Introduction to the Peripheral NS

Question 1

What are the 2 divisions of the peripheral NS?

Answer 1

Autonomic and somatic

Question 2

What are the 2 divisions of the Autonomic NS?

Answer 2

Parasympathetic and sympathetic

Question 3

The branch of the NS that provides unconscious

and involuntary control for heart, blood vessels, visceral organs, and glands is the _

Answer 3

Autonomic NS

Question 4

The branch of the NS that provides conscious and voluntary control of skeletal muscle is the _

Answer 4

Somatic NS

Question 5

What areas of the CNS does the parasympathetic division arise from? What about the sympathetic/

Answer 5

Parasymp - Craniosacral

Symp - Thoracolumbar

Question 6

What are the organ exceptions that receive only sympathetic innervation? (5)

Answer 6

Blood vessels 
Sweat Glands 
Liver 
Spleen 
Adrenals

Question 7

Which is myelinated, the preganglionic fibers or the post ganglionic fibers of the autonomic NS?

Answer 7

The preganglionics are myelinated, post ganglionics are not

Question 8

Where are the postganglionic synapses of the autonomic NS located?

Answer 8

At the effector sites

Question 9

What are 4 major differences between the somatic NS and the autonomic NS (para and symp)?

Answer 9

No peripheral ganglia (cell bodies in CNS)
Motor axons are myelinated (vs. unmyelinated post. ganglionics in autonomic NS)
Loss of spinal efferents = paralysis of muscle (vs. some spontaneous activity in the autonomic targets)
All nerves are cholinergic with nicotinic receptors

Question 10

What is the receptor subtype of the effector organs of the somatic NS?

Answer 10

Nicotinic type 2

Question 11

What is the immediate effect of arrival of the action potential to the nerve terminal?

Answer 11

Causes influx of calcium leading to increased destabilization of vesicles and their fusion

Question 12

In addition to the neurotransmitters, what other substances may be contained in vesicles?

Answer 12

Cotransmitters

Question 13

What are the 2 major neurotransmitter of the autonomic NS?

Answer 13

Acetylcholine and norepinephrine

Question 14

All preganglionic nerves as well as parasympathetic nerves and all somatic nerves release what neurotransmitter?

Answer 14

ACh

Question 15

50% of sweat glands (thermoregulatory) release what neurotransmitter despite their sympathetic innervation?

Answer 15

ACh

Question 16

Majority of post ganglionic sympathetic nerves release _

Answer 16

NE

Question 17

What is the specific population of postganglionic nerves that release a neurotransmitter that isn’t NE? (Besides sweat glands) What is this neurotransmitter?

Answer 17

Smooth muscles of the renal vasculature

Release dopamine

Question 18

What are 3 potential characteristics of cotransmitters as detailed in the notes?

Answer 18

May elicit faster / slower response (modulation)
Feedback inhibition
May be primary NT in other synapses

Question 19

What are the 3 examples of classes of neurotransmitters provided in the notes?

Answer 19

Purines
Peptides
Nitric Oxide

Question 20

What are the 2 autonomic NS anomalies specifically mentioned in the notes? Why?

Answer 20

Thermoreg. sweat gland - Sympathetic innervation by ACh is the NT
Adrenal Medulla - Has no preganglion, innervation directly from CNS (ACh) that elicits Epi and NE release

Question 21

What are the cholinergic sympathetics (i.e. sympathetics that have cholinergic neurotransmission)

Answer 21

Thermoregulatory sweat glands

Question 22

What are the 2 sympathetic innervated structures that receive ACh?

Answer 22

Adrenal medulla

THermoreg sweat glands