BLOOD TYPE 1 Flashcards
whats hemostasis
Series of reactions resulting in the stoppage of bleeding after a break in a blood vessel wall
what are the three stages of hemostasis
1) Vascular spasm
2) Platelet plug formation
3) Coagulation
whats vascular spasm
initiated by the loss of blood/smooth muscle injury/pain receptors and leads to vasoconstriction; protective process to stop blood flow; smooth muscle contracts and stops blood flow
how long does vascular spasm last and what does it allow for
» Attenuates blood loss for ~20-30 minutes
» Allows time for next two steps
what do intake endothelial cells release to keep platelets from aggregating
nitric oxide and prostacyclin (normal condition)
how do platelet plugs form
injury of lining to vessel exposes collagen fibers (so platelets adhere) and platelets release chemicals that make nearby platelets sticky so platelet plug forms
so what happens when damaged endothelium exposes underlying connective tissue?
Platelets adhere to collagen fibers (become activated)
- Swell, form spiked processes, become stickier
what chemicals do platelets release and what do they do
Release ADP, Serotonin, and Thromboxane A2 → enhance platelet aggregation (positive
feedback mechanism)
is primary hemostasis enough to fix most wear and tear
yes
whats coagulation/blood clotting needed for
larger breaks
what are clotting factors
plasma proteins which are inactive until mobilized and form collagen fiber and fibrin
what results in the blood clot (fibrin mesh)
Platelet plug reinforced with fibrin threads (“glue” for the platelets)
what happens to blood when fibrin threads are formed
Blood turns from liquid to gel
whats primary hemostasis
formation of a primary platelet plug
» Plugs small injuries especially in microvessels (< 100 μm) in mucosal tissues
platelet adhesion and aggregation and platelet plug formation
whats secondary hemostasis
formation of insoluble, cross-linked fibrin by activated clotting factors, specifically thrombin
coagulation and platelet plug stabilization
what does fibrin stabilize in secondary hemostasis
the primary platelet plug, particularly in larger blood vessels where the platelet plug is insufficient alone to stop hemorrhage
whats thrombus
Clot in an unbroken blood vessel
- Can be deadly in areas such as heart
what does corornay thrombosis lead to
heart attack
whats embolus
A thrombus that breaks away and floats freely in blood stream
- Potential to clog vessels in critical areas (eg. pulmonary embolism)
what are some causes of thromboemlic disorders
burns, physical blows, fatty material, slow blood flow
what are examples of anticoagulant drugs that block the clotting process
aspirin, heparin, warfarin
