The Skeleton System
A. Choose the correct option.
1. The number of bones in an adult human skeleton is
a. 210. [ ]
b. 208. [ ]
c. 206. [✓]
d. 201. [ ]
2. The bones of the wrist and the ankle are
a. long. [ ]
b. short. [✓]
c. both of these. [ ]
d. none of these. [ ]
3. Heart and lungs are protected by the
a. rib-cage. [✓]
b. skull. [ ]
c. backbone. [ ]
d. girdle. [ ]
4. Jawbone is
a. A-shaped. [ ]
b. I-shaped. [ ]
c. U-shaped. [✓]
d. Y-shaped. [ ]
5. Voluntary muscles are present in
a. lungs. [ ]
b. heart. [ ]
c. legs. [✓]
d. stomach. [ ]
B. Choose the correct option to fill in the blanks:
1. All the bones present in our body forms our (digestive/skeletal) system.
2. The bones of the limbs are (short/long).
3. The (rib-cage/skull) protects the brain.
4. The delicate spinal cord is protected by (backbone/jawbone).
5. The upper jaw (or/and) lower jaw have teeth.
6. Bones are held together by (tendon/ligament).
C. Write T for True and F for False statements.
1. The bone marrow present inside the bones produces the WBCs. [F]
2. Hinge joint is found in the knees. [T]
3. The humerus bone is present is present in the lower limb. [F]
4. The backbone has 44 small bones. [F]
5. The cardiac muscles are found in the wall of the heart. [T]
6. A bent back puts burden on the backbone and joints. [T]
D. Name the following:
1. An example of food rich in vitamin D.
= Cheese.
2. The location where voluntary muscle is present.
= Hand.
3. The location where the gliding joint is present.
= Wrist.
4. The longest bone in the body.
= Femur.
5. The bone in the upper arm.
= Humerus.
6. An example of calcium-rich food.
= Milk.
E. Answer the following questions:
1. Name the minerals present in our bones?
= The minerals present in our bones are - calcium, phosphorus.
2. Define skeleton. Also mention its role.
=The rigid framework of bones of our body is called skeleton. It supports our body and gives shape to our body. It also protects the internal organs of our body.
3. What is the function of rib-cage?
= The rib-cage protects the delicate organs such as the heart and the lungs.
4. What is a vertebra? Where is it present?
= The individual small bones of the back bones are called vertebra.
It is present in our backbone.
5. What do you understand by cartilage? Also write its function.
= Cartilage is a strong, elastic, yellowish or white-coloured substance present around the joints of human body.
The cartilage protects the bones from getting damaged as a result of the movements at the joints.
6. Differentiate between voluntary and involuntary muscles.
=
7. Write any two points related to the care of bones and joints.
= Two points related to the care of bones and joints are -
i) We should eat food items rich in proteins and calcium.
ii) We should do physical activities and exercise regularly.
8. Why do young children need a more protein-rich diet?
= Young children need a greater protein-rich diet than adults to help in their growth and development.
9. Why is good posture important for us?
= Good posture is important for us to keep our backs straight while sitting or standing.
F. Long answer questions:
1. Write about the major bones present in our body are -
i) Skull:- The skull is a hollow, round structure present in the head. It is made up of 22 bones: Eight bones form the part of the skull and fourteen bones form the face. The skull covers and protects the brain. It also give shape to the face.
ii) Jawbone:- It is the U-shaped bone of the lower jaw. It is the largest and strongest bone in the skull. It is the only bone in the skull that can move. It helps us to move our mouth so that we can chew food.
iii) Backbone:- It is a long and flexible bony structure connected to the base of the skull at its top. It is made up of 33 small, ring-like bones. It protects the spinal cord.
iv) Rib-cage:- It is made up of 12 pair of bones called ribs. It is present in the chest region. It protects the delicate organs such as the heart and the lungs.
v) Girdles:- A girdle is a bony, ring-like structure present in the shoulder and hip. The shoulder girdle is made up of the shoulder blade and the collar bone. The hip girdle is made up of three bones fused to form a single bone.
2. Mention the different types of movable joint present in our body.
= The different types of movable joints present in our body are -
i) Ball and socket joint:- A ball shaped end and a cup shaped socket make ball and socket joint. It allows Movement in all directions. Example- shoulder and hip.
ii) Hinge Joint:- This joint allows only back and forth movements. It is found in knees elbows fingers and toes.
iii) Pivot joint:- It allows to move our head side ways. This type of joint are formed between the first and the second vertebra of the neck region of the backbone.
iv) Gliding joint:- It allows the bones to glide against each other. It is found in the bones of wrist and ankle.
3. What is the importance of joints and muscles?
= Importance of joints are -
i) The joints make our body flexible by allowing movement in different directions.
ii) Each of the types of joints allow movement in a certain manner.
The importance of muscles are -
i) Muscles provide support to the bones.
ii) They help the skeleton in moving the limbs and other parts of your body.
iii) Muscles inside the internal organs help them in carrying out important functions. Example cardiac muscles help the heart in pumping blood in different parts of the body.
4. Describe the food items that makes bones and muscles strong.
= i) Proteins help in building muscles. Milk, egg, cheese, fish, meat, beans and pulses are good sources of protein.
ii) Calcium helps in the formation of bones and teeth. Some calcium rich foods are - milk, curd, almond and cheese.
iii) Vitamin C and Vitamin D are important for our bones and muscles. Foods rich in vitamin C are - all citrus fruits, dark green leafy vegetables and tomatoes. Fatty fish, cheese and egg yolks are some sources of Vitamin D.
5. What is the importance of good posture and exercise?
= Good posture and exercise help our body to function properly. It is also important to keep our back straight. It also prevents joint and muscle pain.
6. What are the major functions of bones in the human body?
= The main functions of the bones that form the skeleton are listed as follows:
i) Shape and support:- It gives shape and support to the body.
ii) Protection:- It protects the delicate internal organs such as the brain, spinal cord, heart and the lungs.
iii) Movement: It allows the movement of the various parts of the body.
iv) Production and storage:- Bone marrow present inside the bones produces the red blood cells. The bones of the skeleton also store the mineral calcium.