Phys Exam III Altitude
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WHy is wind chill less at higher altitude?
THeir is a reduction of air density
What happens to solar radiation with increase of altitude?
Solar radiation increases with altitude
What happens to alveolar pressure with hypoxia?
It rapidly decreases then stays constant during hypoxia
What happens to minute ventilation during hypoxia?
It steadly increases over time
What happens to the pressure of oxygen and carbon dioxide during hypoxia?
- Increases pressure of oxygen
- Decreases pressure of carbon dioxide
What do glomus cells in carotid bodies do?
When stimulated they increase ventilation
What stimulates glomus cells?
With hyperventilation it increases pO2 and decreases pCO2 which are opposite forces what does the body do to sustain hyperventilation?
- CO2 + H2O --> H+ + HCO3
- HCO3 is taken out of CSF to reduce pH
- Glomus cells become more sensitive to pO2
- Kidneys excrete more HCO3 lowering plasma pH
During hypoxia what kind of cardiovascular acclimatization happen?
- increase cardiac output
- Hypoxia stimulates HIF1A, which stimulates EPOgene, which stimulates erythopetin (kidneys), which increases RBC
- Affects Hb-O2 dissociation
What are some problems with increase RBC?
- Increases the viscosity, can lead to heart failure
- Risk of infection
What happens to Hb-O2 dissociation during hypoxia cardiovascular acclimization?
Increases the p50, which therefore causes a shift in the Hb-O2 dissociation curve to the right, which has the same binding affinity of O2 at the lungs but decreases the binding affinity of O2 at the tissues making it easier for the tissues to obtain the O2
What is HAPE?
- High altitude pulmonary edema
- Hypoxia induces pulmonary hypertension: locally low pulmonary pO2 triggers vasocontriction
- Hypertension leads to leakage accross capillaries
- Lungs fill with blood and water
How do you treat HAPE?
What is HACE?
- High altitude cerebral edema
- Leakage across blood-brain barrier leads to edema
What is the best treament for HACE?
Get down the mountain
What is AMS
- Acute mountain sickness
- "Altitude sickness"
What would you like to do?
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