Respiratory System

Question 1

List 2 reasons for the decline in vital capacity seen with age.

Answer 1

Vital capacity declines with age because the thoracic wall becomes more rigid and the lungs lose their elasticity.

Question 2

What is the underlying defect in cystic fibrosis?

Answer 2

The underlying defect in cystic fibrosis is an abnormality in a protein (CFTR protein) that acts as a membrane channel for chloride ions.

Question 3

.What distinguishes the obstruction in asthma from that in chronic bronchitis?

Answer 3

The obstructionin asthma is reversible, and acute exacerbations are typically followed by symptom free periods. In contrast obstruction in chronic bronchitis is generally not reversible.

Question 4

.What long term adjustments does the body make when living in high altitude?

Answer 4

Long term adjustments to altitude include an increase in erythropoiesis, resulting in a higher hematocrit; an increase in minute respiratory volume.

Question 5

An injured soccer player arrives by abulance to the emergency room. She is in obvious destress, breathing rapidly. Her blood Pco2 is 26mm Hg and pH is 7.5. Is she suffering from hyperventilation or hyerpnea? explain

Answer 5

The injured soccer player’s Pco2 is low.( recall thatnormal Pco2=40mm). The low Pco2 reveals that this is hyperventilation and not hyperpnea (which is not accompanied by changes in blood CO2 levels)

Question 6

Which chemical factor in blood normally provides the most powerful stimulus to breathe? Which chemoreceptors are most important for this response?

Answer 6

CO2 in blood normally provides the most powerful stimulus to breathe. Central chemoreceptors are most important in this response.