Stomach

The J-shaped stomach is the most distensible part of the GI tract. It is continuous with the esophagus superiorly and empties into the duodenum of the small intestine inferiorly. The functions of the stomach are to store food, to initiate the digestion of proteins, to kill bacteria with the strong acidity of gastric juice, and to move the food into the small intestine as a pasty material called chyme.

How Stomach Acid Kills Pathogens

Esophagus

Peristaltic contraction of muscularis layer of esophagus

Swallowed bolus entering stomach

Stomach

Esophagus

Peristaltic contraction of muscularis layer of esophagus

Swallowed bolus entering stomach

Stomach

■ Figure 18.4 Peristalsis in the esophagus. (a) A diagram and (b) a radiograph showing peristaltic contraction and movement of a bolus into the stomach.

The Digestive System

Swallowed food is delivered from the esophagus to the cardiac region of the stomach (figs. 18.5 and 18.6). An imaginary horizontal line drawn through the cardiac region divides the stomach into an upper fundus and a lower body, which together compose about two-thirds of the stomach. The distal portion of the stomach is called the pyloric region. The pyloric region begins in a somewhat widened area, the antrum, and ends at the pyloric sphincter. Contractions of the stomach churn the chyme, mixing it

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Essentials of Human Physiology

Essentials of Human Physiology

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Responses

  • maxima
    How stomach acid kills pathogens?
    8 years ago
  • kimberly
    What is chyme and hoes the stomach mix this material?
    8 years ago
  • Klaus
    Which stomach layer is in contact with swallowed food?
    6 years ago

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