gaseous exchange

Question 1

partial pressure

Answer 1

pressure exerted by an individual gas when it exists within a mixture of gases

Question 2

diffusion

Answer 2

movement of gas molecules from an area of high concentration to an area of low concentration

Question 3

gaseous exchange is concerned with..

Answer 3

1. getting oxygen from air into the lungs to that it can diffuse into the blood and be transported to the cells of the body
2. removal of carbon dioxide from the blood

Question 4

gaseous exchange at the alveoli

Answer 4

• the partial pressure of oxygen in alveoli is higher than partial pressure of oxygen in blood vessels
• this is because oxygen has been removed by the working muscles so its concentration in the blood is lower and therefore so is its partial pressure

-pp of C02 in the blood entering alveolar capillaries is higher than in alveoli so C02 diffuses into the alveoli from blood until the pressure is equal in both

Question 5

the bigger the concentration/diffusion gradient is

Answer 5

the faster diffusion will be

Question 6

diffusion pathway of oxygen is

Answer 6

alveoli -> blood -> muscles

Question 7

diffusion pathway for carbon dioxide is

Answer 7

muscles -> blood -> alveoli

Question 8

for diffusion the rate of exchange depend on:

Answer 8

partial pressure
gas solubility
temperature

Question 9

how does gaseous exchange occur in the lungs

Answer 9

• oxygen in the lungs is transferred by diffusion to blood through the alveoli
• carbon dioxide is transferred from blood arriving at lungs which is breathed out

Question 10

how does gaseous exchange operate at the muscles

Answer 10

• pp of oxygen has to be lower at the tissues than blood for diffusion to occur.
• pp of carbon dioxide in the blood is lower than tissue