Case 15 Flashcards
What is haemostasis?
Physiological process by which the body stops bleeding after blood vessel injury
What is a thrombus?
Blood clot in a blood vessel or in the heart
What is coagulation?
Process of turning blood from liquid into a gel to form a blood clot
Which protein forms mesh like network in blood clots?
Fibrin
What is fibrinolysis?
Process by which blood clots are broken down and dissolved
Describe process of fibrinolysis?
Plasmin (an enzyme) degrades fibrin
What is an embolism?
When a blood clot or other materials (eg fat) travel through blood stream and become lodged, obstructing blood flow
Three factors which increase likelihood of thrombosis?
Abnormalities of the vessel wall
Abnormalities of blood flow
Abnormalities of bloods constituents
Describe first part of process of blood clot formation (up to platelet plug formation)
1)Injury occurs - and collagen and tissue factors are exposed
2)Vascular spasm - smooth muscle walls contract rapidly to reduce blood flow through damaged vessel
3)Platelets adhere to site of injury and become activated, forming platelet plug
Explain the intrinsic clotting pathway of coagulation cascade?
Occurs inside blood vessel
1)Factor XII (12) activated by Collagen
2)Factor XI (11) activated by factor XII (12)
3)Factor IX (9) activated by Factor XI (11), Factor VIII (8) and calcium ions
4)Factor X (10) activated by Factor IX (9), Factor VIII (8) and calcium ions
Explain the extrinsic pathway of coagulation cascade?
Occurs outside blood vessel
1)Tissue factors and Factor VII (7) activate Factor X (10)
End product of both extrinsic and intrinsic pathways in coagulation?
Factor X (10)
Explain the common pathway of coagulation cascade?
After extrinsic and intrinsic pathways…
Prothrombin is converted into Thrombin by Factor X (10), Factor V (5), calcium ions and phospholipids
Explain final part of coagulation after the common pathway?
1)Soluble fibrinogen converted into insoluble Fibrin strands by thrombin
2)Fibrin strands form a mesh network which trap blood cells and form stable blood clot
3)Clotting factors and platelets reinforce clot making it stronger
What is a venous thromboembolism?
Blood clots in veins
(Eg deep vein thrombosis or pulmonary embolism)
What is deep vein thrombosis?
Blood clot in deep vein (usually legs)
What is pulmonary embolism?
Blood clot in lungs
What is haemostasis?
A process to prevent and stop bleeding when blood vessel is damaged
What are Hypercoagulable states?
A variety of conditions where blood has increased tendency to clot
(Can be genetic caused by various mutations, or acquired eg by cancer, pregnancy or by certain medications)
What are the risk factors for deep vein thrombosis?
Alteration to blood flow (eg immobilisation, pregnancy, obesity)
Vessel wall damage
Hypercoagulable states
What is haemoptysis?
Coughing up blood from respiratory tract