Cardiovascular centre
The cardiovascular centre is a part of the human brain which regulates heart rate through the nervous and endocrine systems. It is found in the medulla oblongata. Normally, the heart beats without nervous control, but in some situations, the cardiovascular centre is responsible for altering the heart rate. It also mediates respiratory sinus arrhythmia.
When a change of blood pH is detected by central chemoreceptors or by peripheral chemoreceptors in aortic bodies and in carotid bodies, or a change of blood pressure is detected by baroreceptors in the aortic sinuses or carotid sinuses, the cardiovascular centre affects changes to the heart rate by sending a nerve impulse to the cardiac pacemaker via sympathetic fibres and the vagus nerve. The cardiovascular centre also increases the stroke volume of the heart. These two changes help to regulate the cardiac output, so that a sufficient amount of blood reaches tissue.
Hormones like epinephrine and norepinephrine can affect 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.
