We learn that the equator is a line around the wide waist of the world. Pleasure cruisers often make a great toâdo about crossing this line on the ocean. Any passenger who owns up to the fact that this is his first crossing may be put through ceremonies such as walking the plank and other merry goingsâon.
Ectoderm â Outer or External Layer â differentiates into the nervous system, epidermis, and the outer part of the integument system â forms the central nervous system, the lens of the eye, cranial and sensory, the ganglia and nerves, pigment cells, head connective tissues, the epidermis, hair, and mammary glands.
The ectoderm is an external layer of germ embryo. In this form, it is in its beginning stages before developing into tissue that covers the body. It is one of the three primary germinal layers, the other layers being the mesoderm and the endoderm.The ectoderm develops the nervous system, external sensory organs as well as the hair and skin glands. The ectoderm itself consists of three separate parts: surface ectoderm, neural ectoderm and neural crest.hese cells also assist in the development of parts of the skeletal system, autonomic nervous system and hormone producing cells. This part of the ectoderm is located between the epidermis and neural tube.