Gas Exchange

http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP15104

Topic 6.4.1

Topic 6.4.2

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. Topic 6.4.2 Diagram from: http://www.sciencequiz.net/jcscience/jcbiology/gapfilling/breathingsystem.htm

Topic 6.4.4

Topic 6.4.5

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

http://highered. mcgraw-hill http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter25/animation__gas_exchange_during_respiration.html Topic 6.4.2

Topic 6.4.3

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

Which process(es) of membrane transport are being used in gas exchange at the membranes of the alveoli? Topic 6.4.3 http://www.footprints-science.co.uk/alveoli.htm

Topic 6.4.3

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

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: http://www.healthandyoga.com/html/news/exercise.html Image: '11,750 Foot Yoga Moment' http://www.flickr.com/photos/94833286@N00/2838289483 Found on flickrcc.net