Serial Section of Coronary Artery

Serial Section of Coronary Artery - * Contractile cells *...

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Cardiovascular System Serial Section of Coronary Artery * This coronary artery opened longitudinally demonstrates severe atherosclerosis * This is thrombosis in a coronary artery. Such a thrombus severely narrows or occludes the lumen and can produce a sudden ischemic event. "Sudden death" as well as infarction can occur. Risk Factors in Heart Disease * Hypercholesterolemia * Hypertension * Cigarette smoking * Obesity * Lack of exercise * Diabetes mellitus * Genetic predisposition * Male gender * Alcohol Atherosclerosis of the aorta w/ mural thrombi Abdominal Aortic Aneurysm This aorta has been opened longitudinally to reveal an area of fairly limited dissection that is organizing. The red-brown thrombus can be seen in on both sides of the section as it extends around the aorta. The intimal tear would have been at the left. This creates a "double lumen" to the aorta. This aorta shows severe atherosclerosis which, along with cystic medial necrosis and hypertension, is a risk factor for dissection. In cardiac muscle, there are two types of cells:
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Unformatted text preview: * Contractile cells * Autorhythmic (or automatic) cells. * Autorhythmic cells exhibit PACEMAKER POTENTIALS. * Depolarization is due to the inward diffusion of calcium (not sodium as in nerve cell membranes). * Depolarization begins when: * the slow calcium channels open (4), * then concludes (quickly) when the fast calcium channels open (0). * Repolarization is due to the outward diffusion of potassium (3). Myocyte Autorhythmic cells Sheet of cells In Contractile cells: Cardiovascular System * depolarization is very rapid & is due to the inward diffusion of sodium (0). * repolarization begins with a slow outward diffusion of potassium, but that is largely offset by the slow inward diffusion of calcium (1 & 2). So, repolarization begins with a plateau phase. Then, potassium diffuses out much more rapidly as the calcium channels close (3), and the membrane potential quickly reaches the 'resting' potential (4)....
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Serial Section of Coronary Artery - * Contractile cells *...

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