GRADE SIX

Hello Boys and Girls, How was school this past week? Did you learn lots of exciting things? Did you participate in exciting activities in Science? Have you completed your endof-term examinations?

Last week, we looked at food and then we started to look at the Digestive System. Do you remember what the alimentary canal looks like? Do you remember the various parts and their names? Look again at the diagram and remind yourself.

Where does the alimentary canal start? Where does it end? Why is it important to chew your food? Does digestion take place in the Mouth? Gullet? Yes Yes No No

Let us continue from where we left off last week. From the mouth the food passes down the gullet (or oesophagus). Remember that no digestion takes place here. Muscles in the walls of the gullet help to push the food down. Have you found out where it goes to? That’s right, it enters the stomach. Locate where your stomach is. Touch it. What does your stomach look like when you have just had a hearty meal (especially those who love to eat)? The stomach is like a bag. It is filled out when there is a lot of food inside and ‘flat’ when it is empty.

The food remains for some time in the stomach. (Do you how many hours it stays there? If you don’t, find out.) The walls of the stomach are very muscular, and so help to mix the food. Inside the stomach, juices from the walls help to digest the food even further. When the digestion there is complete, the food is very soft and like a thick liquid. It then goes into the small intestine where the food may be even further digested (broken down). The walls of the small intestine then allows this digested food to be absorbed into the bloodstream. Through this blood it reaches all the organs and other parts of the body.

That was quite an exhausting trip, wasn’t it? The food that we eat certainly does quite a bit of travelling!

Let’s rest for a short while and do a wordsearch, then answer a few questions afterwards.

Try to find the words: stomach, digestion, gullet, mouth, oesophagus, digest, food, muscular, juices, alimentary, canal, intestine, anus, large

What was your score? Questions: 1. The alimentary canal begins at the _____________ and ends at the _______________.

2. No digestion takes place in the __________. (stomach, gullet, mouth)

3. What is digestion? Explain in your own words. 4. Why is digestion important?

Let us now examine the Excretory System. It is yet another important system of the body.

‘Excretory’ comes from the word excretion. What is excretion? (If you do not know, find out.) Excretion is the process which helps to get rid of unwanted material produced by the body. The body has a special system for getting rid of waste products. Of course you know; it is the Excretory System. The Excretory System is so very important to our body. Can you imagine what would happen if the body does not get rid of its waste materials? That’s right you would become ill. The body would shut down and you could eventually die.

Do you know which organs are the main organs of excretion? The main organs of excretion are the kidneys.

Look at the labelled diagram below of a kidney. below try harder

The kidney is shaped like a bean. (Did you liken it to any other object?) It is reddish in colour and is found toward the back of the abdominal cavity, a bit above the waist. If you put your hands on your waist, your kidneys are situated just where your thumbs rest. You will notice that we mentioned kidneys (plural). We have two kidneys, left and right. You will see them in the diagram of the Excretory System. Diagram showing parts of the Excretory System

The kidneys form a part of the urinary system. Each kidney is composed of thousands of tiny tubes called nephrons. It is in these tiny tubes that urine is produced.