Download 6.4 Gas Exchange - Phoenix Union High School District

6.4 Gas Exchange
http://www.youtube.com/watch?v=HiT621PrrO0
Coloring Activity – 15 minutes
6.4.1
• Ventilation
• The process of moving air into and out of the
lungs.
• It involves muscular movement and requires
energy.
• It maintains a concentration gradient so that
oxygen can continue diffusing into the blood. It
keeps the oxygen concentration higher in the lungs
than in the blood.
6.4.1
• Ventilation – 2 steps
• Inspiration
• Expiration
6.4.5
With a partner…
• Try to figure out what happens each time you inhale and
exhale.
• Determine what happens to each of the following:
•
•
•
•
volume of lungs
Muscles around the ribcage
Diaphragm
Pressure in the lungs
6.4.5
• The external intercostal muscles contract
and move the ribcage up and outward.
• The diaphragm contracts, flattening it
downward.
• Both actions have the effect of increasing
the volume of the chest cavity.
• As the volume increases, the pressure
decreases and the air flows into the lungs.
Inspiration
• The external intercostal muscles relax
and the ribcage moves back down.
• The internal intercostal muscles
contract.
• The diaphragm relaxes, moving it back
up.
• Both actions have the effect of
decreasing the volume of the chest
cavity.
• As the volume decreases, the pressure
increases and the air flows out of the
lungs.
Expiration
6.4.5
• http://www.footprints-science.co.uk/breathing1.htm
• Why is a ventilation system
necessary?
• 1. To maintain a concentration
gradient so that gas exchange can
occur.
• To keep SA:V ratio high so that
diffusion can occur.
6.4.2
The Respiratory System
Pharynx vs. Larynx
• Gas Exchange
• The movement (diffusion) of oxygen from the air
in the lungs into the blood AND carbon dioxide in
the opposite direction.
• There are two sites for gas exchange
• 1.Alveoli: Oxygen diffuses into the blood from the alveoli
and carbon dioxide diffuses from the blood into the alveoli
• 2. Tissues: Oxygen diffuses from blood into the cells and
carbon dioxide diffuses from cells to the blood
6.4.1
6.4.1
Draw this!
• Four features of alveoli allow
efficient gas exchange
• Large surface area
• Thin – things can diffuse quick
• Moist – gases dissolve before passing
through membranes
• Good blood supply – maintains the
concentration gradient
6.4.3
Alveoli
How many membranes
must an oxygen molecule
pass through in order to
enter a erythrocyte?
6.4.1
• Cell Respiration
• The cellular process of releasing energy from food
(large organic molecules). In the presence of
oxygen, 1 glucose molecule yields 36 ATP
molecules.
6.4.1
• Ventilation (V), gas exchange (GE) and
cell respiration(CR) are all dependent on
each other.
• V requires energy provided by CR.
• GE depends on a concentration gradient
provided by V.
• CR is more efficient in the presence of
oxygen which relies on GE.
6.4.1
Ventilation
Where
Energy
Physical or
Chemical
Process?
Gas Exchange
Cell Respiration
Diagram
http://lgfl.skoool.co.uk/keystag
11_48
Asthma
• Draw and label a diagram of the ventilation system,
including trachea, lungs, bronchi, bronchioles and
alveoli.
6.4.4