A. ACTIVITY
Briefly explain the main cause or mechanism of the increase in respiratory rate or depth and/or respiratory difficulties in the following cases: (one to two sentences only)
- Initiation of exercise: During initiation of exercises, an increased respiratory rate can result from the oxygen demand needed to perform the exercise for active muscle contraction, which requires large amounts of oxygen. This is regulated by the chemoreceptors in our body that monitor our CO2 and O2 levels.
- Moderate exercise: Moderate exercises experience a similar effect of increased respiratory rate due to the rising oxygen demand of the body. Due to it having been prolonged—along with the chemoreceptors—the proprioceptors also stimulate the central nervous system to increase breathing of the respiratory system.
- Abrupt ascent into high altitudes: At sudden high altitudes, the thin air causes the air pressure in the environment to decrease, which inversely affects the body’s breathing rate, blood pressure, heart rate, and pulmonary vascular resistance. Because the Peripheral Chemoreceptors sense the sudden change in PCO2 and O2 in the blood, this can also lead to hyperventilation and altitude sickness.
- Paralysis of the phrenic nerve: Paralysis of the phrenic nerve is the temporary reduction or permanent loss of diaphragmatic movement and contraction, which can result in respiratory difficulties. Several causes can be spinal cord injuries, nerve compression, and neuromuscular diseases (e.g., Amyotrophic lateral sclerosis).
- Severe Anemia: Since Anemia is characterized by the lack of healthy red blood cells or hemoglobin that can carry oxygen throughout the body, an increase in respiratory rate and depth is required to compensate for the lack of oxygenated blood. The peripheral chemoreceptors, sensitive to the change in PO2 and PCO2, alert the body for increased ventilation to counter breathing difficulties such as shortness of breath.
- Advanced pregnancy: Advanced pregnant women are more prone to respiratory difficulties due to the expanding uterus and decreased lung volume near the diaphragm due to the growing fetus. To compensate for this and other problems such as reduced lung capacity, an increase in respiration rate and depth is needed to maintain normal oxygen levels.
Reference:
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