Neuro Exam 5 Lecture 1

Front 1

In the visceral efferent (autonomic) nervous system, the sympathetic portion is also known as the ________________ system

Back 1

Thoracolumbar

T1-L2 (IMLCC)

Front 2

In the visceral efferent (autonomic) nervous system, the parasympathetic portion is also known as the ________________ system

Back 2

craniosacral system
S2-S4

para means on other side of the sympathetic nervous system

Front 3

Which cranial nerves are associated with the parasympathetic nervous system?

Back 3

CN III, CN VII, CN IX, and CN X

Front 4

When we talk about the somatic nervous system, we are talking about innervation of what type of muscle?

Back 4

Voluntary (skeletal muscle)

Also somatosensation (particularly from the skin)

-structures of the body wall

Front 5

The visceral nervous system is responsible mainly for the_______________ functions of the body. This includes:

Back 5

involuntary

-innervation of smooth muscle (for example, muscle that lines walls of arteries)
-cardiac muscle
-glandular epithelium (the cellular layers that are secreting various types of fluids into the bloodstream or the body)

Front 6

The visceral nervous system is responsible for innervation of structures of the:

Back 6

body cavity (viscera)

We don't have a ton of control over this nervous system- primarily involuntary

Front 7

The general function of the visceral nervous system is homeostasis.
What is homeostasis?

Back 7

Regulation of the normal internal state of the body. For example:

-heart rate, blood pressure, digestion and metabolism, circadian rhythms, glandular secretion, bowel and bladder, sexual arousal, reproduction, etc.

Front 8

The ANS is subdivided into ____________ and ___________ divisions

Back 8

sympathetic (SNS)
parasympathetic (PSNS)

Front 9

The sympathetic division is also known as the _______________ system and has _____________ effects

Back 9

"fight or flight" (situations of relatively high stress)

(heart rate and respiratory rate increases)

widespread (like over the entire cardiovascular system)

Front 10

The parasympathetic division is also known as the _______________ system and has _____________ effects

Back 10

"rest and digest" (slows the heart rate, brings blood to body cavities- used for digestion for example)

Localized effects (like the change in the shape of the eye- the lens, tears in the lacrimal gland, etc.)

Front 11

What does it mean to say that "dual is the rule"

Back 11

-most organs receive dual antagonistic innervation from both the SNS and PSNS

For example, with the heart, higher levels of sympathetic activity will cause an increase in heart rate, and in contrast, higher levels of parasympathetic activity will cause a decrease in heart rate (kind of a constant balance)

Front 12

What are the exceptions to the "dual is the rule"?

Back 12

-Structures of the body wall (arrector pili, sweat, and sebaceous glands, and limb vasculature) and
the suprarenal (adrenal) gland receive innervation only from Sympathetic nervous system

Front 13

both the SNS and the PSNS use a __________ neuron pathway with a ganglion in the middle to reach their target

Back 13

two-neuron pathway

Front 14

How is the innervation of the autonomic nervous system (SNS & PSNS) different than somatic efferent innervation?

Back 14

With Somatic efferent innervation, from the central nervous system out to its target, it is one neuron only (just the LMN). But autonomics (both SNS and PSNS), from the central nervous system to their targets, is two neurons.

Front 15

What are the two neurons used in autonomic efferent innervation?

Back 15

You have a preganglionic neuron, which will synapse at some ganglion, where there will be postganglionic neuronal cell bodies, and those axons will then travel out to innervate whatever the visceral structure is

Front 16

Where are the cell bodies of preganglionic neurons located?

Back 16

somewhere within the CNS

Front 17

Where are the cell bodies of the postganglionic neurons found?

Back 17

in autonomic ganglia

Front 18

Sensory (both somatic and visceral) is always a _________ neuron pathway to the CNS

Back 18

single

(typically with a pseudounipolar neuron in some sort of a posterior root ganglion)

Front 19

Which neurotransmitters are found within the autonomic nervous system? (SNS and PSNS)

Back 19

-Acetylcholine (ACh)

-Norepinephrine (NE)

-Epinephrine

Front 20

Acetylcholine (ACh) is quite common, and is used by:

Back 20

-preganglionic neurons in both the SNS and PSNS

-postganglionic neurons in the PSNS

-postganglionic neurons in SNS innervating sweat glands (only these release ACh, all other postganglionic neurons in SNS release another type of neurotransmitter

Front 21

With the sympathetic nervous system (SNS), postganglionic neurons release what type of neurotransmitter?

Back 21

Norepinephrine (NE) (typically, one exception

Front 22

What is the exception to sympathetic postganglionic neurons releasing norepinephrine (NE) as their neurotransmitter?

Back 22

postganglionic SNS neurons innervating sweat glands actually release ACh, not NE

Also secretory cells of the adrenal glands (SNS) release epinephrine.

Front 23

Secretory cells of the adrenal gland (SNS) release _______________

Back 23

epinephrine

Front 24

Is the two neuron rule a standard for the entire autonomics (think about adrenal glands)

Back 24

Yes. With the adrenal glands on the kidney, it looks like it is only the preganglionic neuron, but the cells that we are talking about that are present in the suprarenal (adrenal) gland are actually modified postganglionic sympathtic neurons

Front 25

Why is the sympathetic nervous system also called the thoracolumbar system?

Back 25

because it originates from this very restricted span of the spinal cord (T1-L2)

Front 26

What else can be found only at the spinal levels of T1-L2?

Back 26

IMLCC

Front 27

Within the sympathetic nervous system, where are the preganglionic cell bodies found?

Back 27

In the IMLCC of the T1-L2 spinal cord levels

Front 28

Where are the postganglionic cell bodies found in the sympathetic nervous system found?

Back 28

in paravertebral or prevertebral ganglia

Front 29

paravertebral ganglia, where the postganglionic cell bodies of the SNS are found, are also known as:

Back 29

The sympathetic chain ganglia

Front 30

Why is the parasympathetic system also called the craniosacral system?

Back 30

because it has a cranial portion associated with specific cranial nerves (III,VII,IX, and X) and a sacral portion (S2-S4 spinal cord levels)

Front 31

Where are the parasympathetic postganglionic cell bodies found?

Back 31

In a ganglia in or near the wall of a target organ (depends on which nerve it is)

Front 32

In terms of the parasympathetics, CN X, as well as inputs from S2 to S4 are going to synapse:

Back 32

in very small, non-dissectable ganglia located in the wall of the target organ

Front 33

When we look at ganglia that are associated with cranial nerves that are associated with parasympathetic innervation of the head, there actually are discrete dissectable ganglia associated with them. What are the ganglia?

Back 33

-Ciliary

-Otic

-Pterygopalatine

-Submandibular

Front 34

How do you remember which cranial nerve goes with which parasympathetic ganglion?

Back 34

3977-COPS

Front 35

What is the parasympathetic nucleus of the oculomotor nerve (where the preganglionic neuronal cell bodies are located)?

Back 35

The Edinger-Westphal nucleus

Front 36

What contains the parasympathetic postganglionic neuronal cell bodies of the oculomotor nerve?

Back 36

The ciliary ganglion

Front 37

What receives parasympathetic innervation from the oculomotor nerve?

Back 37

-pupillary constrictor muscle

-ciliary muscle (a circular sphincter muscle that controls the shape of the lens and allows your eyes to focus)

Front 38

Where is the ciliary ganglion located?

Back 38

situated right up against the optic nerve itself

Front 39

What occurs in an oculomotor palsy?

Back 39

An oculomotor lesion produces:
-lateral strabismus
-ipsilateral ptosis (drooping of the eyelid)

-ipsilateral dilated pupil (mydriasis) and loss of pupillary light reflex

Front 40

What is a lateral strabismus?

Back 40

Deviation of ipsilateral eye laterally and inferiorly ("down and out")

Front 41

What occurs with mydriasis with an oculomotor palsy?

Back 41

an ipsilateral dilated pupil

Front 42

For the facial nerve (CN VII), where are the parasympathetic preganglionic cell bodies located?

Back 42

In the superior salivatory nucleus (in the caudal Pons)

Front 43

Where are the parasympathetic postganglionic cell bodies of the facial nerve located?

Back 43

-Pterygopalatine ganglion

-Submandibular ganglion

Front 44

What are the targets of the visceral efferent (parasympathetic) component of the facial nerve?

Which ganglia are associated with each target?

Back 44

-lacrimal gland (pterygopalatine ganglion)

-submandibular gland (submandibular ganglion)

-sublingual gland (submandibular ganglion)

Front 45

What is Bell's palsy?

Back 45

An idiopathic disorder of CN VII: thought to be caused by a viral infection or an autoimmune disorder (for whatever reason, the facial nerve becomes inflamed within the temporal bone)

(idiopathic means we don't know what causes it--we are idiots and we can't figure it out)

Front 46

A patient with Bell's palsy will present with which symptoms?

Back 46

-ipsilateral facial paralysis (LMN because it is the upper and lower face)

-hyperacusis

-autonomic symptoms:

-loss of lacrimation (production of tears)
-loss of taste from anterior 2/3 of tongue on affected side

Front 47

What is hyperacusis?

Back 47

Hypersensitivity to sound due to denervation of the stapedius muscle

Front 48

What is the small muscle within the inner ear that helps to dampen sound?

Back 48

the stapedius- so if it is denervated, the individual has hyperacusis

Front 49

Where are the parasympathetic preganglionic neuronal cell bodies of the glossopharyngeal nerve (CN IX) found?

Back 49

In the inferior salivatory nucleus (located in the rostral medulla)

Front 50

The parasympathetic postganglionic cell bodies of CN IX are found in the __________ ganglion.

Back 50

Otic

Front 51

What is the primary target of the glossopharyngeal nerve in terms of its parasympathetic innervation?

Back 51

The parotid gland, which is the major salavatory gland located in the cheek (kind of between our cheek and our ear)

Front 52

Where are the parasympathetic preganglionic neuronal cell bodies of the Vagus Nerve located?

Back 52

In the dorsal motor nucleus of vagus (located in the rostral medulla- just medial to the solitary nucleus)

Front 53

The Vagus nerve has a tremendous area of distribution all through the body cavity and through the thorax, as well as up in the abdomen up to a point. Where all receives parasympathetic innervation of the Vagus nerve?

Back 53

visceral organs of the thoracic and abdominal cavities proximal to the left colic flexure (The left colic flexure is the point where the transverse colon begins to descend)

Front 54

Where are the postganglionic visceral efferent (parasympathetic) neuronal cell bodies of the vagus nerve located?

Does the Vagus nerve have a parasympathetic ganglion?

Back 54

The synapses are occurring within the walls of the target organs themselves - It does not have a separate parasympathetic ganglion

Front 55

Where are the preganglionic neuronal cell bodies of the parasympathetic nervous system located within the sacral portion?

Back 55

In the intermediate zone of spinal cord gray matter and spinal levels S2-S4. It kind of looks like it is in the same place as the IMLCC (like the lateral horn) but in the sacral spinal cord

Front 56

The axons from the preganglionic neurons from S2-S4 will reach their target via what are called:

Back 56

the pelvic splanchnic nerves

Front 57

Does the word splanchnic give you any indication to whether the nerve is carrying sympathetic or parasympathetic signals?

Back 57

No, you have to know specifically which splanchnic nerves it is to know whether is it sympathetic or parasympathetic

Splanchnic simply means that it is going to the viscera

Front 58

Where are the postganglionic parasympathetic neuronal cell bodies of the vagus nerve located (from S2-S4)- so what are the targets?

Back 58

the terminal ganglia are located in the walls of the target organs

(abdominal visceral distal to the left colic flexure; pelvic viscera)

Front 59

The preganglionic neuronal cell bodies of the sympathetic nervous system are located:

Back 59

In the IMLCC (T1-L2)
(intermediolateral cell column)

(looks like the side of Pikachu's head)

Front 60

Where are the postganglionic sympathetic neuronal cell bodies located?

Back 60

In either the paravertebral ganglia or the prevertebral ganglia, depending on their target.

Front 61

Where are the paravertebral ganglia located?

Back 61

When we talk about the paravertebral ganglia, we are talking about the sympathetic chain (trunk), which is bilaterally adjacent to the spinal column. All of the paravertebral ganglia are connected to other paravertebral ganglia superiorly and inferiorly, and this is how the chain forms

Front 62

The paravertebral ganglia connect to the anterior rami of spinal nerves via ___________________ and _________________

Back 62

white rami communicante and gray rami communicante (sing.- communicans)

Front 63

The prevertebral ganglia are the pre-_________ ganglia

Back 63

aortic

Front 64

Why are the prevertebral ganglia called the pre-aortic ganglia?

Back 64

because they are located on the anterior aspect of the aorta in the abdominal cavity (so anterior to the abdominal aorta)

Front 65

What are the prevertebral ganglia concerned with sympathetic innervation to the body cavity?

Back 65

-celiac ganglion

-superior mesenteric ganglion

-inferior mesenteric ganglion

Front 66

The celiac ganglia is associated with the______1_______, the superior mesenteric ganglion is associated with the ________2______, and the inferior mesenteric ganglion is associated with the _________3________

Back 66

1. celiac trunk

2. superior mesenteric artery

3. inferior mesenteric artery

Front 67

There are three pathways that sympathetic neurons can reach their targets. How are they divided?

Back 67

1. If traveling to the body wall (i.e., integument (skin), vasculature of the limbs and body wall, or structures in the head, neck, and scalp)

2. if traveling to the thoracic viscera-so viscera above the diaphragm (heart and lungs)

3.if traveling to abdominal or pelvic viscera (so below the diaphragm (GI tract, urogenital organs)

Front 68

What is the pathway if the sympathetic neurons are traveling to the body wall or head and neck?

Back 68

Starting in the IMLCC, the preganglionic axon will travel out through the anterior root, it will join the mixed spinal nerve and anterior ramus. That preganglionic axon will enter sympathetic chain via the white ramus communicans. If we are already at the appropriate level and the fibers don't need to ascend or descend, then the preganglionic fibers will synapse in the paravertebral ganglion and the now postganglionic fibers will exit the chain to immediately rejoint the spinal nerve via the gray ramus communicante. That spinal nerve will then take the postganglionic fiber out to its target on the body wall.
If the preganglionic fiber was not at the correct level for its target when it reached the paravertebral ganglion, it would then ascend up the chain and would then synapse at the level of its target and exit the chain in the same manner via the gray ramus communicante

Front 69

How do preganglionic sympathetic fibers enter into the sympathetic chain?

Back 69

via the white rami communicante

Front 70

Why is it called white ramus communicans where the preganglionic sympathetic fibers enter the sympathetic chain?

Back 70

because the preganglionic fibers tend to be a bit more myelinated than the postganglionic fibers

Front 71

What is the pathway if the sympathetic neurons are traveling to the thoracic viscera (above the diaphragm)?

Back 71

Starting in the IMLCC, the preganglionic axon will travel out through the anterior root, it will join the mixed spinal nerve and anterior ramus. That preganglionic axon will enter sympathetic chain via the white ramus communicans. The synapse will then occur in the paravertebral ganglion of the sympathetic chain, but instead of the postganglionic axon rejoining the spinal nerve, the postganglionic axon will come directly off of the paravertebral ganglion and head towards its target. Because we are innervating heart and lungs, this collection of postganglionic sympathetic axons is called the cardiopulmonary splanchnic nerve (so this is how the axon travels to its target).

Front 72

What is the pathway if the sympathetic neurons are traveling to the pelvic viscera (below the diaphragm)?

Back 72

Starting in the IMLCC, the preganglionic axon will travel out through the anterior root, it will join the mixed spinal nerve and anterior ramus. That preganglionic axon will enter sympathetic chain via the white ramus communicans. However, it doesn't synapse here, it will continue on as the preganglionic sympathetic axon (descending if it needs to) and will exit off of the sympathetic chain, and as the abodominopelvic splanchnic nerve, will head towards one of those prevertebral, or pre-aortic ganglia where it will synapse, and then the postganglionic fiber will then head out to the target organ.

Front 73

What is an important distinction between the cardiopulmonary splanchnic nerves and the abdominopelvic splanchnic nerves?

Back 73

cardiopulmonary splanchnic nerves are postganglionic sympathetic fibers, while abdominopelvic splanchnic nerves are preganglionic sympathetic neurons.

Front 74

Good job!

Back 74

Keep studying!