Transport of Carbon Dioxide
The partial pressures (in mm Hg) of oxygen (O2) and carbon dioxide (CO2) at alveoli (the site of diffusion) are:
pO2 = 159 and pCO = 0.3
pO2 = 104 and pCO2 = 40
pO2 = 40 and pCO2 = 45
pO2 = 95 and pCO2 = 40
What is the difference between oxygenated and deoxygenated blood?
What are the main factors that affect normal breathing?
- Every 100 ml of oxygenated blood can deliver 20 ml of O2 to the tissues
- Every 100 ml of deoxygenated blood delivers approximately 4 ml of CO2 to the alveoli
- None of these
- Transport of carbon dioxide is carried by haemoglobin in the form of carbaminohaemoglobin
Carbon dioxide dissociates from carbaminohaemoglobin when
pCO2 and pO2 are equal
pCO2 is high and pO2 is low.
pO2 is high and pCO2 is low
None of the above.
Approximately seventy percent of carbon dioxide absorbed by the blood will be transported to the lungs
in the form of dissolved gas molecules
as bicarbonate ions
by binding to R.B.C
- Expiratory Capacity
- Inspiratory Capacity
- Expiratory Reserve Volume
- Total Lung Capacity
Inspiratory capacity is:
The total amount of air that can be inspired after a tidal expiration
The total amount of exchangeable air
Another name for functional residual capacity
The amount of air inspired after a tidal inspiration
Read the following statements and find out the incorrect statement(s).a. The binding of CO2 with haemoglobin is related to the partial pressure of CO2.pO2 is a major factor which could affect this binding.
b. When pCO2 is low and pO2 is high as in the alveoli, more binding of CO2 occurs, whereas when the pCO2 is high and pO2 is low as in the tissues, dissolution of CO2 from carbaminohaemoglobin takes place.
c. At the tissue site, where partial pressure of CO2 is high due to catabolism, CO2 diffuses into blood (RBCsand plasma) and forms HCO−3 and H+. At the alveolar site where pCO2 is low, the reaction proceeds in the opposite direction leading to the formation of CO2 and H2O.
d. Oxygen dissociation curve is highly useful in studying the effect of factor like pCO2, H+ concentration, etc., on binding of O2 with haemoglobin.
- c and d
- b only
- a and b
- b and c
What are the major transport mechanisms for CO2? Explain.
Total lung capacity is equal to:
Vital capacity x Tidal volume
Functional residual capacity + Expiratory reserve volume
Anatomical dead space + Alveolar dead space
Residual volume + Vital capacity
How does pH affect oxygen dissociation curve?
The enzyme which converts carbon dioxide in the RBCs into carbonic acid, protons and bicarbonates and its co-factor is
Carbonic anhydrase and magnesium
Carboxylase and sodium
Carboxylase and zinc
Carbonic anhydrase and zinc
Hamburger shift is also known as
All of the above
Identify the correct statement with respect to the transport of respiratory gases by blood.
Haemoglobin is necessary for the transport of oxygen and carbonic anhydrase for the transport of carbon dioxide.
Haemoglobin is necessary for the transport of carbon dioxide and carbonic anhydrase for the transport of oxygen.
Only oxygen is transported by blood.
Only carbon dioxide is transported by blood
- pCO2 is high and pO2 is low
- pO2 is high and pCO2 is low
- pCO2 and pO2 are equal
- None of the above
The chloride shift occurs in response to
- The H+ released from carbonic acid combines with haemoglobin to form haemoglobinic acid
- Oxyhaemoglobin of erythrocytes is alkaline
- More than 70% of carbon dioxide is transferred from tissues to the lungs in the form of carbamino compounds
- In lungs, the oxygen from the alveolus reaches the blood through active transport
CO2 dissociates from carbamino haemoglobin when
(a) pCO2 is high and pO2 is low
(b) pO2 is high and pCO2 is low
(c) pCO2 and pO2 are equal
(d) None of the above
- Bicarbonate ions
State the different modes of CO2 transport in blood.
Write a note on the affinity of hemoglobin.
- carbamino haemoglobin
- gaseous form
- bicarbonate ions
- carbon monoxide
How does high blood pressure affect gas exchange?
Which one of the following is the correct matching of two capacities and volume ?
- A – I; B – II; C – III; D – IV
- A – IV; B – III; C – I; D – II
- A – II; B – III; C – IV; D – I
- A – III; B – IV; C – I; D – II
Within the blood, oxygen is primarily transported __________________ while the bulk of carbon dioxide is transported _________________.
in association with hemoglobin; as carbon dioxide, dissolved in the plasma
as oxyhemoglobin; as bicarbonate ions
as deoxyhemoglobin; as carbaminohemoglobin
dissolved in the plasma; as carbaminohemoglobin
- potassium bicarbonate
- carbamino haemoglobin
- sodium bicarbonate
- dissolved in plasma
Which of the choices below is not a functional process performed by the respiratory system?
transport of respiratory gases