Selina ICSE Class 9 Biology Solutions Chapter 12 Movement And Locomotion

Multiple Choice Questions:-

1) Your external ear (pinna) is supported by
a) Bone
b) Cartilage
c) Tendon
d) Capsule
Solution: (b) Cartilage

2) The type of joint found at shoulder is also found at
a) Elbow
b) Knee
c) Ankle
d) Hip
Solution: (d) Hip

3) Which one of the following categories of vertebrae are correctly matched?
a) Cervical-7
b) Thoracic-10
c) Lumbar-4
d) Sacral-4
Solution: (a) Cervical-7

4) Human skeleton altogether contains 213 bones. Which of these are the 6 bones?
a) Neck vertebrae
b) Ear ossicles
c) Carpals
d) Metacarpals
Solution: (b) Ear ossicles

Very Short Answer Type:-

Question 1) Name the parts of the skeleton where the following are located: transverse process, glenoid cavity, shoulder-blade, acetabulum.
Solution:

Question 2) Name any two parts of your body where the supporting skeleton is made of cartilage instead of bone.
Solution:
1. External Ear
2. Tip of the nose

Short Answer Type:-

Question 1) What is the difference between a true rib and a floating rib?
Solution:

Question 2) Do the muscles pull the structures, or push them? Explain briefly.
Solution: Structure is pulled by muscles. A muscle has two ends: the fixed end from which it originates and the mobile end, which pushes on another portion of the body. The flexible end is dragged out to create a strong, bony-attached structure known as a tendon. A muscle contracts and gets shorter and thicker when it is triggered by a nerve, pulling the bone at its moveable end. Muscles are unable to extend; they can only contract and relax.

Question 3) Just as the humerus corresponds to femur, what bones correspond to tarsals, metacarpals, ulna and radius respectively?
Solution:

Question 4) What are antagonistic muscles? Give one example.
Solution:
After a muscle has shifted a structure, it cannot be forced to return to its original place. Antagonizing muscles are those that produce opposite motions.
An example of an antagonistic muscle is the biceps, which is located above the upper arm and appears and feels bulging when your arm is flexed at the elbow. Due to contraction, this muscle enlarges, shortens in length, stiffens, and thickens. The forearm is drawn toward the upper arm via biceps contraction. Biceps relaxation, however, will not allow the forearm to return to its initial posture. The triceps muscle, located near the rear of the upper arm, contracts as the arm is stretched or straightened. The two muscles contract in opposition to one another or in opposite ways to bend, flex, and straighten the elbow.

Question 5) Some people in old age complain of stiff joints. What do you think could be a possible reason for it?
Solution:
In order to be properly lubricated, some joints, such as the knee and shoulder joints, must be kept securely in place. These joints contain synovial fluid, a lubricant that acts as a cushion between the bones and reduces friction when moving. Because the amount of lubricating fluid inside the joints diminishes and the cartilage gets thinner as we age, joint movement becomes stiffer and less flexible. The joints feel tight because of the tendency of ligaments to shorten and lose part of their flexibility.

Long Answer Type:-

Question 1) What are the uses of the skeleton in our body?
Solution:
Uses of the skeleton include:
(i) Support and shape: The skeletal system gives the body a framework. It gives the body and all of its parts a clear outline while supporting all of the body’s soft portions.
(ii) Protection: The skeleton guards the body’s vital and fragile internal organs. For instance, the vertebral column protects the spinal cord in humans, much as the skull protects the brain, ribs protect the heart and lungs, and so on.
(iii) Movement: Movement is aided by the skeletal system. To enable locomotion, it coordinates the movements of the connecting bones and muscles.
(iv) Leverage: Certain skeletal system bones and joints act as levers to enhance either movement or force. For instance, a mild biceps contraction may move the hand approximately a foot.
(v) Blood cell production: Haematopoiesis takes place in the skeleton. In the bone marrow of some long bones, several blood cell types, including red blood cells, white blood cells, and platelets, are created.
(vi) Mineral repository: The bones serve as the body’s repository for calcium and phosphorus.

Question 2) What are the different types of joints? Give one example of each type.
Solution:

Question 3) What is the difference between ligament and tendon? What are their functions?
Solution:

Question 4) What are bones made of? Are the bones living or non living? Give reasons
Solution:
(i) A strong, hollow, and rigid connective tissue is bone.
(ii) It is a dense, greyish-white tissue made up of two thirds inorganic elements such as calcium, phosphorus, carbonates, etc. and one third organic compounds.
(iii) The periosteum is the term for the bone’s outside. The periosteum is a thin, dense membrane that surrounds the bone and is made up of an inner and outer cellular layer, nerves, and blood vessels.
(iv) Bone that is compact makes up the following layer. This area’s connective tissue is heavily calcified, very tough, and stiff. Bones seem smooth, white, and solid because to this tissue.
(v) Osteocytes, a kind of bone cell, are organized in concentric rings in the central layer of bone. They are encased in a solid matrix consisting of mineral deposits and collagen fibers.
(vi) Bone marrow, which creates blood cells, is located in the deepest hollow chamber of long bones. The bulk of red blood cells, platelets, and the majority of white blood cells are produced by red bone marrow, which is located at the ends of the bones. Yellow bone marrow aids in the generation of certain white blood cells and has a larger concentration of fat cells than red bone marrow does.
(vii) As long as bones are part of a living organism, they are living tissue. However, when bones are removed from the body, their cells perish, and the bones are afterwards referred to as being dead.

Question 5) Given below is a diagram of human skeleton. Name the bones numbered 1-11.

Solution: