Attempt either A or B - Scottish Highers Human Biology - Question 15 - 2022

The formation of a thrombus, commonly referred to as a blood clot, involves several critical stages:

Formation of a Thrombus

1. Endothelial damage: The initiation of thrombus formation often begins with damage to the endothelium of blood vessels, which can occur due to factors like high blood pressure or atherosclerosis.
2. Clotting factor release: When the endothelium is damaged, various clotting factors are released into the bloodstream.
3. Activation of the coagulation cascade: These factors activate a sequence of biochemical reactions, leading to the conversion of prothrombin into thrombin.
4. Fibrin formation: Thrombin then converts fibrinogen into fibrin, which forms a meshwork or network of threads that stabilizes the clot by binding red blood cells and platelets together.

Damaging Effects

1. Embolus formation: A thrombus can become unstable and break loose, traveling through the bloodstream as an embolus. This can block blood flow in smaller vessels, leading to complications.
2. Myocardial infarction: If a thrombus occludes a coronary artery, it can result in a heart attack (myocardial infarction).
3. Stroke risk: A clot that travels to the brain can cause an ischemic stroke by blocking cerebral arteries.
4. Oxygen deprivation: The presence of a clot deprives tissues of oxygen, potentially leading to cell death.
5. Deep vein thrombosis (DVT): Thrombi can also occur in veins, particularly in the legs, increasing the risk of pulmonary embolism if they dislodge.