Ascending Sensory pathways 2 Flashcards Preview

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Flashcards in Ascending Sensory pathways 2 Deck (68):
1

What are somaesthetic pathways?

perception of bodily senses such as

- pain
- temperature
- touch
- position

2

Where are somaesthetic pathways?

in face and body

3

What number cranial nerve is the trigeminal nerve?

CN V

4

What are the 3 divisions of the trigeminal nerve?

1. opthalmic nerve - V1
2. Maxillary nerve - V2
3. Mandibular nerve - V3

5

Where does the opthalmic division of the trigeminal nerve run in the skull?

superior orbital fissure

6

Where does the maxillary division of the trigeminal nerve run in the skull?

foramen rotundum

7

Where does the mandibular division run in the skull?

foramen ovale

8

What branch of V2 (maxillary nerve) supplies the upper teeth?

Superior alveolar nerve

9

What branch of V3 (mandibular nerve) supplies the lower teeth?

Inferior alveolar nerve

10

What is herpes zoster (shingles)?

infection of the sensory roots of trigeminal nerve

11

How does herpes zoster (shingles) spread/infect?

Along the dermatome - if it affects V2 the maxilla will have a group of shingles blisters on their face along the maxilla

12

What 2 groups do the somaesthetic modalities fall into?

1. modalities that are essential for survival - pain, temp, some touch and pressure

2. modalities that increase detail - discriminative touch and proprioception

13

What is meant by discriminative touch?

2 point discrimination

Vibration

14

How many neurones are involved in the chain from receptor to sensory cortex?

3 neuron chains

15

How do the first order neurones travel?

from PNS to CNS

16

Where are first order neurons found?

cell bodies in the peripheral ganglia

17

How do the second order neurons travel?

across midline

18

Where are the second order neurone found?

extend to thalamus

19

How do third neurones travel?

extend from the thalamus to the post-central gyrus

20

Where are cranial nerve nuclei located?

brainstem

they are very specific

21

Where does sensory information received in cranial nerve nuclei come from?

fibres entering brainstem n cranial nerves?

22

What does the cranial nerve nuclei also give rise to that leave the brainstem in cranial nerves?

motor fibres

23

What is the cranial nerve nuclei equivalent to?

dorsal grey horn in spinal cord

- collection of cell bodies
- where primary sensory neurons synapse withs secondary sensory neurons

24

What is the motor nucleus equivalent to?

ventral grey horn

25

What does the trigeminal central nucleus deal with?

fibres coming from trigeminal nerve

26

Which cranial nerves is general sensation from the head carried by?

CN V, VII, IX, X

27

Which cranial nerve is the major carrier of general sensory info from FACE, NOSE, SCALP and DURA?

trigeminal CNV

28

Which cranial nerve carries sensation for the external ear?

Facial CNVII

29

Which cranial nerve carries sensation from the posterior 1/3 of the tongue, pharynx and middle ear?

Glossopharyngeal CNVIX

30

Which cranial nerve carries sensation from auditory canal, larynx, pharynx and oesophagus?

Vagus CN X

31

Where does information from CN V, VII, IX and X travel? (which pathway?)

same pathway

trigeminal sensory pathway

32

What 3 nuclei make up the trigeminal nerve nuclei?

mesencephalic nucelus

principle sensory nucleus of trigeminal nerve

spinal nucleus of trigeminal nerve

33

Sensory fibres from cranial nerves run through the trigeminal nerve nucleus and to the thalamus?

trigeminal CNV

facial CN VII

Glossopharyngeal CN IX

Vagus CN X

34

Where does the motor nuclei of the trigeminal lie in comparison to the trigeminal nerve?

medial to the sensory nuclei

35

NOTE

LEARN SOMATOTOPIC MAP ON POST-CENTRAL GYRUS

WILL BE ASSESSED

36

In the trigeminal nuclei what are the 3 divisions in the sensory nucleus?

1. mesencephalic nucelus
2. pontine, chief nucleus
3. spinal nucleus

37

Where is the mesencephalic nucleus?

midbrain

38

Where is the pontine/chief sensory nucleus?

Pons

39

Where is the spinal nucleus?

in medulla

40

What is pain and temp received by?

caudal part of the spinal nucleus

41

What is simple touch and pressure received by?

more rostral parts of the spinal nucleus

42

Which sides are the nuclei present?

present on both sides

43

In the pain and temperature pathway where are the primary neuron cell bodies found?

trigeminal ganglion

44

What is the fibre like in the pain and temperature pathway? (2)

thin

slow

45

How do the fibres run in the spinal tract of the trigeminal nerve nuclei in the pain and temp pathway?

caudally

46

Where does the primary neurone synapse with the secondary neurone in the pain and temp pathway?

in spinal nucleus

47

what happens after the synapsing in the spinal nucleus in the pain and temp pathway?

axon crosses over and ascends in trigeminothalamic tract to specific place on thalamus (VPM)

runs very deep to midbrain and pons etc

48

What is VPM and what does it stand for?

ventral posteromedial nucleus

a nucleus of the thalamus

conveys facial sensory information of the trigeminothalamic tract and projects to the post-central gyrus

49

Where is the primary neuron cells found in the touch and pressure pathway?

trigeminal ganglion

50

What are the fibres like in the touch and pressure pathway?

thin

slow

51

Where do the fibres descend in the touch and pressure pathway?

doesn't descend as much as temp

in spinal tract of trigeminal

52

Where does synapsing between primary neurons and secondary neurons take place in the touch and pressure pathway?

more rostrally in spinal nucleus

53

What happens to the axon after synapsing occurs in the touch and pressure pathway?

axon crosses and ascends in trigeminothalamic tract

54

NOTE - TRANSVERSE SECTION THROUGH ROSTRA MEDULLA OBLONGATA

- arcuate fibres - gracile and cuneate tubercles
- spinal tract
-medial leminscus
- pyramids
- spinal nucleus
- central canal
- left trigeminothalamic tract - info from right side (vice versa)

55

What is the trigeminal sensory nucleus like?

dorsal column pathway

56

What kind of modality does the pontine chief sensory nucleus receive in trigeminal sensory nucleus?

discriminative touch

57

What kind of modality does the mesencephalic nucleus in the trigeminal sensory nucleus?

proprioception

58

How is the mesencephalic nucleus an exception?

as it contradicts the generalisation that the first order cell bodies are in the peripheral ganglia

59

Where are primary neurone cell bodies in the discriminatory touch pathway?

trigeminal ganglion

60

What are the fibres like in the discriminatory touch pathway?

fast
fat

61

Where does the primary neurone synapse with the secondary neurone in discriminatory touch pathway?

pontine nucleus

62

What happens after synapsing in the discriminatory touch pathway?

axon crosses and ascends in the trigeminothalamic tract to thalamus

63

What is a key feature of the discriminatory touch pathway?

It does't ascend or descend significantly prior to synapsing

64

Where is the primary neurone found in the proprioception pathway?

mesencephalic nucleus

65

Where do most of the axons in the proprioception pathway travel?

In mandibular division of V

66

Where does the primary neurone synapse in the proprioception pathway?

alongside M nucleys (adjacent to the nucleus)

outside the trigeminal nuclei

67

Where does the axon cross and ascend to in the proprioception pathway?

after synapsing

ascends to thalamus in trigeminothalamic tract

68

What do other fibres in the proprioception pathway do in the proprioception pathway?

contact motor neurons in the trigeminal motor nucleus

- muscles of mastication - jaw jerk reflex