Ectoderm vs Endoderm
An exploration of ectoderm and endoderm would be very interesting, as there are so many interesting differences between these two. First, ectoderm and endoderm along with the mesoderm are the primary germ cell layers of any animal. All the organs and the system of the body are purely based on these three cell layers, and ectoderm and endoderm collectively account for more than two third of the body organs. The location in relative to each other has been the base for naming the germ cell layers during the early embryonic developmental stages. This article explores the basic characteristics of both ectoderm and endoderm and performs a comparison to provide the reader some fast facts about these cell layers.
What is Ectoderm?
Ectoderm is the outermost germ cell layer of the early embryo. It is the first layer of germ cells of an embryo. Ectoderm originates the cells to form many structures of the body including the largest organ skin, sweat glands, hair follicles, nervous system, lining of mouth and anus, and many other organs and systems. Therefore, the importance of the ectoderm is immense and cannot be valued. There are three types of ectoderms identified in vertebrates known as the external or surface ectoderm, the neural crest, and the neural tube. The surface ectoderm forms some of the structures related to the nervous and integumentary systems. The neural crest cells of the embryo form structures or cells related to many systems including endocrine system, Schwann cells of the nervous system, odontoblasts and cemetoblasts of teeth, and Merkel cells of the integumentary system. Neuroblasts or neurons and Giloblasts of the nervous systems are differentiations of the neural tube cells of the embryo. However, all these types of cells, organs, and systems are formed by differentiating the basic germ cells of an ectodermal origin. Thus, the ectoderm of the early embryo could be regarded as one of the most important germ cell layers, which accounts for the skin colour, strength of teeth, nervous system including the brain, and many other features of a particular individual.
What is Endoderm?
Endoderm is the innermost layer of primary germ cells forming in the early embryos. Endoderm starts with flattened cells but later the shapes are changed into columnar cells, and form the epithelial linings of many organs and systems of the body. The endoderm lines mainly the digestive tract, and it covers a vast majority of the gastrointestinal tract excluding the mouth, pharynx, and the anus. Additionally, the respiratory system, endocrine system, auditory system, and urinary system are also lined in different proportions in general by differentiated endoderm germ cells of the early embryo. However, particularly the alveoli, trachea, and bronchi of the respiratory system are endodermic in origin. Moreover, the follicles of the thyroid gland and the thymus of the endocrine system, epithelium of the auditory tube and tympanic cavity of the auditory system, and the urinary bladder and urethra of the urinary system are lined via differentiation of endodermic germ cells. All these cells, organs, and systems are formed in different times during the embryonic stage of any particular animal. Since there are many body systems have the endodermic origin, the importance of the particular germ cell layer is very high and any malfunctioning with that might cause severe consequences.
What is the difference between Ectoderm and Endoderm?
• Ectoderm is the outermost layer of the primary germ cells, but the endoderm is the innermost layer of the early embryo.
• Both cell layers line some common as well as separate organs but endoderm never lines any exteriorly exposed organ.
• Few genes are required to form the ectoderm, but most of the genes of the genome are required to form the endoderm.
• The endoderm cells are mostly columnar shaped while there is no particular shape or has almost all the shapes of cells in ectodermic cells after differentiation.