Cell injury and death Flashcards
Name 5 causes of Cell injury
Hypoxia (Lack of oxygen)
Physical agent
Chemical agent
biological agent
Immunological response
What is the major cause of Hypoxia
Ischaemia
What are the forms of immunological reactions causing problem
Hypersensitive state and autoimmunity
What is the pathogenesis of cell injury
All stresses and noxious influences exert their effects at the molecular or biochemical level
- Structural changes after biochemical derangement
- Histochemical or ultrastructural changes (minutes to hours after injury)
- Changes by light microscopy or on gross examination (hours to days)
Name 4 biochemical mechanism and how does they cause damage
- Mitochondrial damage
==> Calcium efflux ==>Loss Mitochondrial membrane potential ==> Impair Oxidative phosphorylation
–> Reduce ATP production
–> Release ROS that damages lipid, protein and DNA
- Entry of Calcium ion
–> Increase mitochondrial permeability to cause Calcium efflux
—> Activates phospholypase (dmg cell membrane), endonuclease (Dmg DNA) and Protease (Break down membrane and cytoskeletal proteins)
–>Promote apoptosis - Membrane damage
–> Cell membrane: Loss of cellular components
–> Lysosomal membranee: Enzyme digestion of cellular component - Protein misfolding, DNA damage
–> activation of pro-apoptotic protein
What are the 5 reversible injury and the 2 main type of irreversible injury
- Intracellular oedema
- Fatty change
- Hyaline degeneration
- Intracellular accumulation
- Sublethal nuclear damage
Necrosis, Apoptosis
What is intracellular oedema
Derangement of cell membrane causes influx of Na+ ion along with water to cause cell swelling
Or in other words, influx of isotonic solution
What is Fatty change
What is the cells most prone to it
What is the causes of it
It means the non-adipocytes appears like a adipocyte, with abnormal accumulation of fat in the cell
Liver, heart muscle, Renal Tubule
Chemical injury, Hypoxia, Starvation &wasting disease, DM
What is Hyaline degeneration
What is the appearance of hyaline degeneration under H&E staining
The situation when Smooth muscle is replaced by fibrous connective tissue
Homogeneous glassy, pink alteration (intracellular & extracellular)
What are usually accumulated in intracellular accumulations
And their causes
Lipofuscin (Pigment of aging)
Lysosomal storage disease (ie The lack of functional lysosome causing big moelcules to accumulate)
Haemosiderin (due to uptake of excess iron by cell)
For sublethal Nuclear damage
At what cells will the damage cause heritable disease
Else what will be the problem
Germ cell
Neoplasia
What is the difference between cell apopotosis and necrosis in terms of the effect caused
Apoptosis affects single cells within living tissues, usually wont lead to disruption in tissue function
While necrosis means a sheet of cells dying together, disrupting tissue structure
Will apopotosis and necrosis cause
Acute inflammation
Scaring
Are they phyiological or pathological
Cell size change
Cell membrane damaged
Apoptosis no. Necrosis Yes
Apoptosis no. Necrosis May
Apoptosis: Both
Necrosis: Pathological
Necrosis: Enlarged
Apoptosis: Shrinked
Necrosis: Yes
Apoptosis: Intact but structure altered
What are the physiologucal causes for apoptosis
-programmed cell destruction during
embryonic development
– normal cell turnover in adult organs
What are the pathological causes for apoptosis
– UV or ionizing radiation
– cytotoxic T cells
– Cell mediated immunity
– drugs
– tumour cell death