The Gaseous Exchange System

Question 0

Function of cilia

Answer 0

On surface of cells. Waft mucus moving trapped microorganisms and dust to the back of the throat away from the alveoli where it is swallowed into the stomach, this helps to prevent lung infections

Question 1

Function of a goblet cell

Answer 1

Secrete mucus. The mucus traps microorganisms and dust in inhaled air and stops them from reaching the alveoli

Question 2

Function of elastic fibres

Answer 2

Walls of trachea, bronchi, bronchioles and alveoli to help with breathing out. On breathing in the lungs inflate and the elastic fibres are stretched. Then the fibres recoil to help push air out when exhaling

Question 3

Function of smooth muscle

Answer 3

Walls of the trachea, bronchi and bronchioles allows the diameter to be controlled. During exercise the smooth muscle relaxes making the tubes wider so there is less resistance to airflow and air can move in and out of the lungs more easily

Question 4

Function of rings or cartilage

Answer 4

Walls of trachea and bronchi provide support, strong but flexible, it stops the trachea and bronchi collapsing when you breathe in and air pressure drops

Question 5

How are the lungs adapted for efficient gas exchange?

Answer 5

• many alveoli: large SA
• alveolar epithelium and capillary endothelium are only one call thick:short diffusion pathway
• alveoli:good blood supply from capillaries, they constantly take away and bring back more carbon dioxide maintaining concerntrate on gradient
• breathing in and out refreshes air in alveoli keeping concerntrate on gradients high