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39 Cards in this Set
- Front
- Back
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skeletal muscle tissue ______ control _______nueclei attached to bones by_____ used for moving_____ contracts_____ tires_____ |
-voluntary -multi -tendons -skeleton -rapidly -easily |
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Cardiac muscle _____control used for? input from____ |
-involuntary -pumping blood through the heart -only from central nervous sytem -uni or binucleate |
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smooth msucle _____control _____where it is loated ______used for ______how does it contract? |
-involuntary -walls of hollow organs -forcing something through a hollow tube -can contract on own without input from CNS |
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all muscles share 4 main characteristics |
1. Excitability= ability to receive and respond to stimuli 2. Contracility= ability to shorten forcibly when stimulated 3. Extensibility= ability to be stretched 4. Elasticity=Ability to recoil to resting length |
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4 main muscle functions additional functions? |
1. provide movement 2. Maintain posture and body position 3. stabilize joints 4. Generate heat as they contract protect organs, |
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skeletal muscle is an organ made up of 3 features |
1.nerve and blood supply 2.connective tissue sheaths 3. attachements |
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each muscle receives 3 things |
1. nerve 2. artery 3. veins |
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why do nerves supply every fiber of every consciously controlled muscle to control activity |
fine tuned movements |
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epimysium -what kind of connective tissue -surrounds? |
-dense irregular -entire muscle |
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perimysium -what kind of connective tissue -surrounds |
-fibrous connective -fascicles(groups of muscle fibers) |
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endomysium -what kind? -surrounds |
-fine areolar connective -each muscle fiber |
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insertion: attachment to_______ origin: attachment _____ |
-movable bone -immovable bone |
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direct attachment |
epimysium fused to periosteum of bone or prichondrium of cartilage |
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indirect |
connective tissue wrappings extend beyond mscle as ropelike tendon or sheetlike aponeurosis |
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myofibrils -specialization -how many in a muscle fiber -____packed -contains___ |
-highly specialized -100s or 1000s -densely -sarcomeres-functional unit of contraction |
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sarcolema |
plasma membrane of muscle fiber |
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sarcoplasm |
cytoplasm of a muscle fiber |
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sarcoplasmic |
specialized endoplasmic reticulum |
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glycosomes |
granules of stored glucose for energy production |
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myoglobin |
stores oxygen much like hemoglobin for cellular respiration |
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stuff in a muscle fiber |
-sarcolema -sarcoplasm -sarcoplasmic reticulum -mitochondria -glycosomes -myoglobin |
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sarcomere -basic structure |
-bands of intercollating filaments |
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thick red bands called___ thin blue bands called____ |
-myosin -actin |
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zones of sarcomere A: I: Z: H: M |
a: overlapping of actin and myosin I:actin Z:where actin attaches to backbone H:region in middle with no actin M:region where myosin is linked by accesroy proteins |
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titin |
elastic filametns that anchor myosin to z disc and run through its core/proved elasticity |
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tropomyosin -what is it and what does it do |
-long protein that covers actin active sitespreventing myosin from binding |
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troponin -how many subunits and what are they called -what do they bind with |
-3, TNL TNT and TNC -TNL with actin(inhibitory) -TNT to tropomyosin -TNC binds with calcium ions |
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when intracellular CA2+ is low.... -what state is muscle in? -which protein is active |
-muscle relaxed -tropomyosin binds to active sites |
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when intracellular CA2+ goes up what happens? |
-2 ions bind with troponin, TNC subunit and tropomyosin moves off active sites on actin allowing myosin to bind |
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sequence of cross bridge cycling |
1. Formation of cross bridge -ADP and Pi attach to myosin head -myosin head attaches to actin 2. The power stroke -myosin head bends moving actin filament -ADP and pi disassociate 3. Cross bridge detachment -ATP binds to myosin -myosin head detaches 4 Cocking of myosin head -ATP hydrolyzed -myosin head returns to position ready to form another cross bridge |
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sarcoplasmic reticulum -What is it? -What is its function? |
-endoplasmic reticulum that wraps around myofibril -release calcium when the muscle is about to contract |
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T tubules -What are they -function/2 of them -what do they connect? |
-protrusions of sarcolema into cell interior -increase surface area for muscle fibers -help spread impulses to all sarcomeres in muscle fiber -connects myofibrils |
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forms____with terminal cisternae on either side of it which are important for____ |
triads, impulse propagation |
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basic sequence of contraction |
1. Nerve impulse (action potential) arrives at muscle fiber via motor nueron 2. Action potential generated on sarcolema-transfer of ap from nerve to muscle 3. Propagation of action potential along sarcolema 4. CA2+ increase and cross bridge cycle begins |
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step1 : Neuromuscular Junction |
1.action potential arrives at axon terminal of motor nueron 2. Voltage gated ca2 channels open, ca2 enters axon terminal moving down its elechtrochemical gradient 3.ca entry causes ACh to be released by exocytosis 4.ACh diffuses across synaptic cleft and binds to receptors on sarcolema |
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action potential |
charges on either side of cell membrane are momentarily flipped in order to propagate a signal form of an electrical current down the membrane of a cell |
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overvoew of action potential steps |
1. sodium channels open 2.sodium enters 3.cell becomes more positive inside 4.k+ channels open and k leaves cell 5. inside becomes more negative (repolarized) |
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steps 3 and 4 |
-spread of action potential does down T tubules -voltage sensitive tubuleproteins change shaoe -this opens ca2+ channels -ca2 released from sarcoplasmic reticulum -causes formation of cross brisdes |
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excitation contraction coupling |
sequence of events from action potential arriving at neuromuscular junction to the formation of cross bridges |
