Intro to ANS

Question 1

Autonomic Nervous System uses how many neurons?

Answer 1

2. Preganglionic and postganglionic.

Question 2

What types of things does the ANS innervate?

Answer 2

Smooth and cardiac muscle, glands.

Question 3

Enteric Branch of the ANS

Answer 3

Network of neurons in the gut, mostly independent of the CNS, extensive intrinsic activity that includes peristalsis.

Question 4

Sympathetic Branch: Location of preganglionic cell bodies, which nerves carry preganglionic axons, where are the ganglia located?

Answer 4

Thoracic and lumbar levels of the spinal cord, carried by thoracolumbar spinal nerves, ganglia located in chain ganglia or in prevertebral ganglia.

Adrenal gland is the exception

Question 5

Parasympathetic Branch: Location of preganglionic cell bodies, which nerves carry preganglionic axons, where are the ganglia located?

Answer 5

Medulla and sacral level of spinal cord, carried by cranial nerves and sacrospinal nerves, ganglia located near wall of innervated organ.

Question 6

Do postganglionic nuclei of sympathetic branch need to be on the same level of chain ganglia?

Answer 6

No.

Question 7

Can sympathetic preganglionic axons synapse on more than one postganglionic neuron?

Answer 7

Yes.

Question 8

Dominant Tone

Answer 8

Usually the autonomic branch that makes the organ contract or move. For example, GI is parasympathetic (rest and digest).

Question 9

One exception to Dominant Tone

Answer 9

The heart. The dominant tone is parasympathetic, even though it slows the heart.

Question 10

Atrial Innervation

Answer 10

Parasympathetic and sympathetic

Question 11

Ventricular Innervation

Answer 11

Just sympathetic

Question 12

Adrenal Gland Innervation

Answer 12

Just sympathetic

Question 13

Sweat Gland Innervation

Answer 13

Just sympathetic

Question 14

What is special about the fibers that innervate the pancreatic ß cells?

Answer 14

They are only sympathetic fibers, but the preganglionic neuron travels all the way to the organ.

Question 15

Which branch constricts the pupils?

Answer 15

Parasympathetic. Also increases near vision by rounding the eye.

Question 16

Are the actions of the sympathetic and parasympathetic branches always opposing?

Answer 16

No. For example: salivary glands, both systems increase secretions, but different types.

Question 17

Where do autonomic sensory neurons project to?

Answer 17

The NST in the medulla.

Question 18

Baroreceptor Reflex

Answer 18

In carotid and aorta. Contain baroreceptors, when stretch decreases due to decreased BP, signal is relayed to medulla, which increases sympathetic activity, causing vasoconstriction and increased cardiac output, leading to increase in BP.

Question 19

Two major neurotransmitters at ANS synapses

Answer 19

ACh, NE, sometimes DA

Question 20

Which signal is released from adrenal medulla?

Answer 20

Epinephrine.

Question 21

Which neurons release ACh?

Answer 21

All preganglionic neurons (P and S), all parasympatheic postganglionic neurons, some sympathetic postganglionics.

Question 22

Which neurons release NE?

Answer 22

Most of the sympathetic postgangionic neurons.

Question 23

Function of ß Adrenergic receptors

Answer 23

Coupled to Gs.

Question 24

Sensitization

Answer 24

Increase in responsiveness due to under-stimulation. Can happen in seconds or hours.