Respiration and Gas Exchange

Question 1

What are cilia?

Answer 1

Hairs in the trachea and lungs which sweep dust, bacteria and mucus out of the lungs. They sweep mucus in the trachea back to the mouth.

Question 2

How are alveoli adapted for gas exchange?

Answer 2

• Thin walls so less distance for gas to travel
• Permeable
• Lots of them so large surface area
• Good blood supply so there is a high concentration gradient
• Moist so gases can easily diffuse

Question 3

What are the effects of smoking on the lungs and circulatory system?

Answer 3

-Carbon monoxide reduces the oxygen blood can carry which leads to increased heart rate and therefore higher blood pressure. This damages artery walls and increases risk of blood clots. It increases risk of coronary heart disease.
-Tar damages cilia making chest infections more likely.
-Tar irritates bronchus and bronchioles which produces more mucus
-Contains carcinogens
Damages walls of alveoli which reduces surface area and leads to emphysema