The Digestive System

The digestive system is an example of an organ system in which several organs work together to digest and absorb food. For AQA GCSE Biology, you need to know the structure and function of each organ in the digestive system, how they work together, and how the products of digestion are absorbed into the bloodstream. This lesson takes you through the entire alimentary canal from mouth to anus.

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Overview of the Digestive System

The digestive system is essentially a long muscular tube called the alimentary canal (or gut), along with several associated organs. Food enters at the mouth and passes through each organ in turn:

graph TD
    A[Mouth] --> B[Oesophagus]
    B --> C[Stomach]
    C --> D[Small Intestine — Duodenum then Ileum]
    D --> E[Large Intestine — Colon]
    E --> F[Rectum]
    F --> G[Anus]
    H[Liver] -->|Produces bile| D
    I[Gall Bladder] -->|Stores and releases bile| D
    J[Pancreas] -->|Produces enzymes| D
    K[Salivary Glands] -->|Produce saliva and amylase| A

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The Mouth

Digestion begins in the mouth (also called the oral cavity or buccal cavity):