Altered Cell Biology Flashcards
stress (insult)
stimulus that upsets normal homeostasis
Compensation
the body’s attempt to maintain normal homeostasis under stress
cell injury
result of a stimulus in excess of a cell’s immediate adaptive response
reversible cell injury
injury which does not kill the cell (makes it stronger)
apoptosis
- clean, controlled cell death
- cell breaks apart into apoptotic bodies that then get phagocytozed by other cells
- membrane is not ruptured
- no enzymes released
- does not trigger immune response
- does not show in blood test
Necrosis
- messy, uncontrolled cell death
- cell membrane breaks
- causes release of enzymes
- causes inflammatory response
- shows in blood test
atrophy
decrease in the size of cells
hypertrophy
increase in the size of cells
hyperplasia
increase in number of cells
metaplasia
- change of the cell from one type to another
- can be normal or abnormal
- ex. GERD, cells of esophagus change over time to become more like the cells of the stomach from all the acid.
dysplasia
- abnormal cells that are not necesarily cancer, but can be
- change from normal to abnormal
- ex: a wort
neoplasia
- abnormal disorganized growth, if it forms a mass, is called a tumor
- *different from dysplasia because it is larger in size
how does heart muscle get bigger?
- only 1% more cardiomyocytes are made by stem cells per year.
- the individual cardiomyocyte cells grow bigger, making the overall muscle bigger.
What are the four common themes in cell injury?
- ATP depletion
- free radicals and reactive oxygen species
- Increase in intracellular Ca++
- Defects in plasma membrane
ATP depletion
- lack of O2 greatly decreases ATP production
- lack of ATP prevents the Na/K channels from working
Free radicals and reactive oxygen species
- highly reactive chemicals containing oxygen
- Cause oxidation of membranes and other structures
- particularly problematic with reperfusion
Increase in intracellular Ca++:
what can cause it?
what does it cause?
- low ATP and Na+ gradient prevent removal of Ca++ and release of Ca++ from mitochondria and ER
- Ca++ activates many enzymes
- at very high levels Ca++ signals apoptosis
What is the process of a cell being injured by ischemia?
(flow chart)
what changes happen to a cell that makes the injury irreversible?
- rupture of lysosoves and autolysis
- defects in the cell membrane
- karyolysis
- karyorrhexis
karyolysis and karyorrhexis
breaking up of chromatin and the cell nucleus/DNA
hypoxia
low tissue oxygent level
anoxia
very low tissue oxygen level, no oxygen
hypoxemia
low blood oxygen tension
how does anemia effect hypoxia and hypoxemia?
An anemic person can have a normal oxygen tension (because all their hemoglobin are 100% saturated) but low tissue oxygen level because they don’t have enough hgb to bring enough O2 to the tissues.
ischemia
- insufficient blood supply to tissue or organ
- insufficient blood supply to entire body: shock
- nothing dies, tissue will be fine once it is reperfused.
infarction
ischemia that leads to necrosis
embolism
blood clot that moves
(an embolism ambles)
thrombus
a blood clot that clots the same place where it was made.
Superoxide dismutase
- enzyme that breaks down the superoxide radical (O2-) into either regular oxygen or hydrogen peroxide.
- If you exercise vigorously, you will have more SOD
Catalase
- enzyme that converts hydrogen peroxide (H2O2) into water
glutathione peroxidase
- a type of enzyme who’s main function is to prevent an organism from oxidative damage (from giving up an electron to the free radical)
- Can be reduced back to glutathione reductase
- The ratio of reduced glutathione and oxidized glutathione in a cell can measure the cell’s oxidative stress
coagulative necrosis
- cell death caused by ischemia or infarction
- some of the cell structure is preserved for a few days because the injury effects the lysosomal enzymes
- this gives a clumping, coagulative appearance
liquefactive necrosis
- a type of necrosis that turns the tissue into liquid
- usually caused by bacteria or fungus
- the affected cell is completely broken down. Once it has been cleaned up by the white blood cells, it leaves a hole or empty space
Caseous Necrosis
- a form of cell death where the tissue looks cheese-like
- caused by TB
Fat necrosis
- caused when digestive enzymes break down fat
- seen in pancreatitis when the enzymes get to the fat of the omentum
- Lipase breaks fatty acids from triglycerides
- lipase takes up Ca++ (causing low calcium) and makes soaps
Telomere
The end part of the chromosome; gets shorter with every replication.
telomerase
- found in germ cells and stem cells
- prevents the telomeres from shortening when replicated.
elevated levels of ALT and AST wil signify ______
that liver cells are dying
elevated levels of alkaline phosphatase and GGT wil signify _______
problems with the cells of the bile ducts
