BIOL 208 Lecture Notes - Lecture 12: Muscular Layer, Muscularis Mucosae, Loose Connective Tissue
Document Summary
Digestive system: tube running from the mouth to the anus, alimentary canal = gastrointestinal (gi) tract, functions of the gi tract: Propulsion - swallowing (oropharynx), usually by peristalsis - wave contraction of smooth muscle. Mechanical breakdown - chew, mix food with tongue, stomach churns the food, small intestine breaks down food mechanically by segmentation. Digestion - chemical breakdown of nutrients into smaller, absorbable molecules. Absorption - absorbing small molecules into the bloodstream. Retroperitoneal duodenum & pancreas: infection of the peritoneum or connective tissue coverings is called peritonitis - widespread infection of all the mesentery, 4 basic layers of the gi tract: Epidermal cells - produce mucus & secretions and absorb nutrients. Lamina propria - has blood vessels to absorb nutrients. Muscularis mucosa - thin layer of smooth muscle for local movement. Submucosa - loose connective tissue - blood vessels, nerves, lymphatics. Muscularis externa - inner layer of circular muscle & outer layer of longitudinal.
