GENERAL HISTOLOGY

Detailed explanation-1: -The endoderm gives rise to the lining of the esophagus, stomach and intestines, as well as associated organs.

Detailed explanation-2: -The endoderm constructs the digestive tube and the respiratory tube. 15. Four pairs of pharyngeal pouches become the endodermal lining of the eustacian tube, tonsils, thymus, and parathyroid glands. The thyroid also forms in this region of endoderm.

Detailed explanation-3: -The epithelial tissue derived from the endoderm includes the epithelial lining of the digestive tract, except at the open ends, and the epithelial lining of all hollow structures formed as outpockets in the digestive tract. This includes: The parenchyma of the liver including communicating or connecting ducts.

Detailed explanation-4: -The ectoderm gives rise to the skin and the nervous system. The mesoderm specifies the development of several cell types such as bone, muscle, and connective tissue. Cells in the endoderm layer become the linings of the digestive and respiratory system, and form organs such as the liver and pancreas.