inner circular layer

The muscularis externa consists of an inner circular layer and a longitudinal outer muscular layer.

The pylorus of the stomach has a thickened portion of the inner circular layer: the pyloric sphincter.

The intestine has its own pair of muscle layers like the body, but in reverse order-an inner circular layer inside an outer longitudinal layer.

The smooth muscle throughout most of the GI tract is divided into two layers: an outer longitudinal layer and an inner circular layer.

The inner circular layer is innervated by both excitatory and inhibitory motor neurons, while the outer longitudinal layer is innervated by mainly excitatory neurons.