Pathology 01 - Msk - Spinal Reflexes

Front 1

Which direction is sensory receptors

Back 1

Afferent

Front 2

What does muscle spindles detect

Back 2

Muscle length

Front 3

What does golgi tendon organ detect

Back 3

Muscle force/tension

Front 4

Which direction is motor neurons

Back 4

Efferent

Front 5

What are the effector organs

Back 5

Skeletal muscle = Extrafusal muscle fibers and intrafusal muscle fibers

Front 6

What is the function of extrafusal fibers

Back 6

Alpha-motor neuron innv + major skeletal muscle of movement (long large cells)

Front 7

What is the function of intrafusal fibers

Back 7

Gamma-motor neuron innv + muscle spindle receptors (stretch)(short muscle cells)

Front 8

What is the arrangement of extrafusal fibers

Back 8

Extrafusal fibers Arranged in parallel with the muscle spindle

Front 9

Function of muscle spindle?

Back 9

Transmits sensory information (AP) = muscle length (static position) + rate of muscle length change (dynamic movement)

Front 10

Primary nerve endings - function

Back 10

Aka annulospiral - Type Ia nerve fiber + senses "rate of change" (dynamic)

Front 11

Secondary nerve endings - function

Back 11

Aka flower spray - type II nerve fiber + senses absolute length (static)

Front 12

Type Ib nerve fiber

Back 12

Golgi tendon organ

Front 13

Nuclear bag fiber - function

Back 13

Type Ia innv, dynamic

Front 14

Nuclear chain fiber - function

Back 14

Type II innv - static

Front 15

Which direction of innv is gamma-motor neuron

Back 15

efferent

Front 16

Gamma gain

Back 16

Gamma - motor neuron can be activated separately from alpha-motor neurons depends on the state of physical readiness (ie golfers who prepare to swing = ↑ gamma gain)

Front 17

Coactivation

Back 17

Simultaneous alpha + gamma motor neuron activation - optimized sensory feedback during physical activity

Front 18

Myotatic reflex

Back 18

Muscle stretch reflex

Front 19

Example of monosynaptic pathways

Back 19

Ia Fibers synapse directly on alpha-motor neurons (one synapse) (ie knee jerk/patellar tendon reflex)

Front 20

What is the MOA of patellar tendon reflex

Back 20

Tap patellar tendon -> rapid stretch of quads muscle SPINDLES -> Ia fibers fire a burst of activity (Aps) that depolarize the alpha-motoneurons causing a brief contraction of the quadriceps

Front 21

What is the muscle length in ankle clonus

Back 21

Its shortens and lengthens over and over -> UMN lesion

Front 22

What is the arrangement of GTO in the muscle?

Back 22

GTO arranged in series with the extrafusal muscle fibers

Front 23

What is the innv of golgi tendon organ?

Back 23

Senses muscle tension (dynamic) - innv by Type Ib (afferent) -> no motor innv (only sensory)

Front 24

Protective reflex

Back 24

Aka golgi tendon reflex or inverse myotactic reflex - Prevents muscle tears or tendon pulling away from bone(polysynaptic pathway = uses interneurons)

Front 25

Pathway for GTO reflex

Back 25

Too much tension detected (GTO) -> rapid firing of Type Ib afferent nerve -> stimulates inhibitory interneurons -> prevents alpha-motor neuron innv -> relaxes muscle -> prevents injury

Front 26

Flexor reflex

Back 26

Reflex if u burn your hand-> signal goes into posterior ganglion -> interneuron -> synapses at alpha motor neurons(secondary synapse) -> excites biceps + inhibits triceps -> thus moves hand out of the way (3 or 4 neuron pathway)

Front 27

Crossed extensor reflex

Back 27

Trips and automatically put your arms out; stimulus -> flexor reflex in one limb -> the opposite limb extends(signal crossed the middle) (extension of the opposite limb can push the entire body away from the object causing the painful stimulus in the withdrawn limb;

Front 28

Reciprocal inhibition

Back 28

Excites one side of muscle and inhibits the other; stretch reflex excites one muscle -> simultaneously inhibits the antagonist and excites agonist muscle