When there is stimulation of the sympathetic nervous system (SNS), blood is diverted away from the gastrointestinal (GI) tract. What might the nurse assess that would indicate this diversion of blood flow to the GI tract?

A) Myasthenia gravis (MG):
Weakness of the extremities and diplopia (double vision) are hallmark symptoms of myasthenia gravis, an autoimmune disorder that affects the neuromuscular junction. In MG, antibodies attack acetylcholine receptors, leading to muscle weakness that worsens with activity and improves with rest. The weakness typically affects voluntary muscles, including those responsible for eye movement, which leads to symptoms such as diplopia and ptosis (drooping eyelids).

B) Multiple sclerosis (MS):
Multiple sclerosis involves the demyelination of neurons in the central nervous system, leading to a variety of neurological symptoms. While MS can cause weakness and visual disturbances, the typical symptoms of MS include fatigue, muscle spasticity, ataxia, and sensory deficits. Diplopia can occur in MS but is usually accompanied by other neurological signs such as numbness, tingling, or loss of coordination.

C) Cerebral palsy (CP):
Cerebral palsy is a group of disorders affecting movement and posture due to non-progressive brain injury or abnormal brain development, often occurring in early childhood. While CP can cause muscle weakness and coordination issues, it does not typically present with diplopia. Instead, it often involves spasticity, motor impairment, and difficulty with fine motor tasks.

D) Parkinson disease (PD):
Parkinson disease is characterized by tremors, bradykinesia (slowness of movement), rigidity, and postural instability. While PD can lead to muscle weakness and visual issues like blurred vision, it is not typically associated with diplopia as a primary symptom. The hallmark motor symptoms are primarily related to tremor and difficulty initiating movements rather than generalized weakness and double vision.

A) Norepinephrine: Norepinephrine is a neurotransmitter primarily involved in the sympathetic nervous system. It is not involved in terminating the stimulation caused by acetylcholine. Norepinephrine acts on adrenergic receptors, whereas acetylcholine primarily acts on cholinergic receptors.
B) Decarboxylase: Decarboxylase is an enzyme that plays a role in the synthesis of certain neurotransmitters, including dopamine, but it does not have a role in terminating the action of acetylcholine at the effector cell. It is unrelated to the termination of acetylcholine signaling.
C) Catecholamine: Catecholamines (such as dopamine, norepinephrine, and epinephrine) are a group of neurotransmitters involved in the sympathetic nervous system. While they play a role in synaptic transmission, they are not responsible for breaking down acetylcholine or terminating its effects. Their primary function is in adrenergic signaling.
D) Acetylcholinesterase: Acetylcholinesterase is the correct enzyme. It is responsible for breaking down acetylcholine (ACh) in the synaptic cleft after it has stimulated the effector cell. By hydrolyzing acetylcholine into acetate and choline, acetylcholinesterase effectively terminates the signal and allows the effector cell's membrane to repolarize. This action prevents continuous stimulation and ensures proper function of the cholinergic system.