GENERAL HISTOLOGY

Detailed explanation-1: -The muscularis, or muscularis externa, consists of an inner circular muscular layer and a longitudinal outer muscular layer. The coordinated contractions of these layers is called peristalsis, which propels the food through the GI tract.

Detailed explanation-2: -During peristalsis, the circular smooth muscle contracts behind (on the orad side) the bolus and relaxes in front (on the aborad side) of the bolus. At the same time, the longitudinal muscle relaxes orad to the bolus and contracts on the aborad side of the bolus.

Detailed explanation-3: -The muscularis externa of the small intestine consists of smooth muscle fibers arranged into an inner circular layer and an outer longitudinal layer. Between these two muscle layers is a network of unmyelinated nerve fibers and parasympathetic ganglia called Auerbach’s plexus (or myenteric plexus).

Detailed explanation-4: -There are usually two layers; the inner layer is circular, and the outer layer is longitudinal. These layers of smooth muscle are used for peristalsis (rhythmic waves of contraction), to move food down through the gut.

Detailed explanation-5: -Peristalsis is a series of wave-like muscle contractions that move food through the digestive tract. It starts in the esophagus where strong wave-like motions of the smooth muscle move balls of swallowed food to the stomach.