Monday, April 4, 2016 Get a sheet of scrap paper & something to write with

Bellringer What are the parts of the alimentary canal, in order?

You should know that answer by now mouth pharynx esophagus stomach small intestine large intestine anus Get out paper & get ready to take notes

Digestive System Notes

Digestive system functions 1.Mechanical processing 2.Secretion 3.Digestion 4.Absorption 5.Elimination

Digestion The mechanical and chemical breakdown of foods and the absorption of the resulting nutrients by cells Mechanical digestion: breaking down large pieces into smaller ones Chemical digestion: breaks food into simpler chemicals

Alimentary canal About 8 m long Extends from mouth to anus Includes: mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum and anus 4 layers: mucosa, submucosa, muscular layer, and serosa Moves food by peristalsis (wavelike muscle contractions)

Accessory organs Not part of the alimentary canal Food does not travel through these organs, but they help out with digestion Includes: salivary glands- secrete saliva into mouth Liver- aids in metabolism of carbs, lipids and proteins; stores nutrients, secretes bile Gallbladder- stores bile; releases bile into small intestine Pancreas- secretes pancreatic juice into small intestine

Mouth Begins digestion by mechanically breaking down food and mixing it with saliva Includes: cheeks, lips, tongue, palate, pharyngeal tonsils, teeth

Esophagus Connects pharynx to stomach Joins to stomach at the lower esophageal sphincter or cardiac sphincter

Stomach Capacity of about 1L Mixes food with gastric juice, starts protein digestion, absorbs some nutrients and moves food to small intestine. 4 regions: cardiac, fundic, body and pyloric Covered in folds called rugae Chyme- paste of food and gastric juice

Small Intestine About m long Mixes food with bile and pancreatic juice 95% of nutrients absorbed here Regions: duodenum, jejunum, ileum

Small Intestine Mesentery: membrane that attaches small intestine to abdominal wall; contains blood vessels, nerves and lymphatic vessels Small intestine wall contains villi; tiny finger-like projections that increase the surface area of the intestine for absorption

Large intestine about 1.5 m long Absorbs water and electrolytes Forms and stores feces Parts: cecum, colon, rectum, and anal canal Apendix is connected to the cecum; no known function No villi