The Gaseous Exchange System in Mammals

Question 1

what do goblet cells do

Answer 1

secrete mucus

which traps microorganisms and dust particles in the inhaled air

Question 2

what do cilia do

Answer 2

wafts the mucus
moving the mucus upward from the alveoli towards the throat, where its swallowed.
- which can prevent lung infection

Question 3

where are elastic fibres found?

what do they do?

Answer 3

• found in found in the walls of:
  trachea, bronchi, bronchioles and alveoli
• the elastic fibres stretch when breathing IN
• and recoil whilst breathing out

Question 4

where are smooth muscle found

and what do they do

Answer 4

• found in the walls of the trachea, bronchi and bronchioles
• constrict the bronchus, controlling the diameter
• during exercise the smooth muscle relaxes making the tubes wider, so less resistance to air flow, making air easier to move in and out of the lungs

Question 5

RIngs of cartilage

Answer 5

rings of cartilage in the walls of the trachea and bronchi provide support

• stops the trachea and bronchi from collapsing when you breathe in and the pressure drops