White matter tracts Flashcards
1
Q
There are _ pairs of spinal nerves;
_ cervical
_ thoracic
_ lumbar
_ sacral
_ coccygeal
A
There are 31 pairs of spinal nerves;
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
2
Q
The _ root contains axons of somatic motor nerves
A
The ventral root contains axons of somatic motor nerves
* These innervate skeletal muscles
3
Q
The _ root contains axons of somatic sensory nerves
A
The dorsal root contains axons of somatic sensory nerves
* These convey sensation (pain, touch, temperature)
4
Q
The spinal nerve carries _ type of information
A
The spinal nerve carries somatic and visceral motor & sensory information
* The ventral and dorsal roots unite to form a spinal nerve
5
Q
The cell bodies of somatic motor nerves are found in the [location of spinal nerve]
A
The cell bodies of somatic motor nerves are found in the ventral horn
6
Q
The cell bodies of somatic sensory nerves are found in the [location of spinal nerve]
A
The cell bodies of somatic sensory nerves are found in the dorsal root ganglion
7
Q
Sympathetic nerves originate in the [gray matter location]
A
Sympathetic nerves originate in the lateral horns of the gray matter
* Only between T1-L2
8
Q
The lateral horn of gray matter is found in [spinal cord regions]
A
The lateral horn of gray matter is found in T1-L2
9
Q
Sympathetic nerves exit the spinal cord via _ before entering _
A
Sympathetic nerves exit the spinal cord via ventral root before entering sympathetic chain
* These are visceral motor nerves
10
Q
The cell body of visceral motor nerves is in the [spinal nerve region]
A
The cell body of visceral motor nerves is in the lateral horn
11
Q
The cell body of visceral sensory nerves is found in the [region]
A
The cell body of visceral sensory nerves is found in the dorsal root ganglion
12
Q
Most spinal nerves contain 4 distinct types of nerves:
A
Most spinal nerves contain 4 distinct types of nerves:
1. Somatic motor
2. Somatic sensory
3. Visceral motor
4. Visceral sensory
13
Q
The _ rami of spinal nerves combine to form nerve plexuses
A
The ventral rami of spinal nerves combine to form nerve plexuses
* Cervical, brachial, lumbar, and sacral plexuses
* Intercostal nerves don’t form a plexus
14
Q
Cervical plexus forms from [spinal cord rami] and innervates structures within the neck (and diaphragm)
A
Cervical plexus forms from C1-C4 and innervates structures within the neck (and diaphragm)
15
Q
Brachial plexus forms from [spinal cord rami] and innervates the upper limb/shoulder girdle
A
Brachial plexus forms from C5-T1 and innervates the upper limb/shoulder girdle
16
Q
Lumbar plexus forms from [spinal cord rami] and combines with the sacral plexus
A
Lumbar plexus forms from T12-L4 and combines with the sacral plexus
17
Q
Sacral plexus forms from [spinal cord rami] and combines with the lumbar plexus to innervate the lower limb and perineum
A
Sacral plexus forms from L4-S4 and combines with the lumbar plexus to innervate the lower limb and perineum
18
Q
Sensory information from the thumb and lateral arm returns to the spinal cord via the _ spinal nerve and enters the respective spinal cord segment
A
Sensory information from the thumb and lateral arm returns to the spinal cord via the C6 spinal nerve and enters the respective spinal cord segment
19
Q
Neck/shoulder dermatome:
A
Neck/shoulder dermatome: C3,4,5
20
Q
Thumb/lateral arm dermatome:
A
Thumb/lateral arm dermatome: C6
21
Q
Middle finger dermatome:
A
Middle finger dermatome: C7
22
Q
Little finger/medial arm dermatome:
A
Little finger/medial arm dermatome: C8
23
Q
Nipple dermatome:
A
Nipple dermatome: T4
24
Q
Umbilicus dermatome:
A
Umbilicus dermatome: T10
25
Perineum/Perianal dermatome:
Perineum/Perianal dermatome: **S2,3,4**
26
Anterior knee/big toe dermatome:
Anterior knee/big toe dermatome: **L4**
27
Middle toes dermatome:
Middle toes dermatome: **L5**
28
Little toe/lateral foot dermatome:
Little toe/lateral foot dermatome: **S1**
29
[Spinal cord segment] : abduction of the shoulder
**C5** : abduction of the shoulder
30
[Spinal cord segment] : flexion of elbow
**C6** : flexion of elbow
31
[Spinal cord segment] : extension of elbow
**C7** : extension of elbow
32
[Spinal cord segment] : extension of wrist/fingers
**C7** : extension of wrist/fingers
33
[Spinal cord segment] : flexion of wrist/fingers
**C8** : flexion of wrist/fingers
34
[Spinal cord segment] : hip flexion
**L2** : hip flexion
35
[Spinal cord segment] : hip adduction
**L3** : hip adduction
36
[Spinal cord segment] : knee extension
**L4** : knee extension
37
[Spinal cord segment] : ankle dorsiflexion
**L5** : ankle dorsiflexion
38
[Spinal cord segment] : ankle plantarflexion
**S1** : ankle plantarflexion
39
The spinal cord ends at [vertebral levels]
The spinal cord ends at **L1 or L2**
40
Cervical nerves C1-C7 traverse through their corresponding intervertebral foramen _ to the vertebra
Cervical nerves C1-C7 traverse through their corresponding intervertebral foramen **superior** to the vertebra
41
All spinal nerves below _ traverse inferior to the vertebra
All spinal nerves below **C8** traverse *inferior* to the vertebra
* *C8 and below will go below*
42
The lateral horn is the location of _ cell bodies
The lateral horn is the location of **preganglionic sympathetic nerve cell bodies**
43
The white matter is divided into (3) columns:
The white matter is divided into (3) columns:
1. **Dorsal columns** (posterior)
2. **Ventral columns** (anterior)
3. **Lateral columns**
44
The _ is a central region of the spinal cord where axons that convey pain and temperature can cross over to the other side of the cord
The **anterior commissure** is a central region of the spinal cord where axons that convey pain and temperature can cross over to the other side of the cord
45
Dorsal columns convey [type information]
Dorsal columns convey **ascending sensory nerves**
* *Convey touch, pressure, vibration, proprioception*
* *"Be sensative and stay P.C." = posterior column*
46
Anterior columns convey [type information]
Anterior columns convey **descending motor nerves** to control voluntary movements
* *Anterior corticospinal tract*
47
Lateral columns convey [type information]
Lateral columns convey **descending motor nerves** to control voluntary movements
* *Lateral corticospinal tract*
48
Lateral columns convey [type information]
Lateral columns convey **ascending sensory nerves**
* *Spinothalamic tracts*
49
[Tract] detects mechanical-like stimuli (pressure, vibration, fine touch, proprioception)
**Dorsal column medial lemniscus** detects mechanical-like stimuli (pressure, vibration, fine touch, proprioception)
50
[Tract] detects pain and temperature
**Spinothalamic** detects pain and temperature
* *Our nervous system separates mechanical stimuli from pain/temperature*
51
Pain and temperature information crosses over in the _
Pain and temperature information crosses over in the **spinal cord**
52
Mechanical sensations cross over in the _
Mechanical sensations cross over in the **caudal medulla**
53
Dorsal column medial lemniscus tract conveys mechanical information to the [brain region]
Dorsal column medial lemniscus tract conveys mechanical information to the **primary somatosensory cortex**
* *Fine touch, vibration, pressure, proprioception*
54
The DCML involves [#] neurons
The DCML involves **3 neurons**
55
DCML tract:
Neuron 1 cell body: [location]
Neuron 2 cell body: [location]
Neuron 3 cell body: [location]
DCML tract:
Neuron 1 cell body: **dorsal root ganglion**
Neuron 2 cell body: **caudal medulla**
Neuron 3 cell body: **thalamus**
56
Neuron 1 in the DCML pathway senses mechanical sensation in our *lower body* and enters the spinal cord via the _ and ascends to the _
Neuron 1 in the DCML pathway senses mechanical sensation in our *lower body* and enters the spinal cord via the **dorsal column (gracile tract)** and ascends to the **medulla**
57
In the [medullary nucleus] neuron 1 synapses on neuron 2 (DCML)
In the **gracile/cuneate nucleus** neuron 1 synapses on neuron 2 (DCML)
58
Which neuron of the DCML decussates?
**Neuron 2** of DCML decussates in the *medulla*
59
Neuron 2 (DCML) begins in the _ and ascends to the _
Neuron 2 (DCML) begins in the **gracile/cuneate nucleus** and ascends to the **VPL nucleus of the thalamus**
* *Decussates in medulla and ascends via medial lemniscus*
60
The second synapse of the DCML occurs in the _
The second synapse of the DCML occurs in the **VPL of the thalamus**
61
Neuron 3 (DCML) begins in the _ and travels to the _
Neuron 3 (DCML) begins in the **VPL** and travels to the **primary sensory cortex**
* *Traversing the internal capsule*
62
Neuron 1 in the DCML pathway senses mechanical sensation in our *upper body* and enters the spinal cord via the _ and ascends to the _
Neuron 1 in the DCML pathway senses mechanical sensation in our *upper body* and enters the spinal cord via the **dorsal column** and ascends to the **cuneate nucleus**
63
Spinothalamic pathway carries [information] to the [brain region]
Spinothalamic pathway carries **pain and temperature** to the **primary somatosensory cortex**
64
The spinothalamic pathway involves [#] neurons
The spinothalamic pathway involves **3 neurons**
65
Spinothalamic pathway:
Neuron 1 cell body: [location]
Neuron 2 cell body: [location]
Neuron 3 cell body: [location]
Spinothalamic pathway:
Neuron 1 cell body: **DRG**
Neuron 2 cell body: **dorsal horn**
Neuron 3 cell body: **thalamus**
66
When/Where does the first synapse of ST occur?
Pain/temp enters the spinal cord and **immediately synapses in dorsal horn**
67
The ST tract decussates in the [location]
The ST tract decussates in the **spinal cord**
68
Neuron 2 (ST tract) decussates in the spinal cord, ascends via the spinothalamic tract to the [location]
Neuron 2 (ST tract) decussates in the spinal cord, ascends via the spinothalamic tract to the **VPL of the thalamus**
69
The second synapse of the ST tract occurs in [location]
The second synapse of the ST tract occurs in **VPL**
70
Neuron 3 (ST tract) travels from _ to _
Neuron 3 (ST tract) travels from **VPL** to **primary sensory cortex**
71
Another name for spinothalamic tract is _
Another name for spinothalamic tract is **anterolateral system**
72
The site of the spinal cord where spinothalamic tracts decussate is the _
The site of the spinal cord where spinothalamic tracts decussate is the **anterior commissure**
73
Upper motor neurons originate in the _ and synapse on a lower motor neuron
Upper motor neurons originate in the **motor cortex** and synapse on a lower motor neuron
74
Lower motor neurons originate in the _ and project directly onto the muscle
Lower motor neurons originate in the **ventral horn of spinal cord** and project directly onto the muscle
* *Some lower motor neurons will actually be in the brainstem (cranial nerve nuclei) and innervate head/neck*
75
UMN descend through the [portion] of the internal capsule
UMN descend through the **posterior limb** of the internal capsule
76
90% of UMN will decussate in the _ and form the _ tracts
90% of UMN will decussate in the **caudal medulla** and form the **lateral corticospinal tracts**
77
10% of UMN cross over in the _ and form the _ tracts
10% of UMN cross over in the **anterior commissure** and form the **ventral (anterior) corticospinal tracts**
78
LMNs of the *lateral corticospinal tracts* innervate [muscles]
LMNs of the *lateral corticospinal tracts* innervate **limb muscles**
* *For complex motor activities*
79
LMNs of the *ventral corticospinal tracts* innervate [muscles]
LMNs of the *ventral corticospinal tracts* innervate **truncal muscles**
* *Core body muscles for postural control*
80
UMNs of the *corticobulbar tracts* traverse through the [portion] of the internal capsule
UMNs of the *corticobulbar tracts* traverse through the **genu** of the internal capsule
81
Corticobulbar tracts synapse on _
Corticobulbar tracts synapse on **cranial nerve motor nuclei**
82
Why are many cranial nerve motor functions preserved in stroke patients?
**Many cranial nerve motor nuclei receive UMN input from both cortices**
* *CN XII only receives UMN from the contralateral motor cortex*
83
[3 CNs] do not receive corticobulbar tracts; they are controlled by the frontal eye fields
**CN III, IV, VI** do not receive corticobulbar tracts; they are controlled by the frontal eye fields
84
The upper half of the face is controlled by the [CN nucleus] and receives UMN from _
The upper half of the face is controlled by the **upper facial motor nucleus** and receives UMN from **both motor cortices**
85
The lower half of the face is controlled by the [CN nucleus] and receives UMN from _
The lower half of the face is controlled by the **lower facial motor nucleus** and receives UMN from **contralateral motor cortex**
86
When a patient suffers from UMN damage to the facial nerve the [nucleus] remains functional
When a patient suffers from UMN damage to the facial nerve the **upper facial nucleus** remains functional
* *Therefore the upper facial muscles continue to function, while lower muscles are paralyzed*
87
Rubrospinal tract: [function]
Rubrospinal tract: **facilitates arm movements**
* *Augments the lateral corticospinal tracts*
* *E.g. flexor muscles of the upper limb*
88
The rubrospinal tract runs from the _ to the _
The rubrospinal tract runs from the **red nucleus (midbrain)** to the **cervical spinal cord**
89
The tectospinal tract: [function]
The tectospinal tract: **influences reflex head movements in response to visual and auditory systems**
90
The tectospinal tract runs from the _ to the _
The tectospinal tract runs from the **colliculi (midbrain)** to the **cervical spinal cord**
* *Also called the colliculospinal*
91
Reticulospinal tract: [function]
Reticulospinal tract: **helps activate muscles involved in posture/balance/equilibrium**
92
The reticulospinal tract runs from the _ to the _
The reticulospinal tract runs from the **reticular formation** to the **lower spinal cord**
93
Vestibulospinal tract: [function]
Vestibulospinal tract: **controls muscles which respond to changes in gravity and balance**
94
The lateral and medial vestibular nuclei receive input from the _
The lateral and medial vestibular nuclei receive input from the **semicircular canals**
* *Information about head and body position*
95
Inputs to the lateral vestibular nuclei are relayed (ipsilaterally/contralaterally)
Inputs to the lateral vestibular nuclei are relayed **ipsilaterally**
* *Via the lateral vestibulospinal tracts*
96
Inputs to the _ vestibular nuclei are relayed **bilaterally** into the cervical spinal cord
Inputs to the **medial vestibular nuclei** are relayed **bilaterally** into the cervical spinal cord
* *Via the medial vestibulospinal tracts*
97
The lateral vestibulospinal tracts function to _
The *lateral* vestibulospinal tracts function to **activate antigravity muscles to maintain balance**
* *E.g. activating extensor muscles*
* *We call this vestibulospinal reflex*
98
The medial vestibulospinal tracts function to _
The *medial* vestibulospinal tracts function to **stabilize head movements**
* *Vestibulocervical reflex*
99
Mechanical stimuli ascends (ipsilaterally/contralaterally) in the spinal cord
Mechanical stimuli ascends **ipsilaterally** in the spinal cord
100
Pain and temperature stimuli ascend (ipsilaterally/contralaterally) in the spinal cord
Pain and temperature stimuli ascend **contralaterally** in the spinal cord
101
Many cranial nerve motor nuclei receive bilateral corticobulbar UMNs except for _ and _
Many cranial nerve motor nuclei receive bilateral corticobulbar UMNs except for **lower facial nucleus** and **hypoglossal motor nucleus**
102
The [thalamic nucelus] receives sensory stimuli from the body (arms/legs/trunk)
The **VPL** receives sensory stimuli from the body (arms/legs/trunk)
103
The [thalamic nucelus] receives sensory stimuli from the head/face
The **VPM** receives sensory stimuli from the head/face
104
The _ pathways convey sensory stimuli from the head/face to the primary sensory cortex
The **trigeminothalamic pathways** convey sensory stimuli from the head/face to the primary sensory cortex
105
106
The trigeminothalamic tract involves [#] neurons
The trigeminothalamic tract involves **3 neurons**
107
Touch, pressure, and vibration from the face/head is carried by the first neuron of the trigeminothalamic tract and synapses at the [nucleus]
Touch, pressure, and vibration from the face/head is carried by the first neuron of the trigeminothalamic tract and synapses at the **main/principle nucleus of the trigeminal**
108
The trigeminothalamic pathway decussates at the _
The trigeminothalamic pathway decussates at the **pons**
* *The second neuron crosses over in the pons and ascends up the trigeminothalamic tract*
109
The second neuron of the trigeminothalamic tract travels up and synapses in the _
The second neuron of the trigeminothalamic tract travels up and synapses in the **VPM of the thalamus**
110
The third neuron of the trigeminothalamic tract ascends through the internal capsule to the _
The third neuron of the trigeminothalamic tract ascends through the internal capsule to the **primary sensory cortex**
111
Name (3) major classes of specialized sensory receptors found in our bodies
1. **Mechanical receptors**
2. **Free nerve endings**
3. **Proprioceptors**
112
Mechanical receptors are [structure] axons that are specialized to detect touch, pressure, vibration
Mechanical receptors are **large encapsulated receptors with myelinated axons** that are specialized to detect touch, pressure, vibration
113
Are free nerve endings encapsulated?
**No**; free nerve endings are unencapsulated receptors and lightly myelinated
114
Two types of free nerve endings:
Two types of free nerve endings:
**Nociceptors** for pain
**Thermoceptors** for temperature
115
[Sensory receptors] detect mechanical stimuli from muscles/joints
**Proprioceptors** detect mechanical stimuli from muscles/joints
116
(3) types of proprioceptors
(3) types of proprioceptors:
1. **Muscle spindles** (sense muscle length)
2. **Golgi tendon organs** (muscle tension)
3. **Joint receptors** (joint position)
117
Meissner corpuscle senses _
Meissner corpuscle senses **fine touch**
118
Pacinian corpuscle senses _
Pacinian corpuscle senses **deep pressure, vibration**
119
Ruffini's corpuscle senses _
Ruffini's corpuscle senses **stretch**
120
Merkel's disks sense _
Merkel's disks sense **touch/pressure**
121
The mechanical receptors are all associated with [afferent axon type]
The mechanical receptors are all associated with **AB axons**
* *These are large and myelinated*
* *Very quick*
122
Free nerve endings are associated with [afferent axon type]
Free nerve endings are associated with **Adelta axons** or **C axons**
* *Adelta are small, lightly myelinated, slow while C axons are unmyelinated*
123
The proprioceptors are associated with [afferent axon type]
The proprioceptors are associated with **Ia and II axons**
* *These are very large and myelinated*
* *Fastest action potentials*
124
Aalpha axons carry [information]
Aalpha axons carry **proprioception**
125
Abeta axons carry [information]
Abeta axons carry **touch, vibration**
126
Adelta axons carry [information]
Adelta axons carry **pain, temperature**
* *These are fast and myelinated*
127
C axons carry [information]
C axons carry **pain, temperature**
* *These are slow, unmyelinated*
128
_ is a group of diseases of myelin formation; has an intrinsic or genetic cause
**Leukodystrophy** is a group of diseases of myelin formation; has an intrinsic or genetic cause
* *Contrast this with demyelinating diseases like MS*
129
Demyelinating diseases like MS typically involve myelin degeneration with relative preservation of _
Demyelinating diseases like MS typically involve myelin degeneration with relative preservation of **axons**
* *Perivascular inflammatory cells (T lymphocytes) involved*
* *Loss of oligodendrocytes*
130
Burning pain is carried by _ sensory fibers
Burning pain is carried by **C fibers**
* *Responsible for burning pain and hot temperatures*
* *Recall these are the slowest fibers because they are small and unmyelinated*
131
Sharp pain, gross touch, and cold temperature is carried by [sensory fibers]
Sharp pain, gross touch, and cold temperature is carried by **Adelta fibers**
* *Recall that these are small and myelinated so faster than C fibers*
132
Proprioception, vibration, and fine touch is sensed by [sensory fibers]
Proprioception, vibration, and fine touch is sensed by **A-alpha and A-beta fibers**
* *These are the fastest, they are large and myelinated*
