Date: 1 st April 2020 WALT: understand how nutrients are transported around the body - PowerPoint Presentation

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Date: 1st April 2020WALT: understand how nutrients are transported around the body

WILF:I can explain that nutrients come from the food we eat.I understand that the digestive system is responsible to break food down into very small size so nutrients can be extracted.I can identify where the small intestine is.I understand that the exchange of nutrients into the blood stream (through capillaries) happens in the small intestine.I understand that nutrients are absorbed in the blood and transported around the body.

Key vocabulary: digestive system, mouth, oesophagus, stomach, small intestine, large intestine, capillaries, nutrients, absorb, osmosis.

Starter

Let’s recap on the different nutrients that we need

How do these nutrients get transported in our blood to our body cells?

The Digestive System

Can you remember

where the

main parts of the digestive

system are located in the body?

Can you

describe what happens to food in the

digestive

system?

oesophagus

large intestine

small intestine

stomach

In year 4, you learned about the digestive system and what happened to the food when we ate. In today’s lesson, we will first recap on the digestive system and then understand how food/nutrients get absorbed in our blood to be circulated around the body.

As food enters your mouth, your teeth begin mechanically breaking down the food into small and smaller pieces. The saliva starts to chemically break it down as well.

A small flap of skin called your epiglottis makes sure your food goes down your oesophagus. Movements of the smooth

muscles help move that food down your oesophagus. When it reaches your stomach, a circular muscle opens and dumps the food in.

Inside the stomach, cells start to secrete different acids

which

kills most bacteria and starts to chemically break apart the food.  Movements of the smooth muscles in the stomach,

mix

and churn the food up more.  After the food has been well mixed and has a consistency of oatmeal, it is ready to move to the small intestine. 

Food

enters the first part of the small intestine.  The liver mixes in bile, which helps break down fats in the food. The pancreas also secretes digestive enzymes that aid in the digestion process.Most of the nutrients are absorbed from the small intestine and moved into the blood stream via a system of small folds, called

vili.

After the food moves through the small intestine, it enters the large intestine. The role of the large intestine is to remove any extra water from the digested material before it is finally excreted through the anus.Oesophagus

The Process of Absorption

Nutrients are absorbed into the blood in the small intestine.

There are tiny hair-like villi that help this process happen.

The nutrients are carried in the blood to the different parts

of the body that need them.

muscle layers

villi

vein

villus

artery

Villi are folds inside the small intestine. Within the villi, there are capillaries that give out oxygen to the villi

cells and take in carbon dioxide. These capillaries also have a different role. They

also absorb nutrients through a process called

osmosis.

This is an magnified view inside the small intestine.

The Process of Osmosis

ExperimentWe are now going to explain the process of osmosis through an experiment that you can all do at home. The next slide will tell you what you need.In this experiment, the water in the glass will represent blood inside the capillaries.The paper towel represents the wall of the capillaries. The food colouring that you will be using represent the nutrients in the small intestine.

EquipmentFor this experiment, you’ll need a jar (or glass), paper towels, rubber bands (or string) and food

colouring.  MethodFill a jar with water and secure a paper towel in the jar’s mouth (with a rubber band) so that it hangs down into the water, making a water-filled chamber .(Once you place the paper towel over the jar mouth, push the kitchen towel through so some water gets filled inside. Secure in place with rubber bands – See diagram below)Add food colouring (any colour will do, powder or liquid) to the water collected in the paper towel.  Put a few drops of food colouring into the chamber and see what happens.

Task 1

What is happening?

How does that link to how nutrients get absorbed in the blood?

Look at the next slides to find out.

Observation

Osmosis

Osmosis is the process when small particles pass through a semi-permeable (like a sieve – allows only certain particles) material from a place where the particle is in abundance to a place where the particle is in low amount.

Nutrients inside the villi (small intestine) move into the blood through osmosis because the nutrient is in more abundance in the villi than the blood stream.

More nutrients here

https://junior.edumedia-sciences.com/en/media/53-organs-blood-exchanges

Everywhere apart from the small intestine, nutrients move from capillaries to the body cells through osmosis as the blood will have higher amount of nutrients than in the cells.Click on this link and observe how nutrients flow around the body. The animation will only play for a short while. You can restart whenever you want.

The Circulatory System (also known as part of the Cardiovascular System)The circulatory system, which is part of the "cardiovascular" system, is one of the eleven organ systems of the human body. Its main function is to transport nutrients to cells and wastes from cells (Figure 3.4.1). This system consists of the heart, blood, and blood vessels. The heart pumps the blood, and the blood is the transportation fluid. The transportation route to all tissues is a highly intricate blood-vessel network, comprised of arteries, veins, and capillaries.

Nutrients absorbed in the small intestine travel mainly to the liver through the hepatic portal vein. From the liver, nutrients travel upward through the inferior vena cava blood vessel to the heart. The heart forcefully pumps the nutrient-rich blood first to the lungs to pick up some oxygen and then to all other cells in the body. Arteries become smaller and smaller on their way to cells so that by the time blood reaches a cell, the artery’s diameter is extremely small and the vessel is now called a capillary. The reduced diameter of the blood vessel substantially slows the speed of blood flow. This dramatic reduction in blood flow gives cells time to harvest the nutrients in blood and exchange metabolic wastes.Challenge 3 extra reading

Task

2Summarise what you have understood about how nutrients are transported around our body.Challenge 1: Complete the writing frame (next slide)Challenge 2: Begin your writing at the small intestine and use keywords: digestive system, small intestine, nutrients, capillaries, absorb, transport, cells, blood, heart.

Challenge 3: Begin your writing at the mouth and use keywords: digestive system, mouth, oesophagus, stomach, small intestine, villi, nutrients

, capillaries, absorb,

osmosis, transport

,

cells, heart, circulatory system.

Capillaries

Nutrients come from the _______ we eat. The different nutrients are: Carbohydrates, __________, minerals, fats, fibre, vitamins and water.

Nutrients are absorbed in the system in the stomach and small __________. They enter the blood stream via the __________ where they are passed through to the arteries.

The blood is circulated throughout the body by the __________, carrying nutrients around the ________ .

___________ are

absorbed by the cells that need them and water is absorbed by all cells.

intestine

food

capillaries

heart

bodyNutrientsChallenge 1: Fill in th

e gaps with the correct words.

protein