A large proportion of oxygen is left unused in the human blood even after its uptake by the body tissue. This O2

  • Raise the pCO2 of blood 75 mm of Hg.

  • Is enough to keep oxyhaemoglobin

  • helps in releasing more O2 to the epithelial tissues

  • acts as a reserve during muscular exercises

Reduction is vascular tissue, mechanical tissue and cuticle is characteristic of 

  • xerophytes

  • mesophytes

  • epiphytes

  • hydrophytes

Lungs are made up of air-filled sacs the alveoli. They do not collapse even after forceful expiration, because of :

  • Residual Volume

  • Inspiratory Reserve Volume

  • Tidal Volume

  • Expiratory Reserve Volume

The figure given below shows a small part of human lung where exchange of gases 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 O2 and CO2 takes place here

  • B : Red blood cell - transport of CO2 mainly

  • C : Arterial capillary - passes oxygen to tissues

Bulk of carbon dioxide (CO2) released from body tissue into the blood is present as 

  • bicarbonate in blood plasma and RBCs

  • free CO2 in blood plasma

  • 70% carbamino - haemoglobin and 30% as bicarbonate

  • carbamino - haemoglobin in RBCs

Load more