7. It is made up of 8. Made up of 33 small bones it runs down Short-Answer Questions F. Differentiate between the following pairs. 1. Bone and cartilage 2. Hinge and pivot joint 3. Fixed and movable joints 4. Skull and ribcage G. Define each of the following in one sentence. 1. Backbone: 2. Pectoral girdle: 3. Sternum: 4. Ligament: 5. Streamlined body: 100
Answers
Bones and Cartilage
Bone is a hard, inelastic and rigid tissue
Cartilage is a soft, elastic and flexible tissue
Bones are hollow, compact and are of different shapesCartilage is padlike and transparent
Bones have a very hard matrix due to calcium salts. Cartilages have slightly flexible matrix due to a protein called chondrin. Bones cannot be bent. Cartilages can be bent easily at certain parts. Bones can break and result in fracture. Cartilages cannot break as they are flexible
Hinge and pivot joint
Pivot joints are the most mobile of all synovial joints. They allow the bone with the ball head to be moved freely in all planes, Whereas hinge joints allow restricted movements in one plane only. They are capable of bearing heavy loads.
Fixed and movable joints
Fixed joints do not permit movement of the bones they connect; the articulating bones are firmly held together by dense bands of tough, inextensible white fibrous tissue whereas synovial joints allow freedom of movement.
Define
Backbone
The backbone is a line of bones that runs through the centre of our back.
It is made up of many small bones called vertebrae. There are 33 vertebrae. The rib cage is joined to these bones.
Pectoral Girdle
The pectoral girdle is a part of the appendicular skeleton, which connects the upper limbs to the axial skeleton. The human skeleton is divided into two sections, the axial skeleton and the appendicular skeleton.
Sternum
The sternum (or breastbone) is a flat bone located at the anterior aspect of the thorax. It lies in the midline of the chest and has a ‘T’ shape.
Ligament
Ligament, tough fibrous band of connective tissue that serves to support the internal organs and hold bones together in proper articulation at the joints.
Streamlined Body
A streamlined body is a shape that decreases the friction drag between a fluid, such as air and water, and an object that passes through that fluid. Drag is the force which reduces the speed of the motion.
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