The digestive organs

• Biologie
• Middelbare school
• havo
• Leerjaar 2

Welcome!

Today: 

Questions about the digestive system 

Explanation about organs in the digestive system (page 104)

Making homework exercises 

Function of your teeth

The enzyme lipase is dissolved in your saliva. What does this make saliva?

1. Digestive gland
2. Enzyme
3. Digestive juice
4. Digestive substance

Saliva is a digestive juice that mostly digests nutrients that are high in energy. Do they digest protein?

1. Sure
2. No way

Statement: In every digestive juice are the same enzymes because they all digest food.

1. True
2. False

What are we going to learn today?

Today we will be learning:

Out of which organs the digestive system consists of, and what their functions are.

Wat de functies van deze organen zijn.

Which digestive juices break down which nutrients. 

The digestive system

In your digestive system foods get, well, digested. This means:

- The good nutrients are taken in by your body. 

- The rest of the food gets removed from your body. 

Your mouth

The food you eat needs to go through your whole intestinal tract (about 15 meters!). So the food needs to get smooth, whole and wet. All that happens in your mouth. You chew it and your salivary glands add saliva. 

Your teeth

Besides that, by chewing your food you create more surface. This means more space for digestive juices to attach to and digest food more easily. This is a way of mechanical digestion. 

The stomach

When you swallow food, it takes around 7 seconds to reach the stomach through the oesophagus. The food then stays in the stomach for around one hour. Here, gastric glands make gastric juices. This is very acidic and mostly breaks down proteins. 

Duodenum

Through the pyloric sphincter, the food reaches the duodenum, where it gets 

deacidified and some digestive juices gets added:

- The pancreas makes pancreatic juice, which digests fats, carbohydrates and proteins. 

- The liver makes bile, which isn't a digestive juice but it helps the digestion of fats by mixing it with water (emulsification). 

Emulsification 

Small intestine

Food reaches the small intestine relatively quickly after this. Intestinal juices get added as well, digesting the last proteins and carbohydrates. 

The small intestine is also the place where all the digestive products get absorbed. That is why the inside of the small intestine has a lot of surface and blood vessels inside it.  

Dunne darm

Food reaches the small intestine relatively quickly after this. Intestinal juices get added as well, digesting the last proteins and carbohydrates.

The small intestine is also the place where all the digestive products get absorbed. That is why the inside of the small intestine has a lot of surface (protrusions) and blood vessels inside it.  

Large intestine 

Everything that is left over through the small intestine needs to be excreted. That happens with the help of the large intestine.

A lot of digestive juices, thus water, is in the digestive tract right now. So the large intestine re-absorbs a lot of that water. It also adds some other waste it needs to get rid of. After that, it is stored in the rectum. When the rectum is full, you poop it out. 

Homework next lesson:

The homework for next lesson are the exercises of paragraph 2.3, including the plus exercise. You don't need to make the summary. You can work on them now :)