1.What happened to HR when the subject held their breath (near the end of breath
ID: 3514213 • Letter: 1
Question
1.What happened to HR when the subject held their breath (near the end of breath hold)?
2. Assuming this is a sympathetic nervous system effect on the heart, explain how this response was triggered and why.
3. People who hyperventilate my get dizzy due to cerebral vasoconstriction, causing anxiety and further hyperventilation. Such people are sometimes urged to breathe into a paper bag. What good would this do? Explain the physiological mechanisms involved.
4. Explain the difference between a respiratory and a metabolic acidosis.
Explanation / Answer
1. While holding breath, the heart rate first decreases and then increases near the end of breath hold.
2. By holding your breath, you are able to relax your body muscles. This means that holding your breath might actually decrease your heart rate, as the relaxed muscles no longer need a lot of oxygen and CO2 levels are low. After holding your breath for a while, oxygen will run low in your blood, CO2 increases, and the urge to breathe will be very large due to the action of sympathetic nervous system. The ability to relax reduces, and heart rate will start increasing again.
3. Hyperventilating occurs when body receives more oxygen than it needs causing respiratory alkalosis. Breathing into bag lets you re-breathe you exhaled carbon dioxide in hopes of broinging your body back to normal pH level.
4.
Metabolic acidosis Respiratory acidosis Bicarbonate deficit Carbonic acid excess pH lowered pH lowered Respiratory-low pH stimulates respiratory center causing decrease in H2CO3 The most important renal mechanism causes increase in H+ - Na4 exchange, increased ammonia formation. Urinary pH acidic Urinary pH acidic Abnormal increase in anions Depression of respiration due to damage to CNS. Abnormal loss of HCO3 minus ions Insufficient pulmonary blood flow.Related Questions
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