Spinal cord

Question 1

Where does the spinal cord terminate? Name of this location?

Answer 1

at L1/L2 as conus medullaris, at some point the spinal cord stops growing as vertebrae continues

Question 2

dural sac ends at?

Answer 2

L1

Question 3

the cervical and lumbar enlargements correlate with?

Answer 3

the ventral plexuses

Question 4

causa equina

Answer 4

bundle of nerve ROOTS that extend inferiorly from the lumbar and sacral levels that branch off the bottom of the spinal cord like a “horse’s tail.”

Question 5

conus medullaris

Answer 5

conical lower extremity of the spinal cord, WHERE IT ENDS AT L1/L2

Question 6

What are three distinctive spinal cord regional characteristics?

Answer 6

1) overall size
2) proportion of white matter (axons) to gray mater (Cell bodies)
3) unique features (IML cell column; T1-L2/L3)

Question 7

gray matter and white matter are made up of?

Answer 7

gray= cell bodies
white= axons

Question 8

higher level regions of spinal cord have more or less white or gray matter?

Answer 8

less gray; higher level is larger with more motor and movement

Question 9

thickening of gray matter at the end of spinal cord because?

Answer 9

condensation of nerves at conus medullaris; bunch of cell bodies for terminal part of spinal cord

Question 10

the subdural space is below and above what?

Answer 10

below dura and above arachnoid

Question 11

3 types of fiber tracts

Answer 11

1) assosciation
2) commissural
3) projection

Question 12

association fibers

Answer 12

Constricted to the brain on SAME SIDE aka same hemesphere

Question 13

commissural fibers

Answer 13

connecting 1 hemisphere to the other

Question 14

projection fibers

Answer 14

any fiber that projects down or up from the cortex

*ALL motor tracts are projections

Question 15

IMPORTANT association fiber example?

Answer 15

Broca’s area (speech production) to Warnike’s area (speech comprehension)

Question 16

what is the arcuate fasciculus?Also known as

Answer 16

SLF= superior longitudinal fasciculus

**connects Broca’s area (speech production) to Warnike’s area (speech comprehension)

Question 17

What is corpus callosum?

Answer 17

a broad band of nerve fibers joining the two hemispheres of the brain

Question 18

All tracts are made up of what type of fier?

Answer 18

projection

Question 19

what is corona radiata?

Answer 19

is a white matter sheet that continues ventrally as the internal capsule and dorsally as the centrum semiovale. This sheet of both ascending and descending axons carries most of the neural traffic from and to the cerebral cortex

Question 20

what are the 3 sections of projection fibers?

Answer 20

1) posterior funiculus
2) lateral funiculus
3) anterior funiculus

Question 21

the posterior funiculus is completly made up of?

Answer 21

sensory tracts

Question 22

the lateral and anterier supplied by?

Answer 22

by the anterior spinal artery

Question 23

the posterior funiculus is supplied by?

Answer 23

posterior spinal artery

Question 24

the lateral and anterior funiculi are made up of?

Answer 24

sensory and motor tracts

Question 25

all motor information comes from?

Answer 25

pre-central gyruc

Question 26

motor and sensory tracts run through white or gray matter?

Answer 26

white

Question 27

axons of upper motor neuron that go down to synapse on the lower motor neuron, which would be in the ___horn since we're down in the spinal cord

Answer 27

ventral

Question 28

what are the 2 divisions of motor tracts we are going to learn?

Answer 28

they are corticospinal tracts 1) lateral corticopinal tract 2) anterior corticospinal tract * *and has an associated tract called corticobulbar

Question 29

lateral corticopinal tract destined for?

Answer 29

extremities mainly hands/feet; go to OPPOSITE SIDE

Question 30

anterior corticospinal tract destined for?

Answer 30

postural muscles aka trunk; stay on SAME SIDE

Question 31

What tract STAYS on the same side of body? which one doesn't?

Answer 31

lateral corticopinal tract= OPPOSITE | anterior corticospinal tract= SAME

Question 32

___% of corticol spinal tract is lateral?

Answer 32

90% is lateral because there is SO MUCH info going to the hands and feet

Question 33

why are the corticospinal tracts named the way they are?

Answer 33

lateral is in the lateral funiculus | anterior is in the anterior funiculus

Question 34

the corticospinal tract and what other tract start together and then split?

Answer 34

corticobulbar (split in bulb and goes to brain)

Question 35

upper motor neuron (UMN) is in the?

Answer 35

pre-central gyrus

Question 36

voluntary motor route (to leave brain) for corticospinal

Answer 36

1) cell bodies in pre-central gyrus 2) axons descend thru internal capsule 3) cerebral peduncle and pons 4) pyramids of medulla ***cross to opposite at decussation of pyramids 5) axons continue descending until the hit lower motor neuron (LMN) 6a option) CN nuclei (LMN) in brain-stem 6b option) LMN in ventral horn and leaves through other terminal branches

Question 37

internal capsule is a bundle of? Located where?

Answer 37

bundle of white mater that is running in between the thalamus and basal ganglia nuclei

Question 38

all voluntary motor is leaving through?

Answer 38

the same route

Question 39

what does cerebral peduncle?

Answer 39

connects cerebrum to brain-stem

Question 40

define ipsilateral

Answer 40

belonging to or occurring on the same side of the body

Question 41

define contralateral

Answer 41

relating to or denoting the side of the body opposite to that on which a particular structure or condition occurs

Question 42

any lesion that happens in the left cerebral peduncle affects?

Answer 42

right side motor

Question 43

any lesion that occurs in left ventral horn of T2 affects?

Answer 43

left side for motor

Question 44

UMN in one precentral gyrus will synapse on?

Answer 44

CONTRALATERAL LMN

Question 45

what happns to 10% of axons that DON'T decussate?

Answer 45

they will continue as the anterior corticospinal tract along the ipsilateral side

Question 46

each motor tract has how many neurons?

Answer 46

2

Question 47

where does upper and lower motor neuron reside?

Answer 47

``` UMN= within precentral gyrus/motor cortex LMN= within ventral horn of wherever signal terminates to the extremities at ```

Question 48

What does the UMN synapse on if it goes to brain-stem?

Answer 48

cranial nerve nucleii

Question 49

corticobulbar tract is voluntary control of?

Answer 49

skeletal muscle of head and neck through cranial nerve. | NOT eye movements- extraoccular muscles have a different tract

Question 50

corticobulbar tract route

Answer 50

UMN follows same course: precentral gyrus - internal capsule -cerebralpeduncle - synapse on cranial nerve motor nuclei throughout midrain/pons/medulla

Question 51

most cranial nerve nucleireceive bilateral input; what are the 4 big ones?

Answer 51

1) trigeminal 2) hypoglossal 3) nucleus ambiguos (CN 9 and 10) 4) facial (partially) * 5, 7, 9, 10, 12 are all bilateral

Question 52

what CN receivese unilateral input?

Answer 52

unilateral=ipsilateral =CN 11

Question 53

why do unilateral corticobulbar tract lesions produceno remarkable clinical effect on head and neck muscles?

Answer 53

due primarily to bilateral corticobulbar input | *there are exceptions

Question 54

A lesion to the peripheral nerve results in?

Answer 54

loss of function (just like in spinal nerves)