Chapter 20: Locomotion and Movement

Ans: (a) At its dorsal end, each rib has two articulation surfaces. As a result, ribs are known as bicephalic ribs.

Ans:(b) True ribs are the first seven pairs of ribs that are linked to the thoracic vertebrae dorsally and the sternum ventrally. 

Ans:(c) The last two pairs of ribs are called floating ribs because they are not attached ventrally.

Ans: People in old age often experience pain in their joints due to stiff and inflamed joints. This condition is known as Arthritis and is caused due to wear and tear of the joints. Some possible reasons of these symptoms are: 

a) Lack of Vitamin D

b) Lack of Calcium 

c) Smoking

d) Genetic factors

e) Less physical activity

Ans: (a) This will result in reduced heart rate and increased contractility of heart. 

Ans:(b) This will result in tetani which is manifested as rapid spasms in muscles. 

Ans: The calcium ion level in the blood is influenced by calcitonin and parathyroid hormones. Calcitonin regulates calcium levels in the blood when they exceed a certain threshold. Parathyroid hormone regulates calcium levels in the blood when they fall below a certain threshold.

Ans: ‘c’ is the correct answer which says that weight gain is because of improved muscle shape. About 40 – 50% of our body weight is composed of muscles. When a person starts doing intensive exercise, because of this muscles are build up. Due to which excess fat of a person is burnt. These are the reasons that some people tend to gain weight when they begin regular exercise. 

Ans: (a) Muscles have to work harder during severe exercise. The muscles are put under more tension as a result of this.

Ans:(b) While running on a treadmill, her breathing rate went from normal to fast. Muscle energy consumption rose as the demand on the muscles increased. As a result, the muscles had a larger desire for carbs. In addition, the muscles' oxygen consumption increased. An enhanced blood supply to the muscles could meet this need. As a result, the heart and lungs would have to work harder to meet the additional demand

Ans: Gout is a recurrent occurrence of acute inflammatory arthritis. It usually affects the big toe but also affects other joints. This happens because of accumulation of uric acid crystals in joints, tendons and surrounding tissues. This is manifested as throbbing pain in the affected area. 

Ans: The main source of energy for muscular activity is ATP (Adenosine Triphosphate). Mitochondria can be seen in abundance in red muscles. The muscular contraction requires ATP, which is supplied by these mitochondria. White muscles have a lower amount of mitochondria and receive less ATP as a result. As a result, the white muscles rely on anaerobic respiration for ATP during periods of high demand.

Ans: The acetabulum is the articulation point in the pelvic girdle. The acetabulum is formed by the union of three pelvic girdle component bones. The femur articulates with it. The glenoid cavity is the place of articulation in the pectoral girdle. The humerus articulates with it.