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Neuro 1 > Segmental Motor Center > Flashcards

Segmental Motor Center Flashcards

1
Q

Motor unit

A

motor neuron, axon & muscle fibers

‘Muscle unit’ = axon terminal & all the muscle fibers served

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2
Q

Contractile elements work best at what legnth​

A

resting length

have the greatest number cross bridges

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3
Q

Contractile elements at lengthened​ and shortened legnths

A

they do not work as well b/c less to grab onto

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4
Q

Connective tissue and tension

A

Connective tissue that is surrounding the muscles can add some passive tension

when you pull on the connective tissue there is some force on the as well

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5
Q

Eccentric contraction vs. concentric in about of force producced

A

when you take the muscle beyond resting length there is passive tension that is added to the active tension

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6
Q

Slow,S (slow oxidative, SO

A

Small motor neuron

Small amount of muscle fibers

Innervates slow twitch muscle fibers for slow contraction and relaxation time; relatively small forces, resistant to fatigue

Activities with sustained muscular contraction

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7
Q

Fast, fatigue-resistant,FR

A

Largemotor neuron

mediumamount of muscle fibers/unit,

Innervates fast twitch muscle fibers (fast oxidative glycolytic, FOG) for fast contraction & relaxation; generate ~ 2x force as (S)

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8
Q

Fast, fast-fatigue, FF

A

Largemotor neuron,

Large amount of muscle fibers/unit,

Innervates very fast twitch muscle fibers (fast glycolytic, FG) for very fast contraction & relaxation time

Generate large, rapid force;particularly important for brief exertions that require large force,running, jumping.

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9
Q

size largest to smallest of FF SO and FG

A

FF FG S

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10
Q

the larger the axon what happens to the speed of transmission

A

gets faster

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11
Q

FF FG and S - which creates the greatest force

A

FF
has the most fibers per motor neuron

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12
Q

1A afferent primarily targets what type of motor unit

A

slow oxidative

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13
Q

Twitch tension time - slow

A

Slow rise of tension over a greater period of time (gradual force production)

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14
Q

Twitch tension time - fast

A

fast twitch therefore fast force production

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15
Q

Fatigue index Fast

A

rapid changes in high force production by not to be used for long periods

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16
Q

FR energy use

A

Not many capillaries, anerobic metabolism or aerobic (phosphocreatine and glycolysis for their energy production)

Have both enzymes so can do both – so when we are training these are normally what we are training

Not to be used continually

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17
Q

Slow: endurance

A

Endurance, use aerobic metabolism (have more capillary)

Highly vascularized

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18
Q

en recruit fibers what order do we go in

A

S > FR > FF

this is an example of pre writing

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19
Q

Sag

A

if you stimulate a certain rate that allows a relax in-between we will see a sag
rapidly formed cross bridges are less resistance to relaxtion

FF and FR

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20
Q

Potentiation

A

slow

the cross bridges form slowly so they are resistant to relax (strong covalent bonds)

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21
Q

fatigue time - FF

A
  • FF are gone in less then a minute
  • Loss of force
  • FF are fatigable
22
Q

fatique​ time - slow

A
  • Slow can produce force for a long time
23
Q

Three features of motor unit recruitment protect against fatigue:

A

Henneman’s size principle
SMC ‘half centers’
Asynchronous activation

24
Q

Henneman’s size principle

A

principle gradual ramping of force;

S to FR and FF; ‘small to large’

Only get to the fast ones when we need them for force

25
Q

SMC ‘half centers

A

extensor and flexor; alternating activation

Alternative activates between agonist and antagonist

26
Q

Asynchronous activation

A

motor units activated intermittently during the voluntary contraction time

We do not used the same motor unit when we are doing a contraction, there are different motor neuron within the pool

27
Q

Monosynaptic reflex

A

Ia afferent input from the muscle spindle to motor neuron activation back to the same (homonymous) muscle and its

Modified by descending and peripheral inputs

28
Q

H-reflex, e.g. during locomotion

A

Electrical equivalent to the monosynaptic reflex

Consider why? Consequences if not reduced?
Bounding when running – descending paths influence stuff

29
Q

Alpha is what

A

motor neuron

30
Q

Gamma

A

MN to the muscle spindle to keep it sensitive

31
Q

Alpha-gamma co-activation is activated for what kind of contractions

A

all contractions

32
Q

Reciprocal inhibition

A

Ia Inhibitory Interneuron (IaIN) turns off (reciprocally inhibits) the antagonist SMC during activation of the agonist SMC

33
Q

IB afferent from where

A

GTO sensory neuron

34
Q

Autogenic inhibition point

A

Trying to turn off some motor neurons so that others must take over the load

35
Q

IB inhibitory internuron does what

A

regulates recruitment of agonist AMNs in the MN pool at any one time; turns off some active MUs, others take over for force production (a non-reciprocal inhibition).

36
Q

Recurrent inhibition

A

Renshaw (R) cells limit the rate and #of motor units active in the MN pool at any one time. (a non-reciprocal inhibition)

37
Q

non-reciprocal inhibition example

A

Recurrent inhibition and Autogenic inhibition

38
Q

reciprocal inhibition example

A

Reciprocal inhibition

39
Q

The ventral horn is organized into two parts

A

Medial and lateral motor nuclei

40
Q

Propriospinalinterneurons(INs) communicate infromation where

A

information over short and long distances within the spinal cord.

Only travel between segment of the spinal cord (communication within the spinal cord)

41
Q

Medial motor nuclei go to what kind of muscles

A

axial and proximal limb girdle muscles

42
Q

Medial motor nuclei connection

A

Have an interneuron that connects both sides – this allows us to activate things together

If there in an input on the medial side, there will be activation on both sides

43
Q

Lateral motor nuclei to what kind of muscles

A

limb muscle - for limb movement

44
Q

Lateral motor nuclei connection

A

Do not have a connection between the two sides – we normally move one limb at at a time

45
Q

Descending connections medial MN

A

Ventromedial pathways impact medial MNs

Bilateral effects

46
Q

Descending connections lateral MN

A

Dorsolateral pathways impact lateral MNs

47
Q

Ascending connections for both medial and laterl MN

A

Ventrospinocerebellar tract
Spinoreticular/spinothalamic

48
Q

Ventrospinocerebellar tract

A

To cerebellum – this compare what is happening the ventral horn to the cortex plans, and can make correction

Info: motor copy – telling about the state of the of a segmental motor neuron

49
Q

Spinoreticular/spinothalamic

A

To brainstem centers

50
Q

segmental motor center is made up of

A

medial and lateral MN

Neuro 1 (14 decks)

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