1. The Respiratory System
SNC2D

2. Breathing
Why do we breathe?

3. Breathing
Why do we breathe? Because we need oxygen. (and we need to get rid of carbon dioxide)

4. Breathing
Why do we breathe? Because we need oxygen. Why do we need oxygen?

5. Breathing
Why do we breathe? Because we need oxygen. Why do we need oxygen? Because oxygen is a reactant in respiration: oxygen + glucose  carbon dioxide + water which is how our cells get their ______

6. Breathing
Why do we breathe? Because we need oxygen. Why do we need oxygen? Because oxygen is a reactant in respiration: oxygen + glucose  carbon dioxide + water which is how our cells get their energy

7. Breathing
Breathing is an involuntary mechanical action, triggered by an increased level of carbon dioxide in the blood.

8. The Diaphragm
When you inhale, your rib muscles move out and a muscle called the diaphragm moves down to draw air into the lungs.

9. The Mouth and Nose
Air is drawn in through the mouth and nose. The inside of the nose is lined with hairs to filter out dust and pollen and mucus to trap germs (usually bacteria).

10. The Trachea
The air then enters the windpipe, or trachea, which is also lined with mucus and with microscopic hairs called cilia, which sweep in an outward direction.

11. Coughing and Sneezing
Any harmful substances that make it past the hairs and mucus may be forced from the system by the gusts of air produced by coughing or sneezing.

12. No defence
However, the body’s defences work against only small doses of air-borne particles and only for a short time – and only against particulates – not organic chemical compounds like fragrances and pesticides.

13. Asthma
Some contaminants in some people will trigger inflammation of the airways.

14. Asthma
Some contaminants in some people will trigger inflammation of the airways, i.e. asthma. People with asthma inhale corticosteroids (using “puffers”) to reduce the inflammation.

15. The Airways
The trachea branches into two tubes called bronchi, which branch into smaller and smaller tubes.

16. Alveoli
These tubes end in air sacs called alveoli. Surrounding the air sacs are capillaries. The blood in the capillaries absorbs some of the oxygen in the air and releases carbon dioxide.

17. Exhaling
The rib muscles then move inward and the diaphragm moves upward and the carbon-dioxide-enriched air is expelled from your lungs.

18. Respiration
The oxygen-enriched blood returns to the heart to be pumped to all the cells of the body so that they can perform respiration for energy.