The figure given below shows a small part of human lung where exchange of gas takes place. In which one of the options given below, the one part A, B, C or D is correctly identified along with its function.
A – alveolar cavity: Main site of exchange of
respiratory gases
D – capillary wall: Exchange of gases takes
place here
B – red blood cell: Transport of mainly
haemoglobin
C – arterial capillary: Passes oxygen to tissues
a (Correct): A points to the central, hollow space inside the alveolus. This is the alveolar cavity where inhaled air collects. It is the primary site where the exchange of O2 (into blood) and CO2 (out of blood) occurs across the thin respiratory membrane.
b (Incorrect Identification): D points to the basement substance/membrane that lies between the squamous epithelium of the alveolus and the endothelium of the capillary. It is not the capillary wall itself (which is made of cell layers C and the inner layer of the double layer shown).
c (Incorrect Function): B points to a red blood cell (RBC). While RBCs contain hemoglobin, their function is transport of respiratory gases (O2 and some CO2), not the transport of "hemoglobin" itself.
d (Incorrect Identification/Function): C points to the squamous epithelium of the alveolar wall, which is part of the diffusion membrane. It does not "pass oxygen to tissues"; that happens at the systemic level, far from the lung alveoli shown here.
Match the Following: (a) Asthma 1. Inflammation of nasal tract(b) Bronchitis 2.
NextChoose the correct statement regarding the human respiratory system:
Match the Following: (a) Asthma 1. Inflammation of nasal tract(b) Bronchitis 2. Spasm of tracheal mu
HardThe rate of breathing is primarily controlled by the concentration of:
MediumThe respiratory rhythm centre is located in the:
MediumThe enzyme required for the transport of CO2 as bicarbonate is:
MediumEvery 100 mL of deoxygenated blood delivers approximately ______ of CO2 to the alveoli.
HardCO2 is transported in three ways: as carbonic acid, as carbamino-haemoglobin, and as bicarbonates. T
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