Muscular System and Miology PDF

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Summary

1.-The miotomos Come from The beds, so its distribution is equal to that of these: they are 44, approximately; 4 occipital, 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 5 Coccígeos and 3 to 5 degenerative caudal....

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MUSCULAR SYSTEM and MIOLOGY 1.-The miotomos Come from The beds, so its distribution is equal to that of these: they are 44, approximately; 4 occipital, 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 5 Coccígeos and 3 to 5 degenerative caudal. 2.-The miotomos Come from the dermomiotoma Of all the somites of the embryo. They are in medial and deep position with respect to the dermatome, but superficial and lateral to the esclerotoma. The cells of the miotoma They are divided, they move towards their definitive location and they form elongated and fusiform, calling themselves myoblasts, which then join with other myoblasts to form multinucleate and very long muscular fibers, in which they form the classic stretch marks of the Skeletal muscle at the end of the third month. 3.-Towards the end of the fifth week each Myotome It is divided into a small dorsal portion, the epimer and a larger ventral, the hipómero, formed by migration of the cells of the miotoma. The nerves that go to the segmental muscles are also divided into a primary dorsal branch, for the Epimer and a ventral primary bouquet for the hipómero. 4.-The myoblasts of the Epímeros form the extensor muscles of the spine, while the hipómeros They give rise to the lateral and ventral flexor muscles. The myoblasts of the hipómeros Cervical muscles form the geniohioideo and Prevertebral. Those of the thoracic segments are separate in three leaves, which, in the thorax, are represented by the intimate or transverse intercostal muscles of the thorax, the deepest. In the abdominal wall these three muscular leaves form the muscles oblique major or external, oblique minor or internal and transverse of the abdomen. The muscles of the thorax wall retain their segmental character, due to the ribs, while in the abdominal wall the muscles of the various segments are fused and form large layers of muscle tissue. The hypoblast myoblasts of the lumbar segments form the lumbar square muscle as those of the sacral and Coccygeal regions form the pelvic diaphragm and the striated muscles of the anus. In addition to the three Ventrolaterales muscular layers mentioned above, at the ventral end of the hipómeros A ventral longitudinal column appears. In the abdomen region this column is represented by the rectums of the abdomen and in the cervical region to the infrahioideos muscles. In the thorax the longitudinal muscles disappear normally, although they are usually represented by the sternal muscle. 5.-The first signs of the formation of the muscles of the limbs appear to the seventh week of development, in the form of condensation of the Next Mesenchyme To the base of the sketches. The Mesenchyme derivade Cells of the dermomiotoma Of the Semites that migrate to the sketch of the limb to form the muscles. As in other regions, the connective tissue is the one that governs the formation of the muscle and this tissue, which derives from the somatic mesoderm, also gives rise to the bones of the extremity. 6.-The parietal mesoderm, or Somatopleura, along with the ectoderm that covers it forms the lateral and ventral body walls. 7.-The origin of the skin is twofold: the superficial layer (epidermis) derives from the superficial ectoderm and the deep layer (dermis) develops from the underlying mesoderm. In the beginning the embryo is covered by a unique layer of ectodermal cells. At the beginning of the second month, this epithelium is divided and on the surface is deposited a layer of Flattened cells called peridermo The epitriquio. As the cells of the basal layer continue to

proliferate, a third layer is formed, the intermediate zone. Finally, towards the end of the fourth month, the intermediate zone acquires its definitive organization and can be distinguished four layers: basal layer, thorny stratum, grained and corneal. The dermis derives Mesenchyme. During the third and fourth month this tissue, called corion, originates numerous irregular papillary structures, the dermal papillae, which protrude into the epidermis. These papillae usually contain a small-caliber capillary or a terminally sensitive nervous organ. The deeper layer, or subcorionContains abundant adipose tissue. Hairs appear as massive epidermal proliferations that are introduced into the underlying dermis. In the terminal end, the hair buds are invaginal. These invaginals, the hairy papillae, are quickly occupied by the mesoderm, in which glasses and nerve endings develop. The skin and its attachments, such as hairs, fingernails and glands derive from superficial ectoderm. Melanocytes, which confer the skin its color, derive from neural crest cells that migrate to the epidermis. The neoformation of cells takes place in the germinative stratum, after moving to the surface, the cells of the germinative stratum are detached. The dermis comes Mesenchyme....