300816 Lecture Notes - Lecture 7: Coagulative Necrosis, Vascular Resistance, Thrombolysis
Document Summary
Most common cause of cardiac failure and major risk factor for atherosclerosis. Risk factors that affect the sympathetic nervous system include age, sodium intake, posture, stress, exercise. All of these vary the circulating level catecholamines, which increase blood pressure. Sodium retention results from impaired na+ excretion. This leads to blood volume and pressure expansion, which ultimately leads to increase cardiac output. Raised sodium levels also prevent calcium transport out of smooth muscle cells; which raises peripheral vascular resistance, pvr. Increased activity of the renin-angiotensin-aldosterone system elevates pvr and causes volume expansion. However, only a small number of patients with essential hypertension have raise plasma renin levels. Many patients with essential hypertension respond to treatment with ace inhibitors. Process of destruction of heart tissue due to inadequate blood supply, so that coronary blood flow is reduced. Necrosis of the heart muscle, usually left ventricle, is usually due to coronary artery atheroma with superimposed thrombus and haemorrhage.
