Ch 13: Physiology of the Peripheral Nervous System Flashcards Preview

Lehne's Pharmacology for Nursing Care, 9th ed. > Ch 13: Physiology of the Peripheral Nervous System > Flashcards

Flashcards in Ch 13: Physiology of the Peripheral Nervous System Deck (65)
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1
Q

What are the two major subdivisions of the peripheral nervous system?

A

Somatic motor system
Autonomic nervous system

(p. 102)

2
Q

The autonomic nervous system is further subdivided into the…

A

parasympathetic and sympathetic nervous systems.

p. 102

3
Q

What are the 3 principal functions of the autonomic nervous system?

A
  1. regulation of the heart
  2. regulation of secretory glands (B-G-S-S) (bronchial, gastric, salivary, and sweat glands)
  3. regulation of smooth muscles (in blood vessels, bronchi, GI tract, and, urogenital system)

(p. 102)

4
Q

What are 7 regulatory functions performed by the parasympathetic nervous system which have particular relevance to drugs?

A
  1. slowing of heart rate
  2. contracting bronchial smooth muscle
  3. increased gastric secretion
  4. emptying of the bowel
  5. emptying of the bladder
  6. focusing the eye for near vision
  7. constricting the pupil

(p. 102)

5
Q

The sympathetic nervous system has 3 main functions:

A
  1. regulating the cardiovascular system
  2. regulating body temperature
  3. implementing the acute stress (“fight-or-flight”) response

(p. 103)

6
Q

In what 3 ways do the sympathetic nervous system help regulate body temperature?

A
  1. by regulating blood flow to the skin, sympathetic nerves can increase or decrease heat loss
  2. sympathetic nerves to sweat glands promote secretion of sweat, thereby helping the body cool
  3. by inducing piloerection, sympathetic nerves can promote heat conservation

(p. 103)

7
Q

What are the 5 events which make up the fight-or-flight response?

A
  1. increasing HR and BP
  2. shunting blood away from the skin and viscera and into skeletal muscles
  3. dilating the bronchi to improve oxygenation
  4. dilating the pupils (perhaps to enhance visual acuity)
  5. mobilizing stored energy, thereby providing glucose for the brain and fatty acids for muscles

(p. 103)

8
Q

What is feedback regulation?

A

The process that allows a system to adjust itself by responding to incoming information.

(p. 103)

9
Q

From a pharmacologic perspective, the most important feedback loop of the autonomic nervous system is…

A

…the baroreceptor reflex

p. 104

10
Q

The branch of the autonomic nervous system that controls organ function most of the time is said to provide the ___________ ____ to that organ.

A

predominant tone

p. 104

11
Q

There are 2 neurons in the pathway leading from the spinal cord to organs innervated by parasympathetic nerves. The junction, or synapse, between these 2 neurons occurs within a structure called a…

A

…ganglion.

p. 104

12
Q

What is a ganglion?

A

a mass of nerve cell bodies

p. 104

13
Q

What are the nerves cells that go from the spinal cord to the parasympathetic ganglia?

What are the nerves cells that go from the ganglia to effector organs?

A

preganglionic neurons

postganglionic neurons

(p. 104)

14
Q

The anatomy of the parasympathetic nervous system offers two general sites at which drugs can act:

A

(1) The synapses between preganglionic neurons and postganglionic neurons, and (2) the junctions between postganglionic neurons and their effector organs.
(p. 104)

15
Q

Although the adrenal medulla is not a neuron per se, it can be looked on as the functional equivalent of…

A

…a postganglionic neuron of the sympathetic nervous system.

(p. 104)

16
Q

Because the adrenal medulla is similar in function to a postganglionic neuron, the nerve leading from the spinal cord to the adrenal gland is commonly referred to as a…

A

…preganglionic neuron, even though there is no ganglion in this pathway.

(p. 104)

17
Q

How many neurons are in the pathway from the spinal cord to the muscles innervated by somatic motor nerves?
What is the implication of this?

A

only one

Peripherally acting drugs that affect somatic motor system function have only one site of action: the neuromuscular junction.

(p. 105)

18
Q

The PNS uses 3 primary neurotransmitters, (and a 4th whose role has not been demonstrated conclusively). What are these 4?

Any given junction in the PNS uses only ___ of these transmitters.

A

acetylcholine
norepinephrine
epinephrine

dopamine
one

(p. 105)

19
Q

At which specific junctions is acetylcholine used?

A
  1. all preganglionic neurons of the parasympathetic nervous system (PNS) and sympathetic nervous system (SNS)
  2. all postganglionic neurons of the PNS
  3. most postganglionic neurons of the SNS that innervate sweat glands
  4. all motor neurons to skeletal muscles (somatic motor system)

(p. 106)

20
Q

At which specific junctions is norepinephrine used?

A
  1. almost all postganglionic neurons of the sympathetic nervous system (the exception is postganglionic neurons of the SNS that innervate sweat glands)
  2. the adrenal medulla releases some norepinephrine

(p. 106)

21
Q

At which specific junction is epinephrine used?

A

the adrenal medulla

p. 105

22
Q

What are cholinergic receptors?

A

Receptors that mediate responses to acetylcholine

p. 105

23
Q

What are adrenergic receptors?

A

Receptors that mediate responses to epinephrine (adrenaline) and norepinephrine
(Dopamine receptors are also classified as adrenergic receptors, but they respond only to dopamine, not to epi and norepi)

(p. 105)

24
Q

What are the 3 major subtypes of cholinergic receptors?

A

nicotinic N
nicotinic M
muscarinic

(p. 106)

25
Q

What are the 4 major subtypes of adrenergic receptors?

In addition to these 4, what adrenergic receptor type is found primarily in the CNS?

A

alpha 1
alpha 2
beta 1
beta 2

dopamine

(p. 106)

26
Q

Drugs achieve their selectivity for receptor subtypes by having structures that are…

A

…different from those of natural transmitters.

p. 107

27
Q

Although receptor subtypes are of uncertain physiologic relevance, from the viewpoint of therapeutics…

A

…receptor subtypes are invaluable.

p. 108

28
Q

Muscarinic cholinergic receptors on blood vessels are not associated with the nervous system in any way. That is, no autonomic nerves terminate at ________ __________ _________.
Cholinergic receptors on blood vessels do have _____________ significance, because drugs that are able to activate these receptors cause ____________.

A

vascular muscarinic receptors

pharmacologic, vasodilation

(p. 108)

29
Q

What is the response of nicotinic N (neuronal) receptors when activated?

Where are these receptors located?

A

Stimulation of parasympathetic and sympathetic postganglionic nerves and release of epinephrine from the adrenal medulla

All autonomic nervous system ganglia and the adrenal medulla.

(p. 110)

30
Q

What is the response of nicotinic M (muscle) receptors when activated?
Where are these receptors located?

A

contraction of skeletal muscle

at neuromuscular junctions

(p. 110)

31
Q

What is the response to activation of muscarinic receptors of the eye?

A

contraction of the ciliary muscle focuses the lens for near vision; contraction of the iris sphincter muscle causes miosis (decreased pupil diameter)

(p. 110)

32
Q

What is the response to activation of muscarinic receptors of the heart?

A

decreased heart rate

p. 110

33
Q

What is the response to activation of muscarinic receptors of the lung?

A

constriction of bronchi and promotion of secretions

p. 110

34
Q

What is the response to activation of muscarinic receptors of the bladder?

A

contraction of the detrusor increases bladder pressure; relaxation of trigone and sphincter allows urine to leave the bladder; coordinated contraction of detrusor and relaxation of trigone and sphincter causes voiding of the bladder

(p. 110)

35
Q

What is the response to activation of muscarinic receptors of the GI tract?

A

salivation, increased gastric secretions, increased intestinal tone and motility, defecation

(p. 110)

36
Q

What is the response to activation of muscarinic receptors of sweat glands?
What should be noted about innervation of sweat glands?

A

generalized sweating
Although sweating is due primarily to stimulation of muscarinic receptors by acetylcholine, the nerves that supply acetylcholine to sweat glands belong to the sympathetic nervous system rather than the parasympathetic nervous system.

(p. 110)

37
Q

What is the response to activation of muscarinic receptors of sex organs?

A

erection

p. 110

38
Q

What is the response to activation of muscarinic receptors of blood vessels?
What should be noted about cholinergic receptors on blood vessels?

A

vasodilation
They are not associated with the nervous system.

(p. 110)

39
Q

Where are nicotinic N receptors located?

A

on the cell bodies of all postganglionic neurons of the parasympathetic and sympathetic nervous systems, and on cells of the adrenal medulla

40
Q

Where are nicotinic M receptors located?

A

on skeletal muscles

p. 109

41
Q

Where are muscarinic receptors located?

A

on all organs regulated by postganglionic parasympathetic nerves, and on sweat glands

(p. 109)

42
Q

Where are adrenergic receptors located?

A

Alpha, beta, or both adrenergic receptors are located on ALL organs (except sweat glands) regulated by postganglionic sympathetic nerves, and on organs regulated by epinephrine released from the adrenal medulla

(p. 109)

43
Q

What is the response to activation of alpha 1 receptors of the eye?

A

contraction of the radial muscle of the iris causes mydriasis (increased pupil size); remember this because “dilation” has a d in it and so does mydriasis

(p. 111)

44
Q

What is the response to activation of alpha 1 receptors of the arterioles of the skin, viscera, and mucous membranes as well as peripheral veins?

A

constriction

p. 111

45
Q

What is the response to activation of alpha 1 receptors of the male sex organ?

A

ejaculation

p. 111

46
Q

What is the response to activation of alpha 1 receptors of the prostatic capsule?

A

contraction

p. 111

47
Q

What is the response to activation of alpha 1 receptors of the bladder?

A

contraction of trigone and sphincter

p. 111

48
Q

What is the response to activation of alpha 2 receptors of the presynaptic terminals?
(Alpha 2 receptors in the CNS are postsynaptic)

A

inhibition of transmitter release

p. 111

49
Q

What is the response to activation of beta 1 receptors of the heart?

A

increased rate, increased force of contraction, and increased AV conduction velocity

(p. 111)

50
Q

What is the response to activation of beta 1 receptors of the kidneys?

A

release of renin

p. 111

51
Q

What is the response to activation of beta 2 receptors of the arterioles which perfuse the heart, lungs, and skeletal muscles?

A

dilation of arterioles

p. 111

52
Q

What is the response to activation of beta 2 receptors of the bronchi?

A

dilation

p. 111

53
Q

What is the response to activation of beta 2 receptors of the uterus?

A

relaxation

p. 111

54
Q

What is the response to activation of beta 2 receptors of the liver?

A

glycogenolysis, resulting in increased blood glucose levels

p. 111

55
Q

What is the response to activation of beta 2 receptors of skeletal muscles?

A

enhanced contraction, glycogenolysis, resulting in increased blood glucose levels

(p. 111)

56
Q

What is the response to activation of dopamine receptors in the kidneys?

A

dilation of kidney vasculature

p. 111

57
Q

Receptor specificity of adrenergic transmitters is as follows:

(1) epinephrine can activate all…
(2) norepinephrine can activate…
(3) dopamine can activate…

A

(1) …alpha and beta receptors, but not dopamine receptors
(2) …alpha 1, alpha 2, and beta 1 receptors, but not beta 2 or dopamine receptors
(3) alpha 1, beta 1, and dopamine receptors

(p. 111)

58
Q

Acetylcholine is synthesized from…

A

…choline and acetylcoenzyme A.

p. 112

59
Q

Neurotransmission at cholinergic junctions is terminated by…

A

…degradation of acetylcholine by acetylcholinesterase.

p. 114

60
Q

Neurotransmission at adrenergic junctions is terminated by…

A

…reuptake of intact norepinephrine into nerve terminals.

p. 114

61
Q

Following reuptake, norepinephrine may be stored in…

A

…vesicles for reuse or destroyed by monoamine oxidase.

p. 114

62
Q

What are the 3 homeostatic objectives of the sympathetic nervous system during the acute stress response?

A

Maintenance of blood flow to the brain
Redistribution of blood flow during exercise
Compensation for loss of blood (or blood pressure), primarily by causing vasoconstriction

(p. 103)

63
Q

There are 3 basic patterns of autonomic innervation and regulation. What are they?

A
  1. ) Innervation by both divisions of the autonomic nervous system in which the effects of the two divisions are opposed.
  2. ) Innervation by both divisions of the autonomic nervous system in which the effects of the two divisions are complementary.
  3. ) Innervation and regulation by only one division of the autonomic nervous system.

(p. 103)

64
Q

What are the elements of a typical feedback loop?

A

a sensor, an effector, and neurons connecting the sensor to the effector

(p. 104)

65
Q

In most organs, the __________ nervous system supplies the predominant tone. The ________ system, which is regulated almost exclusively by the sympathetic nervous system, in the principal exception.

A

parasympathetic
vascular

(p. 104)

Decks in Lehne's Pharmacology for Nursing Care, 9th ed. Class (110):