What is the trigger for angina pectoris?

A. Hypoventilation causes hypocapnia: Hypoventilation leads to inadequate removal of carbon dioxide (CO₂), resulting in hypercapnia rather than hypocapnia. This occurs because decreased ventilation reduces gas exchange efficiency, allowing CO₂ to accumulate in the blood, which can cause respiratory acidosis.

B. Hypoventilation causes alkalosis: Hypoventilation leads to respiratory acidosis rather than alkalosis. When ventilation is insufficient, CO₂ builds up in the bloodstream, leading to an increase in hydrogen ion concentration and a subsequent drop in blood pH. This is commonly seen in conditions like chronic obstructive pulmonary disease (COPD), neuromuscular disorders, and opioid overdose.

C. Hyperventilation causes acidosis: Hyperventilation results in excessive elimination of CO₂, leading to a decrease in hydrogen ion concentration and an increase in blood pH, causing respiratory alkalosis rather than acidosis. Acidosis occurs when CO₂ retention leads to an increase in hydrogen ion concentration, which is the opposite of what happens with hyperventilation.

D. Hyperventilation causes hypocapnia: Hyperventilation leads to an excessive exhalation of CO₂, causing a reduction in blood CO₂ levels (hypocapnia). This can result in respiratory alkalosis, leading to symptoms such as dizziness, lightheadedness, tingling sensations, and even syncope. It is often seen in conditions like anxiety, panic attacks, fever, or high-altitude exposure.

A. Increase peripheral resistance: An increase in peripheral resistance contributes to hypertension by raising the pressure in the arteries. This condition often results from vasoconstriction or structural changes in the blood vessels, leading to higher overall blood pressure.

B. Decrease in cardiac output: A decrease in cardiac output typically does not cause hypertension. In fact, low cardiac output may lead to hypotension (low blood pressure) since there is less blood being pumped into the circulatory system. This option is the exception when discussing physiological causes of hypertension.

C. Both increased cardiac output and peripheral resistance: Both increased cardiac output and peripheral resistance can lead to hypertension. An increase in either factor can elevate blood pressure, and their combined effect can significantly contribute to the development of hypertension.

D. Increased cardiac output: Increased cardiac output raises blood pressure by delivering more blood to the arteries with each heartbeat. This can occur due to various factors such as increased fluid volume, increased heart rate, or heightened contractility of the heart.