1. Gas Exchange

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5. Why do we need a ventilation system?
We are large organisms. Oxygen cannot diffuse into all our
cells directly from the air, nor can waste products be directly
ejected from the body. We have specialized organ systems,
which are efficient, but need delivery of nutrients and
removal of waste. The ventilation system ensures the blood
can be the medium for this.
We are land-borne. Gases need moist surfaces (membranes) in
order to diffuse. Our lungs are moist membranes, allowing
oxygen to diffuse into the blood and carbon dioxide
to diffuse out.
The ventilation system maintains a large
concentration gradient between the alveoli and
the blood. The constant flow of blood past the alveoli brings
blood with a high CO2 concentration and low O2
concentration. Breathing out keeps the CO2 concentration
in the alveoli low, so it diffuses out of the blood.
Breathing in keeps O2 concentration in the alveoli high,
so it diffuses into the blood.
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Diagram from:

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8. Data Analysis – What does this tidal volume graph tell you about the process of breathing?
See what inferences you can make with regard to –
Amount of air taken in in the average breath
Amount of air pushed out.
Maximum capacity of the lung
Key –
Tidal Volume – regular breathing changes
Inspiratory Reserve – amount a deep breath can intake
Expiratory reserve – amount a heavy exhale can emit

9. http://highered. mcgraw-hill
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11. Type I Pneumocytes Type II Pneumocytes
Transport across the alveolar membrane is assisted by two different types of cells, known as pneumocytes.
Type I Pneumocytes
Extremely Thin,
Adapted to carry out gas exchange
Diagram
Type II Pneumocytes
Secrete a solution containing surfactant that creates a moist environment to prevent the sides of the alveolus to adhere to each other by reducing surface tension.
Light Micrograph

12. Which process(es) of membrane transport are being used in gas exchange at the membranes of the alveoli?
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15. Many major lung diseases are caused by a malfunctioning protein and/or structure within the gas exchange pathway.
Research the causes and consequences of the following diseases:
Tuberculosis
Lung Cancer
Emphysema
Cystic Fibrosis
Causes
Consequences

17. Breathing Exercises – desk yoga
(it’s IB after all, let’s bust some stress)
Simple exercises. Keep your neck straight.
Rotate shoulders forwards, then backwards, 5 times each.
Bend your neck to touch your head to your shoulder, left then right, 5 times each.
Tilt your head forward, touching chest, then backward, 5 times each.
Breathing observation
Close your eyes, breathe normally.
“Observe” the breathing process.
Pranayama
Stand up.
Take gentle, deep breaths.
Feel the air moving in and out, trying to control its flow.
Think happy thoughts about graduation.
Breathing exercises from:
Image: '11,750 Foot Yoga Moment'
Found on flickrcc.net