Cell Injury And Fate Flashcards
What do lethal and sub lethal mean?
Lethal
Cell dearth
Sublethal
Produces injury not amounting to cell death Either reversible or leads to cell death
What are some causes of cell Injury?
Oxygen deprivation Chemical agents Infectious agents Immunological agents Genetic defects Nutritional imbalances Physical agents Ageing
What factors effect the cellular response to cell injury?
Type of injury
Duration
Severity
The type of cell
It’s status (proliferating, age)
Which four intracellular systems are particularly vulnerable and bad to injure?
Cell membrane integrity
ATP generation
Protein synthesis
The integrity of genetic apparatus (DNA…)
What is atrophy?
Shrinkage in the size of a cell or organ by the loss of cell substance
What is hypertrophy?
Increase in the size of cells and consequently an increase in the size of an organ
Can be physiological (normal) or pathological (disease)
Can be cause by functional demand or hormones
Eg when athletes exercise their muscles get bigger
What is hyperplasia?
Increase in cell number in an organ
Physiological or pathological
Physiological can be either hormonal or compensatory
Pathological is usually due to excessive hormonal or growth factor stimulation
Eg in pregnancy
What is metaplasia?
A reversible change in which one adult cell type is replaced by another
Physiological or pathological
Eg in barrats oesophagus when usually squamous epithelial turns columnar due to acid reflux
What is dysplasia?
Precancerous cells which show the genetic and cytological features of malignancy but do not invade the underlying tissue
Eg in late barrats oesophagus
What are the light microscopic changes associated with reversible injury?
Fatty change
Eg in alcoholic fatty disease
Cellular swelling
Eg ballooning
Examples of degenerative changes
What is necrosis?
Confluent cell death associated with inflammation
What are four types of necrosis?
Coagulative necrosis
Liquefaction necrosis
Caseous necrosis
Fat necrosis
What is coagulative necrosis?
Like frying an egg
Something just sets in place
What is liquefaction necrosis
The cells/ organ becomes liquefied
Characteristic of brain necrosis
What is caseous necrosis?
Cheesy
Seen in tuberculosis
What is fat necrosis?
Seen in acute pancreatitis
Enzymes in the pancreas become activated early in the pancreas
Especially fat
Calcium deposits - free fatty acids bind to calcium ions
What is apoptosis?
Programmed cell death
Death of individual cells
No inflammation around the cells
An active energy dependent process
Not associated with inflammation
What is the difference between apoptosis and necrosis?
Necrosis involves a loss of membrane integrity so enzymes and stuff within the cell leaks out and whole sheets of cells die
There is also inflammation
Necrosis also damages healthy tissue around it
In apoptosis parts of the apoptotic cell break off but the cell membrane retains its integrity. These apoptotic bodies are eventually phagocytosed
What are some causes of apoptosis?
Embryogenesis
Deletion of auto reactive T cells in the thymus
Hormone dependant physiological involution
Cell deletion in proliferating populations
Mild injurious stimuli that cause irreparable DNA damage, triggers cel suicide pathways
Physiological or pathological
What is necroptosis?
Programmed cell death that also has inflammation
Seen in some viral infections
