What is pathophysiology? - correct answer not only cellular and organ changes that occur with disease, but with the effects that these changes have on
... [Show More] total body function
Atrophy - correct answer decrease in size of tissue organs resulting from a decrease in cell size or in number of cells
causes include disuse, loss of trophic stimuli (i.e. loss of innervation), insufficient nutrients, decreased blood flow, persistent cell injury, and aging
cells decrease cellular machinery, decrease oxygen/glucose needs, decrease number of organelles
Hypertrophy - correct answer increase in cell size, and thus an increase in amount of functioning tissue mass
results from an increased workload imposed on an organ or body part
involves an increase in the functional components of the cell that allows it to achieve equilibrium b/w demand and functional capacity
Hyperplasia - correct answer increase in number of cells in an organ or tissue
∙can only occur in tissues that are capable of mitotic division
controlled process that occurs in response to an appropriate stimulus and ceases after stimulus has been removed
more dangerous than hypertrophy → b/c of increased division, increased risk of cancer
example: prostate, uterus/breast tissue in pregnancy/puberty
Metaplasia - correct answer reversible change in which one adult cell type is replaced by another adult cell type
∙only kind of cell of that is replaced is present, i.e. epithelial cells are replaced by a different type of epithelial cell
thought to involve the reprogramming of undifferentiated stem cells that are present in tissue
usually occurs in response to chronic irritation and inflammation which allows for substitution of cells that are better able to survive
seen in Barrett's esophagus
Dysplasia - correct answer characterized by deranged cell growth of a specific tissue that results in cells that vary in size, shape and appearance
∙thought of as replacement of mature cell by immature cells, that can differentiate into different cell types
involves sequential mutations in proliferating cell populations
pattern is most frequently encountered in metaplastic squamous epithelium of respiratory tract and uterine cervix
strongly implicated as a precursor to cancer
Levels of Cellular Injury - correct answer stress causes cell to adapt, but at some point it will eventually cause injury
injuries can lead to cell death, but at some point along cellular pathway, the injury can be reversible
at some point, the injury becomes irreversible, and the cell will die, either by apoptosis or necrosis
Stresses: mechanical forces (usually superficial injuries), electrical injuries, (electricity can carry heat that damages, electrical impulses can change electrical balance w/in body), nutritional imbalances, biological agents (viruses/bacteria), poisons
Hypoxia - correct answer hypoxia = lack of oxygen
∙ischemia = lack of blood flow
∙ischemia can cause hypoxia
without oxygen, 2 things happen in cell
∙inability to make ATP affects polarization of membrane
∙not having O2 changes us from aerobic metabolism to anaerobic metabolism
Extremes of Temperature - correct answer Heat
∙accelerates cell metabolism
∙inactivates temperature sensitive enzymes (can alter metabolism)
∙disrupts the cell membrane
∙coagulation of blood vessels
∙coagulation of tissue proteins
Cold
∙increases blood viscosity
∙induces vasoconstriction (SNS)
∙ice crystal formation
∙capillary stasis
∙arteriolar and capillary thrombosis
Chemical Agents - correct answer similar to poisons that can cause cellular damage
lead causes problems in body b/c unlike a lot of other substances, there is no threshold of lead that is safe for the body
∙very high levels of lead can cause mental retardation, coma, convulsion and death
∙low levels of lead can cause reduced IQ and attention span, impaired growth, reading and learning disabilities, hearing loss and a range of other health/behavioral effects
Lead - correct answer no threshold of lead that is safe for the body
able to cross blood-brain barrier
∙confuses calcium transporters and takes the place of calcium
∙unique to lead
∙once it gets into CNS, we don't have a way to get it out
causes an increase in ROS (reactive oxygen species), and a decrease in antioxidant system
can affect kidney → glomerular fibrosis and proximal tubule mitochondrial damage
Mechanisms of Cell Injury - correct answer can be complex
some agents (like heat) produce direct cell injury
some agents (like genetic derangement) produce effects indirectly through metabolic disturbances and altered immune responses
most are caused by:
∙depletion of ATP
∙free radical formation
∙disruption of intracellular calcium homeostasis
Depletion of ATP - correct answer Na-K transporter is first affected
∙uses ATP to pull sodium out of cell and potassium into cell
∙maintains polarization of membrane, keeps cell intact
loss of ATP means that this pump begins to fail
∙when pump fails, membrane depolarizes, see increase of intracellular calcium resulting in cellular swelling
∙this is reversible, but at some point the swelling will get so bad as to cause cell lysis
depletion of ATP also causes the cell to switch to anaerobic metabolism
∙end product here is lactic acid
∙lactic acid causes decrease in cellular pH
∙when cellular pH decreases to a specific point (irreversible cell injury), lysosomes will lyse
→once you lyse the lysosome, it will cause the degradation of the organelles and membrane of the cell
Ischemia-Reperfusion Injury - correct answer this is when there is a blockage, the blockage is removed, and the tissue is reperfused
when you reperfuse that tissue after it has been ischemic, you generally cause more damage with reperfusion that with ischemia
when under oxidative stress, cells will begin to release chemokines and other inflammatory markers
∙reperfusion will cause a massive inflammatory response
commonly seen in MIs, strokes
Free Radical Injury - correct answer ROS: reactive oxygen species → anything with an unpaired electron
∙the danger is that the unpaired electron goes and takes an electron from somewhere else, causing damage to whatever molecule they take from
∙they like to take them from larger molecules that are unable to take electron back → membrane, DNA molecules, large proteins w/in cell [Show Less]