Ascending Sensory Pathways 2 Flashcards
1
Q
How many branches of the trigeminal (V) nerve are there?
A
Three.
2
Q
What is branch V1 of the trigeminal nerve called?
A
Opthalmic.
3
Q
What is branch V2 of the trigeminal nerve called?
A
Maxillary.
4
Q
What is branch V3 of the trigeminal nerve called?
A
Mandibular.
5
Q
Where does the opthalmic branch (V1) of the trigeminal nerve exit the skull?
A
Superior occipital fissure.
6
Q
Where does the maxillary branch (V2) of the trigeminal nerve exit the skull?
A
Foramen rotundum.
7
Q
Where does the mandibular branch (V3) of the trigeminal nerve exit the skull?
A
Foramen ovale.
8
Q
Which branch of the trigeminal nerve supplies the upper teeth, and through what nerve?
A
Maxillary (V2) branch.
-superior alveolar nerve
9
Q
Which branch of the trigeminal nerve supplies the lower teeth, and through what nerve?
A
Mandibular (V3) branch.
-inferior alveolar nerve
10
Q
Which regions of the face does the opthalmic branch (V1) of the trigeminal nerve supply?
A
Forehead
Scalp
Upper eyelid
11
Q
Which regions of the face does the maxillary branch (V2) of the trigeminal nerve supply?
A
Lower eyelid Cheeks Nasal cavity Upper lip and teeth (+ PS to lacrimal and nasal glands)
12
Q
Which regions of the face does the mandibular branch (V3) of the trigeminal nerve supply?
A
Lower lip and teeth Chin Anterior 2/3 of tongue External ear (+ motor to muscle of mastication, and PS to parotid + submandibular glands)
13
Q
What does the herpes zoster virus do after someone has recovered from chicken pox?
A
Resides in sensory roots of specific spinal nerves (e.g. trigeminal). Reactivation»_space; shingles.
14
Q
How are the blisters distributed in shingles?
A
Over the dermatome of the affected spinal nerve(s).
15
Q
What are the 2 group of somaesthetic modalities?
A
- Modalities that are essential to survive
- Modalities that increase detail
16
Q
What are modalities that are essential to survive?
A
Pain, temperature, some touch, pressure.
17
Q
What are modalities that increase detail?
A
- Discriminative touch (2-point, vibration)
- Proprioception
18
Q
What carries information from receptor to the sensory cortex in the body and face?
A
A 3 neuron chain (1, 2, 3*).
19
Q
Where do 1* neurons carry information, and where are there cells bodies located?
A
From PNS to the CNS.
-cell bodies in peripheral ganglia
20
Q
Where do 2* neurons carry information?
A
Axons cross the midline and extend to the thalamus.
21
Q
Where do 3* neurons carry information?
A
From the thalamus to the post-central gyrus.
22
Q
Where are cranial nerve nuclei located?
A
Within the brainstem.
23
Q
Where sensory cranial nerve nuclei receive information from?
A
Fibres entering the brainstem in cranial nerves.
24
Q
What do motor cranial nerve nuclei give rise to?
A
Motor fibres that leave the brainstem in cranial nerves.
25
What is the equivalent of the sensory cranial nerve nuclei in the body?
Dorsal grey horn.
| -receives 1* sensory neurons, and contains cell bodies and synapses
26
What is the equivalent of the motor cranial nerve nuclei in the body?
Ventral grey horn.
| -contains motor fibres
27
Which cranial nerves is general sensation from the head carried in? (4)
- Trigeminal (V)
- Facial (VII)
- Glossopharyngeal (IX)
- Vagus (X)
28
Which pathway does information from cranial nerves V, VII, IX, X travel in
(general sensation from head)?
TRIGEMINAL SENSORY PATHWAY.
| -trigeminal nucleus >> thalamus >> post-central gyrus
29
Which cranial nerve is the major carrier of sensory information from the face, nose, scalp and dura?
Trigeminal nerve (V).
30
Which cranial nerve is the major carrier of sensory information from the external ear?
Facial nerve (VII).
31
Which cranial nerve is the major carrier of sensory information from the post 1/3 tongue, pharynx and middle ear?
Glossopharyngeal nerve (IX).
32
Which cranial nerve is the major carrier of sensory information from the auditory canal, larynx, pharynx and oesophagus?
Vagus nerve (X).
33
How many parts is the sensory trigeminal nucleus composed of?
Three.
| -based on brainstem location
34
What are the 3 parts of the sensory trigeminal nucleus?
- Mesecephalic (rostral)
- Principal/pontine (mid)
- Spinal (caudal)
35
Where does the motor nuclei of the trigeminal lie in relation to the sensory nuclei?
The motor nuclei lies medial to the sensory nuclei.
36
What type of information does the mesencephalic part of the trigeminal sensory nucleus receive?
Proprioception from the face.
37
What type of information does the principal part of the trigeminal sensory nucleus receive?
Discriminative touch and proprioception.
38
Which nerves pass into the principal part of the trigeminal sensory nucleus?
- Trigeminal (V)
| - Facial (VII)
39
What type of information does the spinal part of the trigeminal sensory nucleus receive?
Pain and temperature >> caudal.
| Touch and pressure >> rostral.
40
Which nerves pass into the spinal part of the trigeminal sensory nucleus?
All four (V, VII, IX, X).
41
Where do 1* neuron cell bodies reside from cranial nerves V, VII, IX, X?
Trigeminal ganglion.
| -equivalent of DRG (body)
42
Where do 1* neurons in the pain and temperature pathway go after entering the brainstem?
Descend in spinal tract of trigeminal (lat to spinal nucleus) >> caudal pole of spinal part of trigeminal nucleus.
43
Are the 1* neurons of the pain and temperature pathway deep or superficial?
Very superficial - on outer edge of medulla.
44
How do the 2* neurons of the pain and temperature pathway travel to the thalamus?
Cross the midline and ascend in the trigeminothalamic tract.
45
Summarise how sensory information travels along the pain and temperature pathway in the trigeminal sensory nucleus.
1* neuron (cell bodies in trigeminal ganglion)
>> brainstem
>> fibres run caudally in spinal tract of trigeminal
>> enters nucleus at caudal pole
>> synapses with 2* neuron
>> crosses the midline and ascends in trigeminothalamic tract
>> thalamus (VPM)
>> synapses with 3* neuron
>> post-central gyrus
46
How does the touch and pressure pathway differ from the pain and temperature pathway in the trigeminal sensory nucelus?
In the touch and press pathway;
- 1* neurons don't descend as far in the spinal tract
- synapses with 2* neurons more rostrally in spinal nucleus
47
What are the similarities between the tough and pressure pathway and the pain and temperature pathway in the trigeminal sensory nucelus?
- 1* neuron cell bodies are in trigeminal ganglion
- both descend in spinal tract after entering brainstem
- both 1* neurons enter and synapse in spinal nuceus
- both 2* neurons ascend to the thalamus in trigeminothalamic tract
- both >> VPM (thalamus)
48
Summarise how sensory information travels along the touch and pressure pathway in the trigeminal sensory nucleus.
1* neuron (cell bodies in trigeminal ganglion)
>> brainstem
>> fibres run caudally in spinal tract of trigeminal (not as far as pain and temperature fibres)
>> enters nucleus at rostral spinal pole
>> synapses with 2* neuron
>> crosses the midline and ascends in trigeminothalamic tract
>> thalamus (VPM)
>> synapses with 3* neuron
>> post-central gyrus
49
At the level of the medulla oblongata, where is the spinal tract of trigeminal located?
Very medially/superficial.
50
At the level of the medulla oblongata, what is immediately medial to the spinal tract of trigeminal?
Spinal nucleus of the trigeminal.
| -descending fibres
51
What sort of information does the spinothalamic tract contain?
Contralateral sensory information from the body.
52
What sort of information does the trigeminothalamic tract contain?
Contralateral sensory information from the face/neck.
53
At the level of the medulla oblongata, which is more medial; the spinothalamic tract or the trigeminothalamic tract?
Trigeminothalamic tract in more medial and dorsal.
54
Why is the dorsal column pathway not generally affected by a lesion at the medulla?
Dorsal column pathway runs in medial meniscus – not generally affected unless very large lesion.
55
Which artery runs lateral to the medulla?
Anterior inferior cerebellar artery.
| -enlargement >> lesion
56
What effect would a right-sided lesion affecting the lateral medulla have on sensation from the face?
Right (ipsilateral).
- damage to spinal tract/nucleus of trigeminal
- loss of pain, temperature, touch, pressure
57
What effect would a right-sided lesion affecting the lateral medulla have on sensation from the body?
Left (contralateral).
- damage to spinothalamic tract (DCP more medial)
- loss of pain, temperature, touch, pressure
58
Where does discriminative touch enter the trigeminal sensory nucleus?
Principal/pontine nucleus.
| AKA chief sensory
59
Where does proprioception enter the trigeminal sensory nucleus?
Mesecephalic nucleus.
60
Which pathway is an exception to the generalisation
| that first order cell bodies are in peripheral ganglia?
Mesecephalic nucleus of trigeminal pathway.
61
Where do 1* neurons of the discriminatory touch pathway go after entering the brainstem?
Straight into the principal nucleus.
| -don't ascend/descend
62
Where do 1* neurons of the discriminatory touch pathway synapse?
In the pontine nucleus of the trigeminal pathway.
63
How do the 2* neurons of the discriminatory touch pathway travel to the thalamus?
They cross the midline and ascend in the trigeminothalamic tract.
64
Summarise how sensory information travels along the discriminatory touch pathway in the trigeminal sensory nucleus.
```
1* neuron (cell bodies in trigeminal ganglion)
>> brainstem
>> immediately enters principal nucleus
>> synapses with 2* neuron
>> crosses the midline and ascends in trigeminothalamic tract
>> thalamus (VPM)
>> synapses with 3* neuron
>> post-central gyrus
```
65
What are the similarities between the touch and pressure pathway, the pain and temperature pathway, and the discriminatory touch pathway in the trigeminal sensory nucelus?
- 1* neuron cell bodies are in trigeminal ganglion
- 2* neurons ascend to the thalamus in trigeminothalamic tract
- all >> VPM (thalamus)
66
How does the discriminatory touch pathway differ from the touch and pressure pathway and the pain and temperature pathway in the trigeminal sensory pathway?
- doesn't descend in spinal tract after entering brainstem (ENTERS PRINCIPAL NUCLEUS IMMEDIATELY)
- doesn't synapse in spinal nucleus (PRINCIPAL NUCLEUS)
67
What sort of fibres do the tough and pressure pathway and the pain and temperature pathway contain?
Thin, slow fibres.
68
What sort of fibres does the discriminatory touch pathway contain?
Fat, fast, myelinated fibres.
69
Which nerve do most axons of the proprioception pathway travel in?
Mandibular division of the trigeminal nerve.
70
Where is the cell body of the 1* neuron of the proprioception pathway?
In the mesencephalic nucleus.
71
Where do 1* neurons of the proprioception pathway synapse?
Adjacent to the mesencephalic nucleus (NOT in it).
72
What do the 1* neurons of the proprioception pathway synapse with? (2)
- Some synapse with 2* neurons and ascend to thalamus in trigeminothalamic tract (same as other pathways)
- Some synapse with motor neurons in the trigeninal motor nucleus and >> muscles of mastication
73
How can the motor branch of the mandibular division of the trigeminal nerve be tested?
Jaw jerk reflex.
74
Which nucleus do 1* neurons of the pain and temperature pathway enter and synapse in?
Caudal spinal nucleus.
75
Which nucleus do 1* neurons of the simple touch and pressure pathway enter and synapse in?
Rostal spinal nucleus.
76
Which nucleus do 1* neurons of the discriminative touch pathway enter and synapse in?
Pontine/principal nucleus.
77
Which nucleus do 1* neurons of the proprioception pathway enter?
Mesencephalic nucleus.
| -NB. don't synapse in it
78
Where are 1* cell bodies of the trigeminal pathway located?
In trigeminal ganglia (PNS).
| -except for proprioception fibres which are in mesecephalic nucleus.
