Digestion The Stomach and Digestion Site of food

Digestion

The Stomach and Digestion - Site of food storage and protein digestion - J-Shape organ that can store up to 1. 5 L of food - Movement of food in and out of stomach is regulated by sphincters - Cardiac sphincter: regulates food from esophagus - Pyloric sphincter: regulates food from stomach to small intestine

The Stomach and Digestion cont. • There are millions of cells that line the wall of the stomach that secrete many fluids which called collectively called gastric juice • Gastric juice : Hydrochloric acid (HCl) mucus, pepsinogens and other materials • Pepsinogens: enzymes that when exposed to a low p. H such as conditions in the stomach, turns into its active form pepsin which is a enzyme the digests proteins • What do we know about HCl?

Mucus • A protein produced by a layer of epithelial cells that provide a protective coating • It is alkaline in nature which is basic and protects lining of the stomach from both acid from HCl and pepsin from breaking down proteins of stomach lining • However when mucus is destroyed or not being produced…

Disorder: Stomach Ulcer • Ulcer: a lesion along the surface of an organ -when the mucus membrane is destroyed a peptic ulcer can be formed resulting in tissue being burned an allergic reaction can become stronger resulting in blood vessels breaking down

Heliobacter pylori

Stomach Disorders: Ulcers cont. • Case Study • Have students in pairs or small groups uncover this bacteria Heliobacter pylori and other information about ulcers • Prevalence, demographics, how to detect this bacteria, bacterial weight/amount, effects on every day living/side effects, treatment etc. are all topics the students could discover • Could be in the form of a report, or a presentation, or even a jigsaw activity

Small Intestine Introduction Activities • http: //www. youtube. com/watch? v=4 wa. SJ q. OEJts • Easy way to get the students thinking about the small intestine is having 7 m of yard, tubing etc. and having it passed around the classroom • After this have them put it in a small box • Small intestine is not named small because of its length rather its diameter!

Small Intestine Cont. • 3 parts of the small intestine are the: • Duodenum: - most digestion occurs here • Jejnum: has many folds that continue breakdown and absorption of remaining proteins and carbohydrates • Ileum: less absorption occurs here, unabsorbed particles are pushed through and continued

Digestion in the Small Intestine • How is the small intestine protected if HCl and pepsin- soaked food is sent to it from the stomach?

Small Intestine and Pancreas Interaction

Small Intestine and Pancreas Interaction

Liver and Gall Bladder: Role in Digestion