Human Physiology Respiratory Assignment 2014/15 SURNAMES A-D.
You need to provide concise, but accurate answers, which provide clear explanations. You will need to research some topics beyond the material covered in lectures.

1. Explain how the following change in response to ascent to high altitude, and explain why these are physiologically useful adaptations:

a) The haematocrit

b) Red blood cell 2,3 DPG levels

c) Tissue myoglobin levels (9 marks)

2. Explain why individuals can suffer from the following at high altitude:

a) Cheyne-stokes breathing: At high altitude, the body senses low oxygen levels and this becomes the main drive to breathe. Breathing faster and deeper at high altitude leads to a profound reduction in the carbon dioxide levels in the blood. http://www.altitude.org/sleep_at_high_altitude.php

b) Pulmonary oedema: shortage of oxygen which is caused by the lower air pressure at high altitudes. Increased pulmonary arterial and capillary pressures (pulmonary hypertension) secondary to hypoxic pulmonary vasoconstriction. An idiopathic non-inflammatory increase in the permeability of the vascular endothelium. http://en.wikipedia.org/wiki/High-altitude_pulmonary_edema

excess fluid develops in the lungs, either in the lung tissue itself or in the space normally used for gas exchange. This means individuals are unable to perform gas exchange properly, and so person cannot get enough oxygen to function normally. It is caused, again, by poor acclimatisation and is often more common in males, although it is not clear whether this is behaviour related or due to genetic susceptibility. http://www.climbing-high.com/high-altitude-pulmonary-edema.html (6 marks)

3. Experiments on ventilation rate were conducted where a subject breathed in and out of a spirometer (capacity 9L). The gas inside the spirometer was varied as shown below. In