Spinal Chord and Reflexes

Question 1

Basic structure of spinal chord

Label this diagram

Answer 1

Question 2

How is the white matter of the spinal cord subdivided into areas ina cross section ?

Answer 2

Question 3

What are the funiculi

Answer 3

They are the vertical columns of the white matter of the spinal chord

they transmit information up and down

Question 4

Function of ventral regions

Answer 4

Produce motor output from the efferent nerves inside

Question 5

How is the grey matter of the spinal chord organised into regions?

Answer 5

Intermediolateral cell column only present between T1 (first thoracic vertebra) and L2 (second lumbar vertebra)

Question 6

Function of dorsal regions

How can it be identified ?

Answer 6

To receive sensory input

dorsal root will have swelling from the cell bodies of the sensory neurones

Question 7

Label the structure of a spinal segment from the posterior view

Answer 7

Question 8

What are the meninges and what is their function

Answer 8

3 thin layers of tissue that cover the brain and spinal chord

They provide tight anchoring of CNS to the surrounding bones to prevent side-side movement

allow passage of CSF

Question 9

Label :

A spinal segment

an artery

the meninges

the lumbar/cervical enlargements

Answer 9

Question 10

Afferent information enters via the ___ root

Answer 10

Dorsal

Question 11

Efferent information leaves via the ____ region

Answer 11

Ventral

Question 12

The vertebral column structure

Answer 12

Question 13

where is the cauda equina found in newborns?

Answer 13

L3 - L4

Question 14

where is the cauda equina located in adults ?

Answer 14

L1-L2

Question 15

what is the cauda equina

Answer 15

bundle of nerve roots at the bottom of the spine just below the spinal chord nerves responsible for movement of the legs and bladder

Question 16

label the diagram of a vertebrae cross section

Answer 16

Question 17

Where is local anaesthetic delivered during pregnancy ?

Answer 17

Epidural space

Question 18

Name the ascending funiculi ?

Answer 18

2 for each region of spinal chord ; as they are ascending they are responsible for providing touch, pain, sensation of temperature and proprioception

Question 19

What are the dorsal ascending funiculi present in the cervical region of the spinal chord ?

Answer 19

Gracile(hindlimb)

and cuneate (forelimb)

Question 20

Which ascending dorsal funiculi are present in the lumbar region of the spinal chord ?

Answer 20

Gracile (hindlimb) only

Question 21

What is decussation ?

Answer 21

When fibres cross from one side of a structure to another e.g when a sensory neurone passes through a funiculi that enters through the opposite side of the spinal chord

sometimes dessucation occurs in the brain

Question 22

Label the descending funiculi

Answer 22

Replicated on both sides of spinal chord

7 in total

Question 23

What does corticospinal mean ?

Answer 23

Controls voluntary movement of muscles of limbs

Question 24

function of the reticulospinal funiculi

Answer 24

Regulation of voluntary movements and muscle tone; medial stimulates movement, lateral inhibits movements

Question 25

function of vestibulospinal funiculi

Answer 25

Posture and balance via inneravtion of the anti-gravity muscles (flexors of arm, and extensors of leg)

Question 26

Role of rubrospinal

Answer 26

Promotion of flexor and inhibition of extensor muscle activity

Question 27

Role of tectospinal

Answer 27

Head and eye movement via visual stimuli

Question 28

Define lower motor neurone

Answer 28

Spinal motor neurone

Question 29

Where are upper motor neurones found

Answer 29

In the brain

Question 30

Upper motor neurones innervate …

Answer 30

Spinal motor neurone

Question 31

Alpha spinal motor neurones act on

Answer 31

Extramural muscle fibres that are responsible for contraction

Question 32

Gamma spinal motor neurones innervate ….

Answer 32

Intrafusal muscle fibres in muscle spindles

Question 33

Define humunculus

Answer 33

Spatial orientation of neural tissue relative to location of associated muscles

proximal muscles are linked to medial cell bodies

distal muscles are linked to lateral cell bodies

Question 34

Types of reflexes

Answer 34

Superficial , deep (myotactic) and visceral (autonomic)

Question 35

Superficial reflexes

Answer 35

Corneal

Sneezing (nasal )

plantar (Toes curl down in adults)

Question 36

Myotactic reflexes

Answer 36

Patellar (knee jerk)

Question 37

Visceral reflexes

Answer 37

Pupillary

micturition (peeing)

Question 38

Babinskis reflex

Answer 38

Toes curl up and fan out

seen in healthy babies

sign of upper motor neurone lesion in adults

Question 39

Abnormal babinski reflex is indicative of …

Answer 39

Upper motor neurone damage

Question 40

Describe central modulation of spinal reflexes

Answer 40

Sensory neurones deliver info to spinal chord and its passed onto the brain via ascending motor neurones

inhibition of reflexes is achieved by transmission of an AP down a descending motor neurone within the spinal chord

Question 41

Explain reciprocal inhibition

Answer 41

When a muscle contracts, it’s important that its antagonistic muscle remains relaxed

Inhibitory interneurone activated when a AP arrives from an muscle ; it synapses with efferent motor neurone causing inhibition of contraction in antagonist muscle

Question 42

What are upper and lower motor neurones

Answer 42

Upper motor neurones travel between brain and spinal chord

Lower motor neurones travel from spinal chord to muscle

Question 43

Function of interneurones

Answer 43

To connect spinal motor neurones and sensory neurones

Question 44

Crossed extensor reflex

Answer 44

Afferent sensory neurone

interneurone synapses with 2 antagonistic pair one on either side of body ; opposite effect in either side