ACTIVITY
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)
Initiation of exercise
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Due to neural changes, there is an abrupt increase in ventilation when exercise is initiated. These changes send excitatory signals to the dorsal respiratory group of the medullary respiratory center.
Moderate exercise
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The gradual increase in breathing when exercising moderately is caused by changes in the bloodstream, whether physical or chemical. These include decreased PO2, increased PCO2, and increased temperature.
Asthma attack
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Allergens trigger the smooth muscle to spasm and oversecretion of mucus which could clog the bronchi and bronchioles and worsen the attack.
Abrupt ascent into high altitudes
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At high altitudes, the blood CO2 levels become lower than normal because of the increased rate and depth of breathing stimulated by the low blood O2 levels. The decreased blood CO2 levels cause the blood pH to become abnormally high.
Pneumonia
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Certain microbes, like the pneumococcal bacterium Streptococcus pneumoniae, release damaging toxins when they enter the lungs, causing inflammation and immune responses that have damaging effects on individuals.
Paralysis of phrenic nerve
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When the phrenic nerve is damaged, the electrical signals from the brain stop traveling to the diaphragm muscle.
Severe tuberculosis with resulting lung scar tissue
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The bacterium Mycobacterium tuberculosis multiply and cause inflammation, stimulating neutrophils and macrophages to engulf the bacteria to prevent their spread.
Severe anemia
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Anemia is characterized by lack of hemoglobin which is responsible for carrying oxygen. People suffering from this experience hyperventilation due to their body’s constant effort to bring oxygen levels to normal.
Advanced COPD (Chronic Obstructive Pulmonary Disease)
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Chronic and recurrent obstruction of airflow causes an increased airway resistance.
Advanced pregnancy
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During pregnancy, respiratory resistance increases while respiratory conductance decreases. Total pulmonary and airways resistances decrease in late pregnancy due to hormonally induced relaxation of tracheobronchial tree smooth muscles.