Neuroanatomy- Ascending and Descending Tracts

Question 1

How many pairs of spinal nerves are there?

Answer 1

31 pairs

Question 2

Describe the pathway from spinal cord

Answer 2

Spinal cord –> Rootlets –> Roots –> Pass through subarachnoid space until reach intervertebral foramina –> Posterior root enlarged by dorsal root ganglion –> Roots fuse to form spinal nerve –> Posterior and anterior rami

Question 3

In the PNS which cells produce myelination?

Answer 3

Swann cells

Question 4

What is the name of cone-shaped formed by the termination of the spinal cord?

Answer 4

Conus medullaris

Question 5

What does the conus medullaris continue on as?

Answer 5

Filum terminale which is a thin connective tissue cord anchored to dorsal of coccyx

Question 6

What are the 3 layers of the meninges?

Answer 6

Dura mater
Arachnoid mater
Pia mater

Question 7

What is the name of the ribbon of tissue on the lateral aspect of the spinal cord that suspends it in the canal?

Answer 7

Denticulate ligament

Question 8

Which space in the spinal meninges is filled with CSF?

Answer 8

Subarachnoid space

Question 9

What does the white matter consist of in the spinal cord?

Answer 9

Longitudinally oriented nerves fibres (axons), glial cells and blood vessels

Question 10

What does the grey matter consist of in the spinal cord?

Answer 10

Neuronal soma
Cell processes
Synapses
Glia
Blood vesselsq

Question 11

The small central canal in the spinal cord contains what?

Answer 11

CSF

Question 12

Which ventricle does the small central canal in the spinal cord open into?

Answer 12

The 4th ventricle

Question 13

What are the three columns in the white matter?

Answer 13

Posterior
2 Lateral
Anterior

Question 14

What are the four parts that make up the ‘H’ grey matter in the spinal cord?

Answer 14

Left and right posterior horns

Left and right anterior horns

Question 15

At which spinal levels is there also a lateral horn?

Answer 15

T1- L2

Question 16

What neurons does the lateral horn contain?

Answer 16

Preganglionic sympathetic neurons

Question 17

What are the three major longitudinal arteries and what are their origins?

Answer 17

One anterior spinal artery
Two posterior spinal arteries
Originate from the vertebral arteries and run the length of the spinal cord

Question 18

What are the 3 segmental arteries?

Answer 18

Vertebral artery
Intercostal artery
Lumbar artery

Question 19

What are the arteries that travel along the dorsal and ventral roots?

Answer 19

Posterior and anterior radicular arteries

Question 20

What do cervical vertebrae look like?

Answer 20

Rugby ball

Question 21

The further down the vertebral column the more. white/grey matter?

Answer 21

Grey matter

Question 22

What are the venous drainage of the spinal cord?

Answer 22

Posterior internal vertebral venous plexus

Anterior internal vertebral venous plexus

Question 23

What is the name of the space between the dura and bone in the spinal canal?

Answer 23

Epidural space

Question 24

Where is the primary somatosensory cortex?

Answer 24

On the post-central gyrus

Question 25

Do sensory fibres cross the midline?

Answer 25

Yes, thus the left side of the body is represented on the right cortex

Question 26

How does information from periphery reach the somatosensory cortex?

Answer 26

Travel spinal cord (except face and scalp)

Question 27

Why is there more grey matter in the cervical vertebrae?

Answer 27

Need more grey matter for more sensation in head and neck

Question 28

What are the two ascending tracts that make up the dorsal column?

Answer 28

Fasciculus gracilis | Fasciculus cuneatus

Question 29

What information is carried in the dorsal column?

Answer 29

Fine touch and conscious proprioception

Question 30

Where do fibres cross in the dorsal column?

Answer 30

Fibres cross in medulla

Question 31

How many neurons are involved in the relay from leg to cortex in sending sensory information in the dorsal column?

Answer 31

3!

Question 32

Is spinothalamic ascending or descending?

Answer 32

Ascending (sensory)

Question 33

What information does the spinothalamic tract carry?

Answer 33

Pain, temperature and deep pressue

Question 34

Where do fibres cross in the spinothalamic tract?

Answer 34

Fibres cross segmentally (immediately)

Question 35

Where is the primary motor cortex?

Answer 35

Precentral gyrus

Question 36

Right cortex controls muscles on the right/left side of the body?

Answer 36

Left side of body (contralateral)

Question 37

Motor information is relayed via the ascending/descending tract?

Answer 37

Descending tract

Question 38

Give examples of descending tracts?

Answer 38

Corticospinal tract Tectospinal tract Reticulospinal tract Vestibulospinal tract

Question 39

What does the corticospinal tract divide into?

Answer 39

Lateral and anterior CST

Question 40

What information does the corticospinal tract carry?

Answer 40

Fine, precise movement. particularly of distal limb muscles (e.g. digits)

Question 41

What is the corticospinal tract also called and why?

Answer 41

Pyramidal tract because there are 'pyramids' on the anterior surface of the medulla.

Question 42

Which fibres in the CST cross, lateral or anterior?

Answer 42

Lateral

Question 43

A cerebral vascular accident can result in lack of descending control of corticospinal tract, what clinical impairment occurs?

Answer 43

Spastic paralysis with hyeprflexion of upper limbs

Question 44

Where do the lateral fibres of CST cross?

Answer 44

Caudal medulla

Question 45

Where is input mostly from in the tectospinal tract?

Answer 45

Cervical segments

Question 46

What motor movements do the tectospinal tract mediate?

Answer 46

Reflex head and neck movement due to visual stimuli- tracking function

Question 47

Is the reticulospinal tract ascending or descending?

Answer 47

Descending (motor)

Question 48

Where do fibres originate in the reticulospinal tract?

Answer 48

Pons and medulla

Question 49

What movements do fibres originating in the pons facilitate in the reticulospinal tract?

Answer 49

Extensor movement and inhibit flexor movements

Question 50

How do movements in the reticulospinal tract originating in the medulla differ from the pons?

Answer 50

Facilitate and inhibit opposite movements

Question 51

Is the vestibulospinal tract ascending or descending?

Answer 51

Descending motor

Question 52

What information is carried in the vestibulospinal tract?

Answer 52

Excitatory input to "antigravity" extensor muscles | Falling forwards and counteracting it

Question 53

Where do fibres originate in the vestibulospinal tract?

Answer 53

Vestibular nuclei of pons and medulla

Question 54

What clinical symptoms do patients exhibit in vestibulospinal tract abnormalities?

Answer 54

Decerebrate rigidity | Paraplegia in extension