Digestive system
Definition
The digestive system (gastrointestinal system) is the part of the body that digests food, absorbs nutrients, and removes waste.
Functions
Breaks down food into simple chemicals.
Absorbs nutrients into the bloodstream.
Sends nutrients to the liver for processing.
Produces and removes waste (gas, feces, urine).
Uses enzymes and acids (like hydrochloric acid in stomach) to digest food.
Process
Food enters mouth → broken down by teeth & saliva.
Passes through pharynx → oesophagus → stomach.
In stomach: gastric acid (HCl, pH 1.5–3.5) digests food; mucus protects stomach lining.
Food goes to intestines (small & large) where nutrients are absorbed.
Liver processes nutrients, pancreas and other organs release enzymes/hormones.
Waste leaves body through rectum → anus.
Main Parts (Gut)
Mouth
Pharynx
Oesophagus
Stomach
Small intestine (duodenum, jejunum, ileum)
Large intestine (cecum, colon, rectum)
Anus
Accessory Organs (Not part of gut but help in digestion)
Liver & gall bladder
Pancreas
Salivary glands
Lips, teeth, tongue, epiglottis
Thyroid & parathyroids