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Flashcards in Respiration 4 Deck (9)
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What is Henrys law

Concentration of gas dissolved = s x Partial pressure of gas


What conditions change during deep sea diving

For every 10 metres descended the barometric pressure increases by 1atm

This means by Henry's law that the amount of gas dissolved in the blood will increase.



What is nitrogen narcosis?

Symptoms appear at 30m deep

Due to too much nitrogen dissolving into the blood - Nitrogen has a higher solubility in lipids than it does in blood - Acts like a volatile anaesthetic altering ion cunductance

Causes similar feeling to being drunk

Overcome by shortening depth and duration of the dive or replacing the nitrogen in the gas composition with helium


What is Oxygen toxicity 

At atmospheric pressure Hb is almost entirely saturated - So by increasing pressure any extra oxygen is going to dissolve into the plasma

At 40m its equivelent to breathing in 100% oxygen at sea level

Short term this is ok - long term can cause respiratory tract damage and CNS problems

At 90m can cause seizures/coma

Problems due to increased number of free radicals

Solution is to reduce the conc of O2 in the gas mixture


What is decompression sickness

Build up of N2 in tissues comes with time and depth - If the return to sea level is too fast than the N2 comes out of solution forming bubbles

Solution is to return to sea level slowly

Decompression chamber


What happens to barometric pressures every 5500m>

Falls by a half


How does oxygen offload change from sea level to 3000m?

At sea level oxygen at 100mgHg saturates 98% of Hb

Venous return is around 40mmHg with 75% Hb saturated

So a change in 23% saturation has offloaded 60mmHg to tissue around the body

At 3000m O2 is around 60mmHg

It is in the steep portion of the curve so the same change in saturation meaning venous blood retuns at 30mmHg but only half the amount of oxygen was delivered


What compensations are in place to deal with high altitude?

Increasd in respiratory rate to minimise the difference between alveolar and ambient O2 levels

Increased Co2 loss producing a respiratory alkalosis producing a renal response

Increase in heart rate


What are the breathing conditions for space flight

At launch they breathe oxygen nitrogen mix at 60/40 at a pressure of 258mmHg

258/60 = 154.8mmHg - same as sea level

During space flight they breathe 100% O2 at 155mmHg