Ahs 132 Week 4 Clotting

Front 1

Blood Clotting

Back 1

coagulation
hemostasis
Stop bleeding
reduce risk of hemorrhaging
When bleeding, most likely from capillaries

Front 2

Bleeding

Back 2

Arteries are located the deepest in, so hardest to get to;
then veins;
Then capillaries
Capillaries are most superficial

Front 3

Hemostasis

Back 3

3 Pahses
Vascular phase
Platelet plug phase
Coagulation Phase

Front 4

Vascular Phase

Back 4

Local contraction of the vessel
Vascular spasm causes a decrease in the diameter of the vessel
Lasts about 30 minutes

Front 5

Platelet Phase

Back 5

Attachment of platelets to endolthelium
Platelets then stick to each other and form a platelet plug
Prostacyclin inhibits platelt aggregation so that the platelet plug doesn't get out opf control

Front 6

Platelet Phase

Back 6

Platelets arrive at site of injury and become activated
They release a wide variety of compounds - degranulate
Serotonin and thromboxane stimulate vascular spasms ( vasoconstriction) which closes off the blood vessel
ADP is released which stimulates platelet aggregation and secretion
Clotting factors
Platelet derived growth factor
ADP and thromboxane released from each arriving platelet stimulates further aggregation - positive feedback loop
this positive feedback loop produces a platelet plug

Front 7

Platelet Phase

Limiting the Platelet Plug

Back 7

Platelet aggregation must be controlled and restricted to site of injury and not get out of control
Factors that limit the platelet plug are:
prostacyclin - a prostaglandin that inhibits platelet aggregation and is released by endothelial cells

Front 8

Coagulation Phase

Back 8

3rd Phase of clotting
Does not start until at least 30 seconds after vessel damage ; vascular phase and platelet phase begin within the forst few seconds