Carbon dioxide transport Flashcards
Carbon Dioxide Transport
100 mL of blood carries ….. mL of CO2
CO2 is carried in blood in the form of
dissolved CO2 in plasma (7%)
combined with the globin part of Hb molecule forming …………..haemoglobin (23%)
bicarbonate ions (…..%) in the plasma
CO2 + H2O combine to form car…….. acid that dissociates into …… and bicar………… ions
Carbon Dioxide Transport
100 mL of blood carries 5 mL of CO2
CO2 is carried in blood in the form of
dissolved CO2 in plasma (7%)
combined with the globin part of Hb molecule forming carbaminohaemoglobin (23%)
bicarbonate ions (70%) in the plasma
CO2 + H2O combine to form carbonic acid that dissociates into H+ and bicarbonate ions
Gas Exchange and Transport in Lungs and Tissues
CO2 in blood causes ….. to split from haemoglobin (especially important in the tissues)
This aids Oxygen Unloading
Similarly, the binding of O2 to haemoglobin causes a release of CO2 from blood (especially important in the lungs)
This aids Carbon Dioxide Unloading
Gas Exchange and Transport in Lungs and Tissues
CO2 in blood causes O2 to split from haemoglobin (especially important in the tissues)
This aids Oxygen Unloading
Similarly, the binding of O2 to haemoglobin causes a release of CO2 from blood (especially important in the lungs)
This aids Carbon Dioxide Unloading
Co2 transport: Carbaminohaemoglobin (tissues)
Of the total Co2, 23 % binds to the globin portion of the haemoglobin molecule to form carbaminohemoglobin
Caraminohemoglobin forms in regions of high …………
Co2 transport: Carbaminohaemoglobin (tissues)
Of the total Co2, 23 % binds to the globin portion of the haemoglobin molecule to form carbaminohemoglobin
Caraminohemoglobin forms in regions of high PCO2
Carbaminohemoglobin (lungs)
The formation of carbaminohemoglobin is ……….
In the lungs (lower PCO2), ……….. dioxide dissociates from carbaminohemoglobin
In the capill……….
Carbaminohemoglobin (lungs)
The formation of caraminohemoglobin is reversible
In the lungs (lower PCO2), carbon dioxide dissociates from carbaminohemoglobin
In the capillaries
Bicarbonate ions (tissues)
Of the total CO2 in the blood, 70% is converted to bicarbonate ions within red blood cells
CO2 + H20 = H2CO3 = H+ + HCO3-
car…….. anhy………. between
CO2 + H20 = H2CO3
Bicarbonate ions (tissues)
Of the total CO2 in the blood, 70% is converted to bicarbonate ions within red blood cells
CO2 + H20 = H2CO3 = H+ + HCO3-
carbonic anhydrase between
CO2 + H20 = H2CO3
Bicarbonate ions (Tissues)
Carbonic acid dissociates into hy………. ions and bicar…… ions
Hy……….. ions bind to ha………… (HHB)
Chloride shift occurs when ……….. ions exchange for ……….. ions to maintain electrical …………….
In the plasma, bicar………… ions act as a ………. to control blood ……….
Bicarbonate ions (Tissues)
Carbonic acid dissociates into hydrogen ions and bicarbonate ions
Hydrogen ions bind to haemoglobin (HHB)
Chloride shift occurs when bicarbonate ions exchange for chloride ions to maintain electrical neutrality
In the plasma, bicarbonate ions act as a buffer to control blood pH
Carbon Dioxide Transport
Why form bicarbonate ions?
Although carbon d………. is much more s……… in water than oxygen, it is still not very s…………
On the other hand, bic…… ions are ……… soluble in water and readily go into solution
Thus, carbon dioxide in the form of bi………… ions can be carried much …….. readily in this form and in far ………. amounts of ……….. dioxide can be carried in the ………. in this way
In addition, it forms an excellent buffer in the plasma to limit changes in ….
Carbon Dioxide Transport
Why form bicarbonate ions?
Although carbon dioxide is much more soluble in water than oxygen, it is still not very soluble
On the other hand, bicarbonate ions are very soluble in water and readily go into solution
Thus, carbon dioxide in the form of bicarbonate ions can be carried much more readily in this form and in far greater amounts of carbon dioxide can be carried in the plasma in this way
In addition, it forms an excellent buffer in the plasma to limit changes in pH
Biocarbonate ions (lungs)
In the lungs, Co2 diffuses out of the plasma and into the alveoli
This lover the PCO2 in the blood causing chemical reactions to reverse
Biocarbonate ions (lungs)
In the lungs, Co2 diffuses out of the plasma and into the alveoli
This lover the PCO2 in the blood causing chemical reactions to reverse
Biocarbonate ions (lungs)
Biocarbonate ions diffuse back …….. the ……… blood cell and chl………. ions diffuse ………
Hydrogen ions combine with bicarbonate ions to form carbonic acid
Biocarbonate ions (lungs)
Biocarbonate ions diffuse back into the red blood cell and chloride ions diffuse out
Hydrogen ions combine with bicarbonate ions to form carbonic acid
Bicarbonate ions (lungs)
Bicarbonate in the lungs
Carbonic acid breaks down into carbon ……….. and ………
This reverse reaction is also catalysed by carbonic anh………
Carbonic acid breaks down into carbon dioxide and water
This reverse reaction is also catalysed by carbonic anhydrase
External Respiration
All processes occur simultaneously
Gases always follow their partial pressure gradients
In external respiration, some oxygen dis…….. in the plasma but most enters the RB… and combines with ……….haemoglobin to form ……….haemoglobin and releases a …….
When saturated with oxygen the …….. for carbon dioxide with haemoglobin decreases and any carbon dioxide associated with the haemoglobin ………… and diffuses out into the plasma and hence into the ……….
Thus ………….. loading facilitates ………….. dioxide release – known as the Hald……… Effect.
All processes occur simultaneously
Gases always follow their partial pressure gradients
In external respiration, some oxygen dissolves in the plasma but most enters the RBC and combines with deoxyhaemoglobin to form oxyhaemoglobin and releases a H+
When saturated with oxygen the affinity for carbon dioxide with haemoglobin decreases and any carbon dioxide associated with the haemoglobin dissociates and diffuses out into the plasma and hence into the alveoli
Thus oxygen loading facilitates carbon dioxide release – known as the Haldane Effect.
External Respiration
What happens to the H+
H+ combines with bicarbonate ion, which has entered the RBC in exchange for Cl- (the Chloride shift). This forms ………. acid.
The carbonic acid breaks down into carbon ……….. and water, catalyzed by carbonic an………….
The water may leave the ……. …….. …….. or remain as part of the cytoplasm.
The carbon dioxide diffuses out into the ……… and then into the al…………
In addition the small amount of carbon dioxide dissolves in the plasma diffuses into the alveoli.
External Respiration
What happens to the H+
H+ combines with bicarbonate ion, which has entered the RBC in exchange for Cl- (the Chloride shift). This forms carbonic acid.
The carbonic acid breaks down into carbon dioxide and water, catalyzed by carbonic anhydrase.
The water may leave the RBC or remain as part of the cytoplasm.
The carbon dioxide diffuses out into the plasma and then into the alveoli.
In addition the small amount of carbon dioxide dissolves in the plasma diffuses into the alveoli.
Summary: O2 Loading and CO2 Unloading (lungs)
When hemoglobin is saturated with oxygen. its affinity for carbon dioxide ………….
Oxygen loading facilitates carbon dioxide unloading from hemoglobin
This interaction is called the Haldane effect
ummary: O2 Loading and CO2 Unloading (lungs)
When hemoglobin is saturated with oxygen. its affinity for carbon dioxide decreases
Oxygen loading facilitates carbon dioxide unloading from hemoglobin
This interaction is called the Haldane effect
Internal Respiration
A small amount of carbon dioxide dissolves in the plasma
However, most of the carbon dioxide diffuses into the ……. where it combines with ………. to form carbonic acid, the reaction catalysed by carbonic anhydrase
The carbonic acid dissociates into H+ and bicarbonate ions
The bicarbonate ions diffuse into the plasma in exchange for ……… (Chloride shift)
Within the RBC the H+ are buffered by haemoglobin and they combine. This reduces the affinity for ……… and hae………. with the result that …….haemoglobin dissociates into ……….. and ………..haemoglobin
The effect of …. ions binding to h………… and reduction in affinity for ox………. and haem…………. is termed the Bohr effect
Oxygen diffuses out of the RBC into the plasma and hence into the tissues.
The small amount of oxygen dissolved in the plasma also diffuses into the tissues
Carbon dioxide diffusing into the RBC from the tissues also combines with the haemoglobin. ……….haemoglobin has a high affinity for carbon dioxide and so the carbon dioxide combines with haemoglobin to form carbaminohaemoglobin
Internal Respiration
A small amount of carbon dioxide dissolves in the plasma
However, most of the carbon dioxide diffuses into the RBC where it combines with water to form carbonic acid, the reaction catalysed by carbonic anhydrase
The carbonic acid dissociates into H+ and bicarbonate ions
The bicarbonate ions diffuse into the plasma in exchange for Cl- (Chloride shift)
Within the RBC the H+ are buffered by haemoglobin and they combine. This reduces the affinity for oxygen and haemoglobin with the result that oxyhaemoglobin dissociates into oxygen and deoxyhaemoglobin
The effect of H+ ions binding to haemoglobin and reduction in affinity for oxygen and haemoglobin is termed the Bohr effect
Oxygen diffuses out of the RBC into the plasma and hence into the tissues.
The small amount of oxygen dissolved in the plasma also diffuses into the tissues
Carbon dioxide diffusing into the RBC from the tissues also combines with the haemoglobin. Deoxyhaemoglobin has a high affinity for carbon dioxide and so the carbon dioxide combines with haemoglobin to form carbaminohaemoglobin
Summary 02 loading and CO2 unloading
The interaction between hydrogen ion binding and hemoglobin’s affinity for oxygen is called the Bohr effect
By forming hydrogen ions. carbon dioxide loading facilitates oxygen unloading
Summary 02 loading and CO2 unloading
The interaction between hydrogen ion binding and hemoglobin’s affinity for oxygen is called the Bohr effect
By forming hydrogen ions. carbon dioxide loading facilitates oxygen unloading
