Spinal Cord

Question 1

Conus Medullaris

Answer 1

most caudal end of the spinal cord

located at L1-2 vertebral column levels in adults

Question 2

Filum Terminale

Answer 2

an inferior extension of the pia mater beyond the conus medullaris
anchors spinal cord to the coccyx (bone) at the very bottom of the vertebral canal

Question 3

Cauda Equina

Answer 3

nerve fibers coming from spinal cord segments lumbar 5 to coccygeal 1 which exit the vertebral column below the conus medullaris
occupies the lumbar cistern

Question 4

Lumbar Cistern

Answer 4

subarachnoid space inferior to the conus medullaris

spinal taps done here

Question 5

Tethered Spinal Cord Syndrome

Answer 5

neurological disorder caused by tissue attachments that limit the movement of the spinal cord within the spinal column, resulting in low lying conus medullaris

Question 6

Sulcus Limitans

Answer 6

longitudinal groove that extends the width of the spinal cord, dividing it into dorsal and ventral segments and separating the alar and basal plates

Question 7

Spinal Cord beginning and end

Answer 7

begins at foramen magnum at the interface with the medulla oblongata
ends at the L1-2 vertebral level at the conus medullaris
31 spinal cord segments

Question 8

Cervical Enlargement

Answer 8

supplies nerves to upper extremity

Question 9

Lumbar Enlargement

Answer 9

supplies nerves to lower extremity

Question 10

Spinal Cord Segment nerves

Answer 10

Dorsal roots - ganglia neurons are a part of PNS and send sensory info into CNS
Ventral roots - are in the CNS (don’t have ganglia) and send motor info from brain to PNS

Question 11

Spinal Cord Segments

Answer 11

8 - cervical spinal cord segments
12 - thoracic spinal cord segments
5 - lumbar spinal cord segments
5 - sacral spinal cord segments
1 - coccygeal spinal cord segment

Question 12

Segment Orientation

Answer 12

Dorsal - receives sensory input –> afferent

Ventral - motor output –> efferent

Question 13

Posterior Horn

Answer 13

contains sensory interneurons of the ascending sensory tracts

Question 14

Intermediate Gray Matter

Answer 14

contains neurons that are primarily involved with activity of the autonomic nervous system (unconscious control of body’s systems)

Question 15

Anterior Horn

Answer 15

contains neurons that supply motor signals to skeletal muscles

Question 16

Lissauer’s tract

Answer 16

in posterior horn
made up of both myelinated and unmyelinated axon fibers
convey pain, temperature and crude (light) touch info

Question 17

Marginal Zone

Answer 17

located at the tip of the dorsal horn

relays info about pain, temp

Question 18

Substantia Gelatinosa

Answer 18

located at the top of the dorsal horn
relays info about pain and temp
receives input from Lissauer’s tract

Question 19

Nucleus Proprius

Answer 19

located in the ‘neck’ of the dorsal horn

relays info about proprioception (body position) and crude (light) touch

Question 20

Light/crude touch

Answer 20

poorly localised eg pressure, tickle, itch

Question 21

Fine touch

Answer 21

discriminative touch –> 2 point discrimination

Question 22

Dorsal Nucleus of Clarke

Clarke’s nucleus

Answer 22

located medially at very bottom of dorsal horn
corresponds to medial part of Rexed lamina VII
relays unconscious sensory info about proprioception
only found in thoracic to lumbar spinal segments T1-L2

Question 23

Interomediolateral Nucleus

Answer 23

located in lateral horn within Rexed lamina VII
relays motor info from the organs to and from brain, contains autonomic neurons that give rise to the sympathetic nervous system
T1-L3

Question 24

Lateral Motor Neurons

Answer 24

located in ventral horn

relays motor info from brain to viscera and skeletal muscles of limbs

Question 25

Medial Motor Neurons

Answer 25

located in ventral horn | relays motor info from brain to viscera and skeletal muscles of the trunk and neck

Question 26

Rexed Laminae

Answer 26

system of ten layers of grey matter neurons towards dorsal end involved in relaying sense info neurons towards ventral end involved in executing movement

Question 27

Lamina I

Answer 27

overlaps with marginal zone nucleus | sends info about pain and temp input

Question 28

Lamina II

Answer 28

corresponds to substantia gelatinosa nucleus relay both pai and non-noxious sensation info to brain modulate sensory input to help determine if incoming signals are painful or not

Question 29

Lamina III and IV

Answer 29

contain the nucleus proprius | relays proprioceptive and light touch sense info

Question 30

Lamina V

Answer 30

contains neurons that relay both noxious (pain) and visceral sensory (organ) stimuli

Question 31

Lamina VI

Answer 31

deepest layer of the dorsal horn | relays proprioceptive signals from joints, muscle, and skin

Question 32

Lamina VII

Answer 32

contains cells of Clarke's nucleus, intermediolateral nucleus, and large portion of neurons of the lateral and ventral horns relay proprioception (body position) and motor information to from brain --> viscera found in T1-S4

Question 33

Laminae VIII and IX

Answer 33

represent motor neuron groups in ventral gray horn medial portion: contains motor neurons that innervate muscles of the trunk and neck lateral portion: contain lateral motor nucleus that innervate distal muscles of arms and legs

Question 34

Lamina X

Answer 34

small neurons around central canal | relay motor info from one side of the spinal cord - axons decussate (cross over) here in the gray commissure

Question 35

Ascending Tracts

Answer 35

carry sensory info up the spinal cord to areas of the brain (terminating in cerebrum/cerebellum)

Question 36

Descending Tracts

Answer 36

carry motor info from brain down to specific levels of spinal cord (terminating on skeletal muscles)

Question 37

Reflex Arc

Answer 37

1. receptor organ 2. sensory (peripheral) neuron 3. spinal cord interneuron 4. spinal cord motor neuron 5. effector organ (muscle)

Question 38

Monosynaptic Reflex Arc

Answer 38

reflex arc involving only one synapse

Question 39

Central Pattern Generators

Answer 39

functional units of neurons in the spinal cord built from groups of the more simple spinal reflexes, that produce rhythmic patterned outputs without sensory feedback eg walking, breathing

Question 40

Primary Injury

Answer 40

1. Loss of Neurons/Axons | 2. Demyelination

Question 41

Secondary Injury

Answer 41

1. Loss of Neurons/Axons 2. Demyelination 3. Inflammation 4. Reactive Oxidative Damage and the Astrocytiic Glial Scar 5. Cyst Formation