stages of haemostasis Flashcards
1
Q
haemostasis
A
body’s normal physiological response for the prevention and stopping of bleeding/haemorrhage
2
Q
list stages of haemostasis
A
- vasoconstruction
- primary
- secondary
3
Q
describe vasoconstriction as a stage of haemostasis
A
- walls of the blood vessels have muscle and connective tissue
- to prevent blood being lost from the vessel vasoconstriction narrows vessel and reduces blood entering it
4
Q
haemostasis - what is vasoconstriction promoted by?
A
- endothelial cells that secrete chemical signals
- nerves that detect the break
- myogenic contraction - muscle contraction when in contact with blood
5
Q
primary haemostasis
A
- platelets collect at site of injury
- adhere to exposed collagen in vessel wall + near the leak
- von willebrand factor improves adhesion
- platelets secrete chemoattractants to passing platelets
- platelets activated + release granules
- platelets clump together - aggregation
- endothelium secretes nitric oxide + prostacyclin causing vasodilation and inhibit clotting
6
Q
name 3 chemical attractants in primary haemostasis
A
- serotonin
- thromboxane A2
- ADP
