Cell injury and fate Flashcards
What does lethal mean?
Causes cell death
What does sublethal mean?
Produces cell injury not amounting to cell death
May be reversible
May progress to cell death
How do cardio myocytes adapt?
When put under pressure it adapts by becoming bigger
This is called hypertrophy
Left ventricle becomes much thicker because of increased work the heart is doing
What is infarction?
Cell death due to ischaemia
What causes cell injury?
Age Physical agents Infectious agents Genetic defects Chemical agents Oxygen deprivation Immunological reactions Nutritional imbalances
What happens in myocardial infarction?
Block caused by atheromatous plaque in left coronary artery branch
Heart muscle supplies by arteries dies (O2 deprivation)
What does cellular response to injury depend on?
Type of injury
Duration
Severity
What does the consequence of a cell injury depend on?
Type of cell
Cell status
What 4 intracellular systems are particularly vulnerable?
Cell membrane integrity
ATP generation
Protein synthesis
Genetic apparatus integrity
What are the major consequences of cell injury?
Multiple secondary side effects
Cellular function is lost before cell death occurs
What does atrophy mean?
Shrinkage in size of cell/ organ by loss of substance
E.g. neural atrophy in dementia
What is hypertrophy?
Increase in cell size/ organ size
Can be physiological (Occurs in normal healthy people) or pathological (part of disease process)
What causes hypertrophy?
Caused by increased functional demand or specific hormone stimulation
What is an example of physiological hypertrophy?
Hypertrophy of uterus during pregnancy
What is an example of pathological hypertrophy?
Hypertrophy of muscle fibres in response to hypertension or a valve abnormality
What is hyperplasia?
An increase in number of cells in an organ
Physiological or pathological
Physiological hyperplasia can be normal or compensatory
Pathological hyperplasia usually due to excessive hormonal or GH stimulation
What is an example of physiological hyperplasia?
Proliferative endometrium (uterus) After shedding during menstruation cells have to regrow- cell number increases by mitosis
What is an example of a pathological hyperplasia?
Carcinoma
What is metaplasia?
A reversible change in which an adult cell type is replaced by another
Can be pathological or physiological
What is an example of a physiological metaplasia?
Cervix
Columnar epithelium changes from being columnar to squamous due to pH change of vagina- happens in pregnancy
At end of pregnancy new squamous epithelium becomes columnar again
What is an example of pathological metaplasia?
Barret’s (columnar lined) oesophagus
For reasons such as acid reflux, squamous epithelium becomes columnar
If acid reflux stops it would become squamous again
What is dysplasia?
Precancerous cells which show genetic and cytological features of malignancy but are not invading underlying tissue
What light microscopic changes are associated with reversible injury?
Fatty change
Cellular swelling
These are degenerative changes
What is an example of fatty change?
Alcoholic fatty change
If you drink alcohol you get fatty change and when you stop it goes away
What is an example of ballooning degeneration?
Theres no fat- you can see the cytoplasm whereas in fat cells you cant see cytoplasm
There are strands of cytoplasm in the cell- this is called ballooning
Balloon degeneration is the swelling of a cell due to protein accumulation due to cell cytoskeleton damage
What is necrosis?
Confluent cell death associated with inflammation
What are the types of necrosis?
Coagulative necrosis
Liquefactive necrosis
Caseous necrosis
Fat necrosis
What is coagulative necrosis?
Structure becomes fixed
What is liquefactive necrosis?
Tissue becomes liquefied
What is caseous necrosis?
Means cheesy- oozy and structureless
Occurs in TB
What is fat necrosis?
Death of fat tissue
Occurs in acute pancreatitis- digestive enzymes become activated in pancreas instead of duodenum and digest tissue around it
What is apoptosis?
Programmed cell death
Not associated with inflammation
Can be physiological unlike necrosis
Its energy dependent (Active unlike necrosis)
What are causes of apoptosis?
Embryogenesis
Deletion of auto-reactive T cells in thymus
Hormone- dependent physiological involution
cell deletion in proliferating population
variety of injurious stimuli
What the difference between necrosis and apoptosis?
Apoptosis may be physiological
Apoptosis needs energy
Apoptosis is not associated with inflammation
What is necroptosis?
Programmed cell death associated with inflammation
Has many causes
