Histology Embryology the muscularis externa*k Two layers of smooth muscle Myenteric nerve plexus responsible for peristalsis and segmentation Inner circular layer (circumferential) Myenteric(Auerbachs autonomic)nerve plexus Muscularis externa Longitudinal muscle Circular muscle Outer longitudinal layer --shortens gut Lumen Duct of gland outside alimentary canthe muscularis externa* Two layers of smooth muscle responsible for peristalsis and segmentation • Inner circular layer (circumferential) • Myenteric (Auerbach’s autonomic) nerve plexus • Outer longitudinal layer: ---shortens gut *