1. B6 Respiration
6.2 Gas Exchange

2. Identify and label the parts of the respiratory system

3. Identify and label the parts of the respiratory system
nose
mouth
pharynx
larynx
Bronchus (bronchi)
trachea
plural membrane
rib
lung
intercostal muscle
Alveolus (alveoli)
bronchiole
diaphragm

4. Gas exchange Occurs at alveoli Oxygen diffuses into capillaries
Carbon dioxide diffuses out of capillaries
Occurs at cells
Oxygen diffuses into cells
Carbon dioxide diffuses into capillaries
Copy into your books the diagram on p121

5. Red blood cells in an alvelous
Alveolar circulation

6. Features of gas exchange surfaces
Gas exchange surfaces in animals have features that make them more efficient:
Large surface area
Moist surface so gases will dissolve
Walls that are only 1 cell thick to reduce diffusion distance
A good blood supply to maintain concentration gradient.

8. Click on the “Passage of air” buttons

9. The mechanics of breathing
Inhalation
Exhalation
Intercostal muscles
contract
relax
Diaphragm
contracts
relaxes
Volume of thorax
increases
decreases
Pressure in thorax
Effect
air is pulled in
air is pushed out
Respiratory system

10. Comparing inhaled and exhaled air
What are the differences between inhaled and exhaled air?
inhaled air
nitrogen (78%)
oxygen (21%)
carbon dioxide (0.04%)
other
exhaled air
nitrogen (78%)
oxygen (17%)
carbon dioxide (4%)
other
Copy in the table on p120 to show the different compositions.

11. 1 2 3 4 5 6 7 8 9

12. Mucous and cilia
The cells lining the nose and trachea are designed to trap dust and bacteria.
trachea
ciliated epithelial cells

13. Ciliated epithelial cells
The cells that line the wall of the trachea show two special adaptations.
produce a sticky liquid - mucous
tiny hairs called cilia
Ciliated epithelial cells
We say the cells show specialisation.
These specialised cells have a particular job to do.

14. The presence of mucus and cilia on the lining of the trachea ensures that the air we breathe is clean and free from disease.
ciliated cells
mucus being made by the ciliated cells
microbes travelling down the trachea within inhaled air
microbes become stuck within the mucus
Mucus cells and cilia

15. Tobacco
Tobacco comes from the Americas and was introduced to the rest of the world by traders.
Can be taken in the form of cigarettes, cigars, pipes and chewing tobacco.
The tobacco plant is called Nicotiana tobacca

16. Tobacco The plant makes an insecticide called nicotine
Nicotine acts as an addictive drug in our body
in the blood stream, nicotine acts as a stimulant to make the heart beat faster and the small arteries narrow – thus increasing blood pressure.
nicotine increases the stickiness of blood platelets
Use p to describe the effects of the other components of smoke on our bodies:
Tar
Carbon monoxide
Smoke particles

17. Effects of smoking
Second hand smoke
Effects of smoking
The chemicals in tobacco smoke have effects on the heart, circulatory system and the respiratory system.
Hot tobacco smoke can irritate the mucus-producing cells and cause cilia to stop beating:
Chronic bronchitis is caused when bacteria-filled phlegm (mucus) blocks the bronchi, making it harder to breathe.
“smoker’s cough” to help move the phlegm out
Emphysema is when the walls of the alveoli break down, reducing the surface area for gas exchange making people gasp for breath
Nicotine causes platelets to become stickier, trapping fatty deposits in blood vessels. This narrows the vessel walls and can cause heart disease.
Tar in tobacco smoke is carcinogenic, causing cancer. The most common cancer in smokers is lung cancer. Cancer is when body cells begin to grow out of control.