November 1, 2023 Flashcards
(25 cards)
VT =
tidal volume (about 500mls)
VT = VD (dead space ventilation/about equal to body weight in pounds; pounds to mls) + VA (alveolar ventilation/gas exchange)
Vital capacity?
inspire as much as possible and then expire as much as possible
VC = IRV + VT + ERV
Inspiratory capacity =
maximal inspiration above normal inspiration
IC = VT + IRV
TLC =
RV + ERV + VT + IRV
Residual volume (about 20%) =
air remaining in the lung at all times
what is the formula for minute ventilation (VE)
VE = VT x F
F = frequency = 12 breaths/min
why is Total minute ventilation reduced in Trained people during submaximal exercise
Total minute ventilation is reduced because…
Produce less lactic acid, less acidosis, lower pH change, lower hydrogen ion concentration (high H+ drive increase in ventilation); greater reliance on aerobic system
Decreased sensitivity to neural and chemical CO2 and H+ that drives an increase in VE (doesn’t respond to the same degree)
why is Total minute ventilation is higher in untrained people during submaximal exercise
Ventilate at a higher rate
what are the characteristics of Minute Ventilation (VE) During graded exercise to VO2 max (Trained people):
Ventilate at a lower rate during submaximal exercise
Curve is shifted to the right
Ventilatory threshold is at 70-80% of VO2 max
Have stronger respiratory muscles
160L/min of air
what are the characteristics of Minute Ventilation (VE) During graded exercise to VO2 max (Untrained people):
Ventilate at a higher rate
Ventilatory threshold is at 50-60% of VO2 max
140L/min of air
Ventilatory threshold is at lactate threshold
True or False: Minute ventilation keeps going up even as VO2 plateaus
True
(VE does not limit VO2 max; lung is not a physiological factor)
True or False: First depth increases (taking advantage of reserve volumes), but not frequency; when we get to 50% of VO2 max, then the frequency starts going up
true
PB (barometric pressure) =
760 mmHg =
sum of partial pressures of gases
PN2 + PO2 + PH2O + PCO2
Partial pressure =
fraction of the gas in the air x PB
PI =
pressure of air inspired
PO2= 160
PCO2 = 0.3
PA =
pressure in alveoli
PO2= 105
PCO2 = 40
Pa =
arterial pressure (pressure in blood)
PO2= 100
PCO2 = 40
PT =
pressure in tissue
PO2= 5
PCO2 = >50
hypoxemia
Low PaO2 (less than 100)
Hypercapnia
high PaCO2 concentration
due to the inability of the lung to clear CO2, can lead to respiratory acidosis and loss of consciousness (want to maintain CO2 around 40)
acidosis
The more H+ the more acidic your blood
Hypocapnia:
Due to hyperventilation, can lead to alkalosis, brain blood vessel constriction, dizziness, loss of consciousness
Blowing off excess CO2 (not driven by metabolism)
CO2 is a vasodilator (keeps blood vessels open)
Hypocapnia = constriction
what are the 5 barriers for diffusion of gases at the lung
alveolar membrane
interstitial fluid
capillary membrane
Plasma
red blood cell
O2 and CO2 move in opposite directions of each other through these barriers
what are the effects of acute exercise on capillaries
HR goes up, stroke volume goes up, mean arterial pressure goes up
All of these things open up capillaries
Diffusion capacity plateaus when all capillaries are open
