Sympathetic Nervous System: Interaction of Neurons (Nursing)

00:01 So now let's talk a little bit about the interaction between the pre- and postganglionic neurons.

00:08 After the axons of the sympathetic preganglionic neurons enter the sympathetic trunk ganglia, they may connect with the postganglionic neuron in four different ways.

00:20 The first way, an axon may synapse with the postganglionic neuron in the first ganglion it reaches.

00:28 So for example, it may leave from T1 and then connect or synapse at the T1 ganglia.

00:36 A second way is when an axon may ascend or descend to a higher or lower ganglion before synapsing with its postganglionic neuron.

00:49 So for example, it may exit from T1 but not synapse until it gets to C1, above it, or to T8 below it.

01:00 A third way that they may interact is when an axon continues without synapsing through the sympathetic trunk ganglion and then ends at a prevertebral ganglion, and this is where the synapses occurs.

01:16 The nerves associated with this type of interaction are referred to as splanchnic nerves.

01:23 Finally, an axon may also pass without synapsing through the sympathetic trunk ganglion, the prevertebral ganglion, and then extend all the way to the adrenal medulla of the kidneys.

01:37 The adrenal medulla is part of the renal gland and sits right on top of the kidneys.

01:42 Inside of the adrenal medulla, we have a type of cell called chromaffin cells.

01:49 The chromaffin cells of the adrenal medulla are functionally similar to that of the postsynaptic neuron.

01:56 These cells secrete or release norepinephrine.