Digestive System Alimentary Canal Alimentary Canal Tube from mouth to anus Components Esophagus o Muscular tube Stomach o Storage tank Small Intestine o Nutrient Absorption o Chemical Digestion Large Intestine Appendix Alimentary Canal Four Tunics Submucosa Mucosa Muscularis Externa Serosa Mucosa Inner Layer always next to lumen Lines lumen from mouth to anus Secretes mucus enzymes hormones Absorb digestive products Protects against disease o Absorption of water and elimination of solid waste Tunics Histology Mucosa Epithelium o Simple columnar Lamina Propria o Areolar C T o Capillaries o Lymphatics Muscularis Mucosae o Smooth muscle Submucosa Dense Irregular C T with Elastic Fibers Blood and lymph vessels Meissner s Submucosal Plexus o Controls motility of mucosa Muscularis Externa Smooth muscle o Inner circular o Outer longitudinal Serosa Areolar C T Simple Squamous Enteric Nervous System Self contained nervous system Esophagus Histology Mucosa Stratified squamous to simple columnar Langerhans cells o Phagocytes Lamina Propria Areolar C T Muscularis Mucosa One sheet of smooth muscle o Longitudinal Submucosa Dense Irregular C T Muscularis Externa Part skeletal Smooth Muscle Stomach Histology Mucosa Simple columnar o Fundus Cells Glandular Cells Fundus Cells o Mucous neck cells o Stem cells o Parietal cells o Chief Cells Produce HCI Cardiac Region o Gastric pits shallower Pyloric Region o Gastric pits deep Produce protein enzymes Lamina Propria Areolar C T Muscularis Mucosa Smooth Muscle 3 Layers o Inner circular o Outer longitudinal Submucosa Dense Irregular C T Muscularis Externa Smooth Muscle 3 Layers o Inner oblique o Middle circular o Outer longitudinal Serosa Areolar C T Simple Squamous Stomach Four Regions Cardiac o Entry of food Fundus Body Pyloric Region Stomach Components Mucosal Barrier o Pyloric sphincter controls stomach emptying o Prevents stomach from digesting itself o Epithelial cells with tight junctions o Surface of an epithelial cell that faces lumen Phagocytes that transport antigens to lamina propria Small Intestine Histology Mucosa Simple Columnar Apical surface brush border Cells are absorptive Cells o Goblet Cells o DNES Cells o Microfold Cells Produce hormones Lamina Propria Areolar C T Crypts of Lieberk hn o Glands that lie between villi Paneth Cells o Produce lysosomes Muscularis Mucosae Smooth Muscle o Inner circular o Outer longitudinal Submucosa Dense Irregular C T Meissner s submucosal plexus Peyer s Patch Muscularis Externa Smooth muscle Serosa Areolar C T Simple Squamous Small Intestine Three regions Duodenum Jejunum Ileum o Google Lymphoid follicles that plays a role in the immune system In the submucosa of duodenum there are Brunner s gland Mucous glands Digestive process depends on delivery of chyme digestive secretions True peristalsis after most nutrients is absorbed Small Intestine Components Notes Lacteal o Lymph vessel type o Absorption of lipids Large Intestine Four Subdivisions Cecum Vermiform Appendix o Masses of lymphoid tissue Colon Rectum Colon Rectum Appendix Histology No Villi Crypts of Lieberk hn o Have rectal valves that separate feces from flatus o Google Provide stem cells for renewal of the intestinal epithelium In rectum crypts are deeper and fewer In appendix there is added lymphatic tissue Simple cuboidal changes to stratified squamous Anal Canal Histology Mucosa Submucosa Fibroelastic C T Muscularis Externa Inner and outer smooth muscle Smooth muscle is replaced by skeletal muscle Large Intestine Notes Muscularis is reduced except at the end o Teniae coli 3 Bands of Smooth Muscle Forms Haustra Sac Areas o Definitions Ganglia Cluster of neural bodies Rugae Longitudinal folds Villi Finger like projections of mucosa o Absorptive columnar cells Microvilli Tiny projections of the plasma membrane Apical surface Surface of an epithelial cell that faces lumen Urogastrone Human epidermal growth factor o In duodenum Meissner s Submucosal Plexus Controls motility of mucosa Rectal Valves Internal transverse folds Haustra Sack like areas