A center that moderates the functions of the respiratory rhythm center is located in:
1. Dorsal medulla oblongata
2. Ventral medulla oblongata
3. Pons Varolii
4. Pre-central gyrus of the cerebrum
Pneumotaxic centre which can moderate the functions of the respiratory rhythm centre is present at:
1. Pons region of brain
2. Thalamus
3. Spinal cord
4. Right cerebral hemisphere
The following statements refer to gas carriage by blood. Choose the correct statement:
1. | After leaving the lungs, each litre of blood contains about 20 ml of oxygen. |
2. | Haemoglobin is half saturated with oxygen when the PO2 is about 30 mm Hg |
3. | As the PCO2 rises, the affinity of haemoglobin for oxygen is increased. |
4. | Each litre of arterial blood contains about 50 mL of carbon dioxide. |
In the given diagram of the oxygen dissociation curve, under normal physiological conditions, the partial pressure of oxygen at the tissue level is represented by :
1. A
2. B
3. C
4. D
The partial pressure of oxygen in the alveoli of the lungs is
(1) equal to that in the blood
(2) more than that in the blood
(3) less than that in the blood
(4) less than that of carbon dioxide
Name the chronic respiratory disorder caused mainly by cigarette smoking
1. asthma
2. respiratofy acidosis
3. respiratory alkalosis
4. emphysema
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
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
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