Respiratory Physiology - Control of Ventilation - Acid base balance - exercise Flashcards
What stimulates the increase in ventilation during moderate exercise?
we don’t know
not driven by blood-gas composition
What is the increase in ventilation during exercise proportionate to?
metabolism
How does the PCO2 and PO2 remain constant during moderate exercise?
increased ventilation
Why does ventilation increase during strenuous exercise?
increased lactic acid production
increases [H+]
Why increases more during strenuous exercise, metabolism or ventilation?
ventilation increases more
How can you describe the increase in H+ conc during strenuous exercise?
lactic acidosis
Do you hypo or hyperventilate during strenuous exercise?
hyperventilate
Is arterial gas composition and pH voluntary of involuntary stimuli?
involuntary, we cannot control
Can we override the arterial gas composition and pH
no
What happens of you hold your breath for extended period of time?
oxygen levels fall to low to maintain consciousness, fall too low and brainstem takes over. to recover Oxygen levels
What happens to breathing during hyperventilation?
ventilation is reflexly inhibited by an increase in arterial PO2 r decrease in arterial PCO2/[H+]
Why is hyperventilation dangerous?
oxygen levels fall, faster than your CO2 levels rise.
the oxygen can be so low that you lose consciousness
What is more uncomfortable,
chamber 1: normal PO2 and high PCO2
chamber 2: low PO2 and normal (i.e no) PCO2
chamber 1 very unpleasant
chamber 2: mild discomfort
Why is a chamber with normal PO2 and high PCO2 more distressful?
as soon as you breath in CO2, you disrupt the partial pressure gradient.
reduce partial pressure gradient. moves into the system circulation and moves into tissues
toxic effect
What will breathing in a high PCO2, what receptors are stimulated and what occurs?
central chemoreceptors stimulate the respiratory centre and promote hyperventilation
