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 is the part of the thoracic chamber
1. ribs and vertebral column
2. diaphragm
3. sternum
4. All of these

Inspiration can occur if $\underline{}$ $$ $$ $$ $$ $$ $$ $$ $$ $A$ $$ $$ $$ $$ $$ $$ pressure is less than atmospheric pressure, i.e., there is $\underline{}$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $B$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ pressure in the lungs with respect to atmosphere pressure. Choose the option that fills the blanks correctly.
           A                                 B

1. Intra-pulmonary              Positive

2. Intra-pulmonary              Negative

3. Inter-pleural                   Positive

4. Intra-pleural                   Positive

Inspiration occurs when intra-pulmonary pressure is

1. Higher than atmospheric pressure

2. Lower than atmospheric pressure.

3. Equal to atmospheric pressure.

4. Zero compared to atmospheric pressure.

The mechanism of breathing depends on animal’s
1. habitat
2. level of organisation
3. Both A and B
4. Body segmentation

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

(2)external intercostal muscles

(3)internal intercostal muscles

(4)All of these

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

During inspiration, the diaphragm

1. Contracts

2. Expands

3. Does not move

4. Relaxes

The movement of air into the lungs occurs due to a pressure gradient between the lungs and the atmosphere. So, inspiration occurs when/due to

1. Intra pulmonary is less than the atmospheric pressure

2. Increase in the volume of the thoracic chamber in the dorso-ventral axis

3. Contraction of external inter-costal muscles and phrenic muscles

4. All of these

Contraction of diaphragm:

1. Increases the volume of the thoracic chamber in the antero-posterior axis

2. Increases the volume of the thoracic chamber in the dorso-ventral axis

3. Decreases the volume of the thoracic chamber in the antero-posterior axis

4. Decreases the volume of the thoracic chamber in the dorso-ventral axis