The cardiovascular system consists of the heart and a network of blood vessels that circulate blood to tissues and organs within the body. The heart is a powerful muscle that comprises of four chambers; right atrium, right ventricle, left atrium and left ventricle. Blood enters the right atrium via the superior vena cava from the upper body and the inferior vena cava from the lower body. Blood flow through the heart is unidirectional, which is achieved by valves positioned between the chambers and within the vessels. The autonomic nervous system can be divided into two sub-divisions, the parasympathetic nervous system and the sympathetic nervous system. Sympathetic nervous control of the heart arises from the upper thoracic region of the spinal cord. Short preganglionic efferent nerve fibers, compared to long preganglionic vagal efferent fibers, enter the paravertebral chains of ganglia that are located on either side of the spinal column. The heart itself is capable of generating its own electrical impulses to cause coordinated and rhythmic contractions of its chambers.
|Original language||English (US)|
|Title of host publication||Primer on the Autonomic Nervous System|
|Number of pages||4|
|State||Published - Dec 1 2012|
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