9. Gas Exchange & Smoking

Question 1

3 most common causes of emphysema

Answer 1

• tobacco smoking
• infection
• inflammation

Question 2

Describe the appearance of a section through the wall of a bronchus in a person with chronic bronchitis. [4m]

Answer 2

• damaged cilia
• epithelial cells replaced by scar tissue
• enlargement of goblet cells
• more smooth muscle
• inflammation
• large number of white blood cells

Question 3

Explain how the two by-passes provide an effective treatment for coronary heart disease. [3m]

Answer 3

• the by-pass vessels supply oxygenated blood from AORTA
• supply oxygen to cardiac MUSCLE
• supply glucose/fatty acids
• reduce ANAEROBIC respiration, so muscles can continue to respire aerobically to prevent the death of heart cells

Question 4

Describe the process of gas exchange between the alveolus and the blood. [4m]

Answer 4

1. idea of CO2 out and O2 in
2. DIFFUSION / movement down [ ] gradient
3. across squamous epithelium of alveolar wall
4. and endothelium of capillary wall
5. O2 into RBC
6. steep gradient maintained by ventilation

Question 5

Outline the function of smooth muscle in the gas exchange system. [2m]

Answer 5

• contraction and relaxation
• changes diameter of lumen of trachea/bronchus/bronchiole
• control of air flow in the bronchioles

Question 6

4 functions of cartilage in the human gas exchange system

Answer 6

1. keeps airways open
2. provides support (prevents collapse of trachea and bronchi)
3. allows flexibility when swallowing food
4. rings allow widening during inhalation