Somites

Definition

Somites are segmented blocks of mesoderm that form along both sides of the neural tube in a developing embryo. They give rise to important structures such as vertebrae, skeletal muscles, and dermis of the skin.

5 Must Know Facts For Your Next Test

1. Somites differentiate from the paraxial mesoderm during early embryogenesis.
2. They play a crucial role in the segmentation and organization of the vertebrate body plan.
3. The formation of somites is controlled by a molecular clock mechanism involving cyclic gene expression.
4. Each somite differentiates into three main components: the sclerotome (which forms vertebrae and ribs), myotome (which forms skeletal muscles), and dermatome (which forms dermis).
5. Abnormal development of somites can lead to congenital conditions such as scoliosis or spina bifida.

Review Questions

• What structures do somites ultimately give rise to in a developing embryo?
• How does the molecular clock mechanism influence somite formation?
• What are the three main components that each somite differentiates into?

Related terms

Neural Tube: A structure in the early stage of brain and spinal cord development.

Paraxial Mesoderm: The area of mesoderm cells located adjacent to the neural tube that gives rise to somites.

Sclerotome: The part of a somite that develops into vertebrae and ribs.