Neuromuscular System-sem 2 Yr 1

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| By Scrystl608
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Scrystl608
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Quizzes Created: 1 | Total Attempts: 338
| Attempts: 338
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  • 1/17 Questions

    Contraction is the result of:

    • An incease number of crossbridge attachments
    • Calcium at its basal level
    • An increase of actin filaments
    • Decreasing extracellular calcium
    • Loss of ATP
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About This Quiz

This quiz titled 'neuromuscular system-sem 2 yr 1' delves into the intricate mechanisms of muscle contraction, focusing on myosin crossbridge attachments, muscle fiber types, and the role of ATP and calcium in muscle activity. It's designed for students in their first year of a related program, enhancing understanding of human neuromuscular function.

Muscle Quizzes & Trivia

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  • 2. 

    Where and when does the myosin crossbridge attach?

    • On troponin when calcium is low

    • On troponin c when calcium is high

    • On actin when calcium is high

    • On the sarcomere when sodium is high

    • On actin when calcium is low

    Correct Answer
    A. On actin when calcium is high
    Explanation
    calcium binds to troponin C which changes conformation uncovering the actin to allow myosin attachment. This site remains blocked when calcium is low

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  • 3. 

    What does the process of active state require?

    • Extracellular calcium increase

    • Intracellular calcium increase

    • Intracellular calcium increase and ATP

    • Extracellular calcium decrease

    • ATP

    Correct Answer
    A. Intracellular calcium increase and ATP
    Explanation
    hypercalcemia can cause a sodium channel blocking effect thus causing flaccid paralysis
    hypocalcemia cause the oposite with spontaneous opening of the Na channels due to voltage flux the result is spasticity
    so intracellular ca is used from the SR but to retrieve it requires a pump for active transport- this requires ATP

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  • 4. 

    What is the signal for contraction?

    • Sodium

    • Actin

    • Myosin

    • Calcium pulse

    • Twitch

    Correct Answer
    A. Calcium pulse
    Explanation
    calcium pulse from the SR-There is no calcium current across the cell membrane in SKELETAL muscle during action potential (opposite from cardiac and smooth muscle =incease calcium in blood gives flaccid paralysis of skeletal muscle and increase activity of smooth and cardiac muscle

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  • 5. 

    Which motor units are recruited first?

    • Small

    • Type 2

    • Medium

    • Type 1

    • Large

    Correct Answer
    A. Type 1
    Explanation
    type 1 are small diam fast conduction velocity, and High excitability (easy start) they have few fibers and low contraction force / unit (they are small) they are oxidative and are low fatigue
    type 2 are largr, very fast, hard (low) excitability, they have many fibers and have high contraction force, they are glycolytic and high for fatigue
    there are no "small, medium, or large"

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  • 6. 

    If the muscle ends are clamped at a fixed length prior to the contraction, and the muscle length cannot decrease as the muscle's cell contract, is it :

    • Concentric contraction

    • Isotonic contraction

    • Eccentric contraction

    • Auxotonic contraction

    • Isometric contraction

    Correct Answer
    A. Isometric contraction
    Explanation
    isotonic includes concentric (bicep curl) and eccentric (a overly heavy weight) it has a change in lenght of muscle but the tension remains constant
    auxotonic is a contraction with some flux at the end like with ventricles pumping the blood out
    isometric is right because there is no change in length but force is generated such as hand grips

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  • 7. 

    A muscle showing to have a slow myosin isoenzyme (ATPase rate)/contraction timemoderate Sr pump capacitymoderate diffusion diametersmall motor neuron sizehigh oxidative capacity:mt content, capillary density,myoglobin contenthigh fatigue resistancemoderate glycolytic capacitylow forceaerobic activitytriglycerides as storage fuelis what type?

    • Type 11B/ fg/ ft-b/fast glycolytic/white

    • Type 11A/fog/ft-a/fast oxidative/red

    • Type 1/so/slow oxidative/white

    • Type 1A/fog/ft-a/fast oxidative/red

    • Type 2/so/slow oxidative/white

    Correct Answer
    A. Type 1/so/slow oxidative/white
    Explanation
    The given characteristics indicate that the muscle has a slow myosin isoenzyme, moderate Sr pump capacity, moderate diffusion diameter, small motor neuron size, high oxidative capacity (mt content, capillary density, myoglobin content), high fatigue resistance, moderate glycolytic capacity, low force, aerobic activity, and triglycerides as storage fuel. These characteristics are consistent with type 1 muscle fibers, also known as slow oxidative (SO) or white fibers. These fibers are characterized by their slow contraction speed, high endurance, and reliance on aerobic metabolism.

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  • 8. 

    Where is the storage facility of ATP in the sarcomere?

    • Calcium

    • Sodium

    • Actin

    • Myosin

    • Troponin C

    Correct Answer
    A. Myosin
    Explanation
    binding of crossbridges triggers the release of energy that is stored in the myosin-it is the rotation of the myosin head

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  • 9. 

    Energy expenditure that is greater than oxidative resupply of enegy during exercise is called:

    • Oxygen deficit

    • Oxygen debt

    • Hypoxia

    • Hyperemia

    • Oxygen depletion

    Correct Answer
    A. Oxygen deficit
    Explanation
    hyperemia is blood flow
    hypoxia and oxygen depletion may cause oxygen defict
    O2 debt is the culmination of O2 deficits

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  • 10. 

    A muscle showing to have a very fast myosin isoenzyme (ATPase rate)/contraction timehigh Sr pump capacityhigh diffusion diametervery large motor neuron sizelow oxidative capacity:mt content, capillary density,myoglobin contentlow fatigue resistancehigh glycolytic capacityvery high forceshort term aerobic activitycp,O2 as storage fuelis what type?

    • Type 11B/ fg/ ft-b/fast glycolytic/white

    • Type 11A/fog/ft-a/fast oxidative/red

    • Type 1/so/slow oxidative/white

    • Type 1A/fog/ft-a/fast oxidative/red

    • Type 2/so/slow oxidative/white

    Correct Answer
    A. Type 11B/ fg/ ft-b/fast glycolytic/white
    Explanation
    The given answer, type 11B/ fg/ ft-b/fast glycolytic/white, is the correct answer because the characteristics mentioned in the question align with the traits of type 11B muscle fibers. These fibers have a very fast myosin isoenzyme (ATPase rate), high glycolytic capacity, low oxidative capacity, low fatigue resistance, and high force production. They also have a high diffusion diameter, high Sr pump capacity, and very large motor neuron size. These characteristics indicate that the muscle is designed for short-term, high-intensity activities and relies on anaerobic metabolism for energy production. Additionally, the reference to "white" in the answer refers to the color of these muscle fibers due to their low myoglobin content.

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  • 11. 

    After a muscle relaxes and the compression of the vessels are relieved there is a sustained increase in blood flow. This is called?

    • Hypertrophy

    • Hypoxia

    • Maximal voluntary contraction

    • Reactive hyperemia

    • Hyporemia

    Correct Answer
    A. Reactive hyperemia
    Explanation
    hypertrophy is the increase in the volume of an organ
    hypoxia is O2 deficiency
    maximal voluntary contraction a muscle that exerts more than 70% of its maximal force (compresses blood flow
    reactive hyperemia is the right answer and
    hyporemia is made up

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  • 12. 

    A muscle showing to have a fast myosin isoenzyme (ATPase rate)/contraction timehigh Sr pump capacitysmall diffusion diameter large motor neuron sizevery high oxidative capacity:mt content, capillary density,myoglobin contentmedium fatigue resistancehigh glycolytic capacityv high forcelong term aerobic activitycp,O2 as storage fuelis what type?

    • Type 11B/ fg/ ft-b/fast glycolytic/white

    • Type 11A/fog/ft-a/fast oxidative/red

    • Type 1/so/slow oxidative/white

    • Type 1A/fog/ft-a/fast oxidative/red

    • Type 2/so/slow oxidative/white

    Correct Answer
    A. Type 11A/fog/ft-a/fast oxidative/red
    Explanation
    The given characteristics suggest that the muscle is type 11A, also known as fog/ft-a, which refers to fast oxidative/red muscle fibers. These fibers have a high oxidative capacity, indicated by factors such as mt content, capillary density, and myoglobin content. They also have medium fatigue resistance and high glycolytic capacity. The presence of a fast myosin isoenzyme (ATPase rate) and a large motor neuron size further supports the classification of the muscle as type 11A.

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  • 13. 

    When is ATP initially used in the crossbridge cycle?

    • In rigor mortis

    • In relaxation

    • In excitation

    • In hydrolysis

    • In product release

    Correct Answer
    A. In relaxation
    Explanation
    ATP is used in binding Myosin head to actin and the E is stored in the head

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  • 14. 

    What second messenger is involved in the binding of myosin to actin in skeletal muscle and cardiac muscle

    • Calcium

    • Tropomyosin

    • Troponin c

    • Myosin

    • ATP

    Correct Answer
    A. Calcium
    Explanation
    Calcium is the correct answer because it acts as a second messenger in the binding of myosin to actin in skeletal and cardiac muscle. When calcium ions are released into the muscle cell, they bind to troponin C, which causes a conformational change in the troponin-tropomyosin complex. This change allows myosin to bind to actin, initiating muscle contraction. Without the presence of calcium, the binding of myosin to actin cannot occur, and muscle contraction cannot be initiated.

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  • 15. 

    What is the most efficient method of ATP generation?

    • Glycolysis

    • Phosphorylation

    • Gluconeogenesis

    • Oxidation of fatty acids

    • Chemiosmosis

    Correct Answer
    A. Oxidation of fatty acids
    Explanation
    oxidation of fatty acids is the slowest but most efficient
    phosphorylation is fast but a temporary fix while waiting for permanent
    glycolysis is fast but inefficient

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  • 16. 

    Which is not a primary cause of cellular fatigue in the muscle cell?

    • Increased intracellular ADP

    • Metabolic waste- lactic acid and phosphate

    • Slowed type 2 motor units

    • Depletion of ACh

    • Increased intracellular potassium

    Correct Answer
    A. Slowed type 2 motor units
    Explanation
    the type 2 are the first to stop at which point the type 1 will continue-albiet slower and with less force-but primary is the key word

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  • 17. 

    Fiber types within the skeletal muscle generating force and movement are?

    • Intrafusal

    • Thick filament

    • Extrafusal

    • Thin filament

    • Nuclear chain fibers

    Correct Answer
    A. Extrafusal
    Explanation
    extrafusal are the series of linked sarcomeres (z line-zline)(thick myosin and thin actins) the shortening of sarcomeres generates force and movement via alpha motor neuron AP>release of ACh>binds to nicotinic receptoe>EPP>AP in musc membrane
    intrafusal=not controlled by alpha motor neuron-even though actin and myosin
    parallel to extrafusal
    nuclear chain fibers wrap around end of intrafusal as sensory nerve fibers along with nuclear bag fibers- they report musc contraction status via gamma Efferents
    they are regulators-adjusting sensitivity of sensory system
    they influence flow of info through 1A and 11 Afferents

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  • Current Version
  • Mar 21, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Apr 23, 2010
    Quiz Created by
    Scrystl608
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