Learn: Digestive System in Humans

Welcome!Today we'll learn about the human digestive system, how it breaks down food, and the roles of enzymes. This topic is essential for understanding how our body processes nutrients.

What is Digestion?Digestion is the process of breaking down large, insoluble food molecules into smaller, soluble ones. This allows nutrients to be absorbed into the bloodstream and used by the body for energy, growth, and repair.

The Digestive SystemThe digestive system is made up of organs that work together to digest food. Key organs include the mouth, oesophagus, stomach, liver, pancreas, small intestine, and large intestine. Each organ plays a specific role in digestion.

Key Digestive OrgansEach organ in the digestive system has an important role:Mouth: Chews food and mixes it with saliva, which contains enzymes to start breaking down starch.Stomach: Produces acid and enzymes to digest proteins and churns food into a liquid.Small intestine: Absorbs nutrients into the blood through its thin walls.Large intestine: Absorbs water and forms solid waste (faeces).

Digestive EnzymesEnzymes are biological catalysts that speed up chemical reactions. In digestion, enzymes break down specific types of food:Carbohydrase: Breaks down starch into glucose.Protease: Breaks down proteins into amino acids.Lipase: Breaks down fats into fatty acids and glycerol.

Absorption in the Small IntestineThe small intestine is where most absorption happens. Its inner walls are lined with tiny finger-like structures called villi. These increase the surface area, allowing nutrients to be absorbed efficiently into the blood.

Role of BileBile is produced by the liver and stored in the gall bladder. It helps break down fats by emulsifying them, making it easier for lipase to work.

Tests for Digestion ProductsScientists use tests to identify digested food products:Iodine test: Tests for starch. Turns blue-black if present.Benedict’s test: Tests for glucose. Turns orange-red if present.Biuret test: Tests for protein. Turns purple if present.

Review Time!Great work! You've learned about digestion, enzymes, absorption, and tests for digestion products. Now let's check your understanding.