Transcript 6.2 Respiration gas exchangex - HIS-IGSci-Bio

B6 Respiration
6.2 Gas Exchange
Identify and label the parts of the
respiratory system
Identify and label the parts of the
respiratory system
nose
mouth
Bronchus
(bronchi)
lung
pharynx
larynx
trachea
rib
plural
membrane
intercostal
muscle
Alveolus (alveoli)
bronchiole
diaphragm
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
Red blood cells in an alvelous
Alveolar circulation
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.
Click on the “Passage of air” buttons
The mechanics of breathing
Inhalation
Exhalation
Intercostal muscles
contract
relax
Diaphragm
contracts
relaxes
Volume of thorax
increases
decreases
Pressure in thorax
decreases
increases
air is pulled in
air is pushed out
Effect
Respiratory system
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.
1
2
3
4
5
6
7
8
9
Mucous and cilia
The cells lining the nose and trachea are designed to trap
dust and bacteria.
trachea
ciliated epithelial cells
The cells that line the wall of the trachea show two
special adaptations.
tiny hairs called cilia
produce a sticky liquid mucous
Ciliated epithelial cells
We say the cells show specialisation.
These specialised cells have a particular job to do.
The presence of mucus and cilia on the lining of the trachea
ensures that the air we breathe is clean and free from
disease.
microbes travelling
down the trachea
within inhaled air
ciliated cells
microbes become stuck
within the mucus
mucus being made by the ciliated cells
Mucus cells and cilia
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
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 p164-165 to describe the effects of the other
components of smoke on our bodies:
 Tar
 Carbon monoxide
 Smoke particles
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.