BIOM3010 Lecture Notes - Lecture 13: Supraventricular Tachycardia, Coronary Artery Disease, Orthostatic Hypotension
Document Summary
Deposits of the aging pigment , lipofuscin accumulate. Number of pacemaker cells decrease and fatty, fibrous tissues increase around sa node. The valves of heart thicken and become stiffer: changes may result in slightly slower heart rate. Slight increase in size of heart, especially left ventricle, is common: heart wall thickens, so amount of blood chamber can hold decreases. Heart will fill slower; to compensate, elderly subjects demonstrate a double percent atrial contribution to filling. Effect of changes: under normal circumstances, heart continues to adequately supply to all parts of body. However an aging heart may be slightly less able to tolerate increased workload: examples of stressors include illness, infections, emotional stress, injury, extreme physical exertion. Thickening and stiffening in media of large arteries is thought to be caused by collagen x-link. Smaller arteries may thicken/stiffen minimally; their ability to dilate and constrict diminishes. Age related chages are minimal and do not impede normal functioning.
