Common Vascular Events In Disease And Injury Flashcards
Hemorrhage
Discharge of blood from the blood vessels
Extravasation
Process of discharging blood from the blood vessels into the surrounding tissues
Splinter hemorrhage
Tiny blood clots that tend to run vertically under the nails
Associated with endocarditis
Melena
Black stool - upper GI bleed
Hematochezia
Lower GI bleed - blood in stool that is bright red
Peripartum Hemorrhage
Reproductive - after giving birth
Gross hematuria
Blood in urine
Hemoparicardium
Bleed fills up the pericardial sac
Hemothorax
Bleed in lung - fills up pleural space and may compress the lung
Subdural hematoma
In brain region
Hematoma
Collection of extravasated blood within the surrounding tissues or body space
Epidural bleed - outside the dura
Subdural - below the dura
Intracerebral - inside brain tissue
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Ecchymosis
Hematoma associated with skin or mucous membrane that measures greater than 1cm in diameter
The terms hematoma, ecchymosis, contusion and bruise are often used interchangeably…contusion implies trauma - whereas the other terms may or may not be the cause
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Exsanguination
“Bleed to death,” fatal loss of blood from massive hemorrhage
Exsanguination may be used medically with…
May be used in surgery in a localized sense, when using a tourniquet and temporarily draining blood from a region - “bloodless surgical field”
Hemostasis
Normal and tightly regulated process that maintains blood in a fluid state when appropriate and aims to arrest bleeding in the event of traumatic vessel damage
In the event of traumatic vessel damage, set of regulated steps aims to arrest bleeding, beginning with….
Arteriolar vasoconstriction
The trio in hemostasis?
Vasculature and hydrodynamics of blood flow:
- endothelium
- smooth muscle
- basement membrane
Platelets:
- receptors for binding, aggregation, activation
- phospholipid surface
Coagulation cascade:
-proteins with enzymatic activity leading to fibrin mesh work
Vessel spasm
First response in tissue injury to blood vessel
Reduces the flow of blood from the vessel rupture
Booth local nervous reflexes and humoral factors released from plates (thromboxane) contribute to vasoconstriction
The endothelium normally secretes prostaglandins and nitric oxide to promote vasodilation and keep platelets away. Disruption exposes collagen and releases..
Von Willebrand factor!! (VWF) - triggers platelet adhesion and activation)
Von willebrand factor is released from the endothelium and binds to platelet receptors causing adhesion of the platelets to exposed collagen fibers. As the platelets adhere to the collagen fibers on the damaged vessel wall, they become activated and release ADP and TXA2. The ADP and TXA2 attract additional platelets, leading to platelet aggregation.
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Activated platelets send out processes that help them enmesh.
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What is the goal of the coagulation cascade?
Create fibrin glue to support plug until endothelium and extracellular matrix remodel
Two coagulation pathways
1) intrinsic - begins in the circulation and is initiated by activation of circulating factor XII
2) extrinsic - activated by cellular lipoprotein tissue factor that becomes exposed when tissues are injured.
Both pathways lead to the activation of factor X, conversion of prothrombin to thrombin, and conversion of fibrinogen to fibrin threads that hold the clot together
Fibronigen to fibrin is catalyze by what?
Thrombin