Cell Injury 1 and 2 Flashcards
cell injury is defined as a ____
disturbance in homeostasis
consequences of cell death depend on:
the type of insult, the duration, the severity, and the type of cell
what are the two ways you can “die” at the top of the mountain? AKA, what are the two mechanisms of cell death?
dramatic death, necrosis
quiet death, apoptosis
what are the 3 categories of the causes of cell injury?
extrinsic (trauma, infection, toxins, etc)
intrinsic (genetics)
combined (nutritional imbalances, workload imbalances, immunological issues, etc(
the most common and important cause of cell injury and death is ____
oxygen deficiency
difference between hypoxia and anoxia?
hypoxia: partial reduction in O2 supply
anoxia: complete deprivation of oxygen supply
which cell types are the most sensitive to low oxygen content?
neurons>cardiac myocytes, hepatocytes, and renal epithelium> CT, skeletal muscle
what are the 3 categories of causes of hypoxia?
inadequate intake
blood vessel obstruction
inability to use oxygen
when it comes to the immune system, what are the 3 ways in which cell injury or death can occur
immunodeficiency (immune system damaged or not working)
allergic or hypersensitivity (over reaction)
autoimmune (attacking self)
what are the 2 most common causes of cell injury in general?
ATP depletion
cell membrane damage
cell injury is considered reversible if _____
the injured cell can regain homeostasis and return to a normal functional state
what is the classic morphological change in reversible cell injury called? What is important to remember about this term?
acute cell swelling
this is also indicative of early irreversible damage so it is best to think of acute cell swelling as potentially reversible
acute cell swelling indicates _______
loss of cell volume control (ATP depletion or cell membrane damage)
what 2 functions does the cell membrane serve?
it is a selectively permeable barrier, and it contains ATP dependent ion pumps
explain how hypoxic injury can lead to acute cell swelling
low oxygen leads to low ATP. this causes the ion pumps to fail and sodium moves into the cell. water follows, the cell swells up, the organelles fill with water, leading to extensive vacuolation
explain how membrane damage can cause acute cell swelling
the damage allows sodium to move into the cells, water follows, cell swells, water gets into organelles, extensive vacuolation
what is the main cause of cell membrane injury ?
free radicals
where do free radicals come from?
normal oxidative phosphorylation, exposure to certain toxins, radiation, or drugs, inflammation, and ischemia-reperfusion injury (if blood supply is cut off and there is regeneration, free radicals are formed)
how do free radicals injure a cell?
via lipid peroxidation of the cell membrane (free radicals steal electrons from the lipids in cell membranes)
how does the body naturally combat free radicals?
vitamins A, C,E
enzymes
binding proteins using iron or copper
what is white muscle disease caused by?
free radicals injure the cell membranes and the cell death leads to mineralization in the muscle, making it appear white and chalky
how can we as pathologists identify cell injury?
blood chemistry, microscopic changes, gross changes (can be seen with naked eye)
if the death is sudden there may not be visible change
how are organs with acute cell swelling different than normal organs?
they weigh more than normal, they are pale, swollen, and tissues may bulge
how is acute cell swelling identified under a microscope?
hydropic degeneration and cloudy swelling. the cells appear swollen and are paler in color, the cytoplasm is vacuolated
