Lecture 1 - Cell injury Flashcards
what is aetiology the study of?
The causative agents of a disease
what are the two possible pathways for reversible cell injury?
- cell recovers and returns to normal functioning cell
- irreversible cell injury leading to cell death
what is hydropic swelling?
poor ATP production = malfunction of Na/K pump = excessive Na+ influx into cell = water follows Na+
characterised by large, pale cytoplasm, dilated ER and swollen mitochondria
what is megaly?
when an organ increases in size and weight
e.g. splenomegaly = enlarged spleen
what are the four main terms associated with cellular adaptations?
Atrophy
hypertrophy
hyperplasia
metaplasia
what is atrophy of a cell?
decrease in cellular size
what is hypertrophy?
Increase in cellular size
what is hyperplasia?
cells increase in number by increasing rate of mitosis
what is metaplasia?
cells change from one type to another
what is dysplasia?
A maladaptive cellular adaptation
abnormal or disorderly growth of cells within tissue that can often lead to cancer
what causes cell injury?
When a stress exceeds the cells ability to adapt
what is apoptosis and what is the process of breakdown?
programmed cell death that allows cell to be replaced with a better functioning one.
death signal receptors activate cascade of reactions
= cell shrinks and forms blebs, proteins break down cell components
= DNA fragmentation occurs in nucleus
= fragments are captured in apoptotic bodies (membrane bound structures)
= bodies undergo phagocytosis and lysis (rupture of cell wall/membrane)
Does not result in inflammation
what is necrosis and what are the 6 stages?
unplanned cell death and autolysis (digestion by own enzymes)
- pathological stimulation
- cell enlargement
- loss of membrane activity
- leakage of content
- Inflammation
- nuclear degeneration
what are the four types of necrosis?
Coagulative
liquefactive
caseous
fat
what is coagulative necrosis characterised and caused by?
Protein denaturation causing coagulation
usually results from hypoxia casued by ischemia (restriction of blood flow)
what is liquefactive necrosis characterised and caused by ?
rapid release of lysosomal enzymes which liquefies cell
follows ischemic injury to neurons and glial cells in brain
What type of gangrene results from liquefactive necrosis?
bacterial infection causes necrosis and results in wet gangrene which releases toxins and can be life threatening
what is caseous necrosis caracterised and caused by?
characteristic of lung tissue damaged by TB
resulting in white, soft lung tissue which is walled off from the rest of the lung by WBCs
what is the cause of fat necrosis
usually caused by trauma or pancreatitis
damage causes cells to release triglycerides which are hydrolyzed by pancreatic lipase
what is gas gangrene characterised by?
bubbles of gas in damaged tissue
produce toxins and degradative enzymes
what are common causes of cell injury?
- lack of oxygen
- lack of nutrients = e.g. diabetes
- infection/immune response = bacteria and viral infections, endo and exotoxins
- chemicals = toxins and poisons
- physical factors = biology of aging
what are the four mechanisms of aging?
- cellular change (genetic, environmental, behavioural)
- hormonal degradations (synthesis and secretion deduction)
- Immune function decline
- Degenerative extracellular change (free radical damage, telomers shorten etc)
