Pathological Thrombosis Flashcards
When does pathological thrombosis take plcae?
Occurs in absence of cut or traumatic injury
What are the three main causes of thrombosis.
Changes in the intimal surface of a vessel
Changes in the pattern of blood flow
Changes in the blood constituents
Virchows Triad
What are the main arteries in the heart?
Coronary arteries
Which one of Varchow’s traid describes the alteration in the properties of blood?
Changes in constituents
What is atheroma?
A disease of coronary arteries which results in a build up of lipid under the intimal surface
Only occurs in arteries.
What can atheroma result in?
Abnormal blood flow- both slow and turbulent flow.
What can rupture through the intimal surface of an artery?
Lipids and collagen
What happens when platelets and fibri are exposed to abnromal substances like collagen and lipids?
turbulent flow and are deposited as a thrombus
What does the thrombum block?
the lumen of the coronary artery
Where can the clot form when the thrombum blocks the lumen of the coronary artery.
Clot can now form in the stagnant blood behind the thrombus
Give an example for each of Virchow’s Triad.
Changes in the intimal surface of a vessel (for example: atheroma lipid coming onto surface)
Changes in the pattern of blood flow (for example: a bulge of atheroma changing the flow of blood)
Changes in the blood constituents (for example: smoking making it more likely that platelets aggregate)
If all three of virchow’s triad occured, what may happen?
Cornoery artery thrombosis
What is th conseuqnece of a thrombus bocking the artery?
Complete obstructtuion so no flow beyond blockage
What does partial obstruction lead to?
Decreased flow beyond the blockage
Define ischaemia
Poor blood flow
If ischaemia is sever enoug, what can you get?
Hypoxia
Is ischaemic heart tissue painful?
Often
What happens to a tissue if the artery supplying it is partially blocked?
rECIEVES LESS BLOOD FLOW (ISCHAEMIA.
What happns when there is a severe or total blockage of blood flow?
In severe or total blockage of blood flow the lack of blood flow (ischaemia) leads to severe lack of oxygen (hypoxia) and a localised area of tissue dies
What is the localised area of dead tissue called?
Infarct
What is the process of tissue dying called?
Necrosis.
What is an infarct?
Necrosis as a result of ischaemia (= ischaemic necrosis)
Infarcts can occur in other tissues supplied by other arteries: For instance:
Coronary artery thrombosis – infarct in heart
Cerebral artery thrombosis – infarct in brain
Mesenteric artery thrombosis – infarct in gut
Define embolism.
A mass of material moving in the vascular system and able to become lodged in a vessel and block its lumen
Where do emboli dervive from?
Most emboli are derived from thrombi or clots
They break off and go elsewhere in the circulation
What is it called when thrombi or clots embolise?
Thromboembolism
Give a common example of thromboembolism
Pulmonary embolism.
how does pulmonary embolism occur?
Sluggish flow in leg veins leads to thrombosis and clot formation.
This is because part of thrombus (and clot) breaks off and travels up vein
Describe the movement of the embolus to the heart.
Embolus passes into inferior vena cava, then right heart, then pulmonary trunk, and lodges in pulmonary artery branch
Embolous blcos pulmonary artery and get pulmonary infarct.
Describe a marrow embolism
Fracture a leg marrow enters ruptured vein marrow embolises to lung vessels = Marrow embolism
Discuess an example of an air embolism.
Knife wound to neck. Air enters vein air embolises to heart = Air embolism (never inject a person with air in a syringe!)
