Cardiovascular centre the cardiovascular centre and cause it to increase the rate of impulses sent to the sinoatrial node, or pacemaker, resulting in faster and stronger cardiac muscle contraction and thus increasing the heart rate. Cardiovascular centre The cardiovascular centre is a part of the human brain responsible for the regulation of the rate at which the heart beats through the nervous and endocrine systems. It is found in the medulla oblongata. Normally, the heart beats without nervous control, but in some situations (e.g., exercise, body trauma), the cardiovascular centre is responsible for altering the rate at which the heart beats. It
Cardiac cycle through the atria and fill the ventricular chambers—just before the return of the systole (contractions), ejecting the new blood volume and completing the cardiac cycle. (See Wiggers diagram: "Ventricular volume" tracing (red), at "Systole" panel.) Cardiac diastole is the period of the cardiac cycle when, after contraction, the heart relaxes and expands while refilling with blood returning from the circulatory system. Both atrioventricular (AV) valves open to facilitate the 'unpressurized' flow of blood directly through the atria into both ventricles, where it is collected for the next contraction. This period is best viewed at the middle of the Wiggers diagram—see