Term
| What happens when the axon of motor neuron generates and transmits action potential to the axonal terminals |
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Definition
| results in the release of Acetylcholine from vesicles in the axonal terminals to the neuromuscular cleft (synaptic cleft) |
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Term
| What does binding of ACh to receptors on the motor end plate cause? |
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Definition
| Depolarization- which leads to the generation of action potential at the motor end plate |
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Term
| What occurs when the action potential spreads across the entire sarcolemma and into the T-tubules of the triads |
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Definition
| results in the release of calcium ions from the terminal cisternae of the triads into the sarcoplasm |
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Term
| When calcium ions bind to TnC what happens? |
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Definition
| the removal of tropomyosin from blocking the myosin binding sites on actin |
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Term
| When tropomyosin blockade is gone... |
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Definition
| activated myosin heads=cross bridges bind to the accessible myosin-binding sites on actin |
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Term
| when ADP and Pi dissociate from the cross bridges, the attached crossed bridges change their orientation = |
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Definition
| POWER STROKE - from a right angle to a bent position pulling the attached thin filament inward into the h zone toward the m line = MUSCLE CONTRACTION |
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Term
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Definition
| NEW ATP molecules bind to the attached myosin heads causing them to DETACH |
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Term
| What is responsible for the coupling of excitation to the contraction of skeletal muscles |
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Definition
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Term
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Definition
| lack of new ATP - ATP synthesis ceases - muscles remain contracted --> cross bridge detachment is impossible |
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Term
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Definition
| ATP deficit = can't keep up with demand |
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Term
| Anaerobic catabolism of glucose |
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Definition
| pyruvic acid is converted into LACTIC ACID which reduces blood pH and contributes to muscle fatigue |
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Term
| change in muscle in aerobic/endurance exercises |
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Definition
| increase in capillaries, mitochondria, myoglobin,stamina |
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Term
| change in muscle in resistance exercise |
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Definition
increase in muscle size=hypertrophy
increase in glycogen
bigger muscles=increased muscle strength |
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Term
| why do fast glycolytic fibers tire quickly |
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Definition
| tires quickly because glycogen reserves are short-lived and lactic acid accumulates quickly, making it a fatigable fiber |
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Term
| How are thick and thin filaments in smooth muscle arranged |
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Definition
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Term
| Do smooth muscles have sarcomeres? |
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Definition
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Term
| Do thin filaments in smooth muscle have troponin |
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Definition
|
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Term
| What does calcium bind to in smooth muscle |
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Definition
|
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Term
| do smooth muscles have Z discs? |
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Definition
|
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Term
| What do dense bodies in smooth muscle do? |
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Definition
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Term
| What structures in smooth muscles resist tension? |
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Definition
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Term
| Does the sarcolemma of smooth muscle have T-tubules? |
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Definition
| no, the sarcolemma has shallow cavities called CAVEOLAE = extracellular fluid rich in calcium |
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Term
| Single Unit smooth muscles |
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Definition
-composed of circular and longitudinal smooth muscle sheets
-innervated by autonomic nerve fibers
-electrically-coupled by gap junctions=CONTRACTS AS A UNIT
-stimulated to contract by chemicals
**EXHIBIT PACEMAKER ACTIVITY |
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Term
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Definition
-composed of individual smooth muscle fibers
-LACKS gap junctions=CONTRACT INDEPENDENTLY
-innervated by the autonomic nerve fibers
-stimulated to contract by chemicals
NO pacemaker activity |
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Term
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Definition
-uninucleate
-striated= presence of sarcomeres
-T-tubules present = TRIADS ARE ABSENT
-highly branched cells with membrane junctions called INTERCALATED DISCS
-electrically coupled
-demososmes |
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Term
| Why are cardiac cells electrically-coupled? |
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Definition
| due to the presence of GAP JUNCTIONS and the cardiac muscle contracts as a single unit = FUNCTIONAL SYNCYTIUM |
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Term
| What are intercalated discs? |
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Definition
| membrane junctions- contain gap junctions and desmosomes |
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Term
| What do desmosomes do in cardiac muscle? |
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Definition
| prevent cardiac cells from separating when cardiac muscle contracts |
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Term
| Used by what muscles: Calcium-entry calcium release mechanism |
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Definition
| smooth muscle and cardiac muscle |
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Term
| Calcium channel blocker does what? |
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Definition
| inhibit contraction of smooth muscle and cardiac muscle |
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Term
| striations present in which muscles? |
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Definition
| skeletal muscle and cardiac muscle |
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Term
| Which muscles are sarcomeres present? |
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Definition
| Skeletal and cardiac muscle |
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Term
| which muscles have T-tubules |
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Definition
|
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Term
| in which muscles does Ca2+ bind to TnC |
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Definition
| skeletal and cardiac muscle |
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Term
| presence of gap junctions in which muscles ? |
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Definition
| single-unit smooth muscle and cardiac muscle |
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Term
| function syncytium in which muscles? |
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Definition
| single-unit smooth muscle and cardiac muscle |
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Term
| involuntary muscle control of contraction in what muscles |
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Definition
| smooth muscle and cardiac muscle |
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Term
| voluntary control of muscle contraction in which muscles? |
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Definition
|
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Term
| How does smooth muscle grow? |
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Definition
| hyperplasia and hypertrophy |
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Term
| Skeletal and cardiac muscle grow by... |
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Definition
|
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Term
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Definition
| increase in sie of a tissue or organ independent of the bodys general growth |
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Term
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Definition
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Term
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Definition
| layer of fibrous CT that surrounds each VESICLE |
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Term
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Definition
| bundle of muscle fibers -> consists of a group of endomysium-covered muscle fibers |
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Term
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Definition
| thin CT membrane that surrounds the WHOLE muscle |
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Term
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Definition
| sheath of CT that surrounds each individual muscle FIBER |
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Term
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Definition
| dense CT connecting muscle to bone |
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Term
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Definition
| plasma membrane of skeletal muscle fiber |
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Term
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Definition
| cytoplasm of a muscle cell --> contains glycosomes (stores glucose) |
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Term
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Definition
| smooth endoplasmic reticulum (stores/releases calcium into the sarcoplasm) |
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Term
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Definition
| red pigment that stores oxygen |
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Term
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Definition
| region between two z discs= smallest contractile unit of a muscle fiber= functional unit of a skeletal muscle |
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Term
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Definition
| midline of the I band - anchors thin filaments |
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Term
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Definition
| midline of the A band- not overlapping with A band |
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Term
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Definition
| dark bands of muscle fiber- THICK filament |
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Term
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Definition
| light bands of muscle fiber- regions of THIN filaments not overlapping with A band |
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Term
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Definition
| a grouping of t-tubule with paired terminal cisterns (2) of the sarcoplasmic reticulum- Function= for the release of calcium ions inro the sarcoplasm when the sarcolemma DEPOLARIZES |
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Term
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Definition
| consists of one motor neuron and all the muscle fibers in it |
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Term
| direct attachment of muscle |
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Definition
| the epimysium of the skeletal muscle is fused directly to the periosteum - cranial muscles |
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Term
| indirect attachment of muscle |
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Definition
| the CT wrappings of the skeletal muscle extends as a tendon or an aponeurosis to anchor the muscle to bone, cartilage or fascia |
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Term
| Attachment sites for each skeletal muscle |
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Definition
1. origin= the immovable bone
2. insertion= the bone that moves during muscle contraction |
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