BIOL 221 Lecture Notes - Lecture 2: Aortic Stenosis, Cardiac Stimulant, Stroke Volume
11 Feb 2020
School
Department
Course
Professor
Document Summary
Failure to balance venous return and stroke volume. Pumping action of heart insufficient to meet needs of body. Congestive heart failure chf) is a failure to balance venous return and stroke volume; venous return is higher than needed to support stroke volume. The pumping action of heart is not sufficient to meet needs of body including the oxygen requirements of the heart. Chf is form detrimental form of positive feedback. Intrinsic causes of chf arise within the heart and include cardiomyopathy including cardiac infarct (heart attack). Extrinsic causes include systemic hypertension, which increases afterload, and aortic stenosis, which makes it more difficult to eject blood. Treatments are aimed at lowering fluid accumulation through the use ofdiuretics and reduced salt intake or through the use of cardiotonic drugs that increase the strength of contraction. Decreased pumping action increased edv increased stretch (initially may increase sv slightly), but. Weakness allows blood to accumulate, overstretching heart weaker contraction.
