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Describe the events leading to atherosclerosis.
High blood pressure causes damage to artery endothelium.
This causes an inflammatory response.
WBC enter behind endothelium.
WBC absorb saturated fats & cholesterol.
Fibrous plaque forms. This narrows lumen
This reduces blood flow. This reduces concentration gradients & rate of diffusion.
Blood pressure increases due to positive feedback.
Respiration can’t occur so the cells or tissues die.
Describe the events leading to formation of blood clots.
Damage to artery endothelium exposes collagen fibres. Platelets are activated. Thromboplastin is released. Prothrombin converts into thrombin. Thrombin converts fibrinogen into fibrin. Fibrin polymerises to form mesh, trapping more platelets & RBC. Positive feedback until exposed collagen fibres are covered. Too much clotting can lead to blood clots in arteries. This reduces conc gradients, rate of diffusion and cell death
explain how atherosclerosis can lead to a heart attack.
blood clot in a coronary artery
This reduces flow of blood
This reduces oxygen supply & conc gradients
Rate of diffusion of oxygen is inadequate.
For respiration to occur, heart cell stops functioning.
Heart fails to contract which causes a heart attack.
how does atherosclerosis lead to a stroke
blood clot in brain artery
This reduces flow of blood.
This reduces oxygen supply & conc gradients
Rate of diffusion of oxygen is inadequate
For respiration to occur, ATP levels drop, brain cells stop functioning.
Significant loss of brain tissue function results in a stroke.
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