Gas Exchange

Question 1

Describe how gas particles behave?

Answer 1

In a gas the particles are far apart and moving freely.

Question 2

What are the holes in the lungs called?

Answer 2

Air sacs or alveoli.

Question 3

What are the names of the very tiny blood vessels in the lungs, wrapped around the air sacs.

Answer 3

Capillaries

Question 4

How big is the wall of the air sacs?

Answer 4

It is made of only one layer of very thin cells.

Question 5

How big is the wall of the capillary?

Answer 5

It is also made of only one layer of very thin cells.

Question 6

How close are the alveoli and capillary in the lungs?

Answer 6

They are very close together as the capillary is pressed tightly against the alveolus.

Question 7

What is gas exchange?

Answer 7

Gas exchange is the exchange of gases that happen in the lungs. Inside the alveoli in the lungs the oxygen from the air diffuses into the blood while the carbon dioxide from the blood diffuses into the air.

Question 8

Where does the blood in the capillary come from and according to this which gas will be in huge quantity in the blood?

Answer 8

The heart, but before reaching the heart it visited the organs in the body which contained respiring cells. Those cells took the oxygen from the blood and used it up, releasing CO2 as a waste product. Therefore, the blood will contain a small amount of oxygen and a lot of CO2.

Question 9

Where does the air in the alveoli come from and according to this which gas will be in huge quantity in the air?

Answer 9

The air inside the air sac came from outside the body where the air contains a lot of oxygen and only a small amount of carbon dioxide. Therefore, the air will contain a small amount of CO2 and a lot of oxygen.

Question 10

What separates the air and the blood in the lungs?

Answer 10

The air very close to the blood with just two layers of very thin cells separating them.

Question 11

How does diffusion into the blood by oxygen happen in the lungs?

Answer 11

The oxygen particles in the air are a gas, so they are moving freely. They can easily move from the air, through the thin-walled cells and into the blood. This is called diffusion. The oxygen particles move from where there are a lot of them (in the air) to where there are fewer of them (in the blood).

Question 12

What is diffusion?

Answer 12

Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration, until equilibrium is reached.

Question 13

What happens when the oxygen goes into the blood?

Answer 13

When the oxygen gets into the blood, it dissolves.

Question 14

What happens after oxygen dissolves in the blood?

Answer 14

The oxygen goes into the red blood cells where it combines with haemoglobin.

Question 15

How does diffusion into the air by carbon dioxide happen in the lungs?

Answer 15

There is a lot of carbon dioxide in the blood in the capillary, and only a small quantity in the air inside the air sac. So, the carbon dioxide diffuses into the air in the air sac.

Question 16

What is done to increase the exchange of gases in the lungs?

Answer 16

To increase the exchange of gases in the lung, the alveoli are tiny and uncountable in number. This increases the surface area of the lungs making diffusion easier and faster.

Question 17

Explain what the experiment of agar jelly with holes represents an analogy for?

Answer 17

It is and anology of the air sacs with the dye representing oxygen and the holes air sacs in the lungs.

Question 18

Explain what the experiment of agar jelly with holes show?

Answer 18

It shows that gas exchange occurs better with a large surface area and that the volume of the air sacs doesn’t matter. A smaller volume of air sacs increases the surface area of the air sacs.

Question 19

Is the experiment of agar jelly with holes a good analogy?

Answer 19

Yes, it demonstrates basic principles of diffusion.
No, it does not accurately represent the lungs, which have a highly specialized structure, including a large surface area for gas exchange (due to numerous alveoli), a thin respiratory membrane for efficient diffusion, and active processes such as ventilation (breathing) to maintain concentration gradients.

Question 20

In the second experiment of comparing the carbon dioxide content of inspired and expired air using lime water, what happens to the first tube when you breath out?

Answer 20

Due to the air pressure the lime water moves up the glass tubing.

Question 21

In the second experiment of comparing the carbon dioxide content of inspired and expired air using lime water, what happens to the second tube when you breath out?

Answer 21

Limewater gets cloudy indicating carbon dioxide and is filled with bubbles.

Question 22

In the second experiment of comparing the carbon dioxide content of inspired and expired air using lime water, what happens to the first tube when you breath in?

Answer 22

It is filled with bubbles.

Question 23

In the second experiment of comparing the carbon dioxide content of inspired and expired air using lime water, what happens to the second tube when you breath in?

Answer 23

Limewater gets sucked up the glass tubing.

Question 24

What do you mean by inspired air?

Answer 24

Air you breath in.

Question 25

What do you mean by expired air?

Answer 25

Air you breath out.

Question 26

In which tube did your expired air bubble through limewater?

Answer 26

Second tube

Question 27

In which tube did your inspired air bubble through limewater?

Answer 27

First tube

Question 28

Which gas makes limewater cloudy?

Answer 28

CO2

Question 29

In the second experiment of comparing the carbon dioxide content of inspired and expired air using lime water, what do your results show?

Answer 29

It shows that expired air contains more carbon dioxide than inspired air because the limewater went cloudy quickly when I breathed out in the second tube. The first tube which contains the inspired air went cloudy later on.

Question 30

Describe the relationship between Lung surface area and Body mass.

Answer 30

The larger the body mass, the larger the surface area of air sacs as a larger body has more volume so more air sac increasing surface area for gas exchange.