Question

B12 2008 jun

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capillaries
red blood
cells
A
(ii)
(1)
The diagrams show a section through a healthy long and a s
dhrough a diseased lung
G
on, drawn to the same scale,
5
Diseased lung
Healthy lung
Name the structures labelled A and B.
1. Capillaries
B. Alveoli
State the name of the disease shown in the diagram and explain your reasons for this
[3]
choice.
Name of disease
Explanation
SERE SE IN
3
[2]
Explain the effects that the disease will have on the process of gaseous exchange in
[2]
the diseased lung.
(b)

Answer 1

from what I understood from the question

(a)

(i) A: Capillaries; B: Alveoli

(ii) Name of disease: Emphysema

Explanation: The diagram of the diseased lung shows a loss of elasticity in the walls of the alveoli, which results in the enlargement and destruction of the air sacs. This is a characteristic feature of emphysema.

(b) Effects of emphysema on the process of gaseous exchange in the diseased lung:

Emphysema results in a decrease in the surface area available for gaseous exchange in the lungs. The destruction of the walls of the alveoli reduces the number of available air sacs, and the loss of elasticity in the alveoli walls reduces the ability of the lungs to expand and contract efficiently during breathing. This makes it harder for oxygen to diffuse from the air in the lungs into the bloodstream and for carbon dioxide to diffuse from the bloodstream into the lungs to be exhaled. As a result, people with emphysema may experience shortness of breath and difficulty breathing, especially during physical activity.