A section of an alveolus with a pulmonary capillary indicates the presence of major layers constituting diffusion membrane –

• 3

• 2

• 6

• 10

Which of the following situations would result in the greatest degree of O₂ saturation for haemoglobin, assuming PO₂ remains constant –

• Increased CO₂ levels, decreased temperature

• Increased CO₂ levels, increased temperature

• Decreased CO₂ levels, decreased temperature

• Decreased CO₂ levels, increased temperature

The largest proportion of CO₂ carried by blood is in the form of –

• Molecular CO₂ dissolved in the plasma

• Bicarbonates (HCO₃^–) carried within RBCs

• HCO₃^– carried in the plasma

• Molecular CO₂ chemically bound to haemoglobin

Why do human beings have difficulty breathing at high elevations?

• O₂ makes up lower percentage of air there

• The temperature is lower there

• The barometric pressure is higher there

• PO₂ is lower there

Which of the following represents a larger volume of air than is normally found in the resting tidal volume of a human lung?

• Residual volume

• Inspiratory reserve volume

• Expiratory reserve volume

• All

All of the following can bond with haemoglobin except

• O₂

• H⁺

• CO₂

• HCO₃^–

At rest cardiac output is 5L / min, how much CO₂ is delivered to the lungs to be exhaled each minute?

• 4 ml / min.

• 200 ml / min.

• 5 ml / min.

• 1.34 ml / min.

What structure do RBCs move through single file?

• artery

• arteriole

• capillary

• venule

The oxy-hemoglobin dissociation curve shifts to the right by all the following except:

• Increased carbon dioxide

• Increased pH

• Increased temperature

• Presence of 2, 3 DPG

The affinity of Hb for O₂ is

• Decreased in metabolizing tissue

• Increased at higher body temperature

• Increase at higher than normal 2, 3 DPG levels

• Decreased at more basic than normal pH