1. Digestive System
The Stomach

2. 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. 3. Stomach
Function: mixes, churns, and breaks down food (washing machine)
pH – 1-4
pH of small intestines is about 8

4. 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

5. 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

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

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

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

9. Dogfish shark stomach

10. 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?

11. 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