22. The Respiratory System

As a result of a stroke, Mrs. Minnick's swallowing is uncoordinated. What detrimental effect might this have on her ability to breathe?

Cary hyperventilates for several minutes before diving into a swimming pool. After he enters and begins swimming underwater, he blacks out and almost drowns. What caused this to happen?

The contraction of the diaphragm and the external intercostal muscles begins inspiration. What happens, in terms of volume and pressure changes in the lungs, when these muscles contract?

Differentiate clearly between minute ventilation and alveolar ventilation rate

Which provides a more accurate measure of ventilatory efficiency, and why?

What is the significance of

(a) Boyle's law, to the process of respiration?

When the diaphragm and external intercostal muscles contract,

(a) Exhalation occurs.

(b) Intrapulmonary pressure increases.

(c) Intrapleural pressure decreases.

(d) The volume of the lungs decreases.

(e) The size of the thoracic cavity increases.

Which of the following does not affect the efficiency of pulmonary gas exchange?

a. The surface area of the respiratory membrane

b. The degree of match of ventilation to perfusion

c. The percent saturation of hemoglobin

d. The thickness of the respiratory membrane

Which of the following statements about pulmonary ventilation is false?

a. Normal expiration requires the use of the expiratory muscles to decrease lung volume.

b. The inspiratory muscles increase lung volume, which decreases intrapulmonary pressure.

c. For inspiration to occur, intrapulmonary pressure must decrease below atmospheric pressure.

d. The intrapleural pressure is less than the intrapulmonary pressure; this prevents the lungs from collapsing during expiration.

Match each term with the correct definition. 

Airway resistance     

Surface tension     

Surfactant     

Pulmonary compliance     

V/Q ratio

a. A detergent-like chemical secreted by bronchial smooth muscle that reduces surface tension

b. The matching of ventilation to perfusion

c. Largely determined by the diameter of the airways

d. Caused by the formation of hydrogen bonds between water molecules

e. Determined by the surface tension of the alveoli, the elastic tissue of the lungs, and the condition of the chest wall

If you swallow a large bite of food without properly chewing it first, you will feel discomfort during ventilation. Explain this, considering the arrangement of the trachea and the esophagus.

What factor is most important in keeping the lungs from collapsing?

Predict what would happen to the tidal volume and inspiratory reserve volume if the phrenic nerves were severed. Which muscles would contract to try to compensate for this?