الفهرس 
Contents
IntroductionOnly 14 pages are availabe for public view
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Abstract
Tetrapods are vertebrate animals which have four limbs or leg like appendages that aid as a main tool for movement in the terrestrial environment. Unlike the aquatic vertebrates, tetrapods have acquired many morphological and anatomical features to accommodate to their terrestrial life. Besides the four limbs, which help bearing the gross body weight in the terrestrial environment, they exhibit many structural changes in most organs and systems related to respiration, reproduction, excretion, digestion as well as food and feeding habits. Taxonomically, tetrapoda include four classes: Amphibia, reptilia, aves and mammalia (Narkiewicz & Narkiewicz, 2015). These four classes share many anatomical characteristics including the gastrointestinal tract (GIT). However, some microanatomical features of the GIT especially those related to the architecture of the mucosal layer, are completely different. The type and function of the mucosal cells may differ in the different tetrapod classes.