The effects of lung disease

Question 1

What is tidal volume?

Answer 1

Is the volume of air in each breath – its usually between 0.4dm3 and 0.5dm3 for adults.

Question 2

What is the ventilation rate?

Answer 2

The number of breaths per minute. For a healthy person at rest its about 15 breaths.

Question 3

What is the forced expiratory volume?

Answer 3

Is the maximum volume of air that can be breathed out in 1 second.

Question 4

What is the forced vital capacity?

Answer 4

The maximum volume of air it is possible to breathe forcefully out of the lungs after a deep breath in.

Question 5

Tuberculosis:

Answer 5

This forms small, hard lumps known as tubercles. Infected tissue within tubercles dies and the gaseous exchange surface is damaged, so tidal volume is decreased.

Question 6

Fibrosis:

Answer 6

Is the formation of scar tissue in the lungs. This can be the result of an infection or exposure to substances like asbestos or dust.

Scar tissue is thicker and less elastic than normal lung tissue. This means that the lungs are less able to expand and so can’t hold as much air as normal

Question 7

Asthma

Answer 7

The airways become inflamed and irritated.

The smooth muscle lining the bronchioles contracts and a large amount of mucus is produced. This causes constriction of the airways, making it difficult for the sufferer to breathe properly.

Question 8

Emphysema

Answer 8

Caused by smoking or long-term exposure to air pollution – the foreign particles in the smoker (or air) becomes trapped in the alveoli.

This causes the inflammation, which attracts phagocytes to the area. The phagocytes produce an enzyme that breaks down elastin.

It also leads to destruction of the alveoli walls, which reduces the surface area of the alveoli so the rate of gaseous exchange decreases.