The digestive system
Introduced| English | Meaning |
|---|---|
| digestive system/daɪˈdʒestɪv ˈsɪstəm/ | The organs that take in food, break it down, absorb useful substances and eliminate undigested material. |
| oesophagus/ɪˈsɒfəɡəs/ | The tube carrying food from the mouth to the stomach by peristalsis. |
| small intestine/smɔːl ɪnˈtestɪn/ | The section of the digestive tract where most chemical digestion and absorption of digested nutrients occur. |
| peristalsis/ˌperɪˈstælsɪs/ | peristalsis |
| liver/ˈlɪvə/ | An organ that processes nutrients, regulates blood chemistry, detoxifies substances and produces bile. |
| bile/baɪl/ | The alkaline fluid made by the liver that emulsifies fats, increasing their surface area for lipase. |
| pancreas/ˈpæŋkrɪəs/ | An organ that produces digestive enzymes and hormones including insulin and glucagon. |
| ingestion/ɪnˈdʒestʃn/ | ingestion |
| absorption/əbˈsɔːpʃn/ | Taking a substance or energy into another material or system. |
The journey of a meal
- The food you eat is too big for your cells to use. It must be broken down and absorbed.
- That's the job of the digestive system 消化系统 — a long tube with specialised parts.
Put these parts of the gut in the order food passes through them.
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Mouth → oesophagus → stomach → small intestine → large intestine.
Food is moved along the gut by waves of muscle contraction called:
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Peristalsis squeezes food along the gut.
The main organs
- Mouth → oesophagus 食道 → stomach → small intestine 小肠 → large intestine.
- Food is moved along by waves of muscle contraction called peristalsis 蠕动.
The alimentary canal that food passes through, plus the organs that add digestive juices
Through the digestive system
Food travels along the gut; each part does a different job to break it down and absorb it.
The pancreas makes:
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The pancreas produces enzymes; the liver makes bile.
The organ that produces bile is the ______.
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The liver makes bile; the gall bladder stores it.
Helper organs
- The liver 肝脏 makes bile 胆汁; the gall bladder stores it.
- The pancreas 胰腺 makes digestive enzymes.
Egestion is the removal of undigested food (faeces).
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Egestion removes the waste food that was never absorbed.
Key stages
- Ingestion 摄入 (taking in), digestion (breaking down), absorption 吸收 (into the blood), egestion (removing waste).
Worked example. A piece of bread is chewed (mouth), churned with acid (stomach), digested by enzymes (small intestine), absorbed into the blood, and the leftover fibre is egested. Each organ has its role.
You've got it
- the gut: mouth → oesophagus → stomach → small intestine → large intestine; moved by peristalsis
- the liver makes bile; the pancreas makes enzymes
- stages: ingestion → digestion → absorption → egestion
Write from bile and the small intestine
- Food has been swallowed and churned.
- Digested molecules then leave the gut into the blood.
Where does most absorption happen, and which organ makes bile?
Digestion and absorption are not the same stage.
Which organ makes bile?
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The liver makes bile and the small intestine uses it.