Question 1

Question 1Distinguish 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

Accepted Answer

(a) Difference between true ribs and floating ribs:True ribsFloating ribsThe first seven pairs of ribs are called true ribs.The last two pairs of ribs (11th & 12th) are called floating ribs.They are attached in front of the sternum by means of coastal cartilages.They are not attached to the sternum at all.(b) Difference between ligaments and tendons:LigamentsTendonsLigaments connects two or more bones together.Tendons connect muscle to a bone.Ligaments are elastic.Tendons are inelastic.Ligaments are arranged freely.Tendons are arranged in bundles.Ligaments stabilize joints.Tendons pass tensile forces to the bones from muscles.Prevent chances of dislocationResponsible to cause the muscles to stay intact with parts of the skeleton.(c) Difference between hinge joint and gliding joint:Hinge jointGliding jointHinge joint allows restricted movement in one plane only.Gliding joint allows bones to glide over each other to a limited extent.Example: Elbow, KneeExample: Wrist bone, ankle bone(d) Difference between voluntary and involuntary muscles :Voluntary musclesInvoluntary musclesVoluntary muscles are under our control.Involuntary muscles are not under our control.Voluntary muscles help in the movement of the bones of limbs.Involuntary muscles are present in internal organs and help in movement of food, movement of urine from urinary bladder and so on.The cells are long, cylindrical and unbranched.The cells are spindle shaped.They are multinucleate.They are uninucleate.They are striated.The are unstriated.(e) Difference between Bone and cartilage :BoneCartilageBones consists of the ground substance or matrix that is filled with cells called osteocytes and various inorganic compounds.Cartilage consists of ground substance called matrix that contains cells called chondrocytes.Bones comprise the hard framework of the body.Cartilages are supporting and connecting structures.Bones provide support, protection, and anchorage for muscles.Cartilage acts as a cushion between bones, reducing friction and absorbing shock in joints.Bones have a higher capacity for healing and regeneration.Cartilage has a limited capacity for self-healing.

Question 2

Question 2What are the uses of the skeleton in our body?

Accepted Answer

Uses of skeleton: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.Protection — Several delicate and important organs are well protected by a casing of bones.Example — The skull provides protection to the delicate brain.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.Leverage — Some bones and joints form levers which causes the increase in the speed and distance of the muscle movement.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.The bones are storehouse of calcium and phosphorus for the rest of the body.

Question 3

Question 1(viii)The external surface of bone is covered by a membrane called :PeritoniumPericardiumPeriosteumNone of these

Accepted Answer

PeriosteumReason — 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 4

Question 1(ix)Branched muscles are :StripedCardiacUnstripedBoth (i) and (ii)

Accepted Answer

Both (i) and (ii)Reason — Striped muscles and cardiac muscles are branched.

Question 5

Question 1(x)Involuntary muscles are present in :LegHandIrisHead

Accepted Answer

IrisReason — Iris is made up of involuntary muscles.

Question 6

Question 1(xi)Ischium and Pubis are two specific bones of the girdles in the human body, belonging to (P) ............... and (Q) ............... girdles respectively.P — Pectoral, Q — PelvicP — Pectoral, Q — PectoralP — Pelvic, Q — PelvicP — Pelvic, Q — Pectoral

Accepted Answer

P — Pelvic, Q — PelvicReason — Both ischium and pubis are part of the pelvic girdle, not different girdles. The pelvic girdle is made up of three bones: Ilium, Ischium and Pubis.

Question 7

Question 4What are antagonistic muscles? Give one example.

Accepted 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 8

Question 5Give 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.

Accepted 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 9

Question 3Draw 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

Accepted Answer

Please refer to the full solution above.

Question 10

Question 6The 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 : ...............

Accepted 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 11

Question 7Write 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

Accepted Answer

(a) Knee cap — Patella(b) Shoulder blade — Scapula(c) Collar bone — Clavicle(d) Breast bone — Sternum(e) Bones in the palm — Metacarpals

Skeleton - Movement and Locomotion

Long Answer Type

Multiple Choice Type

Short Answer Type

Structuredapplicationskill Type

Very Short Answer Type