ANATOMY

Detailed explanation-1: -Gastrulation occurs during week 3 of human development. The process of gastrulation generates the three primary germ layers (ectoderm, endoderm, mesoderm), which primes the system for organogenesis and is one of the most critical steps of development.

Detailed explanation-2: -The germ layers form during the process of gastrulation, when the hollow ball of cells that constitutes the blastula begins to differentiate into more-specialized cells that become layered across the developing embryo.

Detailed explanation-3: -The ectoderm gives rise to the nervous system and the epidermal skin cells, the mesoderm gives rise to the muscle cells and connective tissue in the body, and the endoderm gives rise to the digestive system and other internal organs. Organogenesis is the formation of organs from the germ layers.

Detailed explanation-4: -The endoderm is one of the germ layers formed during animal embryogenesis. Cells migrating inward along the archenteron form the inner layer of the gastrula, which develops into the endoderm. It is the first layer to be developed.

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.