The nurse administers a drug that stimulate the parasympathetic nervous system. What physiologic response would indicate that the drug is working?

A) The patella reflex ("knee jerk") activated by tapping the patella tendon: The patellar reflex is a monosynaptic spinal reflex that involves the somatic nervous system but is a reflex action rather than a voluntary motor function. The somatic nervous system governs voluntary movements, but reflex actions like the patellar reflex are involuntary responses that do not require higher brain input, though they involve somatic motor pathways.

B) Abdominal viscera the beginning of depolarization in the cardiac conduction of impulses: This process is primarily under the control of the autonomic nervous system (ANS), not the somatic nervous system. The ANS regulates involuntary processes like heart rate and digestion, while the somatic nervous system controls voluntary movements and somatic sensation.

C) The act of typing a report using a computer keyboard: Typing is a voluntary motor activity, controlled by the somatic nervous system. The somatic system is responsible for conscious, voluntary actions such as moving muscles in the arms, hands, and fingers to type. This is the most accurate example of a somatic function.

D) Withdrawing the hand after touching a hot surface: This is a reflex action known as the "withdrawal reflex," which involves the somatic nervous system. However, it is an involuntary action triggered by a sensory stimulus. While it does involve the somatic system, it is not a voluntary action like typing, and reflexes are considered part of the automatic response mechanisms.

A) Are no longer approved for treating depression: MAO inhibitors (MAOIs) are still approved and used to treat depression, especially in cases where other medications have not been effective. They are not considered obsolete, though their use has become less common due to the availability of safer, more tolerable options. This is not the primary reason why MAOIs may not be prescribed.

B) Are more expensive than other antidepressants: While cost can be a factor in medication choice, it is not the primary reason why MAO inhibitors are less frequently prescribed for depression. There are other more significant concerns, such as side effects and dietary restrictions, that make other medications a preferred first-line choice.

C) Require strict dietary restrictions: This is the most accurate explanation. MAO inhibitors can cause dangerous interactions with certain foods that contain high levels of tyramine, such as aged cheeses, cured meats, and fermented products. Consuming these foods while on an MAOI can lead to a hypertensive crisis, which is a life-threatening condition. Because of these dietary restrictions, patients on MAOIs must adhere to a strict diet, which can be challenging to manage.

D) Can cause profound hypotension: While hypotension can occur as a side effect of MAOIs, it is not the most significant concern. The more serious risk with MAOIs is the potential for a hypertensive crisis due to dietary interactions with tyramine-containing foods, rather than hypotension. Therefore, the dietary restrictions are a more pressing issue than the risk of hypotension.