Question

Pneumotaxic center which can moderate the functions of the rhythmic respiratory center is present in
(a) Pons region of the brain
(b) thalamus
(c) spinal cord
(d) right cerebral hemisphere

Answer 1

Hint: This center is a group of neurons which is a part of the respiratory center present in the brain stem in the hindbrain. There are multiple functions carried out by the brain stem, and each function is carried out by a designated part.

Complete step by step answer:
- The rhythmic respiratory center is responsible for controlling the rhythmic respiration in the body. It is also responsible for the adjustment of respiration in homeostatic responses due to physiological changes.
- The center is made of three major respiratory groups of neurons - two present in the medulla and one in the pons.
- The two regions in the medulla responsible for respiration are the dorsal respiratory group and the ventral respiratory group. Pons has the pontine respiratory group which has two centers - the pneumotaxic center and the apneustic center.
- The pneumotaxic center is located in the upper part of the pons and it controls both the rate and control of breathing.

- The pneumotaxic center is antagonistic to the apneustic center as it is responsible for inhibiting inspiration and cyclically inhibits inhalation. It is known as an ‘inspiratory off-switch.’
- Respiration in the body is present in the form of neural respiration and cellular respiration.
- The dorsal respiratory group initiates inspiration/inhalation. The ventral respiratory group contains groups of neurons that initiate exhalation.
So, the correct answer is the ‘(a) Pons region of the brain’.

Note:
- Damage to the respiratory center causes breathing disorders which cause the patient to be dependent on mechanical ventilation.
- The absence of this center results in an increase in depth of respiration and a decrease in respiratory rate.