Gas exchange

Question 1

What is respiration?

Answer 1

• transport of oxygen from the air to the tissues
• and carbon dioxide from tissues to the air

Question 2

What is external respiration?

Answer 2

• movement of O2 and CO2 between the lungs and the bloodstream

Question 3

What is internal respiration?

Answer 3

• movement of O2 and CO2 between the bloodstream and tissues

Question 4

Why do we breathe?

Answer 4

• fresh air passing through the lungs delivers oxygen to the rbc
• at the same time, CO2 is removed from blood
• this can only happen if fresh air in constantly circulating through the lungs

Question 5

Features of gas exchange surfaces/what makes lungs good for gas exchange?

Answer 5

alveoli has a large internal surface area for efficient gas exchange
each alveoli is well supplied with blood vessels
wall of alveoli is very thin
lungs are deep inside the body to prevent fluid evaporation
lung volume can be changed so air can flow in and out of lungs

Question 6

How is the concentration gradient related to gas exchange?

Answer 6

• the concentration gradient is required for gas exchange
• the difference in concentration of O2 and CO2 means that air can flow
• during external respiration, there’s a difference in CO2 and O2 concentration between the alveoli and capillaires
• constant blood flow and airflow maintains the concentration gradient

Question 7

Concentration gradients and external respiration

Answer 7

• constant blood and airflow maintains the concentration gradient
• blood (capillaries) has a low oxygen concentration since it’s already been delivered around the body
• air in the alveoli has a high oxygen concentration
• therefore, oxygen goes from the air in the alveoli to blood in the capillaries
• blood in the capillaries is high in CO2, but air in the alveoli is low in CO2
• CO2 diffuses out of blood into the alveoli
• expired air contains less oxygen than inspired air

Question 8

concentration gradient and internal respiration

Answer 8

• flow of blood maintain the concentration gradient
• blood (coming from alveoli to the tissue) has high O2 concentration and low CO2 concentration
• tissue has low O2 and high CO2 (produced from celluylar respiration)
• oxygen moves from the blood to tisssue cells
• carbon dioxide moves from tissue into blood
• expired air has less O2, more CO2