Term
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Definition
| skeletal, smooth, cardiac |
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Term
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Definition
striated
voluntary
innervated by SOMATIC NS
ex BICEPS |
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Term
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Definition
unstriated
involuntary
innervated by AUTONOMIC NS
ex INTESTINES |
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Term
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Definition
striated
involuntary
innervated by AUTONOMIC NS
ex HEART |
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Term
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Definition
| One MOTOR NEURON pulling all the FIBERS it INNERVATES |
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Term
| Can a motor neuron innervate many muscle fibers? |
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Definition
YES
Each motor neuron innervates many muscle fibers in a muscle |
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Term
| Can a muscle fiber be innervated by more than one motor neuron? |
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Definition
NO
Each muscle fiber is innervated by only ONE motor neuron |
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Term
| When a motor neuron is activated how many muscle fibers contract? |
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Definition
ALL OF THEM
When a motor neuron is activated ALL FIBERS it innervates contract |
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Term
| What is asynchronous recruitment? |
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Definition
Alternations of motor unit activity
Occurs to prevent fatigue |
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Term
| Skeletal Muscle Fiber Structure |
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Definition
Has MANY NUCLEI & MANY MITOCHONDRIA
composed of MANY MYOFIBRILS |
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Term
| Organization of myofibril |
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Definition
A BAND
H ZONE
I BAND
Z LINE
SARCOMERE
M LINE
CROSS BRIDGES
[image]
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Term
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Definition
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Term
| Thick Filament Structure (IMG) |
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Definition
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Term
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Definition
Composed of MYOSIN MOLECULES
2 golf club heads
Each head contains ACTIN BINDING SITE and a MYOSIN ATPase SITE |
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Term
| Thin Filament Structure IMG |
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Definition
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Term
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Definition
Actin (sphere shaped with myosin binding site, backbone of filament)
Tropomysosin (threadlike proteins lying along actin spiral, COVERS MYOSIN BINDING SITE ON ACTIN)
Troponin (Fastens down each end of tropomyosin, hold in place over myosin binding site) |
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Term
| Transverse Tubules (T TUBULES) |
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Definition
Part of surface membranes of muscle fiber that DIPS INTO FIBER AT JUNCTION OF A & I BANDS
[image]
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Term
| SARCOPLASMIC RETICULUM (SR) |
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Definition
modification of endoplasmic reticulum
SURROUNDS EACH MUSCLE FIBER WITH SEPARATE SEGMENTS ENCIRCLING EACH A AND I BAND
[image]
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Term
| Overview of SLIDING FILAMENT MODEL |
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Definition
1. Ach released by TERMINAL BUTTON of MOTOR NEURON and BINDS to RECEPTORS on MOTOR END PLATE
2. ACH BINDING on motor end plate causes END PLATE POTENTIAL which causes ACTION POTENTIAL to travel down membrane and DOWN T TUBULES
3. ACTION POTENTIAL in T TUBULE causes SARCOPLASMIC RETICULUM to release CALCIUM
4. RELEASED CA binds to TROPONIN (fasteners) causing TROPOMYOSIN to move aside & EXPOSE MYOSIN BINDING SITE on ACTIN
5. CROSS BRIDGE CYCLING: myosin cross bridges (thick filaments) bind to ACTIN (thin filament) & stroke forward pulling ACTIN toward center of sarcomere
6. CA actively taken up by SR when no AP
7. When CA no longer bound to TROPONIN, TROPOMYOSIN back to blocking position, relaxation |
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Term
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Definition
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Term
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Definition
ATP broken down to ADP + Pi by ATPase on Myosin Head
The Head holds on to ADP + Pi, cocked into ready position
In presence of CA myosin binding site on actin uncovered; myosin head binds to actin
on contact of myosin and actin, ADP and Pi released and myosin head strokes forward
Fresh ATP binds to myosin, link with actin broken |
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