Term
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Definition
Physostigimine, DFP: Inhibits
Acetylcholineesterase
AChR channel inhibitors:
tubucurarine, bungarotoxin |
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Term
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Definition
Primary endings: spiral terminals on
nuclear bag and nuclear chain.
Innervated by 1a fiber. Dynamic and
static response
Secondary: Spray like terminals on
nuclear chain fibers. (group 2 fibers)
Static response.
Static - muscle length
Dynamic - rate of stretch |
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Term
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Definition
Provide motor innervation of muscle spindles.
Dynamic y motor neurons: enhance dynamic response of primary endings.
Static y motor neurons: enhance static
response of primary and secondary
endings. |
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Term
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Definition
Supplied by afferent 1b nerve fibers
Terminals interdigitate with bundles of collagen fibers. |
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Term
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Definition
Phasic Stretch reflex: stretching the muscle quickly, detected by primary endings.(patellar tendon reflex)
Tonic Stretch reflex: slower stretch of
muscle. Important in maintenance of
posture. Group 2 afferent fibers (secondary endings) |
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Term
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Definition
Group 1a afferent fibers from primary
endings of muscle spindles
Monosynaptic excitatory connections of these afferents with motor neruons
disynaptic inhibition pathway. |
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Term
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Definition
| Group 1b afferent fibers from golgi tendon organs, act on extensors. |
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Term
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Definition
Troponin T: attaches troponin complex to tropomyosin
Troponin I binds to actin and inhibits contraction.
Troponin C: binds to Ca++, promotes
movement of tropomyosin on actin
filament casing myosin binding sites
to be exposed. |
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Term
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Definition
Essential light chain: stabilizes
myosin head region
Regulatory light chain: can be
phosphorylated and regulates ATPase
activity. |
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Term
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Definition
Z-disc: Zigzag protein that serve as attachment for thin filaments
I Bands: region occupied only by thin filaments
H zone: Central region occupied by just thick filaments
M line: proteins that anchor thickfilaments |
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Term
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Definition
Titan: stabilizes position of contractile filaments. returns contracted sarcomeres to resting length
Nebulin: Inelastic, attaches to Z-disc
Lies along and helps align actin
filaments |
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Term
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Definition
State A: resting state. Partially hydrolyzed ATP. stabilizes cocked position
State B: Exposure of binding sites allows myosin heads to bind. Releases ADP and Pi
State C: Power stroke. Pulls actin toward center of sarcomere
State D: binding of ATP to myosin decreases affinity of myosin for actin. |
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Term
| Length-tension relationships |
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Definition
Optimal Length 2.0um to 2.3 um
Too long and not many cross bridges will form.
Too short: thick filaments run into Z discs and myosin can't find new binding sites. |
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Term
| Length-Force relationships |
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Definition
The force-length relationship depicts a steady state behavior that exists between initial sarcomere length, and force that can be generated.
Passive tension: Elastic recoil of cytoskeleten
Total tension: force from myosin/ actin plus passive tension.
Active Tension: The difference between total tension and passive tension. |
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Term
| Recruitment of motor units |
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Definition
Neurons with lowest thresholds are type 1
slow twitch
Next is Type IIa fibers
Highest thresholds activate Type IIB |
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Term
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Definition
Unfused Tetanus: stimulation is not at maximum value, muscle fiber relaxes slightly between stimuli.
Complete tetanus: Stimulation is fast
enough and fibers do not relax. |
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