Lecture 7 Notes Gas Exchange Case Studies PDF

Lecture 7: 20 Jan Gas Exchange: Case Studies Coping with Hypoxia changing Fick O2 storage changing ventilation changing pigments Reading: Box 24.2 (659), 728- 734, 669-670 1 1  Gas Exchange: Bimodal Breath...

Lecture 7: 20 Jan Gas Exchange: Case Studies Coping with Hypoxia changing Fick O2 storage changing ventilation changing pigments Reading: Box 24.2 (659), 728- 734, 669-670 1 1  Gas Exchange: Bimodal Breathers O2: mostly lungs from air CO2: mostly gills to water requires re-routing of blood 25.17 2 2  Environmental Hypoxia define? what are (natural) environmental causes? air breathers? water breathers? 3 3  Cheat: Spatial Avoidance aquatic surface respiration 4 4   P1 − P2  Change X? J = D  A   anatomically what does X represent?  X  will selection favour increasing or decreasing X? why? (think mathematics) What do you conclude from the data in 23.8? 22.7 23.8 5 5  Changing A: Adaptational adaptational; Titicaca frog  P1 − P2  J = D  A   Lake Titicaca  X  6 6  Changing A: Adaptational Develop alternative surface areas not usually associated with/initially designed for gas exchange Turtle: skin, buccal, cloacal gas exchange 7 7  Other A? 8 8  Changing A: Acclimation “hairy” frog (Trichobatrachus robustus)  C − C2  J = D  A  1   X  9 9  Changing A: Acclimation acclimate carp to hypoxia 14 days, normoxic recovery 7 days measure gill morphology 0, 3, 7, 14 days hypoxia and recovery 10 10  Fish Gill Anatomy 11 11  Changing A: Acclimation ILCM: interlamellar cell mass gill cells that don’t exchange gas 12 12  Changing A: Developmental guinea pigs raised at different “altitudes” Low Alt., High Alt. 13 13  Maintain P1 – P2:  P1 − P2  J = D  A   cheat  X  flexible bag…at what pressure? what part of Dalton’s Law affected? Px=FxPtot 14 14  Changing Tidal Volume 23.21 15 15  Modulating Breathing Respiratory minute volume aka Minute Ventilation VT: tidal volume 𝑅𝑀𝑉 = 𝑉𝑇 × 𝑓 volume inhaled/exhaled in a breath eq. 23.2 f: breath frequency units of RMV? what determines these components? 16 16  Changing Minute Ventilation pre-Bötzinger complex initiates inhalation Stretch receptors stop inhalation 17 17  Does O2 regulate breathing? 18 18  Changing Minute Ventilation pre-Bötzinger complex which would affect initiates inhalation V T? f ? Stretch receptors stop inhalation 19 19  Maintain P1 – P2: Ventilation air breathers: “normally” what acutely controls ventilation? sensed by? in env. hypoxia, O2 becomes important sensed by? 20 20