TRANPORT OF OXYGEN

TRANSPORT OF OXYGEN

1. DR NILESH KATE
MBBS,MD
ASSOCIATE PROF
DEPT. OF PHYSIOLOGY
TRANSPORT OF
OXYGEN.

2. OBJECTIVES.
Uptake of oxygen by pulmonary blood.
Transport of oxygen in arterial blood.
Release of oxygen in tissue.
Vehicle for transport of oxygen.
Saturday, December 10, 2016

3. INTRODUCTION
Transport of gases occurs along
the conc gradient.
Alveolar air PO2 : 104 mm Hg.
Arterial blood PO2 :95 mm Hg
Venous blood PO2: 40 mm Hg.
Tissue interstitial fluid: 40
mm Hg.
Saturday, December 10, 2016

4. UPTAKE OF OXYGEN BY
PULMONARY BLOOD.
Alveolar PO2 -104
mm Hg.
Arterial blood po2 40
mm Hg.
Conc gradient of 64
mm Hg, transport is
rapid.
Saturday, December 10, 2016

5. TRANSPORT OF OXYGEN IN
ARTERIAL BLOOD.
PO
2
in pulmonary veins
104 mm Hg & in aorta
100 mm Hg.
Due to venous
admixture
Bronchial veins mix with
pulmonary capillaries
Coronary blood through
Thebesian Veins.
Saturday, December 10, 2016

6. TRANSPORT OF OXYGEN IN
ARTERIAL BLOOD.
Dissolved form
In combination with
haemoglobin.
Oxygen in Arterial blood –
20ml/100 ml, in venous
blood 15ml/100ml
So 5ml/100 ml
transported from lungs to
tissue.
Saturday, December 10, 2016

7. DISSOLVED FORM
Out of 5 ml transported 0.3 ml
in dissolved form & rest with
Hb.
As per Henry’s law dissolved gas
is proportional to Po2, so there
is NO LIMIT for this transport as
long as Po2 is high.
So dissolved O2 at high Po2
( Hyperbaric Oxygen) is used
for oxygenation in certain
poisoning (CO)where Hb is
denatured.
Saturday, December 10, 2016

8. IN COMBINATION WITH
HAEMOGLOBIN.
Oxygenation of haemoglobin
Oxygen carrying capacity of haemoglobin
O2-Hb dissociation curve.
Shifts in O2-Hb dissociation curve.
Concept of P50 & its significance.
O2-Hb dissociation curve of Hb-F
Effect of carbon monoxide on tranport of O2
Oxygen dissociation curve for myoglobin.
Saturday, December 10, 2016

9. OXYGENATION OF
HAEMOGLOBIN
Oxygen combine with
Hb to form loose &
reversible bond, this is
oxygenation & Not
Oxidation, convert
Deoxyhaemoglobin
into Oxyhaemoglobin.
Time taken 0.1 sec.
Saturday, December 10, 2016

10. OXYGEN CARRYING CAPACITY
OF HAEMOGLOBIN
1 gm of Hb bind with
1.34ml of O2
100 ml blood containing Hb
15gm% (15Χ 1.34) bind
20.1 ml of O2
But due to different shunts
decreases to 19.8 ml out of
which 0.3 ml in dissolved
form & 19.5 ml as
Oxyhemoglobin.
Saturday, December 10, 2016

11. DISADVANTAGE
Only Disadvantage
with this method is
there is Ceiling with
this transport due to Hb
saturation.
% Saturation is Avg
saturation of entire Hb
molecule in the blood.
Saturday, December 10, 2016

12. O2-HB DISSOCIATION CURVE.
When relation between
PO2 & % of Hb saturation
is plotted on graph we get
OXYGEN-HAEMOGLOBIN
DISSOCIATION CURVE.
It shows that % of Hb
saturation increases with
increase in PO2, but this
relationship is not linear
Saturday, December 10, 2016

13. SIGMOID SHAPED CURVE -
CAUSE
When 1 molecule of O2
combines with Hb ,
affinity of Hb increases
& so on
This is called Co-
operative binding
Kinetics.
Due to this O2-Hb
dissociation curve is
Sigmoid.
Saturday, December 10, 2016

14. SIGMOID SHAPED CURVE -
Advantage
Loading Zone – Related
to process of O2 uptake
in lungs.
Even Po2 falls below 60
mmHg saturation is still
90%, so loading zone
provide margin of safety.
Saturday, December 10, 2016

15. SIGMOID SHAPED CURVE -
Advantage
Unloading zone –
related to O2 delivery in
tissue, steep portion
below Po2 60mmHg.
So that relatively large
Oxygen is liberated at
minor fall in o2 tension.
( Buffering Effect)
Saturday, December 10, 2016

16. SHIFTS IN O2-HB
DISSOCIATION CURVE.
Shift to Right
-Decreased affinity of
Hb for O2.
Causes
PCO2 & pH – Increase in
Pco2 shift curve to
Right – Bohr’s effect.
Saturday, December 10, 2016

17. SHIFTS IN O2-HB
DISSOCIATION CURVE.
Temperature – increase
temperature is due to increase
heat production, increased
PCo2 due to rapid metabolism,
decreased PO2 due to rapid
consumption & decreased pH
due to lactic acid accumulation.
2,3-Diphosphoglycerate –
formed during Glycolysis via
EMBEDEN-MEYERHOF
pathway.
Saturday, December 10, 2016

18. SHIFTS IN O2-HB
DISSOCIATION CURVE.
Shift to left – increase
affinity of haemoglobin
for oxygen.
Causes –
Pco2
H + ion conc
Temperature
Fetal haemoglobin
Saturday, December 10, 2016

19. CONCEPT OF P50 & ITS
SIGNIFICANCE.
P50 – partial pressure of oxygen that produces 50%
of saturation
Normal P50 – 25-27 mmHg.
Significance – Hb affinity inversely proportional to
P50 value.
Decreased p50 – Hb gets saturated at low po2, i.e shift to
left
Increased p50 - Hb gets saturated at high po2, i.e shift to
right.
Saturday, December 10, 2016

20. O2-HB DISSOCIATION CURVE
OF HB-F
O2-Hb dissociation
curve shifted to Left
As its affinity for 2,3-
DPG is less than HbA
So its affinity to
combine with oxygen
is more than HbA.
Saturday, December 10, 2016

21. EFFECT OF CARBON MONOXIDE
ON TRANSPORT OF O2
CO has 200 more
affinity for Hb.
Combines with Hb
forms-
Carboxyhaemoglobin
Decreases functional Hb
conc.
And decreases O2
tension & O2 transport.
Saturday, December 10, 2016

22. OXYGEN DISSOCIATION CURVE
FOR MYOGLOBIN.
Present in Muscle specialised
for sustained contraction
Dissociation curve is
Rectangular Hyperbola – as
it takes O2 at low pressure
readily
It does not show Bohr’s effect
At po2 40 mm Hg it is 95%
saturated & Hb 75%
Act as temporary store house
of Oxygen
Saturday, December 10, 2016

23. RELEASE OF OXYGEN IN
TISSUE.
O2 release at Rest
O2 release during
exercise.
Saturday, December 10, 2016

24. O2 RELEASE AT REST
Oxygen Delivery – Normal o2 delivery is 1L/min
Oxygen Consumption – 5ml/100ml/min, so total
is 250 ml/min
Utilization Coefficient - % of O2 consumed out of
oxygen delivered to tissue.
250/1000 × 100 = 25%
Saturday, December 10, 2016

25. O2 RELEASE DURING
EXERCISE.
Depend on Severity of
exercise
Delivery of oxygen –
increased by
Increase blood flow due to
increase cardiac output, local
arteriole dilatation, increase
in open capillaries.
Increase RBC count due to
splenic contraction
Release of oxygen – by
right sift of curve.
Saturday, December 10, 2016

26. VEHICLE FOR TRANSPORT OF
OXYGEN.
At PO2 100 mm Hg
Whole blood – 19.8ml
Hb soln – 19.5 ml
plasma soln – 0.3 ml
At PO2 40 mm Hg
Whole blood – 5 ml
Hb soln – 1.5 ml
plasma soln – 0.18 ml
Saturday, December 10, 2016

27. Thank
You

28. Saturday, December 10, 2016