Carriage of respiratory Gases By Y Stock. Objectives You should be able to: Describe the structure...
-
Upload
basil-morton -
Category
Documents
-
view
217 -
download
0
Transcript of Carriage of respiratory Gases By Y Stock. Objectives You should be able to: Describe the structure...
Carriage of respiratory Carriage of respiratory GasesGases
ByBy
Y StockY Stock
ObjectivesObjectives
You should be able to:You should be able to: Describe the structure of Describe the structure of
erythrocytes.erythrocytes. Describe the role of respiratory Describe the role of respiratory
pigments.pigments.
Understand and interpret Understand and interpret dissociation curves.dissociation curves.
WWW.NIM.NIH.GOV
Red blood cellsRed blood cells
Biconcave discsBiconcave discs 8 micrometers diameter8 micrometers diameter
No nucleusNo nucleus
Made in bone marrowMade in bone marrow Destroyed by liver/spleenDestroyed by liver/spleen
Function: To carry oxygen and Function: To carry oxygen and carbon dioxidecarbon dioxide
Adaptions:Adaptions:
Shape gives a large surface area, Shape gives a large surface area, encouraging diffusionencouraging diffusion
Full of haemoglobinFull of haemoglobin
www.astrographics.com/.../Display/GP2120.jpg
HaemoglobinHaemoglobin
www.chemsoc.org/.../LearnNet/cfb/images/13A.jpgwww.chemsoc.org/.../LearnNet/cfb/images/13A.jpg
HaemoglobinHaemoglobin
Consists of 4 polypeptide chains, Consists of 4 polypeptide chains, each with an iron containing haem each with an iron containing haem group.group.
Each haem group combines with an Each haem group combines with an oxygen moleculeoxygen molecule
Haemoglobin+oxygen=oxyhaemoglobinHaemoglobin+oxygen=oxyhaemoglobin
Hb + 4OHb + 4O22 = HbO = HbO88
Reversible reactionReversible reaction
www.scientific-art.com/.../Haemoglobin.gif
Hb + 4OHb + 4O22 = HbO = HbO88
High partial High partial pressure oxygenpressure oxygen
LungsLungs
Oxyhaemoglobin Oxyhaemoglobin formedformed
Low partial Low partial pressure oxygenpressure oxygen
Active tissuesActive tissues
Oxyhaemoglobin Oxyhaemoglobin breaks downbreaks down
Oxygen releasedOxygen released
Oxygen dissociation curvesOxygen dissociation curves
Found by exposing haemoglobin to Found by exposing haemoglobin to
air mixtures of varying oxygen partial air mixtures of varying oxygen partial
pressures and determining its % pressures and determining its %
saturation.saturation.
www.jcu.edu/biology/RESPS.JPG
S shaped curveS shaped curve
Over the steep section a small fall inOver the steep section a small fall in
Oxygen partial pressure causes a Oxygen partial pressure causes a
sizeable drop in % saturation.sizeable drop in % saturation.
The curve shows that:The curve shows that:
at relatively low oxygen concentrations at relatively low oxygen concentrations there is uncombined haemoglobin in the there is uncombined haemoglobin in the blood and little or no oxyhaemoglobin, e.g. blood and little or no oxyhaemoglobin, e.g. in body tissue in body tissue
at relatively high oxygen concentrations at relatively high oxygen concentrations there is little or no uncombined there is little or no uncombined haemoglobin in the blood; it is in the form haemoglobin in the blood; it is in the form of oxyhaemoglobin, e.g. in the lungs. of oxyhaemoglobin, e.g. in the lungs.
Effect of increased carbon dioxideEffect of increased carbon dioxide
Bohr EffectBohr Effect
Curve shifted to rightCurve shifted to right
Increased COIncreased CO22 causes causes oxyhaemoglobin to unload some of oxyhaemoglobin to unload some of its oxygen.its oxygen.
www.coheadquarters.com/Bohr1.gif
Fate of carbon dioxideFate of carbon dioxide
7-10% dissolves in plasma7-10% dissolves in plasma
20-30% in red cells as 20-30% in red cells as carbaminohaemoglobin (binds to carbaminohaemoglobin (binds to amino acids)amino acids)
60-70% converted to bicarbonate in 60-70% converted to bicarbonate in plasmaplasma
Conversion to bicarbonateConversion to bicarbonate
Carbon dioxide diffuses into red cellsCarbon dioxide diffuses into red cells
Enzyme:carbonic anhydraseEnzyme:carbonic anhydrase
COCO22 + H + H22O = HO = H22COCO33
This dissociatesThis dissociates HH22COCO3 3 = H= H++ + HCO + HCO33
--
HCOHCO33- - diffuses into plasmadiffuses into plasma
HH++ combine with oxyhaemoglobin forming combine with oxyhaemoglobin forming haemoglobinic acid.haemoglobinic acid.
HH+ + + HbO + HbO22 = HHB + O = HHB + O22
Oxygen displaced.Oxygen displaced. Haemoglobin buffering pH changesHaemoglobin buffering pH changes
www.colprado.edu/.../image/figure13g.jpg
Myoglobin -Curve shifted to leftMyoglobin -Curve shifted to left
Myoglobin binds more tightly to Myoglobin binds more tightly to oxygen.oxygen.
Oxygen only given up at very low POOxygen only given up at very low PO22
Images.encarta,msn.com/…/cha/00076b5f.gif
QuizQuiz
Haemoglobin quiz image search RSCHaemoglobin quiz image search RSC