While Mark was cramming for his anatomy test, he read that some parts of the mesoderm become segmented. He suddenly realized that he could not remember what segmentation is. Define segmentation, and give two examples of segmented structures in the embryo.

Segmentation refers to the division of the body or an organ into repetitive, similar units called segments. In embryology, it involves the formation of repeated structures along the body axis, which helps organize the body plan and facilitates specialized functions.

The mesoderm is the middle germ layer in the embryo that gives rise to many tissues, including muscles, bones, and the circulatory system. Parts of the mesoderm become segmented during development, forming structures like somites that contribute to the segmented body plan.

Two key examples of segmented structures derived from the mesoderm are somites and the vertebral column. Somites are blocks of mesoderm that form along the neural tube and later differentiate into vertebrae, skeletal muscles, and dermis.