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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.
Paraxial mesoderm, also known as presomitic or somitic mesoderm, is the area of mesoderm in the neurulating embryo that flanks and forms simultaneously with the neural tube. ...
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 somitomeres organize into somites which grow in pairs. In the fourth week, the somites lose their organization and cover the notochord and spinal cord to form the backbone. In the fifth week, there are 4 occipital somites, 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 8 to 10 coccygeal that will form the axial skeleton.
A dermatome is an area of skin that is mainly supplied by afferent nerve fibres from the dorsal root of any given spinal nerve. [ 1 ] [ 2 ] There are 8 cervical nerves (C1 being an exception with no dermatome), 12 thoracic nerves , 5 lumbar nerves and 5 sacral nerves .
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 ...
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.