Gas Exchange (Core)

Assessment StatementsObj Distinguish between ventilation, respiration and gas exchange Explain the need for a ventilation system Describe the features of alveoli that adapt them to gas exchange Draw and label a diagram of the ventilation system, including trachea, lungs, bronchi, bronchioles and alveoli Explain the mechanism of ventilation of the lungs, in terms of volume and pressure changes caused by the internal and external intercostal muscles, the diaphragm and abdominal muscles. 3 Assessment statements from: Online IB Biology Subject GuideOnline IB Biology Subject GuideCommand terms: What connections can you make with other topics? Gas Exchange

MrT says… I pity the fool who thinks breathing is respiration.

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 past the alveoli brings blood with a high CO 2 concentration and low O 2 concentration. Breathing out keeps the CO 2 concentration in the alveoli low, so it diffuses out of the blood. Breathing in keeps O 2 concentration in the alveoli high, so it diffuses into the blood. Diagram from: Topic 6.4.2

Your Task – To create a life size model of the body over the course of the Human Physiology Unit Circulatory Section– Materials : Large Poster Paper Construction Paper Scissors Tape Markers Steps – 1.Cut out and label a respiratory system and put it on the body in the correct positioning. 2.You must include all of the macro structures (Sinus Cavity, Lungs, Trachea, Bronchii, Bronchioles, Alveoli) with one lung cut so that you can see the internal structures. 3.Make one bundle of Alveoli surrounded with the capillaries coming from the Right Ventricle of the heart, and returning to the Left Atrium.

hill.com/sites/ /student_view0/chapter25/animation__gas _exchange_during_respiration.html Topic 6.4.2

Topic 6.4.3

Which process(es) of membrane transport are being used in gas exchange at the membranes of the alveoli? Topic 6.4.3

Topic 6.4.4

Topic 6.4.5

Carbon Monoxide Poisoning – the silent killer (CO) What is occurring in this graph as a result of prolonged exposure to CO?

Breathing Exercises – desk yoga (it’s IB after all, let’s bust some stress) 1.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. 2.Breathing observation Close your eyes, breathe normally. “Observe” the breathing process. 3.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