Skeleton - Movement and Locomotion

Progress Check 1

Question 1

Fill in the blanks

1. Our skeleton consists of bones, ............... and ...............
2. ............... is the chief component of our skeleton.
3. Shapewise the bones can be classified as ............... , ............... , ............... and ............... .
4. The central hollow part of the long bones is known as ............... .
5. A bone becomes soft and flexible when placed in dilute ............... .

Answer

1. Our skeleton consists of bones, cartilages and ligaments
2. Bone is the chief component of our skeleton.
3. Shapewise the bones can be classified as long, short, flat and irregular .
4. The central hollow part of the long bones is known as bone marrow .
5. A bone becomes soft and flexible when placed in dilute hydrochloric acid .

Progress Check 2

Question 1

Mention if the following statements are true (T) or false (F)

1. Humerus of the upper arm is the longest bone.
2. Axial skeleton includes shoulder and hip girdles.
3. There are 10 vertebrae in the neck.
4. There are three kinds of ribs - true, false and floating.
5. The shoulder girdle is large and trough-shaped.

Answer

1. False
   Corrected statement — Femur in the thigh is the longest and strongest bone in the body.
2. False
   Corrected statement — Axial skeleton includes skull, vertebral column, ribs and sternum.
3. False
   Corrected statement — There are 7 vertebrae in the neck.
4. True
5. False
   Corrected statement — The shoulder girdle is flat and triangular.

Progress Check 3

Question 1

Mention if the following statements are true (T) or false (F).

1. The flexor and extensor muscles of the arm are antagonistic muscles.
2. Muscles can contract as well as elongate.
3. Muscles are attached to bones by ligaments.
4. Cardiac muscle is a voluntary muscle.
5. Bending of arm on elbow is an example of first order of lever mechanism.

Answer

1. True
2. False
   Corrected statement — The muscles can contract but cannot elongate.
3. False
   Corrected statement — Muscles are attached to bones by tendons.
4. False
   Corrected statement — Cardiac muscle is an involuntary muscle.
5. True

Question 2

Match the bones (Column I) with the kind of joint (Column II)

Answer

Multiple Choice Type

Question 1

Your external ear (pinna) is supported by

1. Bone
2. Cartilage
3. Tendon
4. Capsule

Answer

Cartilage

Reason — External ear is made up of cartilage due to which it is flexible.

Question 2

The type of joint found at shoulder is also found at

1. Elbow
2. Knee
3. Ankle
4. Hip

Answer

Hip

Reason — Shoulder has ball and socket joint which is also found in Hip.

Question 3

Which one of the following categories of vertebrae are correctly numbered

1. Cervical — 7
2. Thoracic — 10
3. Lumbar — 4
4. Sacral — 4

Answer

Cervical — 7

Reason — There are seven cervical vertebrae, twelve thoracic, five lumbar and five sacral.

Question 4

Human skeleton altogether contains 213 bones. Which of the following are exactly 6 in number?

1. Neck vertebrae
2. Ear ossicles
3. Carpals
4. Metacarpals

Answer

Ear ossicles

Reason — Ear ossicles have 3 bones each (malleus, incus and stapes); making a total of 6 bones.

Question 5

Which of the following binds the bones together?

1. Tendons
2. Cartilage
3. Ligaments
4. Muscles

Answer

Ligaments

Reason — Ligaments hold bones together.

Question 6

The inorganic constituents of bones are :

1. Calcium and sodium
2. Calcium and phosphorus
3. Carbon and nitrogen
4. Calcium and carbon

Answer

Calcium and phosphorus

Reason — Calcium and phosphorus are major components of bone.

Question 7

Bone cells are technically termed as :

1. Myocytes
2. Chondrocytes
3. Leucocytes
4. Osteocytes

Answer

Osteocytes

Reason — Osteocytes is the technical term used for bone cells.

Question 8

The external surface of bone is covered by a membrane called :

1. Peritonium
2. Pericardium
3. Periosteum
4. None of these

Answer

Periosteum

Reason — Periosteum is a complex structure composed of an outer fibrous layer that lends structural integrity and an inner cambium layer that possesses osteogenic potential.

Question 9

Branched muscles are :

1. Striped
2. Cardiac
3. Unstriped
4. Both (i) and (ii)

Answer

Both (i) and (ii)

Reason — Striped muscles and cardiac muscles are branched.

Question 10

Involuntary muscles are present in :

1. Leg
2. Hand
3. Iris
4. Head

Answer

Iris

Reason — Iris is made up of involuntary muscles.

Very Short Answer Type

Question 1

Name the parts of the skeleton where the following are located: Transverse process, glenoid cavity, shoulder-blade, acetabulum.

Answer

Question 2

Name any two parts of your body where the supporting skeleton is made of cartilage instead of bone.

Answer

Two parts of your body where the supporting skeleton is made of cartilage instead of bone are:

1. External Ear
2. Tip of the nose

Question 3

Name:

(a) Three main constituents of the human skeleton.

(b) Two main divisions of the human skeleton.

(c) Four parts of Axial skeleton.

(d) Five regions of vertebral column.

(e) Four kinds of freely movable joints.

Answer

(a) Bones, Cartilages and Ligaments

(b) Axial skeleton and Appendicular skeleton

(c) Skull, Vertebral Column, Sternum, Ribs

(d) Cervical, Thoracic, Lumbar, Sacrum, Coccyx

(e) Gliding joint, Pivot joint, Hinge joint, Ball and Socket joint.

Question 4

Name the following :

(a) A joint which allows movements in all directions.

(b) The first vertebra of the vertebral column.

(c) A large hole at the back of cranium through which the spinal cord emerges out.

(d) The muscles which cause opposing movements.

(e) The fluid found between the two bones of freely movable joints.

Answer

(a) Ball and socket joint

(b) Atlas

(c) Foramen Magnum

(d) Antagonistic Muscles

(e) Synovial fluid

Question 5

The first pair indicates the kind of relationship that exists between the first two terms. Rewrite and complete the second pair on a similar basis :

(a) Humerus : Glenoid cavity :: Femur : ...............

(b) Thoracic vertebrae : 12 : ............... : 7

(c) Wrist : Carpals :: Ankle : ...............

(d) Biceps : Flexor :: Triceps : ...............

(e) Brain : Cranium :: Spinal cord : ...............

Answer

(a) Humerus : Glenoid cavity :: Femur : Articular Cavity

(b) Thoracic vertebrae : 12 : Cervical : 7

(c) Wrist : Carpals :: Ankle : Tarsal

(d) Biceps : Flexor :: Triceps : Extensor

(e) Brain : Cranium :: Spinal cord : Vertebral column

Question 6

Write the technical terms for each of the following :

(a) Knee cap

(b) Shoulder blade

(c) Collar bone

(d) Breast bone

(e) Bones in the palm

Answer

(a) Knee cap — Patella

(b) Shoulder blade — Scapula

(c) Collar bone — Clavicle

(d) Breast bone — Sternum

(e) Bones in the palm — Metacarpals

Short Answer Type

Question 1

Define:

(a) Skeleton system

(b) Bone marrow

(c) Gristle

(d) Pivot joint

(e) Antagonistic muscles

Answer

(a) Skeleton System refers to the internal framework of bones and other connective tissues including cartilage, ligaments, and tendons that provide support, shape, protection, movement and leverage to the human body.

(b) Bone marrow is a soft, spongy tissue found inside the central hollow space or the marrow of some of the long bones where certain types of blood cells including red and white blood cells are formed.

(c) A pad of cartilage intervertebral disc that forms a kind of cushion between two vertebrae is called Gristle.

(d) Joint that allow rotation about an axis is called Pivot joint.

(e) The muscles that cause opposing movements are called antagonistic muscles.

Question 2

Do the muscles pull the structures, or push them? Explain briefly.

Answer

The muscles in the body provide the means of all movements. Muscles pull the structures. Each muscle usually has two ends- a fixed end where the muscle originates and a movable end which pulls some other part. The movable end is shorter and thicker and hence pulls the bone at the movable end. Muscles can only contract and relax, they cannot lengthen or elongate.
The movable end is projected out to form a tough structure referred to as a tendon which is attached to the bone. When a muscle is triggered by a nerve, contraction of the muscle occurs and it becomes thicker and shorter which causes the bone to be pulled at the movable end.

Question 3

Just as the humerus corresponds to femur, what bones correspond to tarsals, metacarpals, ulna and radius respectively?

Answer

Question 4

What are antagonistic muscles? Give one example.

Answer

A structure that has been moved by a muscle cannot return to its original position without the action of another muscle. Such muscles causing opposing movements are called as antagonistic muscles.

Example of antagonistic muscles—
The flexor muscles or the biceps of the upper arm bends the lower arm over the upper arm (flexes). Extension of the lower arm is caused by the extensor muscles or the triceps. Hence these two muscles are antagonistic or work in the opposite direction.

Question 5

Give reason:

(a) Decalcified bones become soft and flexible.

(b) People in old age complain of stiff joints.

(c) In the female skeleton, the pelvis or hip bone is wider and trough-shaped.

(d) Bones are considered to be a living tissue.

(e) Vertebral column is curved.

Answer

(a) Two-third of entire bone mass is made of calcium and phosphorous. It gives strength and hardness to bones. Therefore, when these inorganic substance are lost or the bone is decalcified, they become soft and flexible.

(b) The freely movable joints are well lubricated by synovial fluid to remove friction between the joint surfaces. With age, the production and quality of synovial fluid decreases, leading to less effective lubrication. This coupled with degeneration of cartilage and ligaments causes stiff joints in old age.

(c) In the female skeleton, the pelvis or hip bone is wider and trough-shaped to adapt for accommodating the foetus in the uterus during pregnancy.

(d) Bones are made up of living cells (osteocytes) that are responsible for their growth, maintenance, and repair. They receive blood supply through a network of blood vessels and they produce red and white blood cells within the bone marrow. Therefore, the bones are considered to be a living tissue.

(e) Vertebral column is curved in order to provide correct posture and balance to our body. It's curvature enables us to minimize all the stress on bones and muscles that arises due to activities.

Question 6

Write one specific location of the following in the human body.

(a) Femur

(b) Malleus, Incus, Stapes

(c) Coccyx

(d) An immovable joint

(e) Sternum

Answer

(a) Thigh

(b) Ear

(c) lower part of back bone

(d) Brain box

(e) In the middle of the front part of the chest.

Long Answer Type

Question 1

Distinguish between the following pairs :

(a) True ribs and floating ribs

(b) Ligaments and tendons

(c) Hinge joint and gliding joint

(d) Voluntary and involuntary muscles

(e) Bone and cartilage

Answer

(a) Difference between true ribs and floating ribs:

(b) Difference between ligaments and tendons:

(c) Difference between hinge joint and gliding joint:

(d) Difference between voluntary and involuntary muscles :

(e) Difference between Bone and cartilage :

Question 2

What are the uses of the skeleton in our body?

Answer

Uses of skeleton:

1. Support and shape — The skeletal system provides a framework to the body. It provides support to all soft parts and gives a definite shape to the body and all body parts.
2. Protection — Several delicate and important organs are well protected by a casing of bones.
   Example — The skull provides protection to the delicate brain.
3. Movement — Some bones are movable on each other which is brought about by the action of muscles that originate on one bone and are inserted into another.
4. Leverage — Some bones and joints form levers which causes the increase in the speed and distance of the muscle movement.
5. Formation of blood cells — Certain types of blood cells including red and white blood cells are formed in the marrow of certain long bones such as the femur.
6. The bones are storehouse of calcium and phosphorus for the rest of the body.

Question 2

Name the different types of joints? Give one example of each type.

Answer

Types of joints with examples are:

1. Immovable joints — Skull bones
2. Partially movable joints — Joints between the ribs and breast-bone
3. Freely movable joints — Hip joint
4. Gliding joint — Ankle bones
5. Pivot joint — Joint between axis vertebrae and atlas
6. Hinge joint — Elbow
7. Ball and socket joint — Shoulder joint

Structured/Application/Skill type

Question 1

The figure given below shows a kind of vertebra. Study the figure and answer the following questions:

(a) Name the vertebra.

(b) Where is this vertebra located?

(c) Label the guideline 1, 2 and 3.

Answer

(a) Thoracic vertebra.

(b) Thoracic region of vertebral column.

(c) The labelled guidelines are:

• 1 → Neural spine
• 2 → Neural canal
• 3 → Body of centrum

Question 2

Draw a neat diagram of the "internal structure of a long bone" and label the following parts :

(a) Hyaline cartilage

(b) Fatty yellow bone marrow

(c) Ligament

(d) Spongy red bone marrow

(e) Compact dense bone

Answer

Question 3

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

Answer

• 1 → Skull/Cranium
• 2 → Clavicle
• 3 → Sternum
• 4 → Humerus
• 5 → Ulna
• 6 → Coccyx
• 7 → Ribs
• 8 → Radius
• 9 → Femur
• 10 → Fibula
• 11 → Tibia