Describe the common symptoms of hypoxia.

• Fuzzy thick feeling of the head
• Slowness of thought
• Poor or lack of judgement
• Clumsiness
• Euphoria
• Mental fixation on trivial tasks
• Loss of visual sharpness, dimming, tunnel vision reduced colour vision
• Deep sighs and hyperventilation
• Blue peripheries (fingers, lips) 

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Explain the causes of hypoxia.

Hypoxia is caused when the oxygen breathed into the lungs has not got sufficient pressure to be able to diffuse through the lung semipermeable membrane into the bloodstream

Thus the body cells have an inadequate delivery of oxygen

Explain the mechanical effect of the partial pressure of oxygen on oxygen transfer in the lungs. 

When the partial pressure of the oxygen in the lungs is or over 102 mmHg then this allows for transfer of oxygen through the lungs to bloodstream

State the partial pressure of oxygen both inside and outside the lungs at sea level.

At sea level the atmospheric air pressure is 760mmHg.

Oxygen makes up 21% of this air which would equate to about 160mmHg of partial pressure

Inside the lungs the minimum pressure that the oxygen must be for diffusion into the bloodstream is 102mmHg

The partial pressure of O2 decreases once breathed in due to the presence of carbon dioxide and water vapour inside the lungs 

Define hypoxia.

Hypoxia is a condition that occurs when the available oxygen in the blood is inadequate for the demands of the body cells  

Describe the role of the lungs in oxygen and carbon dioxide transfer.

Oxygen is breathed into the lungs, diffused through the walls of the lungs and into the bloodstream where it attaches itself to Haemoglobin.

Haemoglobin is the transport system for oxygen within the blood stream

The oxygen is transported through the arteries to cells throughout the body

The Haemoglobin has the property of remaining bound to the oxygen molecules until it enters an area of very low oxygen tension where the oxygen is then released into these tissues

Carbon dioxide diffuses into the blood from the peripheral tissues and is carried in solution to the blood through the veins as carbonic acid.

The veins deliver the carbon dioxide to the lungs where it is exhaled as a waste product

Describe the anatomy and physiology of the respiratory system.

• Respiratory System – The system in the human body that enables us to breathe. The act of breathing includes inhaling and exhaling air in the body, the absorption of oxygen from the air and the discharge of carbon dioxide
• Blood – a fluid that delivers necessary substances such as nutrients and oxygen to the cells 
• Haemoglobin – the transport system for oxygen within the blood 
• lungs – a pair of spongy, air-filled organs located on either side of the chest 
• Arteries – blood vessels that are responsible for carrying oxygen-rich blood away from the heart to the body 
• Veins – blood vessels that carry blood low in oxygen from the body back to the heart for reoxygenation 
• Heart – a muscular pump, about the size of a closed fist, that is divided into two sides, each with two chambers 

Oxygen is breathed into the lungs, diffused through the walls of the lungs and into the bloodstream where it attaches itself to Haemoglobin.

Haemoglobin is the transport system for oxygen within the blood stream

The oxygen is transported through the arteries to cells throughout the body

The Haemoglobin has the property of remaining bound to the oxygen molecules until it enters an area of very low oxygen tension where the oxygen is then released into the tissues

Carbon dioxide diffuses into the blood from the peripheral tissues and is carried in solution to the blood through the veins as carbonic acid.

The veins deliver the carbon dioxide to the lungs where it is exhaled as a waste product

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Explain how the partial pressure of oxygen changes as altitude increases.

As altitude increases the partial pressure of oxygen decreases – but remains adequate up to a height of 10,000 ft.

Above this height, the partial pressure is too low for humans to breath an adequate amount of oxygen 

Describe the variation of pressure as altitude increases.

As altitude increases, pressure decreases 

At 18,000 ft, pressure is approximately 1/2 sea level pressure 

At 34,000 ft, pressure is approximately 1/4 sea level pressure