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YEAR 3 SEMESTER 1 NEURO-ANATOMY > Week 5 - finished > Flashcards

Flashcards in Week 5 - finished Deck (81)
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1

How many pairs of spinal nerves are there?

31

2

What do the dorsal and ventral root join to form? What does this structure later spilt to form?

They join to form the spinal nerve for that segment. This spinal nerve later splits to form the dorsal and ventral rami

3

What kind of information is transmitted through the dorsal root?

Sensory information

4

What kind of information is transmitted through the ventral root?

Motor information

5

What are the names for the thicker sections of the spinal cord which correlate for the upper and lower limbs? Why are they thicker?

The cervical and lumbar enlargements

6

What is grey matter?

Cell bodies

7

What is white matter?

Axons

8

What is the function of the dorsal horn grey matter?

Cell bodies for sensory information

9

What is the function of the ventral horn grey matter?

Cell bodies for motor information

10

What is the function of the lateral horn grey matter?

Cell bodies for autonomic function

11

Where is the lateral horn found?

Between the levels of T1-L2-3

12

What are the separations of white matter called, what makes these separations and what are the 3 regions these separations are named after?

The separations are called funiculi and are divided into these by the horns of grey matter. There are 3 funiculi: Ventral Dorsal Lateral

13

Briefly describe each of the Laminae of Rexed:

1: AKA marginal zone. 2nd order neurons of the ALS found here. 2: AKA Substantia gelatinosa. 2nd order neurons for ALS found here. 3,4,5,6: AKA Nucleus Proprius. Processing of sensory info, input of nociceptive and other senses from both peripheral and visceral areas. (may explain referred pain) 7: AKA Clarkes nucleus. Only in the thoracic and upper lumbar regions. Relays unconscious proprioceptive information about the limbs to the ipsilateral cerebellum. 8: Contains the interneurons for the regulation of skeletal muscle contraction. 9: LMN's for skeletal muscle contraction 10: Surround central canal and receives afferent input similar to laminae 1 and 2.

14

What are A delta fibres?

Myelinated nociceptive fibres

15

What are A beta fibres?

Large myelinated fibres from mechanoreceptors

16

What are C fibres?

Unmyelinated fibres from nociceptors

17

What does the first lamina of rexed do? What is it AKA?

AKA marginal zone. 2nd order neurons of the ALS found here.

18

What does the second lamina of rexed do? What is it AKA?

AKA Substantia gelatinosa. 2nd order neurons for ALS found here.

19

What do the 3rd-6th laminae of rexed do? What are they AKA?

AKA Nucleus Proprius. Processing of sensory info, input of nociceptive and other senses from both peripheral and visceral areas. (may explain referred pain)

20

What does the 7th lamina of rexed do? What is it AKA?

AKA Clarkes nucleus. Only in the thoracic and upper lumbar regions. Relays unconscious proprioceptive information about the limbs to the ipsilateral cerebellum.

21

What does the 8th lamina of rexed do?

Contains the interneurons for the regulation of skeletal muscle contraction.

22

What does the 9th lamina of rexed do?

LMN's for skeletal muscle contraction

23

What does the 10th lamina of rexed do?

Surround central canal and receives afferent input similar to laminae 1 and 2.

24

What 3 tracts ascend in the white matter?

DCML ALS Spinocerebellar tracts

25

What tracts descend in the white matter?

Lateral corticospinal tract Ventral corticospinal tract Medial longitudinal fasciculus Tectospinal tract Vestibulospinal tract Dorsolateral fasciculus

26

Label each of the tracts.

27

Describe the DCML system

Ascending 3 neuron pathway

Gracile & Cuneate fasciculi (cuneate above T6)

Transmits Proprioception, light touch, vibration

1st order neuron cell body in DRG

1st order neuron neuron axon enters spinal cord dorsolaterally, straight into dorsal column

Once in spinal cord axons typically branch to form collaterals

1st order neuron axon ascends in dorsal column

(Others may ascend to the brainstem in separate tracts or may synapse on to motor neurons or interneurons to mediate tendon or postural reflexes)

Ascending fibres synapse onto 2nd order neuron relative nuclei in the medulla. ( Cuneate or Gracile)

2nd order neurons from the medullary nuclei decussate in the brainstem as the internal arcuate fibres to form the contralateral medial lemniscus

Medial lemniscus ascends to synapse at the ventral posterolateral nucleus of the thalamus (VPL) which gives rise the 3rd order neuron or terminal neuron

Terminal neurons project predominantly to areas 3, 1 & 2 of the primary somatosensory cortex via the posterior limb of the internal capsule.

28

Describe the ALS 

Ascending 3 neuron pathway

3 tracts: Spinothalamic, spinomesencephalic and spinoreticular tracts

Relays nociceptive & thermal information, as well as crude touch

1st order neuron cell body in DRG, axon enters spinal cord via dorsolateral tract of Lissauer and synapses in the dorsal horn (laminae 1& 2)

2nd order neurons originate in the dorsal horn and decussate through the ventral white commissure within a few levels of entry to enter the contralateral ALS and ascend to the brainstem and diencephalon where it’s synapses are much more diverse than the DCML

Spinothalamic synapses at the VPL of the thalamus

Spinoreticular synapses in the reticular formation of the medulla and pons

Spinomesencephalic synapses at the reticular formation and periaqueductal grey of the midbrain

The 3rd order neurons which arise from here also have wide spread terminations not only in the 1o somatosensory cortex but also in other cortical and sub cortical areas

  Spinothalamic:   Sharp well localised pain

 

  Spinoreticular:   Dull diffuse pain

 

  Spinomesencephalic:   Important in modulation of pain

29

What type of sensation does the spinathalamic tract transmit?

Spinothalamic:   Sharp well localised pain

 

30

What type of sensation does the spinoreticular tract transmit?

  Spinoreticular:   Dull diffuse pain