Lecture 12: Autonomic Nervous System Flashcards Preview

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Flashcards in Lecture 12: Autonomic Nervous System Deck (82):
1

What actions are controlled by the autonomic nervous system?

Involuntary actions

2

Where is the autonomic nervous system located in the body

CNS (brain and spinal cord) and PNS

3

Is the autonomic nervous system afferent or efferent?

Efferent

4

2 subdivisions of the autonomic nervous system

Sympathetic and parasympathetic

5

What does the parasympathetic system regulate?

Body homeostasis (rest and digest)

6

What does the sympathetic system regulate?

Fight, Fright, or flight

7

What are the parasympathetic and the sympathetic systems anatogonistic of one another?

The sympathetic requires energy while the parasympathetic conserves energy.

8

Similarity between the parasympathetic and sympathetic systems: Embryonic origin of ganglia

Neural crest

9

What is another similarity between the sympathetic and parasympathetic systems

They both use a 2 neuron pathway with a preganglionic nerve fiber in the CNS and a postganglionic fiber in the PNS

10

What does the sympathetic system innervate

Sweat glands, arrector pili muscles, abd blood vessels

11

What does the parasympathetic system innervate

Visceral organs

12

The are the two afferent components of a spinal nerve

Somatic and Visceral afferent components

13

Role of Somatic afferent fibers?

Sense pain, temperature, propriocception, and touch (In other words senses stimuli outside the body)

14

Role of Visceral afferent fibers?

Senses pain and pressure from visceral organs (sense stimuli within the body)

15

Which localizes pain better, visceral or somatic afferent fibers?

somatic

16

What are the two efferent components of a spinal nerve?

Somatic and Visceral efferent components

17

Role of Somatic efferent fibers?

Innervate skeletal muscle

18

Role of Visceral efferent fibers

These are all autonomic fibers- target visceral organs, blood vessels, sweat glands, smooth muscle, and cardiac muscle

19

Describe the 2 neuron system in the autonomic nervous system

The preganglionic nerve fiber originates in the CNS and extends out to the PNS to synapse with the Postganglionic nerve fiber, which is always located in the PNS Which then propagates the synapse to the target organ

20

Where are the cell bodies of the preganglionic fibers ALWAYS located in the sympathetic nervous system

Lateral horn of the spinal cord

21

What spinal cord levels contain the lateral horn?

T1-L2(3)

22

What are the spinal cord levels for the preganglionic sympathetic nerve fibers

T1-L2(3)

23

Is the sympathetic trunk (or paravertebral ganglia) considered post or preganglionic fibers?

Postganglionic because it is not in the brain/spinal cord it is located in the periphery

24

Where does the sympathetic trunk extend

From the skull to coccyx

25

Location of the sympathetic trunk

Paravertebral in location (next to the vertebral column)

26

How many cervical, thoracic, lumbar, and sacral ganglia in the sympathetic chain?

3 cervical
11 thoracic
4 lumbar
4 sacral

27

Ganglion impar

When 2 sides of the trunks on the sympathetic chain unite as one final ganglia in the coccygeal region

28

Where are prevertebral ganglia located

Im front of the vertebral column and cemented on aorta

29

What do prevertebral fibers innervate?

Unpaired visceral arteries

30

What are the different ganglia associated with the prevertebral ganglia

Celical ganglia (pair), aorticorenal ganglia, superior mesenteric ganglia, and inferior mesenteric ganglia

31

Role of white rami communicantes

Brings fibers into the symapthetic trunk from spinal nerve

32

How many pairs of white rams communicantes are there?

14 (From T1-L2)

33

Are the white rams communicantes aggregates of preganglionic or postganglionic nerves?

Perganglionic

34

Why are the fibers in the white rams communicates white?

Because they are slightly myelinated

35

Role of the gray rams communicates

Brings fibers from the sympathetic trunk toothier target organ or gland

36

How many pairs of gray rams communicates are there

31 (there are 31 pairs of spinal nerves- gray rams communicates are distributed to each spinal nerve)

37

Why are the fibers in the gray rams communicates gray

Lack myelin

38

Are the gray rams communicates considered preganglionic or postganglionic fibers?

Postganglionic

39

Where do the greater, lesser, and least splanchnic nerves arise from?

Superior to or at the level of the diaphragm

40

Where does the lumbar splanchnic nerve arise?

Below the diaphragm

41

What is the common goal of the greater, lesser, least, and lumbar splanchnic nerves?

Provide sympathetic innervation to the organs of the abdomen and pelvis

42

What are the sympathetic neurotransmitters for preganglionic fibers?

Acetylcholine

43

What are the sympathetic neurotransmitters for postganglionic fibers?

Norepinephrine except for the postganglionic sympathetic fibers to sweat glands which is acetylcholine

44

Describe the sympathetic pathway to the periphery from levels T1-L2

Preganglionic cell body originates in the lateral horn of the spinal cord leaves via the ventral root and enters the sympathetic chain via the white rams communicates. In the sympathetic chain, the preganglionic cell synapses with the postganglionic cell, which leaves via the gray matter communicates to the peripheral organ (sweat gland, peripheral arteriole, or arrestor pili muscle).

45

Describe the sympathetic pathway to the periphery above or below levels T1-L2

The pre ganglionic fibers from the lateral horn enter the sympathetic chain via the white rams communicantes. The preganglionic fibers then either ascend or desend along the trunk until they reach the level they want to be at. Then the preganglionic fiber synapses with the postganglionic fiber in the trunk and levels via the gray matter communicantes.

46

Why is this pathway described in the previous card important

Allows the entire body to receive sympathetic innervation even though the lateral horn only extends from T1-L2,3 (example: sweaty feet during a run)

47

What are the similarities between the first 2 sympathetic pathways I have already described

They have the same target organs (sweat glands, arrestor pili muscles, peripheral blood vessels

48

Describe the pathway for sympathetic innervation to visceral organs of the thorax

Prevertebral ganglion begin in the lateral horn, travel out of the ventral orotund into the sympathetic chain via the white matter communicates, the signal can then either ascend, descend, or stay at the same level along the sympathetic chain. The preganglionic fibers synapse with the postganglionic fibers in the sympathetic chain BUT do NOT leave via the gray matter communicates. Instead the postganglionic fibers leave medially to form splanchnic nerves that course internally to supply visceral organs

49

What does the pathway previously described provide innervation to?

The heart

50

Describe the sympathetic pathway to the visceral organs of the abdomen/pelvis

The preganglionic fibers begin in the lateral horn, enter the ventral root, enter the sympathetic chain via the white rams communicates. The preganglionic fiber can ascend, descend or stay at the same spinal cord level along the sympathetic chain. The preganglionic fiber DOES NOT synapse in the sympathetic chain and DOES NOT exit via the gray matter communicates. Instead it exits via the splanchnic nerve and synapses on four major groups of ganglia with the postganglionic fiber, which then targets the organ of interest

51

What are the four major groups of splanchnic nerves in the sympathetic pathway for the visceral organs of the abdomen/pelvis along with their spinal cord levers

Greater- T(5)6-9 splanchnic nerve
Lesser- T(9)10-11 splanchnic nerve
Least- T12 splanchnic nerve
Lumbar splanchnic nerve

52

Where does the greater splanchnic nerve synapse

celiac ganglia

53

What does the celiac ganglia innervate

forgut organs

54

Where do the lesser and least splanchnic nerves synapse

aorticorenal ganglia

55

What does the aorticorenal ganglia innervate?

The kidneys

56

What synapses at the superior mesenteric ganglion

collaterals from the celiac ganglion *No splanchnic nerve goes directly into the superior mesenteric ganglion*

57

What does the superior mesenteric ganglion innervate

midgut

58

What synapses at the inferior mesenteric ganglion

The lumbar splanchnic nerves from L1-3

59

What does the inferior mesenteric ganglion innervate?

Hindgut

60

Compare the location of the sympathetic verses the parasympathetic nervous systems

Parasympathetic= craniosacral
Sympathetic= thoracolumbar

61

In the parasympathetic system compare the length of the preganglionic fibers and the postganglionic fibers

The preganglionic fibers are long and the postganglionic fibers are short (the opposite is true in the sympathetic system)

62

CN X (vagus nerve) innervation

Travels all the way through various organs (Heart, bronchi, stomach, small intestine: biggest supply is forgut and midgut. Supplies everything up until the distinction between mid and hind gut/ Starts in brain

63

Major influences of the parasympathetic nervous system

Salivary glands, GI secretion, mobility, control over pupillary sphincter, and peristalisis

64

Where is the parasympathetic nervous system distributed to

Trunk regions such as thorax, abdomen, and pelvis

65

What does the cranial portion of the parasympathetic nervous system consist of

Preganglionic fibers that originate in the brain stem and travel through the cranial nerves

66

Sacral portion of parasympathetic nervous system: Spinal cord levels

S2-4

67

What organs are targeted by the sacral portion of the parasympathetic nervous system?

Reproductive and rectum

68

What is the neurotransmitter for parasympathetic preganglionic and postganglionic nerve fibers

Acetylcholine

69

Does the parasympathetic nervous system go to the periphery

No

70

Does the sympathetic nervous system go to the periphery?

Yes

71

Actions of the parasympathetic and sympathetic nervous system in the gut?

Parasympathetic- Increase peristalsis Sympathetic: Decrease peristalsis

72

Actions of the parasympathetic and sympathetic nervous system in the heart

parasympathetic: decrease heart rate and sympathetic: increase heart rate

73

Actions of the parasympathetic and sympathetic nervous system in sweat glands

SYMPATHETIC ONLY (only one that goes to periphery): Promotes secretion

74

Actions of the parasympathetic and sympathetic nervous system on bronchi/bronchioles

Parasympathetic: Constrict
Sympathetic: Dialates

75

Actions of the parasympathetic and sympathetic nervous system on pupils

Parasympathetic: Light response (pupil constricted)
Sympathetic: Dark response (pupil dilated)

76

Actions of the parasympathetic and sympathetic nervous system on Peripheral blood vessels

SYMPATHETIC ONLY (only one that goes to periphery)- vasoconstriction

77

Actions of the parasympathetic and sympathetic nervous system on blood vessels to skeletal muscle

SYMPATHETIC ONLY- Vasodialation

78

Actions of the parasympathetic and sympathetic nervous system on the adrenal gland

SYMPATHETIC ONLY- The exception organ that receives preganglionic sympathetic fibers to enhance the secretion of adrenaline

79

Actions of the parasympathetic and sympathetic nervous system on salivary glands

Parasympathetic- increase salivation
Sympathetic- Decrease salivation

80

Actions of the parasympathetic and sympathetic nervous system on genitals

Parasympathetic- Erection (S2,3,4 get penis off the floor)
Sympathetic- Ejaculation

81

Mechanism of referred pain

Pain from visceral organs can be "referred" to somatic afferents that enter the same level of the spinal cord and have their cell bodies in the same dorsal root ganglia as the visceral afferents.

82

Examples of referred pain

-Pain in tooth that turned out to be a sinus infection
-Appendicitis which results in pain around umbilicus
-Heart attack can give nagging pain on medial side of the arm resulting from the fact that the same spinal cord segments that feed into the heart are the spinal segments from the arm