 Well, in this module, we will be discussing the primary germ layers, or the primary germ layers that is the result of the gestulation. When the gas is formed, these three layers are the ectoderm, mythoderm, and endoderm. In this module, we will be discussing only the ectoderm, or this ectoderm, which is one of the germ layers that develop early in embryonic life through the process of gestulation. Okay? Okay. During gestulation, the embryo develops or differentiates into three primary germ layers, which are called the inner endoderm, middle, and the upper outer, that is the ectoderm, and the middle, the midoderm. Okay? So, ectoderm, this layer, this is ectoderm, outer layer, which we can see in this diagram, and this is the primitive streak that we discussed in the pistol lectures, and these arrows are showing the movement of the cells, showing the movement of the cells. This diagram that also shows the cut section showing the ectoderm, midoderm, and endoderm cells. Okay? So, ectoderm is the middle layer, which is not any of the ectoderm cells that enter the primitive streak or primitive groove. So, it remains outside, remain outside, and this is what is called a very important layer, and this is what is called a very important layer, and this is what is called a very important layer, and this layer is important to make the body organs, by the process that we call the organogenesis. Okay? so ectoderm develops the surface ectoderm neural crest and the neural tube So this is the neural tube, this is the neural tube, this is the neural tube Then these are the neural crest cells which are differentiated from the region they are moving along this neural plate and this is the neural plate which Dayton develops into the spinal cord and it is completely attached with it, there is a total cord It starts with pre-cordal plate T and then develops and starts moving in world okay the surface ectoderm develops into the epidermis and these are the structures which with the passage of time form ectoderms, these are the structure which has the hair, the nail, the lens of the eye lens of the eye, this is ectodermal in origin then this is sebaceous glands which are formed in the skin then the corneas of the eye, then the tooth enamel, the epidermis, the epithelium of the mouth and nose of the anterior pituitary gland so these are the structures which are ectodermal in origin but there are some organs which form two layers like adrenal gland now after that the neural crest, as we saw in the last diagram the neural crest cells they of the ectoderm develop into peripheral nervous system ecto has CNS, the center nervous system in which there is notochord and then in the spinal cord there is a neural plate then there is invaginate, then there are the hoots so in this way this neural tube is formed this neural tube that develops into later on the spinal cord and then with this neural crest cells there are other cells, there are other structures especially peripheral nervous system adrenal medulla is formed, millenocytes then the facial cartilage is the ear or nose cartilage the cartilage is very flexible bone so after that the neural tube of the ectoderm develops into the brain spinal cord, posterior pituitary or motor neurons or retina so these are the different structures which are derived from the ectoderm so this is the primary germ cell this is one of the germ cells or abhiskebath in the proceeding in the proceeding there is lectures we'll be discussing the medoderm as well as the endoderms so this is all about