respiration 4 Flashcards
what it intrapleaural at apex and base?
interpleaural pressure is greatr (more negative) at apex compared to base.
ventilation better at base to apex
where is perfusion better?
perfusion is better at base to apex - posture
what is daltons law?
total pressure of mixture of gases is the sum of their individual partial pressures
what does henrys law determine?
concenrration of gas dissolved in solution
[GAS]dis = s x Pgas
(s= solubility coefficient)
what is oxygen solubility in saline?
is low - plasma cannot deliver enough oxygen so redblood cells contain haemoglobin.
(250mlo2/min is required by body)
what are 2 states of haemoglobin?
tense - low aff for O2
relaxed - high aff for O2
what is structure of haemoglobin?
tetrameric structure - 4 subunits coming together.
each unit is haem unit and globin chain
in adult Hb what are the chains?
2 alhpa 2 beta
what is haem unit?
porphyrin ring with single Fe atom
what state does iron have to be in for oxygen to bind?
Fe2+
methaemoglobin reductase helps convert Fe3+ to Fe 2+
what happens when temperature is high/low?
when temperature increases haem carries less oxygen (curve to right)
when temperature decrease haem carries more oxygen (curve shifts to left)
what happens to graph/haemoglobin when PH changes?
BOHR effect
PH is higher - haem more oxygen - shift to left
PH lower- haem less oxygen - curve to right
how does 2,3, diphosphoglycerate affect graph?
high DPG - haem less oxygen - shift to right
low DPG - haem more oxygen - shift to left
what happens to curve in tissues undergoing active resp?
shift curve to right -increased temp -more co2 -lower PH -more DPG decreased affinity for oxygen - more in tissue
what is difference in fetal haemoglobin compared to adult?
beta chains replaced by gamma chains
higher aff for O2 for curve shifts left.
