organisation - gas exchange in the lungs

Question 1

where does air pass through into the lungs?

Answer 1

trachea

Question 2

what is a key feature of the trachea?

Answer 2

rings of cartilage to prevent it from collapsing during inhalation

Question 3

what does the trachea split into?

Answer 3

2 smaller tubes called bronchi with one passing to each lung

Question 4

what do bronchi split in to?

Answer 4

small tubes called bronchioles

Question 5

what is at the end of bronchioles?

Answer 5

alveoli (tiny air sacs)

Question 6

what happens in the alveoli?

Answer 6

where gases diffuse in and out of the bloodstream. site of gas exchange

Question 7

how is an alveoli adapted for gas exchange?

Answer 7

• huge surface area
  -very thin walls so short diffusion path
  -very good blood supply

Question 8

what do the adaptations of the alveoli mean?

Answer 8

once oxygen diffuses into the blood, it is rapidly removed ensuring in a steep concentration gradient

Question 9

how does breathing increase rate of diffusion?

Answer 9

brings fresh oxygen into the alveoli and takes away the carbon dioxide. making concentration gradient high for these gases increasing rate of diffusion