Question

Pneumotaxic centre which can moderate the functions of the respiratory rhythm centre is present at (a) pons region of brain (b) thalamus (c) spinal cord (d) right cerebral hemisphere.

Short answer

The pneumotaxic centre is present at the pons region of the brain, so the answer is (a) pons region of brain.

Step-by-step solution

Identify the function of the pneumotaxic center

The pneumotaxic center is part of the respiratory control system in the brain. It helps regulate the rhythm of breathing by inhibiting the activity of the medullary respiratory centers.

Locate the pneumotaxic center

The pneumotaxic center is located in the upper part of the pons, which is a region of the brainstem.

Match the function to the correct location

Since the pneumotaxic center is involved in the control of respiratory rhythm and is located in the pons, the correct answer is the one that mentions the pons region of the brain.

Key concepts

Respiratory Control System

The respiratory control system is an intricate network in the body essential for regulating breathing. Playing a pivotal role are several structures located in the brainstem, which collaborate to ensure smooth and efficient respiratory processes. The medulla oblongata and the pons are two regions partaking in the management of respiratory rhythms.

The medulla houses the primary respiratory centers—the dorsal respiratory group and the ventral respiratory group—which are fundamental for initiating and maintaining the respiratory cycle. These centers receive signals related to carbon dioxide levels and blood pH, allowing them to adjust the depth and rate of respiration accordingly to maintain homeostasis.

In addition to the medullary centers, the pneumotaxic center, stationed in the pons, fine-tunes the respiratory rhythm by sending inhibitory impulses that prevent the overinflation of the lungs. It essentially curtails the inspiratory phase and facilitates the transition to the expiratory phase, thereby contributing to a controlled breathing pattern.

Brainstem Anatomy

Understanding the role of the pneumotaxic center necessitates a brief exploration of brainstem anatomy. The brainstem, often regarded as the most primitive part of the brain, is tasked with several autonomic and life-sustaining functions. It connects the cerebral hemispheres with the spinal cord and can be anatomically divided into three main regions: the midbrain, the pons, and the medulla oblongata.

The pons, located above the medulla and below the midbrain, serves as a bridge between various parts of the nervous system, including between the cerebrum and the cerebellum. It contains nuclei and tracts that are integral to functions such as arousal, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and more. Importantly, it also harbors the pneumotaxic center, which has a profound influence on the rhythm of respiration, underscoring the critical nature of this compact but powerful structure.

Biological Rhythm Regulation

Biological rhythms are the natural cycles of change in our body's chemicals or functions. It's like an internal clock that helps our bodies to anticipate and adapt to the regular rhythm of the day. These rhythms affect everything from our sleep-wake cycles to how we metabolize food and how our hormones are released.

Regulation of these rhythms, especially the circadian rhythm, is influenced by the brainstem among other structures. The pneumotaxic center, as part of the respiratory control system, also imposes a rhythmic characteristic on the function of breathing. By integrating sensory feedback and modulating the activity of respiratory muscles, this center ensures that breathing adapts to the body's needs during various states of activity and rest. Rhythmicity in breathing thus reflects the broader principle of biological rhythm regulation.