Adaptations To Altitude Flashcards
Why is altitude a hypoxic environment?
Low barometric pressure (hypobaric environment)
What kinds of things occur when going higher in altitude
Psychomotor effects due to lack of o2 to brain
Loss of consciousness
What barometric pressure are aircrafts at and what’s the result of this
Barometric pressure of a higher altitude than sea level
Therefore lower po2 levels
What is another way of saying barometric pressure
Atmospheric (mix of all gases)
What is typical mmhg po2 at altitude compared to 100 normally
42
Why is low po2 at altitude affecting gas exchange
Lack of a diffusion gradient between alveoli, blood and tissues
Does minute ventilation increase when in altitude due to low po2
Yes
Increase TV and ventilation rate
What is the acute response to hypoxia called
Hypoxic ventilatory response (ie via peripheral chemoreceptors)
What happens to increase hyper ventilation at altitude
Detection of lower po2 eg 60 mmhg
Detection via glomus cells in carotid peripheral chemoreceptors
Impulse sent down X to drg and vrg to increase hyperventilating
What happens due to the hyperventilation of the peripheral chemoreceptors
Increased respiratory alkalosis as less co2 can react with water
This increased ph is detected / low co2 detected and causes hypo ventilation = not enough oxygen at altitude
Which acute response is there for acid base homeostasis due to hyperventilation at altitude
Renal compensation
How does renal compensation deal with resp alkalosis due to hyperventilation
Reduce HCO reabsorption to reduce ph (HCO is alkali)
Also stop A cell action which excrete H
What is reduced co2 called causing alkalosis
Hypocapnia
How does diamox drug also work to reduce ph for alkalosis due to hyperventilation
It is a CA inhibitor
Stops H2co3 changing to co2 and water
Increase H levels so reduces ph
How does saturation of Hb change in altitude
Saturated until around 2000 when po2 is too low due to hypobaric pressure
Causes dissociation
