Cardiovascular centre
Encyclopedia
The cardiovascular centre is a part of the human brain
responsible for the regulation of the rate at which the heart
beats. 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
. The cardiovascular centre effects changes to the heart rate via sympathetic
fibres (to speed up the heart rate) and the vagus nerve
(to slow down the heart rate). The accelerator and vagus nerves both connect to the sinoatrial node
(SA node). 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 adrenaline can affect the cardiovascular centre and cause it to increase the rate of impulses sent to the sinoatrial node, or "cardiac pacemaker
", thus increasing the rate of the heart beat.
Chemoreceptors may also prompt this regulation.
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
responsible for the regulation of the rate at which the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
beats. It is found in the medulla
Medulla oblongata
The medulla oblongata is the lower half of the brainstem. In discussions of neurology and similar contexts where no ambiguity will result, it is often referred to as simply 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
Respiratory sinus arrhythmia
Respiratory sinus arrhythmia is a naturally occurring variation in heart rate that occurs during a breathing cycle. RSA is also a measure of parasympathetic nervous system activity - which denotes "rest and digest" behaviours.-Overview:...
. The cardiovascular centre effects changes to the heart rate via sympathetic
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...
fibres (to speed up the heart rate) and the vagus nerve
Vagus nerve
The vagus nerve , also called pneumogastric nerve or cranial nerve X, is the tenth of twelve paired cranial nerves...
(to slow down the heart rate). The accelerator and vagus nerves both connect to the sinoatrial node
Sinoatrial node
The sinoatrial node is the impulse-generating tissue located in the right atrium of the heart, and thus the generator of normal sinus rhythm. It is a group of cells positioned on the wall of the right atrium, near the entrance of the superior vena cava...
(SA node). 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
Cardiac output
Cardiac output is the volume of blood being pumped by the heart, in particular by a left or right ventricle in the time interval of one minute. CO may be measured in many ways, for example dm3/min...
, so that a sufficient amount of blood reaches tissue.
Hormones like adrenaline can affect the cardiovascular centre and cause it to increase the rate of impulses sent to the sinoatrial node, or "cardiac pacemaker
Cardiac pacemaker
right|thumb|350px|Image showing the cardiac pacemaker which is the SA nodeThe contraction of heart muscle in all animals with hearts is initiated by chemical impulses. The rate at which these impulses fire controls the heart rate...
", thus increasing the rate of the heart beat.
Chemoreceptors may also prompt this regulation.
See also
- heartHeartThe heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
(especially the section on the cardiac cycle) - chemosensorChemosensorA chemoreceptor, also known as chemosensor, is a sensory receptor that transduces a chemical signal into an action potential. In more general terms, a chemosensor detects certain chemical stimuli in the environment.- Classes :...
s - baroreceptorBaroreceptorBaroreceptors are sensors located in the blood vessels of several mammals. They are a type of mechanoreceptor that detects the pressure of blood flowing through them, and can send messages to the central nervous system to increase or decrease total peripheral resistance and cardiac output...
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