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59 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What are the functions of the skeletal muscle?
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Skeletal Movement, maintain posture and body position, suport soft tissues, guard entrances and exits (opening of digestive tract), maintain body temp., store nutrient reserves
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Pg. 284
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How does skeletal muscle looks like?
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Multinucleated, striated, voluntary, long fibers
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slide 3
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What are the 4 characteristics of skeletal muscle?
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excitable (respond electrically impulse move down muscle), conductive (cause contraction), contractile(muscle shorten), extensible(able to stretch them), elastic (pop back in place, ex: diaphragm, exhale - pop back, inhale - contract)
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Slide 4
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How does a cardiac muscle looks like?
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Branched (small short), 1 nucleus, striated, involuntary, intercalated disc (allow direct communicate w/next cell, cytoplasm can mvoe directly, no need nerve)
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Refers to flashcard 2
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How does a smooth muscle looks like?
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spindle-shaped, no striation-not regularly arranged, involuntary, 1 nucleus (centrally located), arranged in sheet
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Refers to flashcard 4
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What is epimysium?
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Surround the entire muscle, continue in deep fascia
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Largest
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What is perimysium?
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Surround individual, comparted each muscle group
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Medium
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What is fascicle?
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compartment
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Perimysium surround these!
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What is endomysium?
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Surround individual fiber
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Small
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What is sarcolemma?
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Pertains muscle fiber
Cellmembrane of a muscle fiber |
Like cell membrane
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What is sarcoplasm?
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Cytoplasm of the muscle fiber
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"plasm" cell have these
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What is T(transverse) tubules?
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invaginated, allow excitable (action potential move down into muscle)
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Like rubber band
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What is sarcoplasmic reticulum?
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Store calcium
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Minterals for contraction to occur
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Terminal Cisternae?
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On either side of a T tubule, the tubules of the SR enlarge, fuse and form expanded chambers
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Bloated Sarcoplasmic reticulum
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Triad?
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T tubules in the middle with 2 terminal cisternae on either side fo the T tubules
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The 3
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What is myofilaments?
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Protein filaments
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Both thin and thick
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Myosin?
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Thick filament (golf club w/ 2 heads)
Tails, heads |
Must know
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Actin?
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Thin filament (strings of balls), specialized cite (active site for myosin to bind)
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Must know
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Tropomyosin?
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Prevent exposure of active site (double stranded to cover active site)
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No
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Troponin?
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3 globular subunits, 1 bind w/ tropomyosin, 2 binds to 1 G actin, 3 receptor that binds a calcium ion.)
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CA+
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Sarcomere?
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Functional contractile unit
Alternating thick & thin filaments |
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A band?
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Overlap of thick and thin filaments + middle with only thick filaments
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DARK
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H zone?
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Middle of sarcomere with only thick filament
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I band?
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only thin filament
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LIGHT
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M line?
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Middle Line
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Z line?
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Mark the boundary between adjacent sarcomeres.
Attachment of thin filaments, attachment of titin (anchors for myosin) |
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What is it about the structure of the myofibril that gies skeletal muscle its striated appearance?
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Dark band - thick and thin filament overlaps
Light zone - H zone, I band |
Pt. of discussion
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What is Ion Channels?
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Integral membrane proteins
Acts as "channels" to allow specific ions across the cell membrane. Can be gated - gates can be opened & closed based on certain events (charge, ligands...etc.) Leak channels (not gated) |
Gated vs. non gated community
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What requires ATP to move things from interstitial fluid to cytoplasm on cell membrane?
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Na+/K+ pumps
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Active transporters
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How many Na+ and K+ does the sodium potassium pump move across?
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3 Na+ ions from inside to outside
2 K+ ions from outside to inside |
Low sodium
(cell is -1 charged) |
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What happen in action potential?
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Reversal of charge
from + to -/ from - to + Change in voltage inside cell at threshold - fire action potential |
NEED TO KNOW!!!!!!!
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Basics of an action potential beginning w/ resting membrane potential & ending w/ resting membrane potential
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Cell reach threshold, Na+ gate open and Na+ rushes in, (depolorazation - changes from - to +) reaches +30 mV, voltage gated K+ open, Na+ channel closed (K+ deflux repolarization), Reaches hyperolarization "slow and lazy" K+ channel
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Curare?
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Non-depolarizing muscle relaxant, competes w/ Ach for Ach receptors, it blocks Ach receptors so Ach can't binds to receptor. Used as anesthesia.
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Anesthesia
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Synapse?
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Neuron communicate w/ other cells
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On neuron
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Spnaptic knob?
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neuron end
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Motor end plate?
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Muscle end
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on muscle or other cells
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What are the 4 phases of the sliding filament model?
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Excitation, coupling, contraction, relaxation
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Movement of actin & myosin past one another
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What happen in excitation?
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1. Arrival of an action potential
2. Release of ACh. 3. ACh binding at the motor end plate.(Changes the permeability of the motor end plate to Na+ ions) Na+ rushes into the sarcoplasm. 4. Appearance of an Action potential in the sarcolemma (generates AP in sarcolemma, sweeps across the entire membrane surface, down to T tubules) 5. Return to initial state. |
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What happen in excitation-contraction coupling?
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1. AP wave spreads in all direction and continue down T-tubules
2. AP signals opening of Ca+ channels in SR 3. Ca+ binds to troponin 4. Troponin moves tropomyosin out of the way |
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What happen in contraction?
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1. Myosin binds to actin (cross-bridge formation)
2. Power-stroke (attached & pull) ADP + Pi move off 3. ATP binds to detach head 4. ATP hydrolysis - ATP to ADP + Pi ("Re-cocks" myosin head |
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What happen in relaxation?
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1. ACh release stops
2. ACh dissociates from receptor - AChE breaks it down 3. SR actively pumps excess Ca+ back in - Calsequestrin sequesters(putting Ca+ away = can't bind troponin) 4. Tropomyosin moves back to block myosin from binding ACh - AP - Ca+ releases - contraction Action potential depolarized |
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Motor nerve (movement)?
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Motor neuron + muscle fibers = motor unit
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What consist of?
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What is length-tension relationship?
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Tension proportional to # cross bridge attachments
Frequency of stimulation The more cross-bridge, the more forces on myosin to pull actins. |
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What are the periods in muscle twitch?
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1. Laten period - AP is needed happen before contraction occur.
2. Period of contraction 3. Period of relaxation |
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What are the frequency of stimulation?
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one motor unit, purpose to perform smooth contractions, wave summation, tetanus - unfused, fused
muscle fatigue |
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What happen when the greater the force to exert, the more motor unit to recruit?
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Recruitment
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Treppe?
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Later contraction might have greater force. Signals comes right after relaxation and Ca+ builds up
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What is it called when muscles always slightly contracted?
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Muscle tone - to maintain posture respond due to gravity, tuning and adjusting
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Isotonic?
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Force is greater than load.
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Concentric?
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Shorten to do work
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Eccentric?
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contracting while stretching
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Isometric?
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Same Measure
Load is greater than force (Not moving, nor shortening) |
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What muscle do you think would have larger motor units?
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Quadracept & bicept.
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How about small motor units? Why?
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Fingers, for fine movement
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What gives an umps @ beginning and can store phosphate?
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Creatine Phosphate. Transfer to ADP then to ATP
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What split sugar to form pyruvate acid and no oxygen needed, then to lactic acid and produce 2 ATP?
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Anaerobic Glycolysis
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in muscle fatigue & oxygen debt, what causes the muscle inability to contract?
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depleted metabolic reserves, damaged, decrease in pH (acidosis) - denature proteins (destroy shpae of proteins)
Decrease in Ca+ Weariness of muscles & nerves |
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What are the slow muscle fibers?
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(red) aerobic - have myoglobin
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What are the fast muscle fibers?
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(white) not much oxygen, not much mitochondria
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