The alimentary canal is one long, muscular tube with organs along its length that take food in, break it down, absorb what is useful and get rid of the rest. Glands outside the tube pour in juices to help. Follow a mouthful of food through it and name each stage of nutrition as it happens.
Food passes along the alimentary canal: mouth, oesophagus, stomach, small intestine (duodenum then ileum) and large intestine (colon, rectum, anus). The salivary glands, pancreas, liver and gall bladder are associated organs that the food never passes through. Five processes happen on the way: ingestion, digestion, absorption, assimilation and egestion.
Click each organ in the 3D model, or press Follow a mouthful and watch the food travel from mouth to anus. The FOOD IS IN readout names the organ it has reached, and the food moves more slowly through the stomach and the ileum.
| Organ | Main function |
|---|---|
| Mouth | ingestion; teeth chew food; saliva starts starch digestion |
| Salivary glands | secrete saliva containing amylase and mucus |
| Oesophagus | muscular tube carrying food to the stomach by peristalsis; no digestion |
| Stomach | churns food; gastric juice with protease and hydrochloric acid |
| Duodenum | first part of the small intestine; receives pancreatic juice and bile; digestion |
| Ileum | last part of the small intestine; digestion completed; nutrients and most water absorbed |
| Colon | absorbs some of the remaining water, forming faeces |
| Rectum | stores faeces |
| Anus | egestion of faeces |
| Pancreas | secretes pancreatic juice (amylase, protease, lipase) into the duodenum |
| Liver | makes bile; processes absorbed nutrients (assimilation) |
| Gall bladder | stores bile and releases it into the duodenum |
The liver, pancreas, gall bladder and salivary glands are not part of the alimentary canal: food never passes through them. They secrete juices into it.
In the sim the PROCESS readout names what each organ does. The five processes happen in this order as food moves along the gut.
Egestion is not excretion. Faeces are mostly undigested food that never entered the body's cells; excretion removes waste products of metabolism, such as urea and carbon dioxide.
Four quick checks. Each correct answer earns XP and records this skill on your profile.
In the 3D model, which organ does the PROCESS readout link with egestion?
Following a mouthful in the sim, which organ does the food reach straight after the stomach?
The sim describes the oesophagus as doing which of these?
Which organ in the sim stores bile and releases it into the duodenum?
Unlocks once the four checks above are done. Worth more XP, written to IGCSE Paper 2 and Paper 4 standard.
Which list contains only parts of the alimentary canal?
Which term describes the movement of nutrients from the intestines into the blood?
Liver cells convert absorbed glucose into glycogen. This is an example of:
Where is most water absorbed from the alimentary canal?
This skill is now recorded on your profile. Keep the chain going.