Introduction to Pathology Cell adaption and injury
Tags: Pathology Immunology
Cell injury
Cell injury can be caused by many things like: Hypoxia, Ischemia, Chemical agents, Physical agents, Infectious agents, Genetic abnormalities, Lack of substrates amongst other things.
Cells can either adapt or die
Injury
Hypoxia can cause damage because energy needed to maintain the mechanisms of the cell will not be present in high enough concentrations for pumps to work etc
Symptoms of cell injury include
Swelling (from ion pumps not pumping out certain ions enough)
Blebing of plasma membrane
Cell Adaptations
Hyperplasia
In hyperplasia cells multiply to better deal with the stress conditions. We see this in goitre as the cells sense not enough t3 being made and so therefore multiply to make more unfortunatly none will be made as there is usually a lack of iodine
Hypertrophy
This is where the cells enlargen themselves to better deal with stressors eg in high blood pressure an enlargened heart wall is seen as the cardiomyocytes swell in size to be able to pump harder
Atrophy
Atrophy is where a cell decreases in size either as failure to adapt paradoxically or as the current size isnt currently needed
Metaplasia
This occurs in tissues that need to change cell type to survive eg in smokers lung a transition from respiratory epithelia to simple stratified for protection.
Dysplasia
This is where malignancy develops by chance after a metaplasic shift eg rapidly dividing simple stratified epithelia develop into cancer as they are rapidly dividing.
Cell death
Cell death occurs normally or pathologically Normal death is called apoptosis
Many pathways to cause this: dna or protein damage, viral infection, outside influences etc
Occurs after enzyme cascade of proteolystic caspases which make apoptotic bodies Abnormal, unintended cell death is called necrosis This is where the cell cannot maintain its processes to stay alive, Messy, inflammatory and alarming raising molecules are released There are other mechanisms for cell death eg necroptosis pyroptosis ferroptosis etc) 3 stages of nucleus damage Pyknosis dark pinpoint Karyorrhexis fragmentation Karyolysis nothing