I. State whether the statements given below are True or False:
(i) The bones are soft while cartilages are hard.
(ii) Skeleton system gives the body support and protects inner organs.
(iii) Doctors use X-ray films to examine the injuries of bones.
(iv The bones of cranium are flat and held firmly like a zipper.
(v) Upper jaw is movable.
(vi)Five vertebrae of hip and four vertebrae of tail are fused in the human vertebral column.
(vii) Bones in the foot are normally set in an arch.
(viii) A human body is born with about 206 bones.
(ix) There are air sacs connected with the lungs in birds.
(xi) Muscular foot in snail is part of its belly.
(xii) The bones are moved by simultaneous contractions and relaxation of two sets of muscles.
(xiii) All the joints in our body are similar.
(xiv) Cockroaches cannot walk.
(xv) The minute movable bristles in earthworm help in gripping the ground.
Answers
Answer:
Bones also protect the body's organs. The skull protects the brain and forms the shape of the face. The spinal cord, a pathway for messages between the brain and the body, is protected by the backbone, or spinal column. The ribs form a cage that shelters the heart and lungs, and the pelvis helps protect the bladder, part of the intestines, and in women, the reproductive organs.
Bones are made up of a framework of a protein called collagen, with a mineral called calcium phosphate that makes the framework hard and strong. Bones store calcium and release some into the bloodstream when it's needed by other parts of the body. The amounts of some vitamins and minerals that you eat, especially vitamin D and calcium, directly affect how much calcium is stored in the bones.
Bones are made up of two types of bone tissues:
Compact bone is the solid, hard outside part of the bone. It looks like ivory and is extremely strong. Holes and channels run through it, carrying blood vessels and nerves.
Cancellous (KAN-suh-lus) bone, which looks like a sponge, is inside compact bone. It is made up of a mesh-like network of tiny pieces of bone called trabeculae (truh-BEH-kyoo-lee). This is where bone marrow is found.