Explain the transport of O2 and CO2 between alveoli and tissue with diagram.
Transport of O2 : Blood carries oxygen from the alveoli to various body tissues. About 3% of 02 is carried in a dissolved state through the plasma. About 97% of O2 is transported in combination with haemoglobin of the RBCs as oxyhaemoglobin. Partial pressure of O2 is high in the alveoli as compared to pulmonary
blood capillaries, therefore 02 diffuses from alveoli into the pulmonary capillaries and combines with Hb to form oxyhaemoglobin. When this oxygenated blood reaches the different tissues having low partial pressure of 02, the bonds holding O2 to Hb become unstable. As a result, O2 is released from the blood capillaries into the tissues.
Transport of CO2 : Blood carries CO2 from various body tissues to the alveoli. About 7% of CO2 gets dissolved in the blood plasma and is carried in solution. About 70% of CO2 is transported by plasma as bicarbonate ions. From the tissues (which have high pCO2), C02 diffuses into the blood capillaries (which have low pCO2). In the RBCs, CO2 combines with water, to form carbonic acid (H2 CO3 ).H2CO3 is unstable and quickly dissociates into hydrogen ions and bicarbonate ions.
The above reaction is thousand times faster in RBCs as compared to plasma because RBCs contain carbonic anhydrase enzyme that reversibly catalyses the conversion of CO2 and water to H2CO3. About 20-35% CO2 is carried by Hb as carbaminohaemoglobin.
The blood carries CO2 in these three different forms towards the alveoli. CO2 is less soluble in arterial blood than in venous blood. Therefore, some CO2 diffuses from the plasma of the pulmonary capillaries into the alveoli. For the release of CO2 from the bicarbonate, a series of reverse reactions takes place and CO2 is released into the alveoli of the lungs. High pO2 in the pulmonary capillaries due to oxygenation of Hb favours separation of CO2 from carbaminohaemoglobin.
For completion of respiration process, write the given steps in sequential manner.
(a) Diffusion of gases (O2 and CO2) across alveolar membrane.
(b) Transport of gases by blood.
(c) Utilisation of O2 by the cells for catabolic reactions and resultant release of CO2 .
(d) Pulmonary ventilation by which atmos-pheric air is drawn in and C02 rich alveolar air is released out.
(e) Diffusion of 02 and CO2 between blood and tissues.
What will be the p02 and pCO2 in the atmospheric air compared to those in the alveolar air?
(i) pO2 lesser, pCO2 higher
(ii) pO2 higher, pCO2 lesser
(iii) pO2 higher, pCO2 higher
(iv) pO2 lesser, pCO2 lesser
What is tidal volume? Find out the tidal volume (approximate value) for a healthy human in an hour.
Diffusion of gases occurs in the alveolar region only and not in the other parts of respiratory system. Why?
Complete the missing terms
(a) Inspiratory Capacity (1C)=_____+IRV
(b)_____= TV + ERV
(c) Functional Residual Capacity (FRC) = ERV +_____
Have you heard about hypoxia? Try to gather information about it, and discuss with your friends.
Arrange the following terms based on their volumes in an ascending order:
(a) Tidal Volume (TV)
(b) Residual Volume (RV)
(c) Inspiratory Reserve Volume (1RV)
(d) Expiratory Capacity (EC).
Match the following and mark the correct options
Animal Respiratory Organ
A.Earthworm (i)Moist cuticle
B.Aquatic Arthropods (ii)Gills
C.Fishes (iii)Lungs
D.Birds/Reptiles (iv)Trachea
(a) A-(ii), B-(i), C-(iv), D-(iii)
(b) A-(i), B-(iv), C-(ii), D-(iii)
(c) A-(i), B-(iii), C-(ii), D-(iv)
(d) A-(i), B-(ii), C-(iv), D-(iii)
Name the organs of respiration in the following organisms:
(a) Flatworm ____________
(b) Birds ____________
(c) Frog____________
(d) Cockroach____________
A major percentage (97%) of O2 is transported by RBCs in the blood. How is the remaining percentage (3%) of O2 transported?
Name the important parts involved in creating a pressure gradient between lungs and the atmosphere during normal respiration.
Compared to O2 , diffusion rate of CO2 through the diffusion membrane, unit difference in partial pressure is much higher. Explain.
The oxygen – haemoglobin dissociation curve will show a right shift in case of ,
(a) High pCO2 (b) High pO2
(c) Low pCO2 (d) Less H+ concentration.
What is the amount of O2 supplied to tissues through every 100 mL of oxygenated blood under normal physiological conditions?
Arrange the following terms based on their volumes in an ascending order:
(a) Tidal Volume (TV)
(b) Residual Volume (RV)
(c) Inspiratory Reserve Volume (1RV)
(d) Expiratory Capacity (EC).
Define oxygen dissociation curve. Can you suggest any reason for its sigmoidal pattern?
A fluid filled double membranous layer surrounds the lungs. Name it and mention its important function.
Distinguish between
(a) IRV and ERV
(b) Inspiratory capacity and expiratory capacity.
(c) Vital capacity and total lung capacity.
Differentiate between
(a) Inspiratory and expiratory reserve volume
(b) Vital capacity and total lung capacity
(c) Emphysema and occupational respiratory disorder.