Lecture 4

Question 1

sensory receptors for GENERAL senses include _____(x3) and are mostly found ______. They are MAINLY transmitted via ____ to the ____.

Answer 1

• nociceptors (pain)
• mechanoreceptors (touch and proprioception)
• thermoreceptors (temperature)
• on the surface of the skin

Question 2

sensory receptors for SPECIAL senses include _____(x3) and are found in the ________. They are ONLY transmitted via ____ to the ______.

Answer 2

• chemoreceptors (smell, taste)
• mechanoreceptors (hearing and balance)
• photoreceptors (vision)
• head
• cranial nerves
• brain

Question 3

pain temperature and itch are conveyed via the ______

which is considered an ____ and ____ system.

Answer 3

• anterolateral (spinothalamic) pathway
• old
• slow (small and less or unmyelinated axons)

Question 4

touch and proprioception are conveyed via the ___ which is considered a ___ and ___ system.

Answer 4

• DCML pathway
• new
• fast (large myelinated axons)

Question 5

spinal nerves give rise to (x2)

Answer 5

dorsal and ventral roots (further rootlets)

Question 6

dorsal rootlets enter the spinal cord via

Answer 6

the dorsolateral sulcus

Question 7

ventral rootlets exit the spinal cord via

Answer 7

the ventrolateral sulcus

Question 8

Aα and Aβ axons are ____
Aδ axons are _____
C axons are_____

Answer 8

• highly myelinated and fast (touch and prop.)
• slow and least myelinated (pain,temp,itch)
• unmyelinated and slow (pain,temp,itch)

Question 9

The grey matter of the spinal cord is divided into (x3)

Answer 9

• ventral, lateral and dorsal horns

Question 10

The white matter of the spinal cord is divided into (x3)

Answer 10

• ventral, lateral and dorsal funiculus

Question 11

The lateral horn is only present at ____ and carries _____.

Answer 11

• T1 - L2, S1 - S3

- autonomous information for visceral organs

Question 12

where are α-Motoneurons located?

Answer 12

in the ventral grey horns

Question 13

each spinal root carries information to/from _____

Answer 13

a specific part of the body

Question 14

how many nerves are present at each segment of the spinal cord?

Answer 14

cervical - 8 
thoracic - 12
lumbar - 5
sacral - 5
coccygeal - 1

Question 15

where are the spinal enlargements?

Answer 15

cervical (shoulder and upper limbs) and lumbar (pelvis and lower limbs) spinal cord

Question 16

the spinal cord ends at ______

Answer 16

L1 - L2 of vertebral column

Question 17

Why is there a disparity between the vertebral columns and spinal cord?

Answer 17

Because the spinal cord stops growing during childhood (spinal cord stops at L3 at birth), whilst the vertebral column continues growing into adulthood (spinal cord stops at L1-2).

Question 18

The white matter at the cervical level is the largest because

Answer 18

it contains all the axons to and from the brain

Question 19

the grey matter is expanded at cervical, lumbar and sacral spinal segments because

Answer 19

they contain motor neurones and sensory information from the upper and lower limbs.

Question 20

which thalamic nuclei relay to the primary somatosensory, visual and auditory cortices?

Answer 20

• VPL, VPM, PO
• LGN
• MGN

Question 21

sensory (afferent) fibres enter the cortex via the _____limb of the internal capsule.

Answer 21

posterior

Question 22

The cerebrum and diencephalon fuse during development, allowing…

Answer 22

axons from the cerebrum to leave via the internal capsule.

Question 23

the gracile and cuneate fasciculi are separated by the

Answer 23

dorsal intermediate sulcus

Question 24

the fibres of the DCML tract decussate at the ___as the ___

Answer 24

• caudal medulla

- internal arcuate fibres

Question 25

the cortex is made up of how many layers? where do sensory axons terminate?

Answer 25

• six

- layer four (IV)

Question 26

fibres from layers II and III project to…
fibres from layer V project to…
fibres from layer VI project to…

Answer 26

• contralateral and ipsilateral sensory and motor areas
• basal ganglia, brainstem and spinal cord
• thalamus (VPN)

Question 27

the anterolateral system consists of the (x3)

Answer 27

• anterior and lateral spinothalamic tracts
• spinomesencephalic tract
• spinoreticular tract

Question 28

fibres of the anterolateral system enter the spinal cord via ____and decussate at the ______.

Answer 28

• Lassuer’s tract

- ventral commissure

Question 29

where are pyramidal cells/Giant cells of Betz found?

Answer 29

in layers III and V (output layers)

Question 30

The cuneate fasciculus is only present from

Answer 30

T6 and above (mid-thoracic)

Question 31

the reticular formation is….

Answer 31

• a collection fo nerve fibres which make up most of medial portion of the brainstem, responsible for regulating arousal

Question 32

spinothalamic tract terminating in the VPL, MD, VMP nuclei of the thalamus ascend to:

Answer 32

primary sensory cortex, cingulate cortex (emotional response), insular cortex (visceral response)

Question 33

the spinoreticular pathway mediates____and terminates in_____

Answer 33

• emotion and arousal related to pain

- nuclei of reticular formation (Raphe nuclei, parabrachial nucleus)

Question 34

third order neurons of the spinoreticular pathway from the parabrachial nucleus projects to…

Answer 34

the amygdala

Question 35

The Spinomesencephalic tract mediates

Answer 35

• head, eye and hearing orientation towards pain stimuli (tectum)
• pain feedback to spinal cord (periaquaductal gray)

Question 36

how does the periaquaductal grey mediate pain feedback?

Answer 36

the periaquaductal gray recieves input from the cortex, then sends excitatory axons to the raphe nuclei which then sends excitatory neurons to the dorsal horn of the spinal cord which enhances inhibitory function of interneurons to directly suppress nociceptors.

Question 37

The spinocerebellar tract mediates ____and consists of___and ascends______.

Answer 37

• unconscious proprioception
• Clarke’s nucleus (C8, T1-12) or Accessory Cuneate nucleus (located at caudal medulla next to cuneate nucleus)
• ipsilaterally