ
Physiological: can be either hormonal or compensatory eg endometrium
Pathological: usually due to excessive hormonal or growth factor stimulation eg carcinoma
Metaplasia
A reversible change in which one adult cell type is replaced by another
Pathological-barrets oesophagus where normal oesophagus is lined with non keratinising squamous epithelia and stomach lined with columnar,acid reflux can change squamous cells to columnar
Physiological-cervical expansion during pregnancy results in columnar epithelium
Dysplasia
Precancerous cells that show genetic and cytological features of malignancy but not invading underlying tissue
Signs cell shows malignancy
Big nuclei and increased mitosis
What are the 2 light microscopic changes associated with reversible cell injury?
Fatty change- after drinking lots of alcohol big white spots appear in hepatocytes however when drinking stops spots go away
Cellular swelling-ballooning degeneration where cytoskeleton damage causes proteins to accumulate in cells causing swelling
Necrosis
Cell death associated with inflammation
Coagulative necrosis
When structure of cells becomes fixed after cell death
Myocardial infarct
Liquefactive necrosis
Where tissue becomes liquefied
Usually occurs in brain as brain doesn’t have connective tissue
Causeous necrosis
Cells become structure less and oozy
Pulmonary TB
Fat necrosis
e.g. in pancreas there are many digestive enzymes- if they become activated there instead of in duodenum they can digest pancreatic tissue- this includes lipases liquefying fat which causes fat necrosis
Apoptosis
Programmed cell death of individual cells
Caused by embryogenesis eg fingers and joined together,deletion of auto reactive T cells in thymus to prevent autoimmune disease,hormone dependent physiological involutio. Eg in menstruation once hormones are released you get apoptosis
Cell deletion
Necrosis vs apoptosis
- Apoptosis is physiological but may be pathological (e.g. seen in cancers)- necrosis is usually pathological
- Apoptosis is an ACTIVE energy dependent process so cells can maintain membranes and package organelles into apoptotic bodies- necrosis isn’t
- Apoptosis is NOT associated with inflammation unlike the neutrophilic inflammatory response we get from necrosis
- In necrosis usually we see sheets of cells dying (inflammatory response can damage nearby healthy tissue too) whereas apoptosis is usually at an individual cell level
- With necrosis, bits of cell membrane break off so the membrane loses integrity and there’s enzyme leakage- with apoptosis the cell breaks into apoptotic bodies where cell membrane doesn’t lose integrity
Necroptosis
Programmed cell death associated with inflammation
