Afaq Sun Series (new) Science 5 - Unit-2 Our Central Nervous System Solved Exercise

Afaq Sun Series (new) Science 5 - Unit-2 Our Central Nervous System Solved Exercise

Unit-2 Our Central Nervous System

(Solved Excercise)
Point to Remember!
  • The human brain is protected by a bone called the skull.
  • Brain cells that make up the brain are called neurons.
  • The human brain is divided into three main parts: Cerebrum, Cerebellum, and medulla on the basis of their specific Jobs.
  • The largest party of the brain is the cerebrum, it is the thinking part of the brain and controls our voluntary actions. The cerebrum controls body balance, movement, and coordination of muscles, while the medulla controls all involuntary actions.
  • The nervous system consists of the brain, the spinal cord, and nerves. It helps us to communicate by sending and receiving messages.
Solved Exercise

A: Answer the following questions.

1. What is the skull and why is it important?

Ans: Our brain is located inside the head, which is protected by a bone called the skull. The skull is very hard, it shapes the face and protects our brain.

2. Describe a neuron and its functions.

Ans: The brain cells that make up the brain are called neurons. Our brain sends and receives signals through the neurons.

3. What evidence supports that the right side of the brain controls the left side of the body and vice versa?

Ans: Brain injuries to the right side of the brain cause paralysis on the left side of the body and vice versa.

4. Draw a neat and labeled diagram of the human brain in your notebook with a brief note about each part.
 

5. Have you ever seen somebody faint (بے ہوش) ? What do you think what causes somebody to fall unconscious (بے ہوش)?
Ans: The lack of blood flow to the brain is the main cause of the unconscious. It may be caused by Anxiety, Low Blood Pressure, Dehydration, etc.

6. Differentiate between:
  1. Voluntary and involuntary actions.Voluntary Actions: The actions which need thinking and performed by knowingly are called voluntary actions. Examples Writing, Riding Bicycle, etc.

    Involuntary Actions: The actions which do not need thinking or knowing are called involuntary actions. Example Breathing, thinking, etc.
  2. Sensory and motor nerves carry messages from our sense organs to the spinal cord, which carries them to the brain.

    Motor Nerves carry messages from our brain to our muscles to tell them that to do.

B:  Choose and write the correct option.

  1. The _ _ _ _ _ _ _  controls all involuntary actions of the body. (cerebrum, medulla,)
  2. _ _ _ _ _ _ _ _ _ _ nerves carry messages from our sense organs to the spinal cord. (Sensory, Motor,  Autonomic)
  3. The _ _ _ _ _ _ _ _ _  is involved in higher-order thinking skills (Cerebrum, medulla, cerebellum)
  4. _ _ _ _ _ _ _ _ _ is not an example of voluntary action. (Digestion of food, Swimming, Hiking)