Breathing and Exchange - 14-10-23

The chamber formed dorsally by the vertebral column, ventrally by sternum, laterally by ribs and on the lower side by dome-shaped diaphragm is –

• (a) Abdominal cavity

• (b) Thoracic cavity

• (c) Pelvic cavity

• (d) Cranial cavity

The lungs expand in inspiration / inhalation because –

• (a) Diaphragm contracts upward

• (b) The volume of thoracic cavity increases

• (c) External intercostal muscles relax

• (d) Diaphragm relaxes

The process of exhalation / expiration is begun mainly due to –

• (a) The contraction of intercostal muscles

• (b) The contraction of the diaphragm

• (c) The relaxation of muscles

• (d) Low pressure in thoracic cavity

Which of the following statements about the mechanism of ventilation / breathing is false?

• (a) As the diaphragm relaxes, air is expelled from the respiratory system

• (b) During inspiration the lungs act as suction pump

• (c) Inspiration is a passive and expiration is an active process

• (d) For quiet breathing external intercostal muscles and diaphragm play an important role

Inspiration occurs when there is a negative pressure in the lungs with respect to atmospheric pressure. This negative pressure is achieved when –

• (a) Intrapulmonary pressure is less than the atmospheric pressure

• (b) Intra pulmonary pressure is greater than the atmospheric pressure

• (c) Intrapulmonary pressure is equal to the atmospheric pressure

• (d) Intrapleural pressure becomes more than the intraalveolar pressure

Expiration takes place when the intrapulmonary pressure is –

• (a) Greater than the atmospheric pressure

• (b) Lesser than the atmospheric pressure

• (c) Equal to atmospheric pressure

• (d) Equal to intrapleural pressure

Which of the following sequences is correct to initiate inspiration?

I. The contraction of external intercostal muscles 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 anterio-posterior axis

• (a) I, II, IV, V, III, VI

• (b) I, II, III, IV, V

• (c) I, II, IV, VI, III, V

• (d) VI, V, I, II, III, IV

Which of the following sequences is correct to initiate expiration?

I. Relaxation of external intercostal muscles and return of diaphragm and sternum to their normal position

II. Air expelled from lungs

III. Volume of thorax decreases

IV. Intrapulmonary pressure increases

• (a) I, III, IV, II

• (b) II, IV, III, I

• (c) IV, III, II, I

• (d) I, II, III, IV

On an average, a healthy human breathes ______________ times / minute –

• (a) 20 - 40

• (b) 1 - 6

• (c) 12 - 16

• (d) 16 - 25

Additional muscles for forceful breathing are –

• (a) Diaphragm and external intercostal muscles

• (b) Abdominal muscles and internal intercostal muscles

• (c) Diaphragm and abdominal muscles

• (d) External and internal intercostal muscles