Class V: Science [Ch- 4 Skeletal And Nervous System]

Define the terms:

1. Bone marrow- Soft and fatty substance in the bone.

2. Ribcage- Cage of bones around the chest.

3. Reflex action- Automatic response of our body.

4. Tendons- Strong fibers which attach muscles to the bones.

Answer in one line.

1. How many bones are there in an adult human being?

Ans. An adult human being has 206 bones.

2. What do you call a doctor who does bone surgery?

Ans. An orthopedic surgeon does bone surgery.

3. What will happen if we do not have joints?

Ans. If we do not have joints, we would find simple tasks like eating very difficult.

4. What is stirrup?

Ans. The smallest bone in our body present inside our ears is called stirrup.

5. Which are the busiest muscles in the body ?

Ans. Eye muscles are the busiest muscles in the body.

Answer in short:

1. What is the skeletal system? Write all the parts of the skeletal system.

Ans. The framework of bones is called the skeletal system. The skull, ribs, backbone and the limbs constitute the skeletal system.

Answer in detail: 

1. What are the different kinds of muscles and what are their functions?

Ans. There are three different types of muscles:

i) Voluntary muscles present in our arms, legs and neck as they are under our control.

ii) Involuntary muscles help in our breathing and flow of blood. They work on their own.

iii) Cardiac muscles- The muscles of the heart are called cardiac muscles. They pump blood to all the parts of our body.

2. Differentiate between: 

1.     Sensory Nerve Motor Nerve

1. These nerves bring messages These nerves carry commands

From the sense organs to the brain from the brain to the muscles 

Or the spinal cord. Of different organs.

2.     Movable Joints Immovable Joints

1. The joints that help in the The joints that cannot be  

Movement of our body are called moved are called immovable

Movable joints. Joints.

2. Eg- Joints present in our Eg- The joint of the skull,

Arms and legs. The joint between the ribcage

And the breast bone.

Give reason:

1. Radha was having a severe cold, she could not smell the different types of flowers . 

Ans. When we have a cold, the nerves in the nose get blocked and we are unable to smell. That is why Radha could not smell the different types of flowers  .

2. There is pain when the wrist twists or while slipping down if you support your body on the wrist.

Ans. When we slip down and support our body on the wrist our complete body weight shifts on our wrist. As it is made up of soft ligament, it stretches and we feel pain .

Experiment Based Question

Rima accidentally touched a hot pan.

1. What will be her reaction?

Ans. She will quickly remove her hand from the hot pan. 

2. What are these immediate reactions done by our body called as?

Ans. They are called reflex actions.

3. Which organ controls reflex actions?

Ans. Reflex actions are controlled by the spinal cord.

4. Which is the receptor organ in this experiment and why?

Ans. The skin is the receptor organ as it sends the signal to the spinal cord.

5. Which organ is the effector organ in this experiment and why?

Ans. The muscles of the hand are the effector organ as they act after receiving the orders from the spinal cord.

Story Based Question

One evening Sunil heard his mother saying that his grandfather died due to cardiac arrest. Since then he has had a few questions. Lets try  answering his questions. 

1. What is cardiac arrest?

Ans. In cardiac arrest, the heart abruptly stops beating, resulting in the person's death.

2. What are cardiac muscles?

Ans. The muscles of the heart are called cardiac muscles.

3. Which doctor treats heart diseases?

Ans. A cardiologist treats heart diseases.

4. Tick the current answer:

What type of muscles are cardiac muscles?

1. Voluntary muscles

2. Involuntary muscles

Draw a neat, labeled diagram of the structure of an Eye.

 CHAPTER COMPLETED