Select the correct order of sequence required to initiate inspiration.
(i) The contraction of external intercostalmuscles raises the ribs and sternum.
(ii) Volume of thorax increases in the dorso-ventral axis.
(iii) Intrapulmonary pressure decreases.
(iv) Diaphragm contraction.
(v) Air rushes into lungs.
(vi) Volume of thorax increases in the anterior-posterior axis.
(ii) Volume of thorax increases in the dorso-ventral axis.
(iii) Intrapulmonary pressure decreases.
(iv) Diaphragm contraction.
(v) Air rushes into lungs.
(vi) Volume of thorax increases in the anterior-posterior axis.
Important Questions on Breathing and Exchange of Gases
Assertion (): Biconcave shape of mammalian facilitates gas exchange.
Reason (): Biconcave shape provides a high surface to volume ratio.
Match the following respiratory capacities and respiratory volumes of a normal human adult?
| Respiratory capacities | Respiratory volumes | ||
| i) | Residual volume | a) | 2800 mL |
| ii) | Vital capacity | b) | 3000 mL |
| iii) | Inspiratory reserve volume | c) | 1100 mL |
| iv) | Inspiratory capacity | d) | 4000 mL |
Select the favourable conditions required for the formation of oxyhaemoglobin at the alveoli.
Select the correct events that occur during inspiration.
(a) Contraction of diaphragm
(b) Contraction of external intercostal muscles
(c) Pulmonary volume decreases
(d) Intrapulmonary pressure increases
(A) The movement of air in and out of the lungs is carried out by creating a pressure gradient between the lungs and atmosphere.
(B) Inspiration can occur if the pressure within the lungs is more than the atmospheric pressure.
(C) Expiration takes place when the intrapulmonary pressure is lesser than the atmospheric pressure.
(D) The diaphragm and a specialized set of intercostal muscles in between the ribs help in the generation of such pressure gradients for breathing.
How many of the following statements are correct?
