Test 4 Part 3

Question 1

What are the spinal reflexes?

Answer 1

Myotactic reflex
Inverse myotactic reflex
pain withdrawl reflex

Question 2

other names for myotactic reflex?

Answer 2

Deep tendon reflex
stretch reflex

Question 3

what kind of reflex loop is the myotactic reflex?

Answer 3

monosynaptic reflex loop
“might not actually be monsynaptic as there is an internuncial neuron in the middle”?

Question 4

What motor neurons are in monosynaptic reflex loop? And what musclel fibers do they innervate?

Answer 4

alpha motor neurons > extrafusal fibers
gamma (Y) motor neurons > intrafusal fibers

Question 5

Step 1 of myotactic reflex

Answer 5

Gamma motor neuron innervate the intrafual fibers

Question 6

What are the two parts of intrafusal fibers?

Answer 6

nuclear bag
nuclear chain

Question 7

What are the two types of gamma efferent axonal fibers?

Answer 7

Dynamic Y (gamma) motor

Static Y (gamma) motor

Question 8

Ending of Dynamic Y motor axonal fibers?

Answer 8

plate ending

Question 9

Ending of static Y motor axonal fibers?

Answer 9

trail ending

Question 10

Function of Dynamic Y motor axonal fibers?

Answer 10

rate of change in length of intrafusal fibers

Question 11

Function of static Y motor axonal fibers?

Answer 11

length at any moment of intrafusual fiber

Question 12

do both nuclear chain and nuclear bags have both plate and trail endings of efferent axonal fibers?

Answer 12

yes, we think lol

Question 13

Step 2 of myotactic reflex?

Answer 13

activation of afferent limb of reflex

Question 14

What are the two types of sensory fibers in myotactic reflex?

Answer 14

Dynamic sensory Ia fibers

static sensory II fibers

Question 15

Dynamic sensory Ia fiber function?

Answer 15

measure rate of change of intrafusal fiber length

Question 16

static sensory fibers II function?

Answer 16

measure static length of intrafusal fibers

Question 17

What are the endings of sensory Ia fibers?

Answer 17

Annulospiral/primary endings

on both nuclear chains and nuclear bags

Question 18

What are the endings of sensory II fibers?

Answer 18

Flower spray/secondary endings

on both nuclear chains and nuclear bags

Question 19

Step 3 of myotactic reflex?

Answer 19

Alpha motor neurons contorl of the extrafusual fibers - efferent limb of the reflex

Question 20

what controls the Y motor neurons?

Answer 20

CNS

Question 21

How does CNS affect Y motor neurons?

Answer 21

increased gamma excitibility = intrafusal fiber contraction

Decreased gamma excitability = intrafusal fibers relax

(and they stay contracted, except when sleeping)?

Question 22

What determines net gama bias?

Answer 22

balance between + and - CNS signals giving us either inhibition of excitation

Question 23

What does net gama bias effect?

Answer 23

net gamma bias determines alpha bias, which in turn determines the extrafusal fiber contractile state (i.e muscle tone)

Question 24

Describe muscle tone

Answer 24

continuous and passive muscle contraction of muscles at rest

Question 25

What does quadriceps tendon deep tendon reflex test?

Answer 25

L2-L4

Question 26

What does achilles tendon deep tendon reflex ankle jerk test?

Answer 26

S1-S2

Question 27

What places magnitude limitations on the DTRs?

Answer 27

Golgi tendon organ

Question 28

Describe the inverse myotactic reflex

Answer 28

Ib fibers from golgi tendon organ project to spinal cord, this signal tells the spinal cord to stop the muscle contraction

Question 29

Poly synaptic reflex arc?

Answer 29

pain withdrawl reflex

Question 30

Explain the pain withdrawl reflex

Answer 30

painful stimulus transfered via A delta fibers to spinal cord. Efferent A alpha fibers cause contraction of ipsilateral limb and extension of contralateral limb.

There are also informational pathways to the brain but this is not part of the reflex it self

Question 31

How is gray matter organized?

Answer 31

Laminae of Rexed
10 layers of gray matter

Question 32

Where are the sensory cell bodies of the laminae of rexed?

Answer 32

Dorsal Gray horn
I-VII

Question 33

Where are the motor cell bodies of the laminae of rexed?

Answer 33

Ventral and lateral gray horn
VIII-IX

Question 34

Which layer is posteromarginal nucleus?

Answer 34

Layer 1
(entire spinal cord)

Question 35

Which layers make up the substania gelatinosa layers?

Answer 35

layers 2 & 3
(entire spinal cord)

Question 36

Which layers are in nuclueus proprius?

Answer 36

layers 4 & 5
(entire spinal cord)

Question 37

Which layers are in Nucleus dorsalis?

Answer 37

Layer VI
C8-L1

Question 38

What layers are in visceral afferent nucleus?

Answer 38

Layer VII
T1-L3

Question 39

What layers are in interomediolateral cell column?

Answer 39

Layer VIII
T1-L2/3

Question 40

What layers are in sacral parasympathetic nucleus?

Answer 40

Layer VIII
S2-S4

Question 41

What layers in anterior horn cell column?

Answer 41

Layer IX
entire SC

Question 42

What kinds of motor neurons make up ant. horn cell / layer IX?

Answer 42

alpha and gamma motor neurons

Question 43

Lamina X-Gray commisure

Answer 43

Central Zone, gray matter
surrounding the central
canal

Question 44

What kinds of motor neurons make up ant. horn cell / layer IX?

Answer 44

alpha and gamma motor neurons

Question 45

Which two pathways make up the Anterolateral System? And their function?

Answer 45

Paleospinothalamic system (anteriorspinothalamic) crude touch

Neospinothalamic system
(lateralspinothalamic) pain and temp

Both of these are bilateral

Question 46

Archispinothalamic system / propriospinal tract characteristics and function?

Answer 46

pain
bidirectional
Intersegmental fibers

Question 47

Neospinothalamic system function?
(lateral spinothalamic)

Answer 47

sharp, prickling pain, epicritic pain (localized)

temp: hot warm cool cold