Spinal cord

Question 1

structure of spinal cord

Answer 1

cylindrical

Question 2

spinal extends inferiorly from

Answer 2

brain

Question 3

spinal cord is located in

Answer 3

vertebral canal

Question 4

Spinal cord is surrounded by

Answer 4

3 meningeal layers

Question 5

spinal cord extends from _ to _ - 2

Answer 5

Foramen magnum to ~L2
T12-~L3
superior 2/3 vertebral canal

Question 6

impulse conduction 2

Answer 6

permits neural communication between brain and periphery

ascending and descending tracts - sensory and motor info.

Question 7

when does the spinal cord stop going?

Answer 7

4, but vertebral canal continues grow until teens

Question 8

reflex generation

Answer 8

reflexive (involuntary) movements that occur in response to a sensory stimulus

Question 9

circuitry for reflexive movements is constrained within the

Answer 9

spinal cord

Question 10

structure of spinal cord - segment and nerves

Answer 10

31 segments - a pair of spinal nerve/segment - 31 pairs of spinal nerves

Question 11

first and last segment location

Answer 11

spinal segment c1 - vertebrae c1

coccygeal; 31st of spinal cord located at T1-L3

Question 12

spinal nerves enter/exit through?

Answer 12

intervertebral foramina

Question 13

How do nerves from caudal cord continue?

Answer 13

caudally - cauda equina - horse’s tail - caudal cord - sacral and coccygeal segments

Question 14

2 prominent enlargements for

Answer 14

innervation of limbs

Question 15

cervical enlargement - 2

Answer 15

spinal segments C4-T1

Brachial plexus

Question 16

Lumbar enlargement - 3

Answer 16

spinal segments T11-L1
lumbar plexus
sacral plexus

Question 17

Posterior ramus AKA? goes to?

Answer 17

dorsal ramus, back of torso

Question 18

anterior ramus AKA? goes to?

Answer 18

ventral ramus, lateral and anterior torso

Question 19

what rami do the plexuses come from?

Answer 19

anterior

Question 20

plexus

Answer 20

ant rami from various spinal segments come together to form network of nerves

Question 21

What’s the H shape?

Answer 21

central region of grey matter - cell bodies and unmyelinated axons

Question 22

what surrounds the H shape?

Answer 22

surrounding white matter - myelinated axons (ascending and descending tracts

Question 23

what travels through the central canal?

Answer 23

csf

Question 24

How is spinal grey matter specialized?

Answer 24

regionally

Question 25

Sulcus vs fissure in spinal cord

Answer 25

central grooves - posterior vs anterior - fissure is deeper/wider

Question 26

laminae of rexed 1-2

Answer 26

layered organization of neuron cell bodies 
dorsal horn (I-VI): sensory (inter) neurons 
Ventral Horn (IX): motor neuron cell bodies (alpha and gamma)

Question 27

dorsal horns vs ventral horns (structure)

Answer 27

ventral horns are bigger - lumbar region has lateral horns

Question 28

what are lateral horns for?

Answer 28

autonomic system

Question 29

motor neuron pool

Answer 29

all the motor neurons that innervate a particular skeletal muscle

Question 30

Somatotopic arrangement of motor neuron pools 1-2

Answer 30

orderly relationship between location of motor neuron pools and the muscles they innervate - provides a spatial map of body muscles

• longitudinal arrangement: lower vs upper body musculature
• mediolateral arrangement: motor neurons of axial muscles are medial, distal muscles are lateral

Question 31

descending tracts

Answer 31

bundled group of spinal white matter that arise from cell bodies in a source structure (part of the brain) that is more _____
carry motor information, carry signals downwards

Question 32

Descending tracts consist of at least how many MNs and what are they?

Answer 32

2
upper motor neurons
lower motor neurons

Question 33

Upper motor neurons

• location
• originate in (3)
• form

Answer 33

entirely within CNS 
cerebral cortex (motor areas) 
cerebellum 
brainstem 
descending tracts

Question 34

lower motor neurons
- originate in - 1-2
made up of
has 2

Answer 34

CNS - ventral horns of spinal cord, branstem cranial nerve nuclei
alpha motor neurons
spinal and cranial nerves

Question 35

Descending tract pathways 1-5

Answer 35

pathways via which the brain communicates with the skeletal muscles

• pyramidal tracts
• vestibulospinal tracts
• rubrospinal tracts
• tectospinal tracts
• reticulospinal tracts

Question 36

pyramidal tract 1 - 2

Answer 36

contains axons from cortical neurons and divides to form the corticospinal and corticobulbar tracts

• corticospinal - spinal cord - motor neurons to premotor neurons
• corticobulbar - brainstem

Question 37

decussation

Answer 37

Crossing of axons to the contralateral side - perhaps why the left side of the brain controls the right side of the body

Question 38

lateral corticospinal tract - 2

Answer 38

made up of corticospinal fibres that have crossed in the medulla
___

Question 39

ventral corticospinal tract - 2

Answer 39

made up of uncrossed corticospinal fibres that cross near level of synapse with LMNS

Question 40

extrapyramidal systems

Answer 40

descending tracts that do not pass medullary pyramid or corticobulbar tracts

Question 41

When does complete paralysis result?

Answer 41

both pyramidal and extrapyramidal systems are involved

Question 42

two tracts of the dorsal columns and where they synapse

Answer 42

gracile tract - lower limbs - medial
cuneate tract - upper limbs - lateral
respected nucleuses

Question 43

propriospinal tracts

Answer 43

tracts that are confined to the spinal cord and allow connections with neurons in other spinal cord segment (grey matter) - intersegmental synapses

Question 44

propriospinal neurons

Answer 44

interneurons that project to more distant spinal cord segments along myelinated axons.