Medical Neuroscience Kingsley Week 1B

Front 1

Which axons are myelinated, 6-12uM in diameter, relay cutaneous tactile information and have a conduction velocity of 30-60M/s?

Back 1

Abeta

Front 2

Which axons are myelinated, 1-5uM in diameter, have a conduction velocity of 5-30M/s and relay painful modalities?

Back 2

Adelta

Front 3

Which axons are unmyelinated, .5-3uM in diameter, have a conduction velocity of <3M/s and are responsible for nociception?

Back 3

C

Front 4

Define sensory transduction

Back 4

Converting mechanical, chemical, thermal or photic energy into electrical signals useful to the nervous system

Front 5

Receptor and synaptic potentials are _________ (digital/analog)

Back 5

analog

Front 6

Action potentials are _________ (digital/analog)

Back 6

digital

Front 7

Intensity of a stimulus is coded as the ________ of the receptor potential.

Back 7

Amplitude

Front 8

Amplitude of the receptor potential is coded as the _________ of the action potentials.

Back 8

Frequency

Front 9

Frequency of action potentials is coded as the _________ of post-synaptic potentials

Back 9

Amplitude

Front 10

Sensory transduction is an exact transcription of a stimulus (True/False)

Back 10

False (the stimulus is modified by the receptor and through CNS processing (think telephone game))

Front 11

What is the purpose of auxilliary structures such as pacinian corpuscles and merkel's disks?

Back 11

to modify the time course of a receptor potential (eg, pacinian corpuscles respond to a vibrating stimulus)

Front 12

The excitation on a third order neuron has the same S/B ratio as the stimulus (True/False)

Back 12

True

Front 13

Receptors of multiple types can be found in a single neuron (True/False)

Back 13

False (Line labeled coding segregates the information into exclusive channels so that an axon can only carry one type of signal)

Front 14

If you were to stimulate an axon proximally to it's receptor, where would the brain perceive the location of the stimulus to be?

Back 14

At the location of the receptor (explanation of phantom limb syndrome)

Front 15

What are the four modalities of the epicritic (dorsal column) system?

Back 15

fine tactile, 2-point discrimination, proprioception and vibration

Front 16

The _________ is the structure in which the primary afferents of the epicritic (dorsal column) for the lower extremity ascend on the ________ (ipsilateral/contralateral) side of the spinal cord.

Back 16

fasciculus gracilis, ipsilateral

Front 17

The _________ is the structure in which the primary afferents of the epicritic (dorsal column) for the upper extremity ascend on the ________ (ipsilateral/contralateral) side of the spinal cord.

Back 17

fasciculus cuneatus, ipsilateral

Front 18

The primary afferents of the epicritic (dorsal column) system synapse at the ________ and cross the midline to ascend the_________. The secondary neurons then synapse in the ________.

Back 18

Dorsal Column Nuclei (nucleus fasciculus and nucleus cuneatus), Medial lemniscus, Thalamus/Ventrobasal complex

Front 19

At what level of the brainstem do the internal arcuate fibers of the dorsal column nuclei begin crossing to the medial lemnisci?

Back 19

Front 20

Secondary epicritic afferents from the lower extremity travel along the _________ (medial/lateral) side of the medial lemniscus.

Back 20

lateral (upper extremity travels along the medial side)

Front 21

What are the modalities of the protopathic (anterolateral tract) system?

Back 21

pain (nociception and nociperception), temperature and gross tactile

Front 22

What is the primary stimulus of the protopathic (ALS) system?

Back 22

K+

Front 23

"Fast pain" fibers

Back 23

Adelta

Front 24

"Slow pain" fibers

Back 24

C

Front 25

The secondary protopathic (ALS) fibers from the lower extremity travel up the ________ (medial/lateral) side of the anterolateral tract.

Back 25

lateral (body and arm are medial just like the medial lemniscus in the epicritic pathway)

Front 26

Primary protopathic (ALS) fibers synapse and secondary fibers cross the midline before ascending the spinal cord (True/False)

Back 26

True (in the epicratic pathway, the fibers ascend the spinal cord first and then synapse)

Front 27

The trigeminal pathways carry both epicritic and protopathic fibers that synapse immediately upon entering the brainstem at the trigeminal nuclei. (True/False)

Back 27

True

Front 28

At what levels will you find the trigeminal tracts and/or nuclei?

Back 28

Beginning at the spinal cord-medulla transition and ending at the ponto-medullary transition

Front 29

Name the structures circled and the level of the spinal cord.

Back 29

Green - dorsal horn; Red - dorsal column (fasciculus gracilis); Yellow - ventral horn; White - Anterolateral tract; Lumbar Spinal Cord

Front 30

Name the circled structures and the level of the spinal cord.

Back 30

Red - Dorsal column (fasciculus gracilis); White - anterolateral tract; Thoracic spinal cord

Front 31

Name the circled structures and the level of the spinal cord.

Back 31

Red - fasciculus gracilis; Green - fasciculus cuneatus; White - anterolateral tract; Cervical spinal cord

Front 32

Name the circled structures and the level of the brain stem.

Back 32

Pink - Nucleus gracilis; Green - fasciculus cuneatus; Orange - Nucleus cuneatus; Yellow - Spinal trigeminal tract; Brown - Spinal trigeminal tract; Red - Internal arcuate fibers; Blue - Medial lemniscus; White - anterolateral tract; Low medulla (obex)

Front 33

Name the circled structures and the level of the brain stem.

Back 33

Yellow - Spinal trigeminal tract; Blue - medial lemniscus; White - anterolateral tract; Rostral Medulla

Front 34

Name the circled structures and the level of the brain stem.

Back 34

Yellow - Spinal trigeminal tract; Red - spinal trigeminal nucleus; Blue - Medial lemniscus; White - anterolateral tract; Green - Infereior cerebral peduncle; Ponto-Medullary Junction

Front 35

Name the circled structures and the level of the brain stem.

Back 35

Green - Superior cerebral peduncle; Red - Fourth ventricle; Blue - medial lemniscus; White - anterolateral tract; Mid Pons

Front 36

Name the circled structures and the level of the brain stem.

Back 36

Green - Superior cerebral peduncle; Blue - medial lemniscus; White - anterolateral tract; Rostral Pons

Front 37

Name the circled structures and the level of the brain stem.

Back 37

Green - Cerebral aqueduct; White - anterolateral system; Blue - medial lemniscus; Red - Periaqueductal gray; Midbrain

Front 38

Name the circled structures and the level of the brain stem.

Back 38

Red - third ventricle; Blue - medial lemniscus; White - anterolateral tract; Diencephalon

Front 39

Secondary axons of the visceral pain pathway travel through the _________ where they synapse in the __________

Back 39

dorsal columns, nucleus gracilis

Front 40

What would result from lesions to the medial side of the fasciculus gracilis?

Back 40

This would result in an abolishment of visceral pain signals from the ipsilateral side.

Front 41

The anterior horn of the spinal cord is primarily supplied by what artery?

Back 41

Anterior spinal artery

Front 42

The dorsal columns are supplied by what artery?

Back 42

Posterior spinal artery

Front 43

What is known about the location of a lesion if the face is involved?

Back 43

It is above the trigeminal nucleus

Front 44

What artery supplies the medial lemnicus in the medulla?

Back 44

Anterior Spinal artery

Front 45

What artery supplies the spinal trigeminal artery and tract in the medulla?

Back 45

Posterior spinal a.

Front 46

What is area 3,1,2 on the Brodman map?

Back 46

somatosensory area (postcentral gyrus)

Front 47

Interneurons of the protopathic pathway in the spinal cord are ________ (inhibitory/excitatory) and are normally _________ (inhibited/activated).

Back 47

Inhibitory, Inhibited (Gate control hypothesis. Tactile fibers activate the interneurons which in turn inhibit the protopathic pathway, decreasing pain sensation) (rub your hand when you smash it and the pain decreases)

Front 48

Nucleus Raphe Magnus and Nucleus Reticularis Paragigantocellularis are found in the __________ and are involved in the _________ _________ ____________ pathway

Back 48

Medulla, Descending Pain Modulation

Front 49

Name the four nuclei of the descending pain pathways

Back 49

PAG (periaqueductal gray), Locus cerulius, Nucleus Raphe Magnus, Nucleus Paragigantocellularis

Front 50

What neurotransmitter is used by the PAG neurons?

Back 50

Enkephalon

Front 51

Which two descending pain modulation pathways use norepinephrine(noradrenaline) as their neurotransmitter?

Back 51

Locus ceruleus and Nucleus Paragigantocellularis

Front 52

Locus ceruleus and the Periaqueductal Gray (PAG) are located in the _________ and are involved in the _________ __________ _________ pathway

Back 52

Midbrain, Descending Pain Modulation

Front 53

Nucleus Raphe Magnus uses which neurotransmitter?

Back 53

Serotonin

Front 54

What is this cartoon illustrating?

Back 54

Peripheral sensitization

Front 55

Axon sprouting can lead to what pathology?

Back 55

Neuropathic pain - normal stimuli trigger severe pain (can occur post-amputation)

Front 56

What Amendment provides the ability to confront adverse witnesses?

Back 56

6th amendment provides the ability to confront adverse witnesses.

Front 57

What happens when neuronal fibers fail to regenerate, leaving bare postsynaptic junctions?

Back 57

Front 58

Nipples are at what dermatome level?

Back 58

T4

Front 59

Umbilicus is at what dermatome level?

Back 59

T10

Front 60

The knee is at what dermatome level?

Back 60

L4

Front 61

Patient presents with sensory loss to the thumb. What dermatome is affected?

Back 61

C6

Front 62

Patient presents with sensory loss to the third digit. What dermatome is affected?

Back 62

C7

Front 63

Patient presents with sensory loss to the fifth digit. What dermatome is affected?

Back 63

C8

Front 64

Patient presents with sensory loss to the medial aspect of the elbow. What dermatome is affected?

Back 64

T1

Front 65

where is the substantia gelatinosa located?

Back 65

The dorsal horn (lamina II)

Front 66

Patient presents with sensory loss to the great toe. What dermatome is affected?

Back 66

L4

Front 67

Patient presents with sensory loss to the lateral foot and calf. What dermatome is affected?

Back 67

S1

Front 68

Patient presents with sensory loss to the middle of the dorsal foot and medial plantar foot. What dermatome is affected?

Back 68

L5

Front 69

The angle of the jaw receives sensory innervation from what nerve?

Back 69

C2

Front 70

If a patient presents with a ringed pattern of sensory loss unilaterally on part of his face, where would a neuronal lesion be likely located?

Back 70

The spinal trigeminal tract in the medulla

Front 71

If a patient presents with V1-V3 patterned sensory loss, where is the neuronal lesion likely to be located?

Back 71

The trigeminal nerve, peripheral to the spinal cord

Front 72

How would you distinguish a peripheral nerve loss from a CNS lesion?

Back 72

peripheral nerve loss follows a peripheral nerve pattern, a fragment of a dermatome (important in hands and feet)

Front 73

Patient presents with sensory loss to the external acoustic meatus. What cranial nerve is likely involved?

Back 73

CNX

Front 74

A lesion in the medullary portion of the the spinal trigeminal nucleus would affect the fine tactile response of the face (True/False)

Back 74

False (only protopathic pathways affected. a lesion would have to be at the level of the pons to affect the epicritic pathways)

Front 75

How would a patient with peripheral neuropathy caused by diabetes likely present?

Back 75

"Stocking Glove" sydrome. Loss of both sensory modalities in the hands and feet.

Front 76

Patient presents with this pattern of sensory loss of both modalities. What is it called, where must the lesion be located and what could have caused it?

Back 76

This is hemihypoesthesia. The lesion must be located rostral to the trigeminal nuclei (face is involved) and could have been caused by a stroke or neoplasm.

Front 77

A patient presents with this pattern of sensory loss. What is it called and where must the lesion be located?

Back 77

This is called crossed hypoesthesia. The lesion must be in the brain stem because the areas affected involve the face (trigeminal nucleus) and the contralateral side of the body (medial lemniscus).

Front 78

A patient presents with tactile sensory loss on his left lower extremity and pain/temp loss on his right lower extremity. What is this called, how could it have been caused, and on what side of the spinal cord is the lesion?

Back 78

This is called the "Harlequin" or Brown-Sequard Syndrome. It is caused by a lesion/injury that hemisects the spinal cord. This can occur due to tumors, MS or trauma. Because the epicritic has been lost on the left side and the protopathic lost on the right, the lesion is on the left side (epicritic have not yet crossed the midline, protopathic have)

Front 79

What would likely cause this pattern of pain/temp sensory loss and what is it called?

Back 79

This is called syringomyelia. It is cause when a syrinx forms in the central canal of the cervical spinal cord, disrupting the protopathic secondaries as they cross from the dorsal horn to the ALS.