NEURO 661 Lecture Notes - Lecture 8: Edema, Aorta, Sinoatrial Node
Document Summary
A cardiac cycle is the inclusive changes within the heart from the initiation of one heartbeat to the start of the next. One heartbeat involves the contraction and relaxation of the heart chambers. Note that the term systole (sis t -l ) refers to contraction of a heart chamber, whereas diastole (d -as t -l ; dilation) refers to relaxation of a heart chamber. You apply pressure to the open door (av valve) and it closes, and then you apply pressure to the closed door (semilunar valve) and it opens. You then release the pressure on the two spring-loaded doors in the reverse order. Each door returns to its original position the one that was pushed open (semilunar valve) closes, and the door pushed closed (av valve) opens. Learning objectives: identify the two processes within the heart that occur due to pressure changes associated with the cardiac cycle, list the ve phases of the cardiac cycle.
