How does a cat's purr work physiologically? - briefly
A cat's purr is produced by the rapid, rhythmic contraction and relaxation of the laryngeal muscles, which causes vibrations in the vocal cords during both inhalation and exhalation. This mechanism is controlled by a neural oscillator in the brain, generating the characteristic low-frequency sound.
How does a cat's purr work physiologically? - in detail
A cat’s purr is a complex physiological phenomenon that originates from the rapid, rhythmic contraction and relaxation of the laryngeal muscles, primarily the intrinsic laryngeal muscles, in coordination with the diaphragm. These contractions occur at a frequency of 25 to 150 Hertz, a range that has been scientifically linked to therapeutic effects in both cats and humans. The process begins when neural signals from the brain’s central pattern generator, a specialized neural network, stimulate the laryngeal muscles to oscillate. This oscillation causes the vocal cords to separate and come together rapidly, creating a vibration as air passes through the glottis during both inhalation and exhalation. The resulting sound is amplified by the resonating chambers of the throat, mouth, and nasal passages, producing the characteristic purring noise. Interestingly, purring is not solely dependent on the larynx; the diaphragm also contributes by modulating airflow, ensuring a continuous and smooth purr. The precise mechanism is still under study, but it is believed that the hyoid apparatus, a series of small bones in the throat, stabilizes the larynx during this process, allowing for sustained vibrations. Purring is not limited to a single emotional state; cats purr in various situations, including contentment, stress, and even during self-healing. This versatility suggests that purring may serve multiple physiological and psychological functions, such as promoting bone density through low-frequency vibrations, aiding in muscle repair, and reducing stress levels. The autonomic nervous system, particularly the parasympathetic branch, plays a significant part in regulating this behavior, ensuring that purring remains an involuntary yet controlled response. Overall, the cat’s purr is a remarkable interplay of muscular, neural, and respiratory systems, showcasing the intricate biology of these animals.