Briefly explain the main cause or mechanism of increase in respiratory rate or depth and/or respiratory difficulties in the following cases: (one to two sentences only)
1. Initiation of exercise
During the initiation of exercise the main cause or mechanism of increase in respiratory rate or depth and/or respiratory difficulties to higher oxygen demand and increased carbon dioxide production due to increased physical activity. This triggers the respiratory center in the brain to stimulate the respiratory muscles, leading to deeper and faster breathing to meet the body's oxygen needs.
2. Moderate exercise
The abrupt increase in breathing at the start of exercise is due to neural changes that send excitatory impulses to the dorsal respiratory group (DRG) of the medullary respiratory center in the medulla. These changes include (1) anticipation of the activity, which stimulates the limbic system; (2) sensory impulses from proprioceptors in muscles, tendons, and joints; and (3) motor impulses from the primary motor cortex (precentral gyrus).
3. Abrupt ascent into high altitudes
Upon abrupt ascent into high altitudes, the decrease in oxygen concentration in the air triggers an immediate response in the body. This leads to an increase in respiratory rate and depth as the body attempts to compensate for the lower oxygen levels, aiding in the intake of more oxygen and helping to alleviate respiratory difficulties at high altitudes.
4. Paralysis of phrenic nerve
The paralysis of the phrenic nerve, which controls the diaphragm, impairs the normal breathing process. This leads to a decrease in the movement of the diaphragm, resulting in shallow breathing and an increased effort to inhale, causing respiratory difficulties.
5. Severe anemia
In severe anemia, the reduced oxygen-carrying capacity of the blood prompts the body to compensate by increasing the respiratory rate and depth. This compensatory mechanism aims to supply more oxygen to the tissues, but it can lead to respiratory difficulties due to the extra effort required to maintain adequate oxygen levels in the body.
6. Advanced pregnancy
During advanced pregnancy, the growing uterus puts pressure on the diaphragm and lungs, reducing lung capacity. This restriction in lung expansion prompts an increase in respiratory rate and depth as the body compensates for the decreased airflow, sometimes leading to a feeling of breathlessness or respiratory difficulties in pregnant individuals.
Tortora, G. J., & Derrickson, B. (2017). Principles of ANATOMY & PHYSIOLOGY (15th ed.).