Lung health and Diseases

Question 1

Why do our lungs recoil after inhalation?

Answer 1

• elastin in lung tissue
• surface tension in the alveoli (fluid on inside maintains this)

Question 2

Why don’t alveoli collapse?

Answer 2

• surfactant (made by type ll cells of the alveolar epithelium) in the fluid lining of the alveoli lowers surface tension so that they do not collapse at the end of exhalation

Question 3

What is nRDS? (Neonatal respiratory distress syndrome)?

Answer 3

• occurs in premature infants
• lack mature surfactant system
• causes alveolar collapse
• results in poor lung function = low O2 in blood
• treatment is to administer pulmonary surfactant

Question 4

What is lung compliance?

Answer 4

• change in lung volume divided by change in lung pressure
• higher compliance is better
• 1/3 determined by elastin
• 2/3 determined by surface tension

Question 5

What is emphysema (COPD)

Answer 5

• loss of elastin
• reduces lung recoil
• also results in destruction of alveolar walls
• much slower emptying of air from lungs (difficult to breathe out)

Question 6

What is asthma?

Answer 6

• spasms in smooth muscle in airways

Question 7

Two examples of obstructive lung diseases

Answer 7

• Asthma
• COPD (emphysema)

Question 8

Restrictive lung diseases

Answer 8

• Example - Pulmonary fibrosis (less compliant due to scarred tissue)
• difficulty breathing in (less volume of air able to enter lungs)

Causes - breathing in asbestos, coal dust, pollution…