Neuro Exam 5 Lecture 2

Front 1

What is Horner's syndrome?

Back 1

It is a sympathetic syndrome of the head, and it is caused by some sort of interruption of the sympathetic pathway to the head

(lecture 1)

Front 2

What are the signs or symptoms of Horner's syndrome (what are the consequences of interrupting the sympathetic pathway to the head)?

Back 2

All ipsilateral:

- Ptosis (drooping eyelid)

- Miosis (constricted pupil)

- Anhidrosis (lack of sweating)

- Flushing of face (lack of vascular tone)

(lecture 1)

Front 3

What are the muscles that help to elevate the eyelid? are they somatic (skeletal) or visceral (smooth) muscles?

Back 3

-Levator palpebrae superioris (skeletal muscle)

-Superior tarsal muscle (smooth muscle) - helps to elevate the eyelid particularly in cases where you aren't thinking about keeping the eye open- so if that sympathetic pathway is interrupted and you aren't consciously thinking about keeping your eye open, ptosis will occur.

Front 4

There are several locations that we can have lesions of the sympathetic pathway that can produce a horner's syndrome. What are they?

Back 4

You could have a lesion at:

-the hypothalamospinal tract (from cervical spinal cord lesion-transection- as well)

- preganglionic sympathetic neurons

- Postganglionic sympathetic neurons

Front 5

There is a nucleus in the hypothalamus that is going to send its axons all the way down to synapse on the IMLCC. What is this tract called? Where is it located?

Back 5

hypothalamospinal tract

In the lateral part of the medulla (lateral to the nucleus ambiguus above the ollivary nucleus and medial to the spinothalamic tract)

Front 6

A lesion in the hypothalamospinal tract could cause both Horner's syndrome and ________________ syndrome.

Back 6

lateral medullary (Wallenberg)

Front 7

Where would the lesion of the preganglionic sympathetic neurons have to be lesioned to cause Horner's syndrome?

Back 7

-If you had a thoracic spinal cord transection from T1-T3, or a lesion of the sympathetic chain itself

Front 8

Postganglionic sympathetic neuronal cell bodies are found in the:

Back 8

cervical chain ganglion (check this)

Front 9

If you had a lesion of the cervical chain ganglion or of the carotid artery, this would be a lesion to __________________. What syndrome could this cause?

Back 9

-Postganglionic sympathetic neurons

Horner's syndrome

Front 10

We actually see Horner's syndrome of part of the constellation of signs that characterize ________________ syndrome

Back 10

Wallenberg

(lateral medullar)

Front 11

What occurs in lateral medullary (Wallenberg) syndrome? Which tracts or nuclei are affected?

Back 11

-loss of contralateral pain and temperature sensation from the body (spinothalamic tract)

-loss of ipsilateral pain and temperature sensation from the face (spinotrigeminal nucleus & tract

-nystagmus, vertigo, nausea, vomiting (vestibular nuclei)

-hoarseness and contralateral deviation of uvula (nucleus ambiguus)

-ataxia (inferior cerebellar peduncle)

-ipsilateral Horner's syndrome (hypothalamospinal tract)

Front 12

Most commonly, Lateral medullary (Wallenberg) syndrome is caused by an occlusion to ____1_______ (which is a branch of the ______2________ artery)

Back 12

1. PICA

2. Vertebral artery, so an occlusion to the vertebral artery would impact PICA)

(end lecture 1)

Front 13

We can divide the visceral sensory fibers into two types. ________ and __________.

Back 13

pain and non-pain

Front 14

as a general rule, pain sensations coming from the viscera are going to travel back up via the _______1_______ pathway, while non-pain sensations travels back to the CNS via _______2______ pathways.

Back 14

1. sympathetic

2. parasympathetic

Front 15

non-pain sensations are received by which type of receptors?

Back 15

-mechanoreceptors

-baroreceptors

-chemoreceptors

-thermoreceptors

Non-pain sensations are not causing tissue damage

Front 16

What do mechanoreceptors sense?

Back 16

stretch and pressure - this would be just normal distention that isn't causing any type of pain, just monitoring the state of, for example, the GI tract or the stomach

Front 17

Baroreceptors measure:

Where are they?

Back 17

blood pressure

Near the bifurcation of the common carotid artery

Front 18

What do chemoreceptors monitor?

Back 18

blood gas (gas tension)

pO2, pCO2, pH

Front 19

What type of receptors receive pain sensation?

For example?

Back 19

Nociceptors (typically free nerve endings)

-mechanical damage, ischemia, ulceration, etc.

Front 20

Nociceptors respond to:

Back 20

some sort of tissue damage- could be mechanical, for example, very sudden distention of the gut tube can cause visceral pain, could be a loss of blood being delivered to a particular region of the tissue, you lose oxygen and nutrients (ischemia, i.e. cell death in that area), could be ulceration of GI tract (erosion of gut tube), etc.

Front 21

When ischemia occurs, the body produces all sorts of chemical responses to that ischemia, and the ______________ are very responsive to those physiological changes of ischemia.

Back 21

nociceptors

Front 22

Mechanoreceptors, responsible for sensing stretch and pressure, are located throughout the _____1_______. The afferent nerve fibers travel with _____2___ nerves, but in the opposite direction.

Back 22

1. viscera

2. parasympathetic

Front 23

Parasympathetic up to the left colic flexure is ____1_____ nerve, but once we get past the left colic flexure and into the abdominal and pelvic organs, those are being supplied parasympathetically by ______2_______ nerves, that are coming from the _____3_______ spinal cord levels

Back 23

1. vagus

2. pelvic splanchnic nerves

3. S2-S4

Front 24

Non-pain sensation that would be associated with the abdominal and pelvic viscera will travel back to the CNS via the ________1_________.

Where do we find the cell bodies, and where do the central processes enter the spinal cord?

Back 24

1. Pelvic splanchnic nerves

- The cell bodies of the pseudounipolar neurons are located in the posterior root ganglia, so the peripheral processes bring the information back, and then the central processes enter the spinal cord via posterior roots

Front 25

What pathway would non-pain sensation travel back from the heart?

Back 25

The vagus nerve

(because it is the parasympathetic innervation to the heart)

Front 26

What are the physiological receptors?

Back 26

-Baroreceptors

-chemoreceptors

Front 27

Where are baroreceptors located?

Back 27

in the carotid sinus (at a kind of expansion or bulge at the bifurcation of the common carotid artery)

Front 28

Where are chemoreceptors located?

Back 28

In the carotid body (right at the bifurcation of the common carotid artery as well) and the aortic arch

Front 29

From the aortic arch, The fibers of the chemoreceptors would travel back up the the CNS via the _____1_____ nerve, and from the carotid sinus and carotid body, the baroreceptor and chemoreceptor fibers would travel back to the CNS via CN ____2____ (the ____3____ nerve), and would then project to the _____4. ______ nucleus

Back 29

1. vagus

2. IX

3. glossopharyngeal nerve

4. solitary nucleus

Front 30

Where are the cell bodies of the physiological receptors located? (baroreceptors and chemoreceptors)

Back 30

in cranial nerve ganglia

Front 31

The __________ nucleus is really the visceral sensory nucleus of the brainstem

Back 31

solitary

Front 32

_____1________ are free nerve endings that respond to tissue damage, and travel with _____2_____ nerves (in the opposite direction).

Back 32

1. nociceptors

2. sympathetic

Front 33

The cell bodies of the nociceptors are located in the _____1______ and their central processes enter the spinal cord via _______2________.

Back 33

1. posterior root ganglia

2. posterior roots

Front 34

What is referred pain?

Back 34

it refers a phenomena where there is tissue damage in some sort of organ (typically in the body cavity itself)- that pain, while it may be diffusely felt in the area where the tissue damage is happening, there can also be pain sensation from an area of the skin that is quite distance from the actual pain- or actual tissue damage- is occuring

Front 35

Why does referred pain occur?

Back 35

because central processes of pseudounipolar neurons conveying visceral pain sensation (back from the internal organs) and somatic pain sensation (from the dermatomes) will synapse and converge onto the same neuron in the posterior horn. So because these signals converge onto the same neurons, it is possible that This neuron that receives input from both, will receive the pain sensation from the organs and is thinking that there is actually pain coming back from the skin itself (25:30 slide 6)

Front 36

What is important about referred pain?

Back 36

It actually provides health professionals with a window into the body in a non-invasive way

Front 37

There are areas along the skin of the body where if an individual experiences pain in those areas, it could indicate that they are having tissue damage somewhere in the body. What is this referred to as?

Back 37

referred pain

Front 38

What is the most common incidence of referred pain?

Back 38

A heart attack where pain radiates down the left arm (particularly the case in men, females don't show this quite as much)

Front 39

If you have pain in the midcervical area of your shoulder (C3, C4, C5 dermatome) what internal structure may have tissue damage?

Back 39

The diaphragm

Front 40

In the parasympathetic innervation to the heart, the preganglionic visceral efferent cell bodies are found in the _____1_________, and the preganglionic fibers are traveling via the _____2_____ nerve

Back 40

1. dorsal motor nucleus of vagus

2. vagus (CN X)

Front 41

Explain the pathway for the parasympathetic visceral efferent fibers moving towards the heart.

Back 41

The preganglionic cell bodies are in the dorsal motor nucleus of vagus in the rostral medulla, and from there the preganglionic axons travel via CN X to synapse in the terminal ganglia of the heart (remember the ganglia are right in the wall of the target organ) where the postganglionic cell bodies are located. the postganglionic axons synapse on the conduction system of the heart (the SA and AV nodes).

Front 42

PSNS stimulation ___________ heart rate and strength of contraction

Back 42

decreases (rest and digest)

Front 43

Where do parasympathetic postganglionic axons synapse on the heart?

Back 43

on the conduction system of the heart-
- sinoatrial nodes (SA) &

- atrioventricular nodes (AV)

Front 44

In the sympathetic innervation to the heart, the preganglionic visceral efferent cell bodies are found in the ______1________. The postganglionic cell bodies are found in ________2______

Back 44

1. IMLCC of T1-T5

2. paravertebral ganglia

Front 45

Explain the sympathetic pathway to the heart

Back 45

The preganglion cell bodies begin in the IMLCC of T1-T5, and the preganglionic fibers travel through the anterior roots to the white rami communicans where they then synapse on paravertebral ganglia (sympathetic chain) the location of the postganglionic cell bodies. The postganglionic cell bodies them travel from the paravertebral ganglia via the cardiopulmonary splanchnic nerves where they will then synapse on SA and AV nodes in the conduction system of the heart.

Front 46

Sympathetic stimulation _______________ heart rate and strength of contraction

Back 46

increases (fight or flight)

Front 47

It is a balance between which systems that determines heart rate and strength of contraction?

Back 47

sympathetic and parasympathetic

Front 48

Where are the cardiac control centers located?

Back 48

in the reticular formation of the medulla

Front 49

The cardiac control centers have influence from the more central portions of the ______1______, and also receive visceral afferent information (non-pain) from those physiological receptors (chemoreceptors and baroreceptors) from the (bifurcation) carotid body/sinus and the aortic arch via cranial nerves ______2___ and _______

Back 49

1. hypothalamus

2. CN IX, CN X

Front 50

The visceral afferent fibers from the physiological receptors first go to the _______1________, and then project onto the _________2________

Back 50

1. solitary nucleus

2. cardiac control centers (either the cardiac acceleratory center or cardiac inhibitory center)

Front 51

What would occur with the cardiac control centers if you suddenly had low blood pressure?

Back 51

The physiological receptors- the baroreceptors- particularly in the carotid sinus, would detect the low blood pressure, and visceral afferent fibers would then project their central processes into the solitary nucleus. Neurons in the solitary nucleus would then project to the cardiac acceleratory center, and the neurons from the cardiac acceleratory center would then project to the spinal cord and synapse on sympathetic preganglionic neurons in the IMLCC. The preganglionic nerve fibers would then synapse in the paravertebral ganglia (sympathetic chain) on the postganglionic cell bodies and the postganglionic nerve fibers would then project to the heart and cause an increase in heart rate and blood pressure.

Front 52

If the baroreceptors detected high blood pressure, what would occur?

Back 52

It would project from the solitary nucleus to the cardiac inhibitatory center, and then that would project to the dorsal motor nucleus of vagus to activate the vagus nerve, which will then slow the heart down (rest and digest)

Front 53

With autonomic control of the urinary bladder, the sympathetic system does two things. What are they, and what does this allow for?

Back 53

1. Causes a contraction of the internal urethral sphincter

2. relaxes the detrusor muscle

This allows the bladder to fill and prevents it from emptying.

Front 54

What is the smooth muscle of the urinary bladder?

Back 54

The detrusor

Front 55

At a certain point, the bladder will become full enough that the visceral non-pain sensation will start to be detected by what?

Back 55

The stretch receptors in the bladder wall will detect "fullness"

Front 56

Below the pelvic pain line, we have that exception where both pain and non-pain visceral information travels back via _____________ pathways.

Back 56

parasympathetic

Front 57

once the fullness of the bladder has been detected, we are going to have two systems that are going to operate. What are they and what do they do?

Back 57

1. parasympathetic system- causes contraction of the detrusor muscle and relaxation of the internal urethral sphincter

2. somatic motor (voluntary) system- the pudendal nerve projects to the external urethral sphincter and maintains a tonic contraction of the sphincter until it is voluntarily inhibited

Front 58

The voluntary control of the urinary bladder is via the __________ nerve

Back 58

Pudendal

Front 59

Parasympathetic innervation to the urinary bladder is coming from the ___________ spinal cord levels

Back 59

S2-S4

Front 60

If we were to lesion the sacral portion of the spinal cord or the cauda equina, what would occur?

What type of disorder would this be equivalent to?

Back 60

You would have what is called a flaccid, or autonomous bladder.

This would be equivalent to a LMN type of disorder

Front 61

What occurs if you have an autonomous, or flaccid bladder?

Back 61

Both voluntary somatic control and parasympathetic reflex control are lost

the urinary bladder fills to capacity and overflows and you have continuous dribbling of the urinary bladder.

Front 62

If we were to lesion the spinal cord above the S2-S4 level, what is this called? What is still in tact? What do we lose?

Back 62

This is called a reflex, or a spastic bladder. The parasympathetic reflex is still in tact but we lose the voluntary control.

Front 63

A spastic, or reflex bladder, is analogous to what type of lesion?

Back 63

An upper motor neuron lesion

Front 64

What occurs with a reflex, or spastic bladder?

Back 64

As the bladder fills, the stretch receptors are activated, which activates the parasympathetic nervous system to contract the detrusor muscle via a reflex arc, and so what happens is that the urinary bladder fills and empties about every 1-4 hours, so you have this cycle of filling and emptying.

Front 65

The __________ nervous system lines the gut tube and prevents reflexive actions within the gut tube itself.

Back 65

enteric

Front 66

The enteric nervous system is regulated by the ___________ nervous system

Back 66

Autonomic

It is a separate component of the ANS for regulating the GI tract; it has a local reflex response

Front 67

Keep going!

Back 67

You can do it!

Front 68

With parasympathetic autonomic control of the bowel, the cell bodies will be in the ________1_______ for innervation proximal to the left colic flexure, or in the _______2________ for innervation distal to the left colic flexure.

Back 68

1. Dorsal motor nucleus of vagus (proximal)

2. intermediate zone of S2-S4 (distal)

Front 69

with parasympathetic autonomic control of the bowel, the preganglionic fibers will travel in ___1___ or _____2_____, and the postganglionic fibers will regulate the ________3________

Back 69

1. CN X

2. Pelvic splanchnic nerves

3. enteric nervous system

Front 70

_________________ activation facilitates peristalsis of the bowel and glandular secretion

Back 70

PSNS (parasympathetic nervous system)

Front 71

With sympathetic autonomic control of the bowel, explain what occurs?

Back 71

The preganglionic cell bodies begin in the IMLCC of T6-L2, and then the preganglionic fibers travel in anterior roots to the white rami communicante to the sympathetic trunk (chain) to the abdominopelvic splanchnic nerves, where they will then synapse on the postganglionic cell bodies at the prevertebral ganglia. The postganglionic fibers will then regulate the enteric nervous system

Front 72

___________________ activation inhibits peristalsis of the bowel and glandular secretion

Back 72

SNS (sympathetic nervous system)

Front 73

peristalsis of the bowel itself can continue to occur normally because of the:

Back 73

enteric nervous system

Front 74

With autonomic control of the sex organs, it is a balance between _____________ and ______________

Back 74

sympathetics and parasympathetics

Front 75

With autonomic control of the sex organs, parasympathetics have their cell bodies in the _____________1_______, and the preganglionic fibers travel in _________2________ nerves.

Back 75

1. intermediate zone of S2-S4 spinal cord (preganglionic cell bodies here)

2. pelvic splanchnic nerves

Front 76

With autonomic control of the sex organs, in females, parasympathetic postganglionic fibers innervate ________________ and ________________

Back 76

-Vaginal glands (secretion)

-Erectile tissue of the clitoris

Front 77

With autonomic control of the sex organs in males, parasympathetic postganglionic fibers innervate:

Back 77

erectile tissue of the penis

Front 78

With autonomic control of the sex organs, parasympathetic innervations are critical for ______________, both in males and females

Back 78

erectile tissues

Front 79

With autonomic control of the sex organs, the sympathetic preganglionic cell bodies are in the ______________.

Back 79

IMLCC of T10-L2

Front 80

With autonomic control of the sex organs, what is the pathway of the sympathetic preganglionic fibers?

Back 80

The sympathetic preganglionic cell bodies start in the IMLCC of T10-L2, then the preganglionic fibers travel in anterior roots to WRC to the sympathetic trunk, through the abdominopelvic splanchnic nerves, and then synapse at prevertebral ganglia.

Front 81

With autonomic control of the sex organs in females, the sympathetic postganglionic fibers innervate:

Back 81

blood vessels and smooth muscles of the uterus and the vagina

Front 82

With autonomic control of the sex organs in males, the sympathetic postganglionic fibers innervate the _________, ___________, and ____________

Back 82

-ductus deferens

-prostate gland

-seminal vesicles

Front 83

What is an example of a coordination of both the sympathetic and parasympathetic system in control of the sex organs?

Back 83

The parasympathetic system will facilitate the erectile tissues in both the male and female, but in both the male and female, it is the sympathetic system that will facilitate orgasm, as well as male emission and ejaculation. So in order for sexual function to occur normally, you have to have the synergistic activation of both the sympathetic and the parasympathetic systems

Front 84

Is it possible for individuals with spinal cord injuries to have sexual function?

Back 84

Depending on where the spinal cord injury is, yes, you can have sexual functions. There can be reflexive sexual functions with the male (produce erection and ejaculation), and even spinal cord injured females can conceive and deliver (carefully monitored), because contraction of the uterus is actually a hormonally induced type of process. So these reflexive activities can still be in tact

Front 85

Spinal cord injuries above the T6 level prevent most of the spinal cord from receiving descending signals that inhibit sympathetic activity. Due to this, what is a condition that can occur?

Back 85

autonomic dysreflexia

Front 86

What occurs in autonomic dysreflexia?

Back 86

It is most severe in patients that have spinal cord injuries above the T6 level. If the descending signals are lost, then the sympathetic reflexes become hyperactive

Front 87

What are characterizations of autonomic dysreflexia?

Back 87

-hypertension (high blood pressure)

-urinary retention (this is what normally allows the bladder to fill)

-piloerection (erection of the hair on your skin)

-profuse sweating

This can be very dangerous (especially hypertension)

Front 88

_______________ is often elicited by noxious stimuli below the level of the lesion, such as an over-stretching of the bladder or rectum

Back 88

autonomic dysreflexia

Front 89

Why is autonomic dysreflexia a life-threatening medical emergency?

Back 89

Due especially to the sudden spike in blood pressure