الأسبوع 4 · المحور 1، الباب 2 «الحفاظ على صحة الجسم» (ب): الجلد والعظام والعضلات والهضم · 3 دروس
2
Bones, muscles and moving
Discover P3 Term 1: Axis 1, Chapter 2
GoalExplain how bones and muscles help us move and protect soft organs, and use a paper-and-straw finger model.
New words
skeleton · all the bones in the body togethermuscle · a part of the body that pulls to make bones movejoint · a place where two bones meet and can bendprotect · to keep safe from harm
Explanation
Your bones make up your skeleton. It holds your body up like the frame of a house. Bones cannot move by themselves. Muscles are fixed to the bones, and when a muscle gets shorter, it pulls the bone. Bones bend at joints such as the elbow, knee and finger. Muscles and bones also protect soft organs. The skull works like a helmet for the brain. The ribs form a cage around the heart and lungs. Hold your arms out sideways for a minute: you can feel your shoulder muscles working! Even when you sleep, muscles move your ribs so that you can breathe.
Worked examples
When Marwan lifts a bag, the muscles in his arm get shorter and pull the arm bones. The elbow is the joint that bends.
A fall on the playground: Farida’s skull protects her brain like a helmet, and her ribs protect her heart and lungs like a cage.
The straw finger. A grown-up cuts a paper finger and 4 pieces of straw. The paper is like bones. The straws are glued on, and a 30 cm yarn goes through them like a muscle. Pull the yarn at the bottom, and the finger bends at the 3 joints.
Class activity
Make a straw finger, with a grown-up who does the cutting. Trace your finger on card and cut it out (grown-up). Fold it in three places. Glue 4 short pieces of straw along it. Thread a 30 cm yarn through all the straws and tape the end at the tip. Hold the base flat and pull the yarn. Which part is like a bone? Which part is like a muscle?
Practice
1
Which part of the body works like a helmet for the brain?
The skull.
2
What do muscles do to bones?
They pull the bones to make them move.
3
In the straw finger, what is like the muscle?
The yarn that we pull.
4
The finger model has 4 pieces of straw and 3 folds. How many pieces and folds are there altogether?
