BIOLOGY [3 marks Question Answer]

A typical vertebra has a main body or centrum and a neural canal in the centre of the neural arch, arising from the sides of the centrum. Neural spine is a flat, longitudinal projection. There are side projections called transverse processes. The articular facets help in j oining the two adj a cent vertebrae.

The skeletal system performs the following functions in an animal:
(i) It provides a framework to support the body and gives a definite shape and form to the body.
(ii) It helps to protect some of the vital organs like heart, lungs, brain and spinal cord.
(iii) It provides the base for attachment of muscles and several bones so as to make body movements possible.
(iv) Bones act as storehouse of some minerals like calcium and phosphorus.
(v) Red bone marrow of long bones of limbs produces red blood cells and granulated white blood cells in their hollow cavities

(a)
1. Scapula;
2. Shoulder joint;
3. Humerus;
4. Bicep;
5. Tricep;
6. Radius;
7. Tricep
8. Elbow Joint;
9. Ulna.
(b) Bicep muscles and triceps are antagonistic muscles.
(c) Bicep muscles.
(d) Shoulder bones.
(e) Ball and socket joint.

(a) Synovial joint is a movable joint present between the adjoining bones which can move independently. The articulating surfaces of the two bones are covered with articular cartilage. The joint is covered with a synovial membrane which secretes synovial fluid for lubrication.
(b) These are found in elbow joint, knee joint, femur and pelvic girdle, etc.
(c) The cartilages cover the ends of the adjoining bones. They function to absorb shock and reduce friction during movement.
(d) 1 and 5 -epiphyseal bone
2- synovial cavity
3- synovial fluid
4- synovial membrane

Importance of pectoral girdle:
(i) It provides support to the anterior portion of the body.
(ii) Provides surface articulation of fore arms.
(iii) Provides surface for muscle attachment.
(iv) Provides protection to vital organs like heart and lungs.
Importance of pelvic girdle:
(i) Provides surface articulation of hind limbs.
(ii) Provides surface for joining of muscles.
(iii) Provides protection to the uterus.
(iv) Protects from shocks.