MECHANICS OF BREATHING

Question 1

• is the mechanical act of breathing and is accomplished by expansion of the chest, both vertically and horizontally.

Answer 1

External respiration or ventilation

Question 2

• is accomplished through contraction of the diaphragm.

Answer 2

Vertical expansion

Question 3

• occurs as intercostal muscles lift the sternum and elevate the ribs, resulting in an increase in anteroposterior (AP) diameter

Answer 3

Horizontal expansion

Question 4

• slight negative pressure is created in the lungs in relation to the atmospheric pressure, resulting in an inflow of air into the lungs.

Answer 4

Inspiration

Question 5

• mostly passive in nature and occurs with relaxation of the intercostal muscles and the diaphragm.
• As the diaphragm relaxes, it assumes a domed shape. The resultant decrease in the size of the chest cavity creates a positive pressure, forcing air out of the lungs.

Answer 5

Expiration