The central nervous system (CNS) cells, where the impulses for the sympathetic nervous system (SNS) originate, are located where?

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.

A) Decreased bowel sounds:
When the sympathetic nervous system (SNS) is activated, such as during stress or a "fight-or-flight" response, blood is redirected away from the gastrointestinal (GI) tract to vital organs like the heart and muscles. This results in decreased gastrointestinal motility and function, which is reflected in a reduction in bowel sounds. Decreased bowel sounds are a direct consequence of reduced blood flow and decreased activity in the GI system.

B) Increased blood glucose level:
While it is true that SNS activation can lead to an increase in blood glucose due to the release of catecholamines (e.g., epinephrine), this response is related to the body’s preparation for physical exertion and not directly a result of blood being diverted from the GI tract. The increase in glucose levels is more about energy mobilization rather than an effect on blood flow to the GI tract.

C) Decreased immune reaction:
Sympathetic stimulation can indeed have effects on immune function, typically suppressing immune responses during a stress response. However, this is not directly linked to blood being diverted away from the GI tract. Immune suppression is more about the body prioritizing immediate survival (e.g., diverting energy to muscles for fight-or-flight) rather than a specific physiological consequence of GI blood flow changes.

D) Increased blood pressure:
Sympathetic nervous system activation does lead to an increase in blood pressure due to vasoconstriction and increased heart rate. However, increased blood pressure is a broader systemic response to SNS stimulation, and it is not directly related to blood being diverted from the GI tract. Blood pressure increases as part of the general "fight-or-flight" response, but it does not specifically indicate changes in GI blood flow.