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The dermatome is the dorsal portion of the paraxial mesoderm somite which gives rise to the skin . In the human embryo, it arises in the third week of embryogenesis . [ 2 ] It is formed when a dermomyotome (the remaining part of the somite left when the sclerotome migrates), splits to form the dermatome and the myotome. [ 2 ]
[4] [5] However, the segmentation clock model is highly evolutionarily conserved. [ 6 ] Intrinsic expression of "clock genes" must oscillate with a periodicity equal to the time necessary for one somite to form, for example 30 minutes in zebrafish, 90 minutes in chicks, and 100 minutes in snakes.
Following is a list of spinal nerves and points that are characteristically belonging to the dermatome of each nerve: [4] Dermatomes of the lower limb (modified, from Fender, after Foerster) C2 – At least one cm lateral to the occipital protuberance at the base of the skull. Alternately, a point at least 3 cm (1.2 in) behind the ear.
Similarly a dermatome is an area of skin that a single nerve innervates with sensory fibers. Myotomes are separated by myosepta (singular: myoseptum ). [ 2 ] In vertebrate embryonic development , a myotome is the part of a somite that develops into muscle.
The notochord and the neural tube activate the protein SHH, which helps the somite to form its sclerotome. The cells of the sclerotome express the protein PAX1 that induces the cartilage and bone formation. The neural tube activates the protein WNT1 that expresses PAX 2 so the somite creates the myotome and dermatome.
The following other wikis use this file: Usage on bs.wikipedia.org Dermatom; Miotom; Usage on en.wikiversity.org WikiJournal of Medicine/Medical gallery of Mikael Häggström 2014
The first seven somitomeres give rise to the striated muscles of the face, jaws, and throat. [2]The remaining somitomeres, likely driven by periodic expression of the hairy gene, begin expressing adhesion proteins such as N-cadherin and fibronectin, compact, and bud off forming somites.
The peripheral nervous system (PNS) is divided into the somatic nervous system, the autonomic nervous system, and the enteric nervous system.However, it is the somatic nervous system, responsible for body movement and the reception of external stimuli, which allows one to understand how cutaneous innervation is made possible by the action of specific sensory fibers located on the skin, as well ...