GLAND IN SUBMUCOSASEROSA MESENTERY LONGITUDINAL MUSCLEPLEXUS OF AUERBACHCIRCULAR MUSCLEPLEXUS OF MEISSNERSUBMUCOSAMUSCULARIS MUCOSALAMINA PROPRIAMUCOSA GLAND OUTSIDE GUTLUMEN EPITHELIUMFig. General structure of the wall of the mammalian gut and associated structures(i) Generalized histology of alimentary canal : The alimentary canal consist of following layers from outer to inner side:(a) Serosa : Outermost, mesodermal, single layered made up of squamous epithelial cells.(b) Muscular layer : Mesodermal, consist of outer longitudinal and inner circular layer. Muscles are involuntary unstriated. In between the two layers there is a nerve network called the plexus of Auerbach.(c) Submucosa : Mesodermal, made up of connective tissue and contains major blood vessels, lymphatic vessels, nerve fibres etc. Mucous glands are also present in some parts of alimentary canal. In this region nerve network, called plexus of Meissner.