Question

Describe briefly about the structural layers of the Alimentary tube

Answer 1

The digestive system consists of the alimentary canal and its glands. The alimentary canal is a hollow tube made of smooth muscle. The length of the alimentary canal is about 8 meters.

The structure of wall of alimentary canal consists of,

1). The mucosal layer

2). The submucosa

3). Muscularis propia

4). Serous layer

The mucosal layer is again composed of

i). the inner non-keratinizing stratified squamous epithelium

ii). The middle lamina propria

iii). The inner muscularis muscosa

The submucosa consists of

i). Loose connective tissue

ii). Lymphoid follicles and lymphatics and blood vessels

iii). Nerves (Meissner plexus) and submucosal glands

The mucus secreted by the submucosal glands lubricates the esophagus and protect the esophageal layer from the harsh food and gastric juices. The submucosal layer also contains the blood vessels, nerves, and lymphatics.

The inner circular muscle layer and the outer longitudinal muscle layers of muscularis propia contract and allow the peristaltic movement of the esophagus, which is essential for the passage of food through the esophagus.

The serous layer outer covering of the alimentary canal. It consists of the visceral peritoneum (made of epithelium). The serous layer cells secrete the serous fluid, which helps to keep the surface of the tube moistened. The serous fluid allows the free sliding of organs of digestive tract.