AP BIOLOGY

Detailed explanation-1: -The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from the outer layer of germ cells.

Detailed explanation-2: -germ layer, any of three primary cell layers, formed in the earliest stages of embryonic development, consisting of the endoderm (inner layer), the ectoderm (outer layer), and the mesoderm (middle layer).

Detailed explanation-3: -The germ layers develop early in embryonic life, through the process of gastrulation. During gastrulation, a hollow cluster of cells called a blastula reorganizes into two primary germ layers: an inner layer, called endoderm, and an outer layer, called ectoderm.

Detailed explanation-4: -The surface ectoderm will give rise to the epidermis, external glands, hair, nails, anterior pituitary, and the apical ectodermal ridge amongst others. The functions of the surface ectoderm include hormone regulation by the adenohypophysis, acting as a barrier against the external involvement, and homeostasis.

Detailed explanation-5: -Ectoderm-It is the outermost layer that forms nails, hair, etc. Endoderm-It is the innermost layer that forms the stomach, colon, urinary bladder, etc. Mesoderm-It is the middle layer between ectoderm and endoderm which forms bones, cartilage, etc.