Pathology Flashcards
what is hypertrophy?
an increase in cell size
what is hyperplasia?
increase in cell number
what is atrophy?
decrease in cell size and/or number; survival is maintained by decrease in function
what is metaplasia?
replacement of one cell type by another
important characteristics of necrosis?
- always pathologic
- have nuclear degradation
- disruption of plasma membrane
- digestive enzyme leakage
- cellular swelling
- inflammation
important characteristics of apoptosis?
- can be normal or pathologic
- nuclear shrinkage and fragmentation into nucleosome size paritcles
- plasma membrane stays intact
- no leakage of enzymes and no inflammation
what is coagulative necrosis?
protein denaturation but the cell and tissue framework remains
when do you often see coagulative necrosis?
in hypoxia or ischemia
what is liquefactive necrosis?
complete digestion of tissue - becomes liquid mass
when do you often see liquefactive necrosis?
in bacterial infections and hypoxia of CNS
what is gangrenous necrosis?
when coagulative necrosis occurs in the extremities, called wet gangrene when accompanied with bacterial infection
what is caseous necrosis?
a type of necrosis where it looks cheesy - it is friable and proteinaceous
when do you see caseous necrosis?
tuberculosis
what is fat necrosis?
when lipases spill out into adipose tissue and the fat cells are liquefied - the fatty acids are released and combine with calcium to produce chalky areas
what is fibrinoid necrosis?
when proteins (ab/antigens often) are deposited in blood vessels
what are the two pathways for apoptosis?
mitochondrial and death receptor pathways
describe the mitochondrial pathway for apoptosis.
cellular stress causes BCL proteins to be activated, they activate Bax and Bak which insert into mitochondrial membrane and create pores, cytochrome C is released and activates caspases which cause apoptosis
describe the death receptor pathway of apoptosis.
the plasma membrane death receptor binds with its ligand (TNF, Fas receptors) and this binding signals caspases that control apoptosis
what are some morphological features of reversible cell injury?
fatty change (lipid vacuoles in cytoplasm) and cellular swelling
what can fatty change be a sign of?
alcohol abuse, diabetes
what is lipofuscin?
it is the “wear and tear” pigment common in aging - it is a sign of free-radical injury and lipid peroxidation; it’s yellow-brown
what is hemosiderin?
it’s a golden yellow-brown pigment that is a storage form of iron
what is dystrophic calcification?
calcium deposition when there is necrosis, can occur in normal calcium metabolic situations)
what is metastic calcification?
this occurs when calcium metabolism is out of balance - usually with hypercalcemia (no necrosis)
what are the key events of acute inflammation?
vascular dilation, exudation, leukocyte migration and accumulation
describe histamine’s function as a mediator of acute inflammation.
histamine is made in mast cells, platelets, and basophils; it causes increased vascular permeability, vasodilation, and it activates endothelial cells to prep for leukocyte migration
describe serotonin’s function as a mediator of acute inflammation.
serotonin is made in platelets and it functions to increase vascular permeability and vasodilate
describe thromboxane’s function as a mediator of acute inflammation.
thromboxane is made by the cyclooxygenase pathway and it functions to vasoconstrict and cause platelet aggregation
describe prostacyclin’s function as a mediator of acute inflammation.
prostacyclin is made by the cyclooxygenase pathway and it funcitons to vasodilate and inhibit platelet aggegation.
describe prostaglandin’s function as a mediator in acute inflammation.
prostaglandin is made by the cyclooxygenase pathway and it functions to increase vascular permeability, vasodilate, cause fever.
describe leukotriene B’s function as a mediator of acute inflammation
a product of the lipoxygenase pathway (5-LO)and it functions as a chemotactic susbtance for neutrophils (and can also activate them)
describe the functions of leukotrienes C, D, E in acute inflammation
these are products of the lipoxygenase pathway (5-LO) and their function is to cause neutrophil activation and adhesion as well as bronchospasm and increased vascular permeability and vasodilation
describe the funciton of lipoxin in acute inflammation
this is a product of the lipoxygenase pathway (12-LO) and it functions to inhibit neutrophil adhesion and chemotaxis (anti-inflammatory)
describe the function of platelet activating factor in acute inflammation
made by platelets, mast cells, endothelial cells, and leukocytes; functions to
- bronchoconstriction
- oxidative burst
- vascular permeability and vasodilation
- leukocytes adhesion
- chemotaxis
- platelet aggregation
what do TNF/IL-1 do locally?
they increase endothelial adhesion molecule expression, they increase vascular permeability and vasodilation, they activate leukocytes, and cause production of chemokines, cause fibroblast proliferation and collagen synthesis
what do TNF/IL-1 do systemically?
cause fever, leukocytosis, acute phase response, decrease appetite, increase sleep need
what cells do CXC chemokines act on?
neutrophils
what cells do CC chemokines act on?
basophils, eosinophils, lymphocytes, and monocytes
what cells do C chemokines act on?
lymphocytes
what cells do CX3C chemokines act on
mononuclear cells
describe the function of reactive oxygen species in inflammation.
they are made by NADPH oxidase in leukocytes (among other cells) and they function to destroy microbes and can even cause endothelial injury to increase vascular permeability
what antioxidants can take care of ROSs?
glutathione, SOD, and catalase
what is the role of nitric oxide in acute inflammation?
NO is made in neural cells (nNOS), endothelial cell (eNOS) where it is constituitively being made and in macrophages (iNOS) where it is induced by IL-1, TNF, IFN-gamma, and endotoxin
it is made by NO synthase from L-arginine
what mediators stimulate the production of NO is macrophages?
IL-1, TNF, IFN-gamma, and endotoxin
what are the three types of proteases present in the large azurpohilic granules of neutrophils
acid proteases, neutral proteases, anti-proteases
what are three complement inhibitors?
C1 inhibitor, decay accelerating factor and CD59 which prevent formation of C3 convertase
how is bradykinin made and what does it do?
kininogen is cleaved by kallikrein to make bradykinin which functions to increase vascular permeability, cause smooth muscle contraction and vasodilation
what are three ways to increase vascular permeability?
- intracellular gaps form when endothelial cells are signalled
- cell injury from external
- intential cell injury from ROS/NO
what are the protein interactions responsible for leukocyte rolling?
the sialyated-lewis glycoproteins on the leukocytes bind to E and P selectins on endothelial cells
what stimulates expression of E selectins on leukoctyes?
TNF and IL-1 from macrophages
what stimulates expression of P selectins on leukocytes?
histamine!
what are the protein interactions that are responsible for tight adhesion?
integrins on the leukocyte bind to ICAM-1 and VCAM-1 which are induced by TNF
what protein is responsible for diapedesis?
PECAM-1 driven by chemokines