1. The document discusses the transport of oxygen and carbon dioxide in the blood and tissues. It describes how oxygen is carried by hemoglobin in red blood cells and is transported to tissues where it is released, while carbon dioxide is transported primarily as bicarbonate in the blood and transported to the lungs to be released. 2. The oxygen dissociation curve is explained, showing hemoglobin's affinity for oxygen at different partial pressures. Factors like pH, temperature, and 2,3-DPG can shift the curve right or left. 3. Carbon dioxide is transported in three forms - dissolved, as bicarbonate, and bound to hemoglobin. The chloride shift and Bohr and Haldane effects

1. TRANSPORT OF OXYGEN
& CARBON DIOXIDE IN
BlOOD AND BODY
TISSuES
ChAPTER 40
DR FARZANA

2. OBjECTIvES
At the end of this chapter students
must be able to
 Explain partial pressures of gases
 Describe transport of O2 in the
body
 Draw the oxygen dissociation curve
and explain significance of flat and
steep portions

3.  Name and explain the factors
which shift oxygen dissociation
curve to right and left
 Explain transport of CO2 in the
body write briefly on Bohr’s effect,
Haldane effect and chloride shift

4. RESPIRATORY GAS
TRANSPORTATION

5. OXYGEN TRANSPORT
DElIvERY SYSTEm
• Objective
– Efficient Supply of Oxygen to tissues according
to their metabolic needs.
• Factors affecting Oxygen delivery
i. Amount of Oxygen entering lungs (Atmospheric
Air PO2
ii.Adequacy of Pulmonary Gas Exchange
(Respiratory Membrane)
iii.Blood Flow to the Tissue (Local Regulating
Factor)
iv.Oxygen Carrying Capacity of Blood (Amount and
Type of Hb)

6. OXYGEN TRANSPORT
• O2 carried by red blood cells
(erythrocytes)
– Hemoglobin (Hb)
– Normal hemoglobin concentration is 150 g/L or
15g/dL
– Carries 65 times more O2 than plasma
• Dissolved O2 in plasma
– Low capacity to carry or transport O2

7. FORmS OF OXYGEN
TRANSPORT
• Chemical combination with Hb
– Oxygenation 97%
• In dissolved state 3%
– Amount of dissolved related directly to
partial pressure (PO2)
– 0.0003 ml O2/100 ml/mmHg
• Arterial blood –PO2 104mmHg

8. ChEmICAl COmBINATION OF
O2 TO hB
• Oxygenation
• Loose, Reversible, Binding of O2 to
Haem in Lungs Hb 4 + 4O2  Hb4O8
• Volume of O2 Carried (Hb Bound)
- 1.34 ml/g Hb
- Normal Hb 15 g/dl
- 20 ml/dl

9. ThE TRANSPORT OF OXYGEN IN BlOOD
- hAEmOGlOBIN
• Hb + 4O2 → Hb(O2)4
• Over 95% of O2 is carried in this way
• Red blood cell (erythrocyte)

10. OXYGEN SATuRATION &
CAPACITY
• Up to four oxygen molecules can bind
to one hemoglobin (Hb)
• Ratio of oxygen bound to Hb
compared to total amount that can be
bound is Oxygen Saturation
• Maximal amount of O2 bound to Hb is
defined as the Oxygen Capacity

11. uPTAkE OF O2 BY PulmONARY
CAPIllARY BlOOD
OxygenTransportMechanism-DnaTube.com-ScientificVideoandAnimationSite.flv

12. uPTAkE OF O2 BY
PulmONARY
CAPIllARY BlOOD

13. uPTAkE OF O2 BY
PulmONARY CAPIllARY
BlOOD
• Arterial PO2 = 40 mmHg
• Alveolar PO2 = 104 mmHg
• Difference = 104-40 = 64 mmHg
• Rapid rise in PO2 as blood passes
through the capillaries and becomes
equal to alveolar PO2. Therefore
• Venous PO2 =104 mmHg

14. uPTAkE OF O2 BY
PulmONARY CAPIllARY
BlOOD DuRING EXERCISE
• During strenuous exercise= O2
required 20 times the normal
• Increased COP = stay of blood in
capillaries is decreased to half normal

15. CONT:
• Due to safety factor
increased diffusing capacity
blood becomes saturated in initial
1/3rd
of capillary and little O2
enters the blood in subsequent
part of capillary
• During exercise with shortened stay
of blood in capillaries, blood is fully
oxygenated

16. TransporT of oxygen in The
arTerial Blood
• 98% of blood enters the left Atrium
 Oxygenated up to a PO2 of about
104 mmHg
• Shunt Flow: 2 percent  Shunt Flow
• Venous admixture of blood  PO2
change 104 to 95 mmHg

17. effecT of Venous
admixTure

18. TransporT of oxygen
from The lung To The
Body Tissue
 Diffusion of Oxygen from the
Alveoli into the Pulmonary Blood
due to difference in partial
pressure of Oxygen (Po2).
 Po2 of Alveoli > Po2 of Pulmonary
Capillary Blood
 Po2 of Pulmonary Capillary Blood >
Po2 in the tissues

19. gas conTenT of Blood
(hB = 14.5 g/dl)
• Arterial Blood
- 100 ml of blood combines with 19.4ml of O2
– Po2 95 mmHg
– %Hb saturation 97%
• Venous Blood
- 100 ml of blood combines with 14.4ml of O2
– Po2 40 mmHg
– % Hb saturation 75%

20. oxygen uTilizaTion
coefficienT
– Thus 5ml of O2 is transported by each
100 ml of blood through tissues per
cycle
– During exercise ….increased cellular O2
utilization ….decreased interstitial
PO2…..15 mmHg
– Venous blood 100ml combines with 4.4 ml of O2
( sat 20% , PO2 18mmHg)
– Thus 15 ml of O2 is transported by each 100
ml of blood through tissues per cycle

21. diffusion of o2 from
peripheral capillaries in
To Tissue fluid

22. Volume of o2 deliVered
(in Tissues)
• 5ml/dl/min
• 250 ml/5L/ min
• Increases three times in exercise
Factors Affecting affinity of Hb for O2
• Temperature
• PH of Blood
• Hb concentration
• 2, 3 DPG
• CO

23. summary of gas
exchange in lungs &
Tissues

24. effecT of Blood flow &
raTe of o2 consumpTion on
Tissue po2

25. diffusion of o2 from
peripheral capillaries
To The Tissues
• O2 used by the cells, PO2 in
peripheral tissue cells remains lower in
the peripheral capillaries
• There is considerable distance
between capillaries and cells.
• Therefore cellular PO2 ranges b/w 5-
40mmHg average 23mmHg

26. conT:
• Only 1-3mmHg of O2 pressure
normally required for full support of
chemical processes that incorporates
O2 in the cell
• Low intracellular PO2 of 23 mmHg is
enough and provides large safety
factor.

27. role of o2 in hB
TransporT
• 97% by blood Hb
• 3% by plasma
• When PO2 is high in pulmonary
capillaries……O2 binds with Hb
• When PO2 is low in tissue
capillaries……O2 released from Hb

28. PO2 40mmHg
% Sat 75%
Vol% 14.4
PO2 95mmHg
% Sat 97%
Vol% 19.4

29. effecT of Blood po2 on
QuanTiTy of oxyhB

30. The oxygen hemogloBin
dissociaTion curVe
Reveals the
amount of
haemoglobin
saturation
at different
PO2 values.

31. 31
Oxygen DissOciatiOn
curve
• The O2 dissociation curve graphically
illustrated the percentage of Hb that is
chemically bound to O2 at each O2
pressure.
• The curve is S-shaped with a steep slope
between 10 and 60 mm Hg and a flat
portion between 70 and 100 mm Hg.
• The flat and steep portions of the curve
each have a distinct clinical significance.

32. 32
significance Of the flat
POrtiOn
• The flat portion of the curve shows that
the P02 can fall from 100 to 60 mmHg
and the Hg will still be 90% saturated
with 02
• At pressures above 60mm Hg, the standard
dissociation curve is relatively flat. This
means the oxygen content does not change
significantly even with large changes in the
partial pressure of oxygen.

33. 33
significance Of steeP
POrtiOn
• PO2 reductions below 60 mm Hg produce a
rapid decrease in the amount of O2 bound
to hemoglobin.
• Clinically, when the PO2 falls below 60 mm
Hg, the quantity of O2 delivered to the
tissue cells may be significantly reduced.
• As oxygen partial pressures decrease in
this steep area of the curve, the oxygen is
unloaded to peripheral tissue readily as the
hemoglobin’s affinity diminishes.

34. 34
the P50
• A common point of reference on the
oxygen dissociation curve is the P50.
• The P50 represents the partial
pressure at which the hemoglobin is
50% saturated with oxygen,
typically 26.6 mm Hg in adults.
• The P50 is a conventional measure of
hemoglobin affinity for oxygen.

35. 35
shifts in the P50
• In the presence of disease or other
conditions that change the hemoglobin’s
oxygen affinity and, consequently, shift the
curve to the right or left, the P50 changes
accordingly.
• An increased P50 indicates a rightward
shift of the standard curve, which means
that a larger partial pressure is necessary
to maintain a 50% oxygen saturation,
indicating a decreased affinity.
• Conversely, a lower P50 indicates a
leftward shift and a higher affinity.

36. 36
factOrs that effect the
02 DissOciatiOn
– pH- Change in the blood pH
– Temperature- as temperature
increases the curve moves to the
right
– 2,3 Diphosphoglycerate-Increases
2,3 DPG results in decreased
affinity
– Carbon monoxide

37. 272727

38. 27
27
2727
5050 ------
Decreased
affinity
Unloading
Increased
affinity
Loading

39. 39
clinical significance Of
shifts
• Individuals with PaO2’s within normal
(80-100) limits are rarely afected by
shift changes.
• However, when a patients PaO2 falls
below 80, a shift to the right or left
can have remarkable effects on the
hemoglobin’s ability to pick up and
release oxygen.

40. 40
right shifts
• Right shift decrease the loading of oxygen
onto Hb at the A-C membrane.
-Decreased affinity
• The total oxygen delivery may be much
lower than indicated by a particular Pao2
when the patient has some disease process
that causes a right shift.
• Right shift curves enhance the unloading of
oxygen at the tissue level.

41. 41
left shift
• Left shift curves enhance the loading
capability of oxygen enhance the loading
capability of oxygen at the A-C membrane.
• The total oxygen delivery may be higher
than indicated by a particular PaO2 when
the patient has some disease process that
cause a left shift.
• Left shift curves decreases the unloading
of oxygen at the tissue level.

42. factOrs altering
haemOglObin saturatiOn
exercise

44. factOrs affecting
DisassOciatiOnBLOOD
TEMPERATURE
temperature
• reduces
haemoglobin
affinity for O2
• hence more O2 is
delivered to
warmed-up tissue
•Respiratory Response to Exercise

45. carbOn DiOxiDe
cOncentratiOn

46. CARBON mONOXIDE
CONCENTRATION
• Interferes with O2 transport
because it has 200 times more
affinity for Hb
• Competes with O2 for same sites
for binding and decreases
functional Hb

47. BLOOD pH

48. 2,3 DpG – 2,3
DIpHOspHOGLyCERATE
2,3 diphosphoglycerate,
generated by glycolysis
during anaerobic
metabolism, binds to Hb and
decreases affinity for O2

49. sTORED BLOOD
• Packed red blood cells (PRBC) used for
virtually all blood transfusions are stored
cold and have significantly diminished
levels of 2,3 DPG
• Hb in stored blood would initially show a
left shift in the Hb-O2 disassociation
curve

50. VENOus HB AffINITy sHIfT
• Shift to the right
reducing the affinity
for O2 below Po2 of 70
mmHg
• Shift occurs because of
rising Pco2 & [H ions] –
Bohr effect = an
increase in [H+
]
decreases Hb’s affinity
for O2
• Enhances the quantity
of O2 released in
systemic capillaries
• Increases delivery of
O2 to tissues

51. HEmOGLOBIN &
myOGLOBIN
• Myoglobin is single
chained heme
pigment found in
skeletal muscle
• Myoglobin has an
increased affinity
for O2 (binds O2 at
lower Po2)
• Mb stores O2
temporarily in
muscle

52. CARBON DIOXIDE
• Volatile waste product of cellular
metabolism
- Intracellular Pco2 46 mmHg
– Interstitial Pco2 is 45 mmHg
– Diffuses into systemic capillaries with
arterial Pco2 40 mmHg
– Venous Pco2 is 45 mmHg
– Alveolar air Pco2 is 40 mmHg

53. mECHANIsms Of CO2
TRANspORT
Complex mechanism of CO2 transport
Carbon dioxide transported by blood in
three forms:
1. Dissolved directly in blood
2. Bicarbonate ion (HCO3-
) & Carbonic acid (H2CO3)
3. Bound to hemoglobin & plasma proteins

54. MOST CO2 TRANSPORTED
AS BICARBONATE (HCO3-
)*

55. • When CO2 molecules diffuse from the
tissues into the blood, 7% remains
dissolved in plasma and erythrocytes,
23% combines in the erythrocytes
with deoxyhemoglobin to form
carbamino compounds, and 70%
combines in the erythrocytes with
water to form carbonic acid, which
then dissociates to yield bicarbonate
and H+
ions

56. CHLORIDE sHIfT AND
REVERsE CHLORIDE sHIfT
• Most of the bicarbonate then moves
out of the erythrocytes into the plasma
in exchange for Cl-
ions & the excess H+
ions bind to deoxyhemoglobin. The
reverse occurs in the pulmonary
capillaries and CO2 moves down its
concentration gradient from blood to
alveoli.

57. CARBON DIOXIDE
TRANspORT

58. DIffERENCEs BETwEEN
BOHAR AND HALDANE
EffECTs
• BOHAR EFFECT
1.It is the effect
by which the
presence of CO2
decreases the
affinity of Hb for
O2
• HALDANE EFFECT
1.It is the effect by
which combination
of O2 with Hb
displaces CO2 from
Hb

59. 2. Was postulated
by Bohr in 1904
3. Occurs at tissues
and systemic
capillaries
4. In tissues ……
metabolism
↑PCO2 & PO2↓
45 mmHg 40 mmHg
2. Described by
Jhon Scott
Haldane in 1860
3. Occurs at
alveolar and
pulmonary
capillary blood
4. Hb+O2…..HbO2
HbO2 has low
tendency to
combine with CO2

60. • CO2 enters the
blood and O2
released from
blood to
tissues…..Shifting
O2 disosiciation
curve to right…O2
to tissues
• O2+Hb….H+ and
CO2
• H+ + HCO3-
….H2CO3….H2O
+
CO2…..Released
from blood to
alveoli