Stomach

Definition

The stomach is a muscular organ in the upper abdomen that plays a key role in digestion by secreting acid and enzymes to break down food. It also offers a barrier to pathogens through its acidic environment.

5 Must Know Facts For Your Next Test

1. The stomach's acidic environment (pH 1.5-3.5) helps kill most ingested pathogens.
2. Helicobacter pylori is a bacterium that can colonize the stomach lining and cause ulcers or gastritis.
3. The stomach has specialized cells, such as parietal cells that secrete hydrochloric acid and chief cells that release pepsinogen.
4. Gastric mucosa protects the stomach lining from being digested by its own enzymes and acid.
5. Certain microbiota, like Lactobacillus species, can survive in the stomach's acidic environment and contribute to overall gut health.

Review Questions

• What role does the acidic environment of the stomach play in infection control?
• Which bacterium is known for causing ulcers and gastritis by colonizing the stomach?
• Name two types of specialized cells found in the stomach and their functions.

Related terms

Hydrochloric Acid (HCl): A strong acid secreted by parietal cells in the stomach, crucial for digestion and pathogen elimination.

Pepsinogen: An inactive enzyme released by chief cells in the stomach that is converted to pepsin for protein digestion.

Gastric Mucosa: The mucous membrane layer of the stomach which contains glands and gastric pits; it protects against self-digestion.