Answer:
Gastrulation is the process where the developing embryo forms the process of the 3 germ layers. These germ layers are formed due to the movement of the single-layered blastula. Gastrulation starts during the third week of the human embryo.
The three germ layers give rise to different organs of the fetus. The 3 layers are ectoderm or outer layer, mesoderm or middle layer, and endoderm or inner layer.
These 3 germ layers give rise to different organs of the human fetus. Ectoderm forms epidermis, skin, hair, olfactory organs, eye lense. glands like pituitary. Sensory nerves, skeleton, pigment cells are also formed from ectoderm.
Ectoderm also forms a neural tube that further divides to form the brain, spinal cord.
Mesoderm form the vertebral column, skeletal muscle, excretory organs, reproductive organs. It also forms blood cells, blood vessels, body cavity or coelom.
The inner layer endoderm gives rise to the lining of the digestive tract, liver, pancreas, bladder, etc.
