BMS130 Lecture Notes - Lecture 7: Pulmonary Vein, Vitamin, Aorta
CARDIOVASCULAR SYSTEM
Lecture 7
Describe the process of clot retraction and repair
- Clot retraction occurs within 30 minutes
- Platelets contain contractile proteins (actin & myosin)
- Platelet contraction pulls on fibrin threads which pull broken blood vessel
walls togethe
- Platelet-derived growth factor secreted by platelets and endothelial cells
- Mitotic stimulant for fibroblasts and smooth muscle to multiply and
repair damaged vessel
- Fibrinolysis (dissolution of a clot)
- The conversion of the inactive plasma enzyme plasminogen into
plasmin (a fibrin dissolving enzyme) by factor XII
Explain what stops blood from clotting in the absence of injury
Platelet repulsion
- Due to secretion of prostacyclin and nitric oxide by endothelial cells which
inhibit platelet aggregation
Thrombin dilution
- By rapidly flowing blood heart slowing in shock can result in clot formation
Natural anticoagulants
- Heparin (from basophils and mast cells) interferes with formation of
prothrombin activator
- Antithrombin (from liver) deactivates thrombin before it can act on
fibrinogen
Name and describe 3 consequences of unwanted blood clotting
1. Thrombosis - abnormal clotting in unbroken vessel which is most likely to
occur in leg veins of inactive people
2. Embolism – the thrombus may break free and travel in the blood (embolus)
and may lodge in smaller vessels like the heart, brain or lungs (embolism)
3. Myocardial Infarction - may occur if clot blocks blood supply to the heart
(coronary arteries) and causes tissue death (necrosis)
Discuss the importance of Vitamin K in the clotting process
- Vitamin K is required for the synthesis of 4 clotting factors (II, VII, IX, X) by
the liver including prothrombin
Document Summary
Describe the process of clot retraction and repair. Platelets contain contractile proteins (actin & myosin) Platelet contraction pulls on fibrin threads which pull broken blood vessel walls togethe. Platelet-derived growth factor secreted by platelets and endothelial cells. Mitotic stimulant for fibroblasts and smooth muscle to multiply and repair damaged vessel. The conversion of the inactive plasma enzyme plasminogen into plasmin (a fibrin dissolving enzyme) by factor xii. Explain what stops blood from clotting in the absence of injury. Due to secretion of prostacyclin and nitric oxide by endothelial cells which inhibit platelet aggregation. By rapidly flowing blood heart slowing in shock can result in clot formation. Heparin (from basophils and mast cells) interferes with formation of. Antithrombin (from liver) deactivates thrombin before it can act on. Discuss the importance of vitamin k in the clotting process. Vitamin k is required for the synthesis of 4 clotting factors (ii, vii, ix, x) by the liver including prothrombin.
