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Layers of the Alimentary Canal.The wall of the alimentary canal has four basic tissue layers: the mucosa, submucosa, muscularis, and serosa. The enteric nervous system in humans consists of some 500 million neurons [11] (including the various types of Dogiel cells), [1] [12] 0.5% of the number of neurons in the brain, five times as many as the one hundred million neurons in the human spinal ...
1.2.1 Peripheral nervous system. 1.2.2 Neuroendocrine system. ... This is a list of cells in humans derived from the three embryonic germ layers ... Muscle Myoblast ...
Unlike the CNS, the PNS is not protected by the vertebral column and skull, or by the blood–brain barrier, which leaves it exposed to toxins. [3] The peripheral nervous system can be divided into the somatic nervous system and the visceral nervous system. Each of these have a sensory and a motor division.
The myenteric plexus (or Auerbach's plexus) provides motor innervation to both layers of the muscular layer of the gut, having both parasympathetic and sympathetic input (although present ganglion cell bodies belong to parasympathetic innervation, fibers from sympathetic innervation also reach the plexus), whereas the submucous plexus provides secretomotor innervation to the mucosa nearest the ...
The muscle of the inner layer is arranged in circular rings around the tract, whereas the muscle of the outer layer is arranged longitudinally. The stomach has an extra layer, an inner oblique muscular layer. [1] Between the two muscle layers is the myenteric plexus (Auerbach's plexus). This controls peristalsis.
The peripheral nervous system (PNS) is a collective term for the nervous system structures that do not lie within the CNS. [17] The large majority of the axon bundles called nerves are considered to belong to the PNS, even when the cell bodies of the neurons to which they belong reside within the brain or spinal cord.
The human brain is primarily composed of neurons, glial cells, neural stem cells, and blood vessels. Types of neuron include interneurons, pyramidal cells including Betz cells, motor neurons (upper and lower motor neurons), and cerebellar Purkinje cells. Betz cells are the largest cells (by size of cell body) in the nervous system. [40]
Nervous tissue, also called neural tissue, is the main tissue component of the nervous system.The nervous system regulates and controls body functions and activity. It consists of two parts: the central nervous system (CNS) comprising the brain and spinal cord, and the peripheral nervous system (PNS) comprising the branching peripheral nerves.