Lung Diseases

Question 1

What is tuberculosis caused by?

Answer 1

Bacteria

Question 2

How is TB spread?

Answer 2

Droplet infection (sneezing and coughing)

Question 3

How does TB affect lung function?

Answer 3

Small, hard lumps (tubercles) are formed. Infected tissue within these dies, and the exchange surface is damaged, so tidal volume decreases. This means less air can be inhaled as the surface area of the lungs and alveoli decreases. Ventilation rate has to increase to compensate for this.

Question 4

What is fibrosis?

Answer 4

The formation of scar tissue in the lungs as a result of infection or exposure to substances such as asbestos. Scar tissue is thicker and less elastic than normal lung tissue.

Question 5

How does fibrosis affect lung function?

Answer 5

As the scar tissue is thicker and less elastic than normal lung tissue, the lungs are unable to expand as much so can’t hold as much air as normal. This leads to a reduced tidal volume and FVC. The lungs lose their ability to transfer oxygen into the bloodstream so gas exchange is much slower. Diffusion is slower across a thicker membrane. Ventilation rate increases

Question 6

What is asthma?

Answer 6

A respiratory condition where the airways become inflamed and irritated.

Question 7

What happens during an asthma attack?

Answer 7

The smooth muscle lining the bronchioles contracts and a large amount of mucus is produced. This causes constriction of the airways

Question 8

How does asthma affect lung function?

Answer 8

Air flow in and out of the lungs is severely reduced, so less oxygen enters the alveoli and moves into the blood. FEV 1 is reduced

Question 9

What is emphysema? What is it caused by?

Answer 9

A lung disease caused by smoking or long term exposure to air pollution. Foreign particles in smoke become trapped In the alveoli, so the number of alveoli decreases

Question 10

How does emphysema affect lung function?

Answer 10

It causes inflammation, so phagocytes are attracted to the area and break down elastin. Loss of elastin means that the alveoli can’t recoil to expel air so it remains trapped. The walls of the alveoli are destroyed. This reduces surface area, which in turn reduces the amount of oxygen transferred by the lungs into the bloodstream, making it difficult to breathe. Ventilation rate increases.

Question 11

What is elastin?

Answer 11

A protein found in the walls of the alveoli, it helps the alveoli return to their normal shape after inhaling and exhaling air.