Cell Injury Flashcards
Causes of cell injury
Hypoxia
Ischaemia
Physical agents
Chemicals agents
Microbial agents
Immunologic causes
Nutrition derangements
Ageing
Psychogenic causes
Idiopathic
Define atrophy
Reduction in number and size of parenchymal cells of organ or its part which was once normal is called atrophy
Eg of physiological atrophy
A trophy of lymphoid tissue with age
A trophy of thymus in adult life
Atrophy gonads after menopause
Atrophy of brain with aging
Pathological atrophy
Starvation atrophy
Ischemic atrophy
Dis use a trophy
Neuropathic atrophy example polymyelitis motor neurone disease nerve section
Endocrine trophy example hypopitutism hypothyroidism
Pressure atrophy examples are erosion of spines by tumor in nerve root erosion
Hypertrophy
Hypertrophy is an increasing size of parenchymal cell resulting in enlargement of the effected organ or tissue
Physiological hypertrophy
Enlarge uterus in pregnancy
Pathological hypertrophy
Hypertrophy of cardiac muscle
Due to:
1. Systemic hypertension
2. Aortic disease
3. Mitral insufficiency
Hypertrophy of smooth muscle example
1. Cardiac achalasia
2. Pyloric stenosis
Compensatory hypertrophy of an organ when contralateral organ is removed example following nephrotomy on one side in young patient there is compensatory hypertrophy as well as hyperplasia of the nephrons of the other kidney
Hyperplasia
Hyperplasia is an increase in the number of parenchymal cell resulting in enlargement of the organ and tissue
Physiological hyperplasia
1.Hormonal hyperplasia examples are enlargement of female breast during pregnancy and lactation and also uterus
2. Compensatory hyperplasia
Pathologic hyperplasia
Benign interastatic hyperplasia in old age
hyperplasia of skin in non healing ulcer
Metaplasia
Metaplasia is defined as reversible change in one type of mature differentiated epithelial or Mesenchymal to another type of mature epithelial or mesenchymal
Metaplasia
Metaplasia is defined as reversible change in one type of mature differentiated epithelial or Mesenchymal to another type of mature epithelial or mesenchymal
Dysplasia
Dysplasia means disordered cellular development of preceded or accompanied with metaplasia and hyperplasia. it is therefore also referred to as a typical hyperplasia
Steps of reversible cell injury
- Decrease generation of cellular ATP damaged by ischemia
- Intercellular lactic acidosis which causes nuclear clamping
3.damage to plasma membrane pumps
There is damage to sodium potassium pump which causes hydrox swelling means the swelling of the cell
There is failure of calcium pump which causes mitochondrial spelling and deposition of phosphor lipid rich amorphous density - Reduce Protein synthesis as a result of hypoxia endoplasmic reticulum and Golgi apparatus swell up thus I
What are mylien figures
Mylene figures are derived from membrane enclosing water and dissociated lipoproteins between laminate of injured membrane
Changes occurring during irreversible cell injury
- Calcium influx which cause mitochondrial damage disabling its function. Morphologically it appears in the form of vacuole in the mitochondria and deposit of amorphous calcium salt in mitochondrial matrix
- Activated phospholipase: increased calcium in flux activates phospholipase this intern degrade phospholipid which are main constituent of lipid bilayer membrane
- Activated intracellular proteases cause cytoskeletal damage. This cytoskeleton microfilaments and intermediate filament can be damaged by proteases or also the result of cell swelling
- Activated endonuclease cause nuclear damage
- There is rupture of the lysosomal membrane which causes the release of the lysosomal enzyme and ultimately the cell death
Condensation and clumping of nucleus which becomes dark basophilic
Pyknosis
Nuclear fragmentation into small BITS dispersed in the cytoplasm
Karyorrhexis
Dissolution of the nucleus
Karyolysis
Ischaemia reperfusion injury
Due to excessive accumulation of oxygen species or free radical
Cytotoxicity of free radical
- Lipid peroxidation
- Dna damage
- Oxidation of proteins
- Cytoskeletal damage
What are antioxidant
Antioxidants are endogenous or exogenous substances which inactive the free radical the substance include
Vitamin e A c
Sulphydryl containing compound eg cysteine and glutathione
Oxygen burst
Incoming activated neutrophils utilises oxygen quickly and further release large excess of oxygen free radical
What are the two types of stress protein in cell injury
Heart shock protein
Ubiquitin
Accumulation of water within the cytoplasm of the cell
Hydropic change
Intracellular hyaline
Hyaline droplets in Pct due to protein urea
Hyaline degeneration of rectus abdominis muscle called zenkers
degeneration in typhoid fever
Intracellular hyaline
Hyaline droplets in Pct due to protein urea
Hyaline degeneration of rectus abdominis muscle called zenkers
degeneration in typhoid fever
Necrosis
Necrosis is defined as localised area of death of tissue followed later by degeneration of tissue by hydrolytic enzyme liberated from dead cell it is invariably a company by inflammatory reaction
Most common type of necrosis caused by irreversible focal injury mostly from sudden cessation of blood flow
Coagulative necrosis
Focus of coagulative necrosis in early stage is pain firm and slightly
Infarct
What is the hallmark of coagulative necrosis
Conversion of normal cells into Tombstone that is outlines of cells are retained and type can still be recognise but the cytoplasmic and nuclear details are loss
Seen in focal bacterial or, occasionally, fungal infections, because microbes stimulate the accumulation of inflammatory cells and the enzymes of leukocytes digest the tissue.
Liquefactive necrosis
The type of necrosis which is found in centre of focib of tubercular infection
Caseous
Special form of cell that occurring at mainly fat rich and atomic location in the body
Fat necrosis
Examples of fat necrosis
Traumatic fat necrosis of breast especially in heavy and pendulous breast
Mesenteric fat necrosis due to acute pancreatitis
Fibrinoid necrosis
Fibrinoid necrosis is characterized by the deposition of the fibrin like material which has properties of Fibrin examples are auto immune vasculitis
Calcification
Deposition of calcium salts in tissue other than osteoid and enamel is called calcification
Dystrophic- necrotic, severe atherosclerosis
Metastatic - normal, hypecalemia
