Approximately seventy percent of carbon dioxide absorbed by the blood will be

transported to the lungs

1. as bicarbonate ions

2. in the form of dissolved gas molecules

3. by binding to RBC

4. as carbamino-haemoglobin

The figure shows a diagrammatic view of human respiratory system with labels A, B, C

and D. Select the option, which gives correct identification and main function and/or

characteristic.

1. A-trachea-long tube supported by complete cartilaginous rings for conducting

inspired air

2. 8-pleural membrane-surround ribs on both sides to provide cushion against rubbing

3. C-alveoli-thin walled vascular bag-like structures for exchange of gases

4. D-lower end of lungs-diaphragm pulls it down during inspiration

Which one of the following is the correct statement for respiration in humans?

1. Cigarette smoking may not lead to inflammation of bronchi

2. Neural signals from pneumotoxic centre in pons region of brain can increase the

duration of inspiration

3. Workers in grinding and stone breaking industries may suffer, from lung fibrosis

4. About 90% of carbon dioxide ($C{O}_2$) is carried by haemoglobin as carbamino haemoglobin

People who have migrated from the planes to an area adjoining Rohtang Pass about six

months back

1. have more RBCs and their haemoglobin has a lower binding affinity to O₂

2. are not physically fit to play games like football

3. suffer from altitude sickness with symptoms like nausea, fatigue, etc.

4. have the usual RBC count but their haemoglobin has very high binding affinuty to O₂

A large proportion of oxygen is left unsused in the human blood even after its uptake by

the body tissues. This O₂

1. raises the P_CO2 of blood to 75 mm of Hg

2. is enough to keep oxyhaemoglobin

3. helps in relasing more O₂ to the epithelial tissues

4. acts as a reserve during muscular exercise

What is true about RBCs in humans?

1. They carry about 20-25 per cent of CO₂

2. They transport 99.5 per cent of O₂

3. They transport about 80 per cent oxygen only and the rest 20 per cent of it is

transported in dissolved state in blood plasma

4. They do not carry CO₂ at all

Which two of the following changes (1-4) usually tend to occur in the plain dwellers when

they move to high altitudes (3,500 m or more)?

(1) Increase in red blood cell size

(2) Increase in red blood cell production

(3) Increased breathing rate

(4) Increase in thrombocyte count Changes occurring are

1. (2) and (3)

2. (3) and (4)

3. (1) and (4)

4. (1) and (2)

What is vital capacity of our lungs?

1. Inspiratory reserve volume plus tidal volume

2. Total lung capacity minus expiratory reserve volume

3. Inspiratory reserve volume plus expiratory reserve volume

4. Total lung capacity minus residual volume

The haemoglobin of a human foetus

1. has a lower affinity for oxygen than that of the adult

2. its affinity for oxygen is the same as that of an adult

3. has only 2 protein subunits instead of 4

4. has a higher affinity for oxygen than that of an adult

People living at sea level have- around 5 million RBC per cubic millimeter of their blood

whereas those living at an altitude of 5400 metres have around 8 million. This is because

at high altitude:

1. people get pollution-free air to breathe and more oxygen is available

2. atmospheric O₂ level is less and hence more RBCs are needed to absorb the required

amount of O₂ to survive

3. there is more UV radiation which enhances RBC production

4. people eat more nutritive food, therefore more RBCs are formed