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Block 2: Neuroscience > Lecture 5 > Flashcards

Lecture 5 Flashcards

(59 cards)

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1
Q

(Types of Motor Units)
“Size Principle”?

A

Order of recruitment - slow (1) to fast fatiguable (3)

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2
Q

(Types of Motor Units)
Motor Unit?

A

Single motor neuron and muscle fibers that it innervates

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3
Q

(Types of Motor Units)
Motor Neurons Pool?

A

All motor neurons innervating a given muscle

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4
Q

(Types of Motor Units)
Small?

A

-Fatigue slowest
-Can carry on for extended periods of time
-3rd

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5
Q

(Types of Motor Units)
Intermediate?

A

-Fatigue intermediate
-2nd

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6
Q

(Types of Motor Units)
Large?

A

-Fatigue fastest
-Cannot maintain
-3rd

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7
Q

(Muscle Spindles)
Spindle?

A

Connective tissue sheath that contains intramural muscle fiber arranged in parallel with extrafusal fibers

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8
Q

(Muscle Spindles)
Sensory Nerve Endings innervate?

A

Intrafusal Muscle Fibers:
-Group Ia (measure muscle length (stretch) and rate of change of length (velocity) (play a role in initial movement)
-Group II (measure muscle length (stretch) (play a role in maintenance of movement)

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9
Q

(Muscle Spindles)
(Sensory Nerve Endings innervate)
Group Ia?

A

-Measure muscle length (stretch) and rate of change of length (velocity)
-Play a role in initial movement

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10
Q

(Muscle Spindles)
(Sensory Nerve Endings innervate)
Group II?

A

-Measure muscle length (stretch)
-Play a role in maintenance of movement

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11
Q

(Stretch (Myotatic) Reflex)
Negative feedback regulation of muscle length is an example of?

A

“Direct Activation” of alpha motor neurons

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12
Q

(Stretch (Myotatic) Reflex)
When a muscle is stretched, Ia afferents?

A

Excite alpha motor neurons that innervate stretched muscle
(monosynaptic stretch reflex)

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13
Q

(Stretch (Myotatic) Reflex)
Ia afferents inhibit?

A

Alpha motor neurons that innervate “antagonistic” muscle
(di-synaptic reflex: an inhibitory interneuron is interposed between Ia afferent and motor neuron (that innervate unstretched muscle))

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14
Q

(Alpha-Gamma Co-Activation)
Indirect Activation of alpha motor neurons?

A

-Gamma motor neurons selectively innervate intramural muscle fibers
-Causes contraction of 2 ends of intramural muscle fibers

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15
Q

(Alpha-Gamma Co-Activation)
Process keeps intramural fibers contracted while extrafusal fibers?

A

Contract (Ia spindle afferents remain activate and ready for increase in load)

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16
Q

(Alpha-Gamma Co-Activation)
Process keeps intramural fibers contracted while extrafusal fibers?

A

Contract (Ia spindle afferents remain activate and ready for increase in load)

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17
Q

(Tendon Organs)
Located in bundle of small tendon fascicles adjacent to?

A

Musculotendinous junction

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18
Q

(Tendon Organs)
Sensory nerve endings innervate tendon organs?

A

Group Ib measure stretch of tendon by muscle force when working against a load (plays role in reduction of force)

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19
Q

(Tendon Organs (Inverse Myotatic) Reflex)
Negative feedback regulation of?

A

Muscle Force

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20
Q

(Tendon Organs (Inverse Myotatic) Reflex)
During instances of extreme force we want to?

A

Relax muscle to avoid injury
(motor neurons to synergistic muscles are inhibited via inhibitory interneuron)
(motor neurons to antagonistic muscles are excited via excitatory interneuron)

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21
Q

(Tendon Organs (Inverse Myotatic) Reflex)
Stretch Reflex is a form of?

A

Negative feedback regulation of muscle stretch

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22
Q

(Tendon Organs (Inverse Myotatic) Reflex)
Bicep Curls?

A

Syngeristic

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23
Q

(Tendon Organs (Inverse Myotatic) Reflex)
Tricep Extension?

A

Antagonistic

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24
Q

(Tendon Organs (Inverse Myotatic) Reflex)
Inability to?

Study These Flashcards
A

Complete a set or rep at the gym

25
(Myotatic Reflex + Inverse Myotatic Reflex) Collectively stretch and tendon organ reflexes contribute to?
Generation of appropriate stiffness for "support" and "shock absorber" functions
26
(Myotatic Reflex + Inverse Myotatic Reflex) Muscle Stiffness?
Change in Force/ Change in Length
27
(Myotatic Reflex + Inverse Myotatic Reflex) Stretch (myotonic) reflex tends to?
Increase muscle stiffness
28
(Myotatic Reflex + Inverse Myotatic Reflex) Tendon organ (inverse myotatic) reflex tends to?
Decrease muscle stiffness
29
(Spinal Flexor Reflex) Flexor Reflex?
Response to noxious stimulation of skin or muscle
30
(Spinal Flexor Reflex) Cutaneous nociceptors evoke?
Polysynaptic spinal reflex for withdrawal and support
31
(Spinal Flexor Reflex) (Cutaneous nociceptors evoke polysnaptic spinal reflex for withdrawal and support) Stimulated limb is?
Withdrawn (flexed) -Extensor muscle relaxed -Flexor muscle contracts
32
(Spinal Flexor Reflex) (Cutaneous nociceptors evoke polysnaptic spinal reflex for withdrawal and support) Other limb is?
Extended for maintenance of posture/locomotion -Extensor muscle contracts -Flexor muscle relaxed
33
(Upper Motor Neurons) Spinal cord motor neurons are influenced by?
Descending pathways from the Brain
34
(Upper Motor Neurons) Upper Motor Neurons are neurons in Brain that?
Project to spinal motor circuits and motor neurons that directly innervate muscles
35
(Upper Motor Neurons Syndrome) Sequence after lesion?
1) First (Hypotonia (spinal shock)) 2) Later (Spasticity)
36
(Upper Motor Neurons Syndrome) Down-regulation of potassium-chloride cotransporter (KCC2) contributes to?
Spasticity after spinal cord injury
37
(Upper Motor Neurons Syndrome) Down-regulation of potassium-chloride cotransporter (KCC2)?
1) Cotransporter is down regulated after spinal cord injury 2) Depolarization of Cl- equilibrium potential and reducing strength of postsynaptic inhibtion 3) Hyperexcitability
38
(Upper Motor Neurons Syndrome) Possible Future Therapies?
Neutrophil factor BDNF up regulates transporter after injury
39
Central Pattern Generator (CPG)?
An assembly of neurons (in spinal cord) which can generate and control spatial and temporal activity of motor neurons (used for rhythm generation during activities like walking)
40
(Central Pattern Generator (CPG)) 2 Classes of Mechanism for CPG?
-Pacemaker -Emergent Network Property
41
(Central Pattern Generator (CPG)) Pacemaker?
Cells have intrinsic membrane properties that cause periodic "bursts" of APs (ex. alternating inward (Ca) and outward (K+) currents)
42
(Central Pattern Generator (CPG)) Emergent Network Property?
No cell has bursting properties. Reciprocal inhibition and adaptation in a network account for alternating activity in flexors and extensors
43
(Optogenetics and CPG) Optogenetics?
Light-gated ion channels or transporters, expressed in neurons using cell specific promoters
44
(Optogenetics and CPG) 2 Types?
-Channelrhodopsin 2 (ChR2) -Halorhodopsin
45
(Optogenetics and CPG) Channelrhodopsin 2 (ChR2)?
-Associated with glutamatergic neurons -Gated by blue light and conducts H+, Na+, K+, and Ca2+ ions -Leads to depolarization (open up and allow influx of positive ions)
46
(Optogenetics and CPG) Halorhodopsin?
-Associated with glutamatergic neurons -Gated by green/yellow light and conducts Cl- ions -Leads to hyperpolarization (conduction of Cl- ions)
47
(Optogenetics and CPG) Excitation using blue light (channelrhodopsin) displayed?
Rhythmicity between right and left sides
48
(Optogenetics and CPG) Inhibition using green light (halorhodopsin) displayed?
Importance of right/left control based on location in spinal cord
49
(Optogenetics and CPG) Selective excitation of glutamatergic neurons turns on?
CPG
50
(Optogenetics and CPG) Coordination of left and right sides provided by?
Commissural Interneurons
51
(Optogenetics and CPG) Halorhodopsin (when shine light at L2)?
IL5 flexor activated and extensor inhibited
52
(Optogenetics and CPG) Halorhodopsin (when shine light at L5)?
IL2 flexor inactive and extensor activated
53
(How do reflexes alter pattern generation?) Reflex feedback is not necessary for?
Rhythm generation
54
(How do reflexes alter pattern generation?) Reflex feedback influences?
Phase durations and pattern
55
(How do reflexes alter pattern generation?) Tap box?
Change rhythm to overcome additional flexion during swim phase
56
(REM Sleep) Brainstem (pons) modulates?
Muscle Tone and Locomotion during REM sleep
57
(REM Sleep) In a normal human, pons sends excitatory signaling to command centers responsible for?
Muscle Tone and Inhibitory signaling to command centers responsible for locomotion (prevents unwanted movement during REM sleep, while maintaining muscle tone)
58
(REM Sleep) Lesions to pons (ex. stroke) prevents?
Excitatory/Inhibitory signaling to be sent to respective command centers thus leading to unwanted movements and issues of muscle tone during REM
59
(REM Sleep) Lesions to pons (ex. stroke) prevents?
Excitatory/Inhibitory signaling to be sent to respective command centers thus leading to unwanted movements and issues of muscle tone during REM

Block 2: Neuroscience (5 decks)

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