Somite

Somite is a division of the body of an animal or embryo. In humans, somites are spheres of mesoderm that form along the neural tube during embryonic development. They give rise to important structures such as the vertebral column, skeletal muscle, and dermis.

Development

Somites are formed from the paraxial mesoderm. This process, known as somitogenesis, begins in the third week of human embryonic development. The paraxial mesoderm is divided into segments, and each segment will eventually form a somite. The process of somitogenesis is controlled by a complex network of genes and proteins.

Structure

Each somite is composed of a dorsal part called the dermomyotome, which gives rise to the dermis and skeletal muscle, and a ventral part called the sclerotome, which forms the vertebral column. The dermomyotome is further divided into the myotome, which forms skeletal muscle, and the dermatome, which forms the dermis.

Function

Somites play a crucial role in the development of the vertebrate body plan. They give rise to the segmented pattern of the vertebral column and play a role in the development of the peripheral nervous system. In addition, somites are involved in the formation of the axial skeleton, voluntary muscles, and dermis of the skin.

Clinical significance

Abnormalities in somite development can lead to a variety of congenital disorders. These include vertebral segmentation disorders such as scoliosis, kyphosis, and spondylosis. In addition, somite abnormalities can result in muscular dystrophy and other muscle disorders.

See also

• Embryogenesis
• Mesoderm
• Neural tube

References

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  End of week 4 embryo with somites