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These cells produce an electrical impulse known as a cardiac action potential that travels through the electrical conduction system of the heart, causing it to contract. In a healthy heart, the SA node continuously produces action potentials, setting the rhythm of the heart (sinus rhythm), and so is known as the heart's natural pacemaker.
The Purkinje fibers are specialized conducting fibers composed of electrically excitable cells. [3] They are larger than cardiomyocytes with fewer myofibrils and many mitochondria. They conduct cardiac action potentials more quickly and efficiently than any of the other cells in the heart's electrical conduction system. [4]
Cells in the sinoatrial node, located in the right atrium of the heart, spontaneously depolarize approximately 100 times per minute. Although all of the heart's cells have the ability to generate action potentials that trigger cardiac contraction, the sinoatrial node normally initiates it, simply because it generates impulses slightly faster ...
These form the ventricular system of the brain: [8] The neural stem cells of the developing brain, principally radial glial cells, line the developing ventricular system in a transient zone called the ventricular zone. [9] The prosencephalon divides into the telencephalon, which forms the cortex of the developed brain, and the diencephalon.
The vagus nerve of the parasympathetic nervous system acts to decrease the heart rate, and nerves from the sympathetic trunk act to increase the heart rate. [8] These nerves form a network of nerves that lies over the heart called the cardiac plexus .
The "little brain in the heart" is an intricate system of nerve cells that control and regulate the heart's activity. It is also called the intrinsic cardiac nervous system (ICNS). [15] It consists of about 40,000 neurons that form clusters or ganglia around the heart, especially near the top where the blood vessels enter and exit.
Purkinje cells or Purkinje neurons, named for Czech physiologist Jan Evangelista Purkyně who identified them in 1837, [2] are a unique type of prominent large neurons located in the cerebellar cortex of the brain. With their flask-shaped cell bodies, many branching dendrites, and a single long axon, these cells are essential for controlling ...
The cardiovascular centre affects changes to the heart rate by sending a nerve impulse to the cardiac pacemaker via two sets of nerves: sympathetic fibres, part of the autonomic nervous system, to make heart rate faster. the vagus nerve, part of the parasympathetic branch of the autonomic nervous system, to lower heart rate.