What is digestion? Write about digestion of food in brief.

Digestion is the process by which food is broken down into smaller, absorbable components that can be utilized by the body for energy, growth, and maintenance of bodily functions. It involves both mechanical and chemical processes that occur in the gastrointestinal tract.

1. Mechanical Digestion: Begins in the mouth where teeth chew and grind food into smaller pieces, increasing its surface area for enzymatic action. In the stomach, muscular contractions mix and churn food, further breaking it down.

2. Chemical Digestion: Involves the action of enzymes that break down complex molecules into simpler forms. Enzymes produced by salivary glands, stomach lining, pancreas, and small intestine catalyze the breakdown of carbohydrates, proteins, and fats into sugars, amino acids, and fatty acids.

3. Digestive Enzymes: Amylase breaks down carbohydrates into sugars (e.g., starch into glucose), proteases break down proteins into amino acids, and lipases break down fats into fatty acids and glycerol.

4. Absorption: After digestion, nutrients are absorbed through the walls of the small intestine into the bloodstream. Villi and microvilli in the small intestine increase the surface area for efficient absorption.

5. Remaining Waste: Indigestible materials and waste products pass into the large intestine, where water is absorbed, and the remaining material is formed into feces for elimination.

Overall, digestion is a complex and coordinated process that ensures nutrients from food are broken down and absorbed, providing the body with the essential components needed for growth, energy production, and maintenance of health.