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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.
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.
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.
A negative feedback loop is then needed to return the body to its resting state by signaling the parasympathetic nervous system. [8] Prolonged stress leads to many hazards within the nervous system. Various hormones and glands become overworked, and chemical waste is produced, resulting in the degeneration of nerve cells.
Betz cells are the largest cells (by size of cell body) in the nervous system. [40] The adult human brain is estimated to contain 86±8 billion neurons, with a roughly equal number (85±10 billion) of non-neuronal cells. [41] Out of these neurons, 16 billion (19%) are located in the cerebral cortex, and 69 billion (80%) are in the cerebellum ...
Brain cells make up the functional tissue of the brain. The rest of the brain tissue is the structural stroma that includes connective tissue such as the meninges , blood vessels , and ducts. The two main types of cells in the brain are neurons , also known as nerve cells, and glial cells , also known as neuroglia. [ 1 ]
Purkinje cells are specifically generated from progenitors in the ventricular neuroepithelium of the embryonic cerebellar primordium. [17] The first cells generated from the cerebellar primordium form a cap over a diamond-shaped cavity of the developing brain called the fourth ventricle forming the two cerebellar hemispheres.
The enteric nervous system functions to control the gastrointestinal system. Nerves that exit from the brain are called cranial nerves while those exiting from the spinal cord are called spinal nerves. The nervous system consists of nervous tissue which, at a cellular level, is defined by the presence of a special type of cell, called the ...