Autonomic Nervous System

Front 1

What is another name for the Autonomic Nervous System?

Back 1

the Visceral Motor System

Front 2

What does the ANS control? What kind of neurons is the ANS comprised of?

Back 2

Automatic, involuntary functions.

Motor neurons.

Front 3

What are the two divisions of the ANS and what does each division do?

Back 3

Parasympathetic division - maintains homeostasis
Sympathetic division - prepares for stressful situations ("fight or flight rxns")

Front 4

The motor neurons of the ANS innervate what structures?

Back 4

1. Cardiac muscle
2. Smooth muscle (in most hollow organs)
3. Glands (both endocrine and exocrine)

Front 5

How are the motor neurons organized?

Back 5

In a two-neuron chain. A preganglionic neuron with a cell body in the CNS, and a postganglionic neuron with a cell body in a ganglion in the PNS.

Front 6

Briefly describe the Sympathetic division of the ANS.

Back 6

A.K.A. the Thoracolumbar Outflow. Originates in the spinal cord levels T1-L2. The preganglionic nerve cell bodies are located in the intermediolateral (IML) cell column.

Front 7

Where do the preganglionic nerve fibers of the Sympathetic division go?

Back 7

The preganglionic nerve fibers exit the CNS via a ventral nerve root to enter the spinal nerves T1-L2.

Front 8

After exiting the CNS and entering the spinal nerves, where do preganglionic nerve fibers travel?

Back 8

Through the white communicating rami (14 pairs) and enter the sympathetic chain ganglion.

Front 9

Once in the sympathetic chain ganglion, what paths can a preganglionic nerve fiber take?

Back 9

1. Can synapse with a postganglionic neuron at the same level.
2. Ascend or descend to another level to synapse.
3. Continue on to a collateral ganglion in the abdominal or pelvic cavity before synapsing.

Front 10

How do sympathetic nerve fibers synapse at the same level?

Back 10

A preganglionic neuron originates in the lateral horn, continues through the ventral nerve root and into the spinal nerve, then through the white communicating rami into a sympathetic ganglion. Here it synapses with a postganglionic neuron, which then exits via the gray communicating rami and out through DPR or VPR.

Front 11

How do sympathetic nerve fibers ascend and descend to synapse at different levels?

Back 11

The preganglionic neuron enters the sympathetic chain ganglion and moves either up (above T1) or down (below L2) to synapse with a postganglionic neuron.

Front 12

How do sympathetic nerve fibers travel to internal organs?

Back 12

Instead of synapsing in the chain ganglion, the preganglionic neuron will go through the splanchnic nerve into a collateral ganglion, where it will then synapse with a postganglionic neuron that stimulates the target organ.

Front 13

What are the sympathetic chain ganglia?

Back 13

Bilateral structures that are located adjacent to the vertebral column. Extend from the base of the skull to the coccyx.

Front 14

How do the sympathetic chain ganglion connect to the spinal nerves?

Back 14

White communicating rami (14 pairs) and the gray communicating rami (31 pairs).

Front 15

Describe the white communicating rami.

Back 15

There are 14 pairs that are associated with the spinal nerves T1-L2. Preganglionic neurons travel through the white communicating rami before synapsing.

Front 16

Describe the gray communicating rami.

Back 16

There are 31 pairs associated with each spinal nerve. Postganglionic neurons will travel through the gray communicating rami when exiting through the spinal nerve.

Front 17

What are the components of the Visceral Reflex Arc?

Back 17

1. A sensory neuron, classified as GVA.
2. Connecting neuron (in spinal cord)
3. Two motor neurons, GVE (preganglionic and postganglionic)

Front 18

What is another name for the Parasympathetic division of the ANS?

Back 18

Craniosacral Outflow

Front 19

Where does the cranial portion of the parasympathetic division originate?

Back 19

In the brain stem.

Front 20

Where do the preganglionic parasympathetic neurons originate?

Back 20

In the brain stem motor nuclei associated with cranial nerves (CN) III, VII, IX, and X.

Front 21

Which cranial nerves do parasympathetic preganglionic nerve fibers use to distribute throughout the cranial region?

Back 21

CN III, VII, and IX.

Front 22

Where are the four parasympathetic ganglia located?

Back 22

-CN III
-two ganglia from CN VII
-CN IX

Front 23

What cranial nerve do parasympathetic preganglionic nerves fibers use to distribute to the abdominal and thoracic viscera?

Back 23

CN X. These fibers synapse in the walls of the target organs.

Front 24

Where does the sacral portion of the parasympathetic division originate?

Back 24

In spinal cord levels S2-S4.

Front 25

Where do parasympathetic preganglionic nerve fibers from the sacral portion go?

Back 25

They exit the CNS via the VNR of S2-S4, then they enter the pelvic splanchnic nerves. They synapse with short postganglionic neurons in the walls of the target organs.

Front 26

Where are the parasympathetic postganglionic neurons?

Back 26

Contained entirely within the walls of the target organs.

Front 27

What are neurotransmitters?

Back 27

Chemicals released at synapses between:
-Preganglionic and postganglionic neurons
-Postganglionic neurons and effector organs.

Front 28

What neurotransmitters are released by parasympathetic neurons?

Back 28

The parasympathetic preganglionic neurons release Ach.
The parasympathetic postganglionic neurons also release Ach.

Front 29

What neurotransmitters are released by sympathetic neurons?

Back 29

The sympathetic preganglionic neurons release Ach.
The sympathetic postganglionic neurons release NE (norepinephrine).

Front 30

What neurotransmitters are released by the sympathetic neurons that stimulate the sweat glands?

Back 30

Preganglionic releases Ach. Postganglionic releases Ach.

Front 31

What neurotransmitters are released by the sympathetic neurons that stimulate the suprarenal medulla?

Back 31

This is the exception to the rule (for components of the visceral arc). There is just the one preganglionic neuron that synapses in the suprarenal medulla and releases Ach. This stimulates the suprarenal medulla to secrete epinephrine into the blood.