Ascending and Descending Pathways Flashcards Preview

Neurology > Ascending and Descending Pathways > Flashcards

Flashcards in Ascending and Descending Pathways Deck (34):
1

What is the name given to the end of the spinal cord situated at L1/2?

Conus medullaris

2

What connects the spinal cord to the dura?

Denticulate ligament

3

What is present in the white matter?

Longitudinally oriented axons, glial cells and blood vessels

4

What is present in the grey matter?

Neuronal soma
Cell process
Synapses
Glia
Blood vessels

5

What is an extra addition to the grey matter at T1-L2?

Lateral horn containing the preganglionic sympathetic neurones

6

What is the arterial supply to the spinal cord?

3 major longitudinal arteries
Segmental arteries
Radicular arteries

7

What is the origin of the major longitudinal arteries supplying the spinal cord?

Vertebral arteries

8

What is the origin of the segmental arteries supplying the spinal cord?

Vertebral
Intercostal
Lumbar arteries

9

What is the venous drainage of the spinal cord?

Longitudinal and segmental veins

10

What do the radicular arteries supply?

The dorsal and ventral roots

11

What is the epidural space?

Space between the dura and bone which contains adipose tissue and the anterior and posterior epidural venous plexuses

12

Where is the primary somatosensory cortex and the sensory cortical homunculus?

Post central gyrus

13

What does the dorsal column/medial lemniscus system detect?

Fine touch
Proprioception

14

Where do fibres from the dorsal column decussate?

Medulla

15

Describe the dorsal column

Fibres enter dorsal root ganglion where they will project into dorsal column
Ascend to the medulla where they will synapse at the nucleus gracilis/cuneatus
Decussate after synapse and ascend to the thalamus via the medial lemniscus
Synapse in thalamus and ascend to the postcentral gyrus at the somatosensory cortex

16

What does the spinothalamic tract detect?

Pain
Temperature
Deep pressure

17

Describe the spinothalamic tract

Nervce cell bodies in dorsal root ganglion
Enter spinal cord and synapse in the posterior horn in tract cells
Decussate and ascend up the spinal cord on the contralateral side
Synapse in thalamus
Ascend to the postcentral gyrus of at the somatosensory cortex

18

Where is the primary motor cortex found?

Precentral gyrus

19

What is the main motor tract?

Descending corticospinal tract which is divided into the lateral and ventral tracts

20

What movements will the corticospinal tract control?

Fine, precise movements particularly of distal limb

21

Where will the corticospinal tract decussate?

85% at the caudal medulla called the decussation of the pyramids

22

What will crossed fibres of the corticospinal tract form?

Lateral CST

23

What will uncrossed fibres form?

Ventral CST

24

What will the motor fibres pass through whilst in the brain from the motor cortex to the thalamus?

Internal capsule

25

Where are the pyramids of the medulla found?

Anterior surface of medulla

26

What can a CVA of the internal capsule result in?

Lack of descending control of the corticospinal tract resulting in spastic paralysis with hyperflexion of upper limbs
Decortical posturing

27

What is the tectospinal tract?

Input to cervical segments
Mediates reflex head and neck movement due to visual stimuli

28

Where is the tectum found?

Posterior area of midbrain

29

Where does the reticulospinal tract originate?

Areas of reticular formation in pons and medulla

30

What is the function of the reticular system?

Integrate cranial nerve reflexes
Participate in conduction and modulation of pain
Influence voluntary movement
Regulate autonomic activity
Integrate basic functions like respiration and sleep
Activate the cerebral cortex

31

What is the vestibulospinal tract?

Excitatory input to antigravity extensor muscles

32

Where do the vestibulospinal fibres originate?

Medial and lateral vestibular nuclei in the pons

33

From where do the medial and lateral vestibular nuclei receive input?

Vestibular apparatus and cerebellum

34

Describe decerebrate rigidity

Vestibulospinal tract; lesions of the brainstem at level of midbrain can result in a lack of descending cortical control of this tract resulting in domination of extensor muscle tone and hyperextended spastic paralysis