Digestive System The Stomach

Create a stomach Stomach: Width: 7-13 cm Length: 15-25 cm Greater curvature: 4-5 times larger than the Lesser Curvature Esophagus: 25 cm esophagus Pyloric Sphincter Lesser Curvature Greater Curvature duodenum

3. Stomach Function: mixes, churns, and breaks down food (washing machine) pH – 1-4 https://www.youtube.com/watch?v=-U5JyODRVng pH of small intestines is about 8

protect it from stomach acid Stomach pH 1-4 esophagus pH >4 A. Cardia (Cardiac region): secretes mucous to give to the esophagus protect it from stomach acid Stomach pH 1-4 esophagus pH >4

secretes acids and enzymes to break down food 3. Stomach B. Fundus : secretes acids and enzymes to break down food C. Body: mixes and churns food secretes acids and enzymes https://www.youtube.com/watch?v=XPGVoWn3Z54 https://www.youtube.com/watch?v=x26C9AWeIes

Stomach D. Pylorus: secretes hormone gastrin which triggers HCl (hydrochloric acid) to be released

Stomach E. Pyloric sphincter : ring of muscle that determines when chyme (broken down food) goes into the small intestine

Rugae Rugae: folds of muscle inside stomach, stretch out when stomach is full (increase surface area inside stomach)

Dogfish shark stomach

Digestive System Disorders What is Acid Reflux? What structures are effected with Acid Reflux? What foods or medicines can cause Acid Reflux? Who is usually prone to getting Acid Reflux? How can one prevent Acid Reflux from occurring?

3. Stomach Gastric Juices: Pepsin – speed up the breaks down of proteins (catalyst) HCl (hydrochloric acid)– pH 2; breaks down food; antimicrobial (kills bacteria) Mucus – protects wall from acidic chyme and pepsin Gastrin – hormone that regulates stomach secretions (HCl) and movement Intrinsic factor –takes vitamin B12 off of proteins (meat, fish, poultry, eggs) and absorbs it B12 – DNA synthesis and RBC production