Ch.15 Flashcards
What are hypobaric conditions?
Reduced Pb seen at altitude
What does hypobaric conditions result in?
Hypoxia and hypoxemia
How is pulmonary ventilation affected by acute altitude exposure?
Increases immediately at rest and sub max exercise but not maximal
What does a decrease in PO2 stimulate?
Chemoreceptors in aortic arch and carotids
When pulmonary ventilation increases, how is TV affected?
It is increased and increase in ventilation rate for several hours/days
How is ventilation affected at altitude?
It is increased which means hyperventilation
What is respiratory alkalosis?
Blowing off CO2 which causes high blood pH
What does alkalosis cause?
The oxyhemoglobin curve shifts left and it prevents further hypoxia-driven hyperventilation
What effect does the increased excretion of bicarbonate from the kidneys have on the blood?
It minimizes blood buffering capacity and reverses alkalosis which means blood pH decreases to normal
What are the short-term affects of acute altitude exposure?
Respiratory water loss which increases urine production
Lose up to 25% plasma volume
Short-term increase in hematocrit (O2 density)
What happens to the red blood cell count at altitude?
It increases after weeks/months
What triggers EPO to be released from kidneys?
Hypoxemia
Does cardiac output increase at altitude (sub max and rest)?
Yes, it increases despite decrease in plasma and stroke volume
What supplements this increase in cardiac output?
The increase in HR which was caused by an increase in sympathetic nervous system activity
What happens to CO with max exercise?
It decreases due to decrease in SV and HR
