During inspiration which of the following events takes place
1. Diaphragm and external intercostal muscles contracts
2. Diaphragm and internal intercostal muscles relax
3. Intra Pleural pressure is less than atmospheric pressure
4. Both A and C

During expiration which of the following events takes place
(1)Diaphragm and external intercostal muscles contracts

(2) Diaphragm and external intercostal muscles relax

(3)Inter Pleural pressure is less than atmospheric pressure

(4)Both A and C

During inspiration there is __________pressure in the lungs with respect to atmospheric pressure.
(1)positive

(2)negative

(3)neither positive nor negative

(4)All of these

Which of the following is true for inspiration
(1)thoracic chamber volume increases

(2)Diaphragm contracts

(3)pulmonary volume increases

(4)All of these

Which of the following is true for expiration except
(1) thoracic chamber volume reduces

(2)Diaphragm contracts

(3)pulmonary volume decreases

(4)All of these

Pressure gradient between the lungs and atmosphere is maintained by
(1)diaphragm

(2)external intercostal muscles

(3)internal intercostal muscles

(4)All of these

The volume of air involved in breathing movements can be estimated by using
1. ECG
2. Sphygmomanometer
3. spirometer
4. Barometer

Which of the following events happen when air enters lungs
1. Ribs and sternum raised
2. volume of thorax increased
3. Diaphragm contracted
4. All of the above

Which of the following events happen when air expelled from lungs
1. Ribs and sternum returned to original position
2. volume of thorax decreased
3. Diaphragm relaxed and arched upwards
4. All of the above

On an average, a healthy human breathes ______times/minute.
1. 70-72
2. 20-25
3. 12-16
4. 120-80