JК
Английский язык :: Беликова Елена
Страница: 10 из 68After proliferation of the caudal portion of the sclerotomes, the vertebrae are formed, each consisting of the caudal part of one sclerotome and cephalic part of the next.
While the notochord persists in the areas of the vertebral bod ies, it degenerates between them, forming the nucleus pulposus. The latter, together with surrounding circular fibers of the annulus fibrosis, forms the intervertebral disc.
New words
skeletal – скелетный
mesoderm – мезодерма
cartilage – хрящ
fibroblasts – фибробласты
chondroblasts – хондробласты
osteoblasts – остеобласты
paraxial – параксиальный
flat – плоский
bone – кость
9. Muskular system
Skeletal (voluntary) system.
The dermomyotome further differentiates into the myo-tome and the dermatome.
Cells of the myotome migrate ventrally to surround the in-traembryonic coelom and the somatic mesoderm of the ventrolateral body wall. These myoblasts elongate, become spindle-shaped, and fuse to form multinucleated muscle fibers.
Myofibrils appear in the cytoplasm, and, by the third month, cross-striations appear. Individual muscle fibers increase in diameter as myofibrils multiply and become arranged in groups surrounded by mesenchyme.
Individual muscles form, as well as tendons that connect muscle to bone.
Trunk musculature: By the end of the fifth week, body-wall musculature divides into a dorsal epimere, supplied by the dorsal primary ramus of the spinal nerve, and a ventral hypomere, supplied by the ventral primary ramus.
Epimere muscles form the extensor muscles of the vertebral column, and hypomere muscles give rise to lateral and ven tral flexor musculature.
The hypomere splits into three layers. In the thorax, the three layers form the external costal, internal intercostal, and transverse thoracic muscle.
In the abdomen, the three layers form the external oblique, internal oblique, and transverse abdomii muscles.
Head musculature.
The extrinsic and intrinsic muscles of the tongue are thought to be derived from occipital myotomes that migrate forward.
The extrinsic muscles of the eye may derive from preoptic myotomes that originally surround the prochordal plate.
The muscles of mastication, facial expression, the pharynx, and the larynx are derived from different pharyngeal arches and maintain their innervation by the nerve of the arch of origin.
While the notochord persists in the areas of the vertebral bod ies, it degenerates between them, forming the nucleus pulposus. The latter, together with surrounding circular fibers of the annulus fibrosis, forms the intervertebral disc.
New words
skeletal – скелетный
mesoderm – мезодерма
cartilage – хрящ
fibroblasts – фибробласты
chondroblasts – хондробласты
osteoblasts – остеобласты
paraxial – параксиальный
flat – плоский
bone – кость
9. Muskular system
Skeletal (voluntary) system.
The dermomyotome further differentiates into the myo-tome and the dermatome.
Cells of the myotome migrate ventrally to surround the in-traembryonic coelom and the somatic mesoderm of the ventrolateral body wall. These myoblasts elongate, become spindle-shaped, and fuse to form multinucleated muscle fibers.
Myofibrils appear in the cytoplasm, and, by the third month, cross-striations appear. Individual muscle fibers increase in diameter as myofibrils multiply and become arranged in groups surrounded by mesenchyme.
Individual muscles form, as well as tendons that connect muscle to bone.
Trunk musculature: By the end of the fifth week, body-wall musculature divides into a dorsal epimere, supplied by the dorsal primary ramus of the spinal nerve, and a ventral hypomere, supplied by the ventral primary ramus.
Epimere muscles form the extensor muscles of the vertebral column, and hypomere muscles give rise to lateral and ven tral flexor musculature.
The hypomere splits into three layers. In the thorax, the three layers form the external costal, internal intercostal, and transverse thoracic muscle.
In the abdomen, the three layers form the external oblique, internal oblique, and transverse abdomii muscles.
Head musculature.
The extrinsic and intrinsic muscles of the tongue are thought to be derived from occipital myotomes that migrate forward.
The extrinsic muscles of the eye may derive from preoptic myotomes that originally surround the prochordal plate.
The muscles of mastication, facial expression, the pharynx, and the larynx are derived from different pharyngeal arches and maintain their innervation by the nerve of the arch of origin.