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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. 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 also mediates respiratory sinus arrhythmia. When a change of blood pH is detected by chemoreceptors or a change of blood pressure is detected by stretch receptors in aortic and carotid bodies, the cardiovascular centre effects changes to the heart rate by sending nerve impulse to pacemaker (or SA node) via sympathetic fibres (to cause faster and stronger cardiac muscle contraction) and the vagus nerve (to cause slower and less strong cardiac muscle contraction). The cardiovascular centre also increases the stroke volume of the heart (that is, the amount of blood it pumps). 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 "cardiac pacemaker", resulting in faster and stronger cardiac muscles contraction and thus increasing the rate of the heart beat. Chemoreceptors may also prompt this regulation. ==See also== *heart (especially the section on the cardiac cycle) *chemoreceptors *baroreceptors 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cardiovascular centre」の詳細全文を読む スポンサード リンク
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