H6+Gas+exchange

H Further human physiology - H1 Hormonal control - H2 Digestion - H3 Absorption of digested foods - H4 Functions of the liver - H5 The transport system - H6 Gas exchange

This diagram of Haemoglobin shows both the four sub-units (each one is capable of carrying a molecule of oxygen) and the Iron ion which is key to haemoglobin's affinity with oxygen. image from:[| http://themedicalbiochemistrypage.org/hemoglobin-myoglobin.phpi]
 * Starter**


 * Assessment statements** (IBO notes added to some point to clearly indicate what needs to be understood and what does not)
 * H.6.1 || Define partial pressure. ||
 * H.6.2 || Explain the oxygen dissociation curves of adult hemoglobin, fetal hemoglobin and myoglobin. ||
 * H.6.3 || Describe how carbon dioxide is carried by the blood, including the action of carbonic anhydrase, the chloride shift and buffering by plasma proteins. ||
 * H.6.4 || Explain the role of the Bohr shift in the supply of oxygen to respiring tissues. ||
 * H.6.5 || Explain how and why ventilation rate varies with exercise. Limit this to the effects of changes in carbon dioxide concentration leading to a lowering of blood pH. This is detected by chemosensors in the aorta and carotid arteries that send impulses to the breathing centre of the brain. Nerve impulses are then sent to the diaphragm and the intercostal muscles to increase contraction or relaxation rates. ||
 * H.6.6 || Outline the possible causes of asthma and its effects on the gas exchange system. ||
 * H.6.7 || Explain the problem of gas exchange at high altitudes and the way the body acclimatizes. ||

Log in to the [|DCS Bridge] to obtain your workbooks and supporting resources
 * Workbooks and Worksheets **

Steven Taylor ( [|i-Biology] ) has a great presentation to view and take notes from before starting your notebook media type="custom" key="24444936"
 * Presentations and tutorials **

A tutorial on the changes in O2 and CO2 partial pressure and gas exchange from McGraw and Hill

[|i-Biology] has a very good set of links and videos to support your learning

Mr Rothery has concise notes on oxygen [|dissociation curves] and [|CO2 transport]. These notes are aimed at A-level students, use what is relevant to your IB course.

Good notes on the respiratory system and gas exchange from Miami University.

The Bohr effect - use the [|Get Body Smart animation] produce your own graph to show the affect of pH upon O2 dissociation media type="custom" key="20520036"

Use [|click4biology] to review and complete your notes

View the [|i-Biology] presentation, read your textbook and consult [|click4biology] and links above. Now follow the the included guidelines to complete your set of Bioknowledgy notes. media type="custom" key="24444950"
 * Approach**

It has been recently discovered that diving mammals possess specialised adapted myoglobin to allow them to store large amounts of oxygen in muscle tissue. Read either the summary by BBC or the full article in Science to learn more. This is relevant to just to your studies in gas exchange, but also in protein structure and evolution.
 * Interesting Extras**

We suffer from altitude sickness when the PO2 of oxygen drops too low. Scuba divers have the reverse problem PO2 increases as they descend to greater depths. Too much PO2 can cause oxygen toxicity. Oxygen is not normally a substance we consider to be toxic, but the effects dramatic. Use the articles to find out more:
 * Midwest scuba diving magazine
 * Scottish diving medicine