Breathing and Exchange of Gases , Quiz 3

Pneumotaxic centre is present in –

• Pons

• Medulla oblongata

• Cerebrum

• Cerebellum

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

The breathing centre initiates ventilation in response to –

• A decrease in air pressure

• A decrease in O₂

• An increase in CO₂

• The rate of gas exchange in the alveoli

All of the following factors play role in the regulation of respiratory rhythm except –

• CO₂

• H⁺ conc.

• O₂

• None of the above is correct

The respiratory disorder which leads to irreversible distension and loss of elasticity of alveoli of lungs is

• bronchitis

• bronchial asthma

• emphysema

• SARS.

A disease characterised by accumulation of fluid with dead WBCs occupying most of the air space in alveolar sac is

• Pneumonia

• Bronchitis

• Emphysema

• Bronchial asthma

Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because :-

• There is a positive intrapleural pressure

• Pressure in the lungs is higher than the atomospheric pressure.

• There is a negative pressure in the lungs.

• There is a negative intrapleural pressure pulling at the lung walls.

CO2 is carried in blood by hemoglobin in the form of :

• Sodium bicarbonate

• Potassium bicarbonate

• Carbamino compound

• Methaemoglobin

Dissociation of oxyhaemoglobin in blood increases when there is

• Increase in pH and decrease in CO₂ concentration

• Decrease in temperature and increase in O₂ concentration

• Increase in CO₂ concentration

• Decrease in pH and increase in CO₂ concentration

The cells which do not respire

• Epidermal cells

• Sieve cells

• Cortical cells

• Erythrocytes