Digestive System of Man

Chapter Overview

The digestive system converts complex food substances into smaller, soluble molecules that can be absorbed and used by body cells. Digestion begins in the oral cavity, where teeth mechanically break food into smaller pieces and salivary enzymes begin chemical digestion. The swallowed food then moves through the esophagus by peristalsis and enters the stomach.

In the stomach and small intestine, digestive juices containing enzymes break carbohydrates, proteins, and lipids into absorbable products. Most digestion and absorption take place in the small intestine. Glucose and amino acids enter blood capillaries, while most absorbed lipids enter lymphatic vessels before reaching the bloodstream.

The chapter also explains the functions of the large intestine, liver, bile, and pancreas. Students learn how the nervous system and hormones such as gastrin and secretin regulate digestive secretions. These concepts are important for FBISE SLO-based MCQs, short questions, long questions, and conceptual board-exam answers.