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

According to Bohr's effect

1.  Hemoglobin oxygen binding affinity is inversely related to acidity.

2.  Hemoglobin oxygen binding affinity is inversely related to concentration of ${\mathrm{CO}}_2$.

3.  Hemoglobin oxygen binding affinity is directly related to acidity.

4.  Both 1 and 2.

Consider the characters of a respiratory control center in humans:
I. It is located in pons
II. It moderates the functions of respiratory rhythm center
III. Its absence results in an increase in depth of respiration

The respiratory control center is:

1. Pneumotaxic center

2. Apneustic center

3. Chemosensitive zone

4. Dorsal group

Which of the following situations would result in the greatest degree of ${\mathrm{O}}_2$ saturation for haemoglobin, assuming ${\mathrm{PO}}_2$ remains constant-

1.  Increased ${\mathrm{H}}^{+}$ levels, decreased temperature.

2.  Increased ${\mathrm{CO}}_2$ levels, increased acidity.

3.  Decreased ${\mathrm{CO}}_2$ levels, decreased acidity.

4.  Increased ${\mathrm{CO}}_2$ levels, increased temperature.

Which of the following disease is caused mainly due to cigarette smoking

1. Asthma

2. Emphysema

3. Bronchitis

4. Rhinitis

Difficulty in breathing due to inflammation  of bronchi and bronchioles leads to

1. Asthma

2. Emphysema

3. Occupational Lung Disease

4. Rhinitis

Which of the following is not true about hering breuer reflex

1. It is activated when a normal mechanism to switch off inspiration does not work timely due to any reason.

2. It is activated when a normal mechanism to switch off expiration does not work timely due to any reason

3. It prevents the alveoli from overstretching and bursting

4. It normally remains inactive

Pneumotaxic Centre is present in the

1. forebrain

2. midbrain

3. Hindbrain

4. Diencephalon

Aortic arch and carotid artery receptors cannot recognise changes in

1. CO_2­ Concentration

2. O_2­ Concentration

3. H⁺ ions Concentration

4. All of these

The respiratory centre is highly sensitive for

1. CO_2­

2. O_2­

3. H⁺ ions

4. Both A and C