Digestive System Overview

Digestive System Overview

• The digestive system includes organs that form the alimentary canal (food passes through) and accessory organs (aid digestion).
• Alimentary canal organs include the large intestine (colon, rectum, anus).
• Accessory organs include structures not directly involved in food passage.

Digestive Processes

• Mechanical digestion: physically breaking down food into smaller pieces without changing its molecules.
• Absorption: moving small food molecules and ions into the bloodstream from the intestines.
• Egestion: eliminating undigested food as faeces.
• Assimilation: absorbing nutrients into body cells after absorption into the blood.

Ingestion and Mechanical Digestion

• Ingestion occurs first, where food enters the body.
• Teeth mechanically break down food particles.

Peristalsis

• Peristalsis is the muscular contractions that force food down the esophagus.

Stomach Function

• Hydrochloric acid in the stomach sets a suitable pH for enzymes and kills pathogens.

Liver and Bile

• Bile aids fat digestion and neutralizes stomach acid.
• Bile is stored in the gallbladder before release into the duodenum.

Pancreas

• The pancreas produces digestive enzymes (amylase, protease, lipase) released into the duodenum.

Small Intestine (Ileum)

• The ileum absorbs food and water into the bloodstream through villi.

Large Intestine

• The large intestine absorbs water from food and forms faeces.

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