Mrs Abrey Lesson 9 alveoli and ventilation
Post on 04-Jul-2015
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On wbs write out a flow diagram showing the route that O2 and CO2
gas takes
Structure of lungs and exchange
• Label the diagram to show the following:
– Red blood cells, capillaries, alveoli, air in , air out, Thin cell wall
• Colour in the arrows RED for the movement of oxygen and BLUE for the movement of carbon dioxide
• Describe and explain 3 adaptations of the alveoli for efficient gas exchange.
How are alveoli adapted?Alveoli have several adaptations that help to make gas exchange very efficient:
They are very thin – only one cell thick.
They are covered by a network of fine capillaries, enabling gases to pass almost directly between the lungs and bloodstream.
They are moist, encouraging gas molecules to easily dissolve.
They have a large combined surface area, allowing large amounts of gases to be exchanged with each breath.
Ventilation
Lesson objectives
• All will be able to describe the ventilation process
• Most will be explain how muscle bring about changes in pressure
• Some will be able to evaluate the limitations of the lungs in the bell jar as a model for ventilation
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
Ventilation
• How does inhaled and exhaled air differ?
• Can you explain why there are these differences?
Gas Inhaled Exhaled
Oxygen
Carbon dioxide
Nitrogen
Ventilation
• How do we get the oxygen and rid of carbon dioxide?
• Breathing in is also known as inhalation.
• Breathing out is also known as exhalation
Ventilation
• Place hand on your ribs and breathe in – what happens?
• What do the different parts in the bell jar represent?
• How does air get drawn into the lungs?
Ventilation
Ventilation
• Complete the statements to show how we inhale air– The intercostal muscles (between the ribs)
contract/relax
– The rib cage moves …… and …… and the diaphragm flattens.
– The volume of the thorax (chest) increases/decreases
– Causing the pressure to increase/decrease
– Air ……………………………….
Ventilation
• Now write your own flow diagram showing what happens when we breathe out…
Ventilation
• Complete the statements to show how we exhale air– The intercostal muscles (between the ribs)
contract/relax
– The rib cage moves …… and …… and the diaphragm becomes domed.
– The volume of the thorax (chest) increases/decreases
– Causing the pressure to increase/decrease
– Air ……………………………….
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