Challenges to normal respiration

Question 1

how much oxygen do we need at rest

Answer 1

3.5 mL/kg/min
(160 mL/min/m2)
240 mL/min

Question 2

what adaptions do we have to increased O2 demand

Answer 2

increased minute ventilation
increased O2 delivery - increased cardiac output and increased arterial O2 content
increased O2 extraction

Question 3

what is the limiting factor in severe exercise

Answer 3

lactate

Question 4

what is the ventilatory response to exercise

Answer 4

vertical phase one increase in minute ventilation
phase 2 gradual slope increase into plateau
phase 3 end of exercise and large drop in in minute ventilation then a gradual slope back down to resting level

Question 5

what is the acute response to altitude

Answer 5

hyperventilation - peripheral chemoreceptors
alkalosis - limits excessive hyperventilation
CSF bicarbonate excretion (followed by renal)
diuresis, hyponatraemia
acute out sickness - PA pressure, pulmonary oedema, cerebral oedema

Question 6

what happens during acclimation

Answer 6

erythropoesis increase
hyperventilation
increased cardiac output
reduced 2,3 DPG

Question 7

what are the effect of breath holding when doing into depth

Answer 7

alveolar gas tensions
immersion pressure
nitrogen

Question 8

what are the different pressures and PO2 values

Answer 8

check home screen

Question 9

what are the issues with nitrogen during depth

Answer 9

Narcotic
Detectable at > 4 Atm
Serious impairment > 10 Atm
Anaesthesia > 30 Atm
Density
Increases with high pressures
Increased work of breathing
Solubility in tissues
Comes out of solution on ascent

Question 10

how do you overcome nitrogen damage during depth

Answer 10

using oxygen or helium mixtures for diving

Question 11

what two problems can occur during fast ascent

Answer 11

tissue bubbles and arterial gas embolism