BOD Exam 2
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an increase in the amount of blood in the vasculature in a given part of the body due to local vascular dilation
Hyperemia & Congestion
Congestion is either _____ or ______.
acute - leading to anoxic injury
chronic - leading to hypoxic injury
Congestion may result in (5)
Secondary effects of hemorrhage (4)
resorption of fluid
erythrocytes lysed & phagocytosed
fibrinolysis - breakdown of clots
potential scarring - ingrowth of granulation tissue from hematoma
local arteriolar dilation leading to an increase in the amount of blood in the vasculature
venous engorgement is called
During liver congestion, hypoxic injury occurs where? It results in what?
Periphery of the acinus (connecting central veins)
loss of hepatocytes and fibrosis
Lung congestion is caused by
interference with blood flow through left heart
Pulmonary congestion leads to (2)
edema & fibrosis
What is hemosiderosis
macrophages in lungs eat RBCs and iron builds up
When does hypostatic congestion occur?
Post mortem gravity
ante mortem recumbent animals
Edema may be classified as (3)
Edema fluid that contains both serum and blood is called
Causes of generalized edema (3)
hepatic failure or malnutrition/malabsorption
Cardiac edema occurs when
there is venous congestion resulting in increased blood volume and increased hydrostatic pressure (blood is forced out into the tissues)
renal failure causes generalized edema by
urinary protein loss & decreased oncotic pressure
Why does hepatic failure or malabsorption cause generalized edema?
Decreased plasma oncotic pressure - fluid goes out and doesn't come back in
What is ansarca?
generalized edema over entire body
Three causes of localized edema
inflammatory edema or vascular injury
Termination of blood loss from the vasculature is called
Hemostasis is maintained by
pro and anti-coagulant mechanisms
formation of a solid adherent blood clot within the lumen of a vessel or the heart
Three types of blood clots
Thrombi (excessive clot formation)
post-mortem blood clotting (chicken fat clot)
Three events in hemostasis
platelet plug - platelets adhere to damaged endothelial cells and each other
coagulation - enzymatic cascade involving pre-formed clotting factors in blood
Three steps of platelet activation
adhesion and shape change
secretion (release reaction)
What promotes platelet adhesion?
von Willebrand's factor binds subendothelial collagen and platelets bind to that
What causes platelet aggregation?
ADP and Thromboxane A2 promote formation of primary plug
Thrombin promotes further aggregation and polymerizes fibrin producing definitive plug
Platelet aggregators (6)
ADP and Thromboxane A2
platelet activating factor
Important coagulation cofactor
Anticoagulant factors of endothelial cells
NO & PGI2 inhibit platelet aggregation
modulate fibrinolysis via plasminogen activators & inhibitors
Plasminogen is present where?
plasma and platelet membranes
Plasminogen active form
Two plasminogen activators
tissue type - produced by endothelial cells
urokinase like - present in plasma
DIC stands for
Disseminated Intravascular Coagulation
DIC is characterized by (4)
widespread activation of clotting mechanisms
consumption of platelets and clotting factors
activation of fibrinolysis
Causes of DIC
infection, trauma, neoplastic disease
Pathogenesis of DIC
massive release of tissue factor or thromboplastic substances into the circulation
In Gram negative sepsis, what is the first step in the DIC mechanism?
Endotoxin induces expression of tissue factor, IL-1, TNF in monocytes & macrophages
What do IL-1 and TNF do?
induce tissue factor expression from endothelial cells and upregulate WBC binding
During gram negative sepsis, endotoxin ultimately causes what?
widespread activation of clotting and fibrinolysis in microvasculature
Gram negative sepsis ultimately causes DIC by doing what?
using up platelets and clotting factors and causing microvascular hemorrhage
Is thrombosis a normal component of hemostasis?
Local control of clotting cascade (3)
proteins C & S
Virchow’s Triad for thrombosis pathogenesis:
Damage to vessel
increased coagulability of blood
changes in flow
BOD Exam 2
Biology of disease exam 2