Lesson 2 (Esophagus and Stomach)

Esophagus

• Muscular,mucus-lined tube about 10 in long

• Moves food from pharynx to stomach by peristalsis, alternating contractions of muscles

Stomach

• Muscular organ in upper left quadrant

• Bolus enters at the cardioesophageal sphincter

• Contraction of muscles mixes partially digested food with highly acidic gastric juices to make chyme

Cardia-Stomach regions

Where stomach connects to esophagus

Fundus -Stomach regions

Upper part of stomach

Body-stomach regions

Main part of stomach

Pylorus-stomach regions

Funnel- shaped end that connects to small intestine

Mucous membrane

• Lines the stomach

• Found in rugae folds in the stomach when it is empty

• When full, ridges flatten can hold 1 gallon food/fluid

• Secretes mucous that protects the lining of the stomach from the acid

Microscopic gastric glands-mucous membranes

• Secrete glands secrete gastric juices and hydrochloric acid (HCL) into stomach

• HCI, very strong acid (pH 1 or 2) activates enzymes and kills bacteria

Pepsin-mucous membranes

• Enzyme breaks down proteins into amino acids

Stomach functions

• Acts as a storage for food

• Contracts to mechanically breakdown food

• Chemical breakdown of protein begins

• Delivers chyme through pyloric sphincter to the small intestine

Sphincters

• rings of muscle, at each end of esophagus keep bolus moving and keep the acid and food in your stomach from coming back up (heartburn/acid reflux)