Exam 1 Flashcards
list 4 ways cells can adapt to stress what describe what they are
- hypertrophy - increase in cell SIZE
- hyperplasia - increase in cell NUMBER
- atrophy - decrease in cell SIZE
- metaplasia - change in cell PHENOTYPE
list 2 biochemical pathways that can cause hypertrophy
- phosphoinositide 3-kinase/Akt pathway
2. signaling downstream of G protein couples receptors
list 2 ways hypertrophy can manifest
- increase entire CELL size
2. increase the size of ORGANELLES (can be induced by drugs and can lead to increased tolerance to them)
what is hyperplasia?
can it occur along side with hypertrophy?
an increase in the NUMBER of cells
sure can
list 2 types pf physiologic hyperplasia? when would each be used?
- hormonal - increases functional capacity of tissue when needed (puberty, pregnancy)
- compensatory - increases tissue mass after damage or resection (liver transplant)
what is pathologic hyperplasia usually caused by? give 2 examples of this condition.
caused by an excessive amount of hormones or growth factors
endometrial hyperplasia, benign prostatic hyperplasia
list 6 common causes of atrophy
- decreased workload
- loss of innervation
- diminished blood supply
- inadequate nutrition
- loss of endocrine stimulation
- prolonged tissue pressure
list 2 mechanisms for atrophy
- decreased protein synthesis
2. increased protein degradation (uniquitin-proteosome pathway)
what are lipofuscin granules (brown atrophy)
cellular debris in autophagic vacuoles that resist digestion in lysosomes. they persist as membrane-bound residual bodies
define metaplasia
a reversible change in which one differentiated cell type is replaced by a different cell type
list 3 examples of metaplasia
- conversion of pseudostratified ciliated columnar epithelium in the respiratory tract with squamous epithelium in chronic smokers (loss of mucociliary elevator)
- barrett esophagus: conversion of esophageal squamous epithelium with intestine-like columnar cells due to refluxed gastric acid
- myositis ossificans: bone formation in muscle
list 4 cellular morphologic alterations (due to injury) that are reversible (in sequence?)
- swelling of the cell and its organelles
- blebbing of the plasma membrane
- detachment of ribosomes from the ER
- clumping of nuclear chromatin
what are some signs that a tissue is experiencing cellular swelling?
- pallor, increased turgor and increase in weight of the organ (it can be difficult to detect at the cellular level under light microscopy)
- however, small, clear cytoplasmic vacuoles (pinched off ER) can sometime be seen
what are the causes of necrosis and apoptosis? how do they work?
necrosis: sever membrane damage (lysozyme enzymes leak out and digest the cell)
apoptosis: cell’s DNA or proteins are damaged beyond repair (nuclear dissolution and fragmentation of the cell without loss of membrane integrity)
list the order of irreversible cell changes over the duration of an injury
1st. biochemical alterations (leads to cell death)
2nd. ultrastructural changes of cell (blebbing, mito. changes, dilation of ER, nuclear alterations)
3rd. light microscopy changes
4th. gross morphological changes
necrotic tissue can display increased eosinophilia in a H & E stain. why?
because the necrotic cells lose most of their cytoplasmic RNA (which binds hematoxylin [blue]) but has increased denatured cytoplasmic proteins (which binds eosin [red])
define karyolysis, pyknosis and karyorrhexis and hoe they appear under microscopy.
karyolysis: loss of DNA due to degradation by endonucleases (the basophilic [blue] nucleus slowly fades away)
pyknosis: condensation/shrinkage of the nucleus (the basophilia of the nucleus increases as it shrinks in the cell)
karyorrhexis: the nucleus undergoes fragmentation (nucleus breaks apart then completely disappears around 1 to 2 days)
list 6 patterns of tissue necrosis
- coagulative
- liquefactive
- gangrenous
- caseous
- fat
- fibrinoid
list 3 characteristics of coagulative necrosis. what is a common cause of this?
- the tissue will mostly maintain its architecture (you can identify which tissue is damaged under microscopy)
- the tissue will be very firm
- it will consist mostly of anucleate, eosinophilic [red] cells
most commonly caused by ischemia
list 2 characteristics of liquefactive necrosis. what are some common causes? where does it most commonly occur?
- its characterized by the digestion of dead cells
- it’s typically creamy and yellow (mixture of dead leukocytes and purulent matter)
commonly caused by bacterial infections and sometimes fungal
most common in CNS cells
what other types of necrosis are commonly seen along with gangrenous necrosis. what tissues does gangrenous necrosis typically affect.
- coagulative necrosis due to the loss of blood supply
- liquefactive necrosis due to bacterial infection in affected tissues (wet gangrene)
it typically involves multiple tissues at the same time
what does a caseous necrotic lesion look like micro and macroscopically
what condition is it cormally associated with?
microscopically: amorphous granular debris ( fragments and lysed cells) enclosed in a distinctive inflammatory border (higher concentration of WBCs around an area with few nuclei visible)
macroscopically: white, cheeselike and crumbly
normally associated with the foci of a TB infection
what is fat necrosis?
what is a cause of it?
what does it look like microscopically? macroscopically?
focal area of fat destruction
release of activated pancreatic lipase into the pancreatic substance and/or paritoneal cavity
microscopically: shadowy outlines of nectoric fat cells with basophilic [blue] calcium deposits. almost looks like brown fat mixed in with white fat
macroscopically: white, chalky, rice-like granules
what is the cause of fibrinoid necrosis?
what do they look like microscopically?
the deposition of immune complexes and fibrin in blood vessles
microscopically: they appear as an amorphous, (acellular?) band around a blood vessel
what % of ATP depletion can a cell handle before some of its critical functions are affected?
5 to 10%
depletion of ATP in the cell can cause a loss in the activity of the Na efflux pump. how would this effect the cell (in excessive amounts)?
it would cause in increase of intracellular sodium, which would cause an influx of Ca and an efflux of K resulting in cellular (and ER) swelling, loss of microvilli and membrane blebbing
depletion of ATP in the cell can cause an increase on anaerobic glycolysis. how would this effect the cell (in excessive amounts)?
it would cause a decrease in glycogen, increase in lactic acid (and therefore a decrease in pH) and ultimately result in clumping of nuclear chromatin
depletion of ATP in the cell can cause ribosomes in a cell to detach from the ER. how would this effect the cell (in excessive amounts)?
it would cause a decrease in protein synthesis which would lead to lipid deposition
list 3 things that can damage a mitochondria
- increased cytosolic Ca
- reactive oxygen species
- oxygen deprivation
what is the consequence of the formation of a mitochondrial high-conductance pore
what does it span?
loss of mito. membrane potential which leads to a failure in oxidative phosphorylation, then depletion of ATP, then necrosis
spans both the membranes and connects the matrix to the cytosol
where would you find cytochrome C and caspaces in mitochondria? how do they relate to apoptosis?
they are found in between the two membrane layers. they can initiate apoptosis via increasing the permeability outer membrane
where is Ca typically found in the cell? what is the result of it leaving these areas?
sequestered in the ER and mitochondria
an increase in cytosolic Ca can activate numerous enzymes (proteases, endonucleases, ATPases) this inducing apoptosis via direct activation of mito. caspases
list 3 pathologic reactions caused by free radicles
- lipid peroxidation (unsaturated double bonds of lipids attacked)
- oxidative modification of proteins
- lesions in DNA
differentiate hypoxia and ischemia
hypoxia is reduced oxygen availability whereas ischemia is a decrease in oxygen AND nutrients due to reduced blood flow
which type of injury is more sever, ischemia or hypoxia?
ischemia because it prevents both aerobic energy production (due to reduced oxygen availability) AND anaerobic energy production (due to reduced glycotic substances getting to the tissue)
list the sequence of events of ischemic cell injury (4 steps)
- oxygen tension within the cell decreases (therefore depletion of energy and everything associated with that)
- influx of Ca
- progressive loss of glycogen
- decreased protein synthesis
what is one approach for reducing the damage of ischemic cell injury? what tissue is this method most useful with?
induce transient hypothermia (core body temp down to 92 degrees) thus producing a reduced metabolic demand on the stressed cells, decreased swelling, suppressed the formation of free radicles and inhibition the host inflammatory response
what is a ischemia-reperfusion injury?
what is the proposed mechanism for this?
the loss of cells in addition to those that were irreversibly damaged from ischemia due to reperfusion of blood to the area.
list 4 proposed mechanism for ischemia-reperfusion injury
- overproduction of free radicles (more ROS & RNS made and decreased activity of antioxidants)
- influx of Ca into cells
- production of inflammatory cytokines to tissue
- activation of the complement system in tissue
for the following cell death types, tell whether they cause acute inflammation:
- necrosis
- apoptosis
- necrosis - yup
2. apoptosis - nope
name 4 ways cells are lost due to pathologic apoptosis
- excessive DNA damage
- accumulation of misfolded proteins
3 viral (all intracellular pathogens?) infection - atrophy of parenchymal cells (functional cells of an organ) after duct obstruction [ex. pancreas, parotid gland, kidney]
differentiate the morphology of a apoptotic cell vs. a necrotic cell
Apoptotic: cell (and organelles) shrinks, chromatin condenses (nucleus may also break apart), blebbing off of non-leaking, dense apoptic bodies.
necrotic: initial swelling, loss of plasma (and organelle) membrane integrity, contents leak out to neighboring cells
what are the two groups of caspases? what is the general function of these groups? which specific caspases fall into these groups?
- initiators (caspase-8 &9) - caspaces become catalytically active
- executioners (caspase-3 & 6) - caspases trigger the degradation of critical cellular components
what are the two mechanisms of apoptosis and what are they associated with? what caspases do they activate?
- intrinsic (increased permeability of mitochondria) - activation of caspase-9
- extrinsic (death receptor-initiated)
- activation of caspase-8 & 10