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69 Cards in this Set
- Front
- Back
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EVENTS
1.AP conduction in motor neuron= |
depolarizes terminal
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EVENTS
2. ACh released at NMJ= |
crosses cleft
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EVENTS
3. ACh binds to ACh gated ion channes= |
increase Na G
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4. Na influx-depolarizes muscle=
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produces EPP
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5. EPP-->AP (muscle) conducted all over muscle surface depolarizing?
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entire muscle membrane including T tubules, SR depolarizes as well
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T tubules are
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extensions of the sarcolemma located near the Z disc, which increase the surface area of the muscle membrane
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Z disc runs parallel to the
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T tubule
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6. Depolarization of SR now releases?
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Ca++ onto myofibrils
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7. Ca++ triggers
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filament interaction, sliding of actin and myosin
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8. filaments overlap
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shortening muscle
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9. Ca++ pumped into?
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SR (sequestered) ends contraction
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B. SLIDING FILAMENT MECHANISM
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is what the entire mechanism is called
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SFM
1. Relaxed |
barely overlapping
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2. Contracted
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overlapped with Z discs close together
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C. MYOSIN COMPLEX
1. Globular |
protein heads
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Myosin complex
2. cross bridges? |
flexible hinges where they join into myosin
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Myosin complex
3. at the head? |
molecule of ATPase enzyme
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D. ACTIN COMPLEX (3 COMPONENTS)
1. F-actin |
is a double stranded protein molecule, the ends attach to the Z disc
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AC
2. Tropomyosin |
is a protein that wraps around F actin
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Tropomyosin blocks
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the active sites if the muscle is relaxed.
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Tropomyosin has ? molecules (active sites) for myosin interaction
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ADP
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AC
3. Troponin |
system that helps to bind tropomyosin to actin, 3 subunits
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Subunits of troponin
1. Troponin I |
has affinity for actin
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SOT
2 Troponin t |
affinity for tropomyosin
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SOT
3. troponin c |
affinity for calcium
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E. TROPONIN-TROPOMYOSIN COMPLEX (T-TM)
1. inhibits actin myosin binding sites by? |
blocking active sites
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T-TM
2. ? inhibits the T-TM inhibition |
calcium
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T-TM cont.
2. Ca binds to Troponin C this ? |
pulls tropomyosin into groove
unblocks actin filaments unblocks active sites |
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T-TM
3. Interaction and movement is called |
power stroke
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T-TM
3.cont. a. ? binds to actin and pulls inward |
myosin head
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T-TM
3. POWER STROKE cont. b. ? provides energy for power stroke |
cleavage of ATP (on myosin head)
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3.cont.
c. new ATP allows release of |
actin and myosin
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3. cont.
d. binding and release occurs in a racket motion indep of one another why? |
more efficient and shortening is much faster
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F. SARCOMERE LENGTH & TENSION
1. max tension develops at max level of overlap between? |
actin & myosin filaments
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SLT
2. Tension ? @ the point where? |
Z discs run into myosin bands
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SLT
3. No tension develops if? |
actin and myosin filaments are too far apart
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G. LOAD VS VELOCITY
1. Velocity is maximal if ? |
muscle contracts with no load
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L VS V
2. Velocity decreases with |
increasing load
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EXCITIATION/CONTRT. COUPLING
A. MUSCLE ACTION POT. 1.AP in muscle is of ? duration than in nerves, it is also ? than in nerves |
longer duration/ slower
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MAP
2. ? resting potentials |
similar -70 to -90
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MAP
3. Ap travels deep into the fiber by the |
transverse tubule system
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B. T-TUBULES
1. extensions of ? into the heart of the cells to the opposite side |
sarcolemma
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TT
2. Tiny tubules purpose |
brings AP
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TT
3. AP depolarizes ?, what is next to them? |
t tubules, sarcoplasmic reticulum
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C. SARCOPL. RETICUL (SR)
1. ? is released when depolarized |
Calcium
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SR
a. greatest conc of Ca in Sr is |
at terminal cisternal at end of SR
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SR
b. t tubule depolarization triggers SR to release? |
Ca that is dumped into the cytoplasm
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SR
c. Ca released into the cytoplasm binds to ? |
troponin c & pulls tropomyosin off actins active site.
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SR
C. cont Ca released into the cytoplasm allows what interaction |
actin myosin interaction (disengages troponin tropomyosin inhibitor)
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SR
C. cont Ca released unblocks ? sites |
active sites (were blocked by tropomyosin) & contraction occurs
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SR cont
2. SR is filled with what pump |
Ca
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SR cont
2. a. ? pump in the walls of SR |
ATPase
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SR cont
2. b. pumps constantly to ? |
requester Ca into SR
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MOTOR UNIT OUTPUT=
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one motor neuron axon and all indivdual muscle fibers it innervates
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MUO
A. WHOLE MUSCLE CONTRACTION= |
MANY MOTOR UNITS
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A. WHOLE MUSCLE CONTR.
1. isometric= |
muscle contracting w/out shortening (means same length)
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WMC
2. isotonic= |
muscle contractions without changing tension, fixed load (same tension)
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MUO
B. Summation multiple fiber summation= |
recruitment of additional motor units
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Summation
-size principle |
stronger signal will recruit larger motor units
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Summation
2. Freq. summation |
an increase rate of contraction
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Summation
3. tetanization= last as long as ? present |
represents max freq summation
Ca. |
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C. FATIGUE
1. follows rate of ? |
muscle glycogen depletion=metabolic fatigue (no fuel)
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FATIGUE
2. neuromuscular fatigue= |
(in tx fatigue) loss/depletion of ACh
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Fatigue
3. interruption of blood flow lose |
O2
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D. HYPERTROPHY
1.Fiber hypertrophy |
increase in size due to max force exertion
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HYPERTROPHY
is the result of ? |
increased # of myofibrils, with a build up of glycolytic enzymes in cells
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E. ATROPHY
1. If muscle unused= |
rate of decay of contractile protein eceeds rate of replacement
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ATROPHY
2. Denervation= |
no signals, atrophy begins immed. upon denervation
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Denervation can develop contracture=
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fibrous tissue replaces muscle tissue
fibrous tissue shortens permanently with time. |
