Question

The autonomic nervous system usually reaches its target via how many neurons?

1) One neuron
2) Two neurons
3) Three neurons
4) Four neurons

Answer 1

The autonomic nervous system typically reaches its target via two neurons - a preganglionic neuron synapsing with a postganglionic neuron which affects the target organ.

Step-by-step explanation:

The autonomic nervous system generally reaches its target using two neurons: a preganglionic neuron and a postganglionic neuron. The preganglionic neuron originates in the Central Nervous System (CNS) and synapses with the postganglionic neuron located in a ganglion outside the CNS, which in turn acts upon the target organ. This arrangement allows the autonomic nervous system to control functions like heart rate and digestion through divisions known as the sympathetic and parasympathetic systems, which work antagonistically to each other to maintain homeostasis.

In the case of sympathetic activation, such as in a 'fight or flight' response, the neurotransmitter norepinephrine is released at the target organ. Conversely, during parasympathetic activation, which supports 'rest and digest' functions, acetylcholine is the neurotransmitter that's released. These pathways involve intricate chemical signaling to regulate the body's internal environment without conscious control.