BLOOD COAGULATION Flashcards
the father of medicine and observed that the blood of a wounded soldier congealed as it cooled
Hippocrates
he noted that blood cooled when removed
Aristotle
in 1627, _______ observed clots in veins
Mercurialis
in 1770, ______ challenged the cooling theory, believing that air and lack of motion were important in the initiation of clotting
Hewson
_______ assembled the coagulation factors
Morawitz
arresting of bleeding
hemostasis
achieved through the process of balancing bleeding and clotting
hemostasis
coagulation that occurs physiologically, resulting in sealing of break in a vasculature
hemostasis
essential to protect the integrity of the vasculature
hemostasis
“clotting”
thrombosis
formation of blood clot inside a blood vessel, obstructing the flow of blood
thrombosis
greek word “thrombos” meaning a lump or a clump
thrombosis
complex network of interactions involving vessels, platelet and coagulation factors
coagulation
relies on a system of checks and balances between thrombosis and hemorrhage that includes procoagulant and anticoagulant
hemostasis
coagulation is divided into two major systems:
- primary system of hemostasis
- secondary system of hemostasis
comprises platelet function and vasoconstriction
primary hemostasis
defined as primary platelet plug
primary hemostasis
serves to immediately limit bleeding through the formation of platelet plug
primary hemostasis
- coagulation factors
- platelet phospholipid
secondary hemostasis
substrates in a series of delicately balanced enzymatic reactions that culminate in fibrin formation
secondary hemostasis
After injury, the following may take event:
1. Rapid vasoconstriction for up to ____ minutes, reduces blood flow and promotes contact activation of platelets and coagulation
2. Platelets adhere immediately to the exposed subendothelial connective tissue. The aggregated platelets enhanced vasoconstriction by releasing _______ and vasoactive amines, like _______ and ________
3. Coagulation this initiated through both the intrinsic and extrinsic system
4. Finally, fibrinolysis occurs following the release of tissue plasminogen activators from the vascular wall. Fibrinolytic removal of excess hemostatic material is necessary to reestablish vascular integrity
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thromboxane A2
serotonin
epinephrine
vasospasm, narrowing of the arteries caused by a persistent contraction of the blood vessels, vasoconstriction
blood vessel spasm
contraction of blood vessel wall
vasoconstriction
short lived reflex reaction of the smooth muscle in vessel wall
vasoconstriction
narrowing of the blood vessels resulting from the contraction of the muscular wall of the vessels
vasoconstriction
occurs immediately and lasts briefly
vasoconstriction
allows increased contact between the damaged vessel wall, blood platelets and coagulation factors
vasoconstriction
effectively prevents bleeding in small blood vessels, but it cannot prevent bleeding in larger vessels
vasoconstriction
opposite of vasodilation
vasoconstriction
prevents bleeding by contracting vessels, by initiating contact activation of platelets with aggregation, and activating coagulation system
vascular system
- vessels that take blood away from the heart
- distributing vessels that leave the heart
✓have the thickest walls of the vascular system
✓blood with oxygen
arteries
- return of blood to the heart
- thin walled with elastic fiber
- larger than the arteries, and have more irregular lumen
veins
smaller subdivisions of arteries and veins
arterioles and venules
small branch of artery leading to capillaries
arterioles
- transport blood from arteries to capillaries
- play a key role in regulating blood flow into the tissue capillaries
arterioles
- microscopically sized veins
- a small blood vessel in the microcirculation that allows blood to return from the capillary beds to drain into larger blood vessels
- 7microns to 1mm
venules
- most numerous of the blood vessels
- composed only of tunica intima, consisting of thin wall of simple squamous endothelial cells
capillaries
- larger and have more irregular lumen than arteries
- relatively thin walled
- weaker middle coat
- fewer nerves are distributed to the veins than the arteries
- small structures consisting of supportive basement membrane to which a single layer of endothelium is tightly anchored
capillaries
- composed only of one cell later of simple squamous epithelium
- thinnest walled and most numerous of the blood vessels
capillaries
specialized type of capillaries found in the bone marrow, spleen and liver
sinusoids
surface of the endothelium that lines the lumen-simple squamous epithelium
tunica intima
thickest coat, composed of smooth muscle and elastic fiber
tunica media
consist of fibrous connective tissue
tunica adventitia
- the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles
vasoconstriction
lining the lumen of the blood vessel, and are the principal regulators of vascular functions
endothelial cells
