1. Gas Exchange

2. Gas Exchange (cont’d) Look back at the aerobic respiration equation.
What 2 substances are needed?
What 2 substances are the waste products?

3. Gas Exchange (cont’d)
In organisms there are places where oxygen enters and carbon dioxide leaves.
When one gas enters and another gas leaves, that surface is for Gas Exchange
These surfaces have certain characteristics

4. Characteristics of GE surfaces
The surface must be:
1)Permeable / thin enough to allow for diffusion

5. Characteristics of GE surfaces
The surface must be:
2) Close to an efficient transport system to take gases to and from the exchange surface.

6. Characteristics of GE surfaces
The surface must be:
3) Kept moist, to stop cells from drying out and dieing.

7. Characteristics of GE surfaces
The surface must:
4) Have a large surface area, so that a lot of gas can diffuse at the same time.
5)Good supply of oxygen

8. Function (physiology)
Lung
Spongy, air-filled organs that are on either side of the heart.
EXTRA CREDIT: go to youtube.com
search for “balloon lung model”
Watch videos, create model, share with class.

9. Lung

10. Function (physiology)
Trachea:
Pipe to supply the lungs with air.
Supported by rings of cartilage.

11. Trachea
Lung

12. Function (physiology)
Larynx
Also known as the voice box
Can tighten muscles known as vocal cords, as air passes over
these muscles they
vibrate, producing
sound.

13. Larynx
Trachea
Lung

14. Function (physiology)
Bronchi
Around your heart, the trachea splits into 2 tubes. These two branches are called the left and right Bronchi. (singular: bronchus)
One bronchus goes into each lung, and then continue to branch into even smaller tubes.

15. Larynx
Trachea
Lung
Bronchi

16. Function (physiology)
Bronchioles
Tubes that branch off the bronchi, ending in tiny air sacs called alveoli.

17. Larynx
Trachea
Lung
Bronchioles
Bronchi

18. Homework1-31-13 10 pts. Correct order: Characteristics of gas exchange
Mouth
Trachea
Bronchus
Alveoli
Characteristics of gas exchange
Permeable/ thin for diffusion
Close to transport system
Needs to be moist (if it dries, it dies)
Large surface area for diffusion
Supply of oxygen
The process which removes carbon dioxide from the cell and oxygen from cells is diffusion

19. Get out your “Flash Cards”
Put “Aerobic Respiration” on the back
Put the cards in correct order
Write these definition in yesterday’s notes
Respiration - chemical reactions that breakdown nutrient molecules(glucose) in living cells to release energy
Aerobic Respiration - release of large amounts of energy in cells by breaking down food substances (glucose) in the presence of oxygen

20. Tell me what we have made
We made a model of something we are studying in this unit.
Look at what you see:
Draw it
Describe each part and what it represents. Use qualitative and quantitative descriptions
Share your ideas with your neighbor

21. Function (physiology)
Alveoli
At the end of each bronchiole are many tiny air sacs called alveoli.
This is where gas exchange ACTUALLY TAKES PLACE.
Surrounding the alveoli are capillaries, tiny blood vessels. Oxygen diffuses from the alveoli into the capillary, CO2 is opposite.

24. What are we really breathing?
The composition of exhaled air (air that is breathed out) is very different from the composition of inhaled air (air that is breathed in).

25. Composition of Air
Inhaled air has the same composition as normal air, it contains:
78% nitrogen
21% oxygen
1% inert gas such as argon
0.04% carbon dioxide
little water vapor
Exhaled air is saturated with water vapor, it contains:
78% nitrogen
17% oxygen
1% inert gas such as argon
4% carbon dioxide
saturated with water vapor