الأسبوع 5 · المحور الأول، الوحدة الأولى، المفهوم 1.2 «كيف تعمل الحواس؟» (ب): زمن الاستجابة والجهاز العصبي · 3 دروس
3
The nervous system team
Discovery Education Science P4: Term 1, Unit 1, pp. 47–57
GoalDescribe the nervous system as a team and write a claim, evidence and reasoning answer about the dolphin.
New words
nervous system · the brain, spinal cord and nerves working togetherspinal cord · a thick bundle of nerves inside the backbonereflex · a very fast reaction that happens without thinking
Explanation
The nervous system is a team of three parts. The brain is the control centre. It makes sense of messages and decides what to do. The spinal cord is a thick bundle of nerves that runs down inside your backbone, like a main road between the brain and the body. The nerves are the smaller roads that branch out to the skin, the muscles and the sense organs. Messages travel both ways: from the senses to the brain, and from the brain to the muscles. Some reactions are even faster. A reflex is a very quick reaction without thinking, such as blinking when something comes close to your eye. The spinal cord can send the order to the muscles straight away.
sense organ→nerve→spinal cord→brain→spinal cord→nerve→muscle
Worked examples
Fill the gaps. Word bank: brain, nerves, spinal cord. “The ___ is the control centre. The ___ run to every part of the body. The ___ is inside the backbone.” Answer: brain, nerves, spinal cord.
A fly flies near Habiba’s eye and she blinks before she even thinks. That is a reflex: a very quick reaction that keeps the eye safe.
Part
Dolphin answer
Claim
Sound is a super sense.
Evidence
It finds fish in murky water by echoes.
Reasoning
Sound travels well where sight is poor.
Claim, evidence, reasoning about the dolphin. Claim: sound is a super sense for dolphins. Evidence: dolphins find fish in murky water by clicks and echoes. Reasoning: in cloudy water eyes see little, but sound travels well, so listening to echoes lets the dolphin hunt.
Class activity
Body map. Lie a big piece of paper on the floor. A friend draws your outline. Draw the brain in the head, the spinal cord as a thick line down the middle and nerves as thin lines to the hands, feet and eyes. Colour the three parts differently. Show a family member and explain the team.
Practice
1
Which part is the control centre of the nervous system?
The brain.
2
Where is the spinal cord?
Inside the backbone.
3
Is this a reflex: pulling your hand back at once when you touch something very hot by accident? Explain.
Yes. It is a very quick reaction before you can think, and the spinal cord helps send the order.
4
Is this evidence or reasoning? “A dolphin found a fish in cloudy water by using clicks.”
