L7 - transporting gases in exercise Flashcards
what does the extent of gas dissolving into a fluid depend on.
pressure of the gas
solubility (CO2 is 24x more soluble than O2)
temp of the gas
time (if time constraint)
ficks law of diffusion
gas diffusion rate.
= Area / Thickness x D x (p1-p2). only one you can change is pressure gradient.
Daltons law
total pressure of gas mixture = partial pressure.
how does desaturation limit exercise?
Some people can bind all of them with oxygen.
Whereas most people will lower saturation as the exercise gets more intense. loosing oxygen as fit people will have such a high CO that the blood moves so fast through the heart it cannot saturate
three more pulmonary factors that limit exercise
COPD
pulmonary pressure - more we breath in and out we create a vacuum pulling blood into the heart, equally having to generate pressure to push the blood out. which has a struggling effect on CO.
High work of breathing
respiratory muscle fatigue, hard to generate pressure, train more. And increase sympathetic outflow. more info fromfatugued muscles that will shut down blood vessels due to increase sympathetic, so limit blood flow to locomotive.
oxygen transport in the blood.
arterial transport = 175-200 mL o2 . L-1 blood. (1/5 of your arterial blood is oxygen)
almost all (99%0 of o2 is bound to Hb.
o2 offloaded at rest vs exercise
25% O2 offloaded to tissue at rest. 80-90% offloaded during exercise.
co2 transport
60-80% as bicarbonate
20% bound to Hb (4 per)
5-10% dissolved in plasma, whihc establishes PCO2 and tightly regulated, drives Ve.
what carries oxygen TO MUSCLES
myoglobin.
Factors that help to unload O2 to metabolically active tissues:
Bohr effect. curve sgift to the right favours offload. for increase temp and co2 but decrease in pH.
3 DPG - binds to Hb and decreases its affinity for O2. produced in RBC as a byproduct of glycolysis. Higher in altitude, exercise, anaemia, females.
what does buffer mean
chemical and physiol mechanisms that prevent this change.
what do acids and bases do in a solution.
Acids dissociate in solution; release H+
. Bases do opposite.
why is pH is important for many biol/physiol functions
pH is concentration of protons (acids have H+> OH-) pH is logarithmic scale. (So small changes bigger than may seem)
what is important about H+ and CO2
CO2 and H+ both metabolites; are tightly related to each other, andstimulate breathing; both indicate inadequate breathing and/orperfusion.
what are our three buffering mechanisms
Chemical (bicarbonate, phosphate, protein (incl Hb))
Pulmonary ventilation
Renal function
