Muscle Contraction and Purkinje Fibers Quiz
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Questions and Answers

What provides room for myosin and actin to bind during muscle contractions?

  • ADP attachment
  • Loss of phosphate (correct)
  • Sliding of filaments
  • ATP detachment
  • Which specialized bundle of neurons generates action potential at a faster rate than other areas of the heart?

  • AV node
  • Bundle of His
  • Purkinje fibers
  • SA node (correct)
  • What causes the influx of Ca2+ and Na+ into the cells during depolarization?

  • Removal of positive ions
  • Opening of K+ channels
  • Resting membrane potential
  • Increased action potential (correct)
  • What is responsible for the elongated graph in autorhythmic cells?

    <p>Continuous response</p> Signup and view all the answers

    What breaks the cross bridge formed between actin and myosin during muscle contraction?

    <p>ATP attachment</p> Signup and view all the answers

    What interconnected cardiomyocytes by GAP junctions to involve the entire heart in each contraction?

    <p>Purkinje fibers</p> Signup and view all the answers

    What is the primary function of gap junctions in the cardiovascular system?

    <p>Allowing electrical activity (action potentials) to pass through</p> Signup and view all the answers

    What distinguishes ventricular fibrillation from atrial fibrillation?

    <p>Ventricular fibrillation is life-threatening due to reduced cardiac output</p> Signup and view all the answers

    What is the role of the sympathetic nervous system in the cardiovascular system?

    <p>Facilitating fight or flight responses with adrenaline</p> Signup and view all the answers

    During early ventricular diastole, what is the state of the atria and ventricles?

    <p>Both are relaxed, and atria begin to passively fill up with blood</p> Signup and view all the answers

    What is the main purpose of valves in the cardiovascular system?

    <p>Preventing backflow of blood and allowing build-up of pressure</p> Signup and view all the answers

    What can be measured as a biomarker for myocardial necrosis?

    <p>Troponin</p> Signup and view all the answers

    What is the primary responsibility of blood in the body?

    <p>Transporting nutrients and waste products</p> Signup and view all the answers

    What structure provides lubrication to the heart and prevents over inflation?

    <p>Pericardium sac</p> Signup and view all the answers

    What is the function of T tubules in muscle cells?

    <p>Extending deep into a fibrous core to reach every microfibril</p> Signup and view all the answers

    Which structure in the muscle cells provides a rapid source of energy?

    <p>Mitochondrion</p> Signup and view all the answers

    Where does the intrinsic conduction system of the heart initiate the cardiac cycle?

    <p>SAN (sinoatrial node)</p> Signup and view all the answers

    What type of cells are autorhythmic and able to intrinsically start a conduction system in the heart?

    <p>Cardiac cells</p> Signup and view all the answers

    What is the role of the sinoatrial node in the heart?

    <p>It provides a necessary delay in the cardiac cycle</p> Signup and view all the answers

    What causes the muscle to contract in the heart?

    <p>Binding of Ca2+ to troponin moves tropomyosin away from myosin binding sites on actin</p> Signup and view all the answers

    What is the main characteristic of the cardiac muscle contractions?

    <p>They are myogenic and occur spontaneously</p> Signup and view all the answers

    What is used as a biomedical marker to determine myocardial infarction (MI) severity?

    <p>Free floating troponin</p> Signup and view all the answers

    What provides room for myosin and actin to bind during muscle contractions?

    <p>Repositioning of energised myosin head</p> Signup and view all the answers

    Which specialized group of cells generates impulses at a faster rate than any other areas of the heart?

    <p>Sinoatrial node</p> Signup and view all the answers

    What is the primary function of gap junctions in the cardiovascular system?

    <p>To involve the entire heart in each contraction</p> Signup and view all the answers

    What distinguishes cardiac muscle contractions from skeletal muscle contractions?

    <p>The ability to maintain a rhythm without external stimuli</p> Signup and view all the answers

    What does necrosis indicate in terms of cardiac biomarkers?

    <p>Free floating troponin in blood or surrounding tissue</p> Signup and view all the answers

    What is responsible for connecting each of the cardiomyocytes together?

    <p>Gap junctions between cells</p> Signup and view all the answers

    Study Notes

    Muscle Contraction and Cardiac Function

    • The sliding filament theory provides room for myosin and actin to bind during muscle contractions.
    • The sinoatrial (SA) node, a specialized bundle of neurons, generates action potentials at a faster rate than other areas of the heart.
    • The influx of Ca2+ and Na+ into cells during depolarization is caused by electrical impulses.
    • The elongated graph in autorhythmic cells is responsible for the slow diastolic depolarization.
    • ATP breaks the cross-bridge formed between actin and myosin during muscle contraction.
    • Gap junctions interconnect cardiomyocytes, allowing the entire heart to be involved in each contraction.

    Cardiovascular System

    • The primary function of gap junctions in the cardiovascular system is to facilitate the conduction of electrical impulses between cardiomyocytes.
    • Ventricular fibrillation is distinguished from atrial fibrillation by its irregular and rapid contraction of the ventricles.
    • The sympathetic nervous system increases heart rate and contraction force in the cardiovascular system.
    • During early ventricular diastole, the atria are in the diastolic phase, and the ventricles are in the isovolumic relaxation phase.
    • The main purpose of valves in the cardiovascular system is to ensure unidirectional blood flow.

    Blood and Cardiac Biomarkers

    • Blood is primarily responsible for transporting oxygen and nutrients to tissues and removing waste products.
    • The pericardium provides lubrication to the heart and prevents over-inflation.
    • T-tubules in muscle cells facilitate rapid transmission of electrical impulses.
    • The sarcoplasmic reticulum provides a rapid source of energy for muscle cells.
    • Troponin can be measured as a biomarker for myocardial necrosis.
    • The primary responsibility of blood is to transport oxygen and nutrients to tissues and remove waste products.

    Cardiac Muscle and Conduction System

    • The intrinsic conduction system of the heart initiates the cardiac cycle in the sinoatrial (SA) node.
    • Autorhythmic cells, such as those in the SA node, can intrinsically start a conduction system in the heart.
    • The sinoatrial node is responsible for generating the heart's rhythmic contractions.
    • Muscle contraction in the heart is caused by the electrical impulses generated by the sinoatrial node.
    • The main characteristic of cardiac muscle contractions is their involuntary and rhythmic nature.
    • Cardiac troponin is used as a biomedical marker to determine myocardial infarction (MI) severity.
    • Necrosis, as indicated by cardiac biomarkers, suggests cardiac tissue damage or death.

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    Description

    Test your knowledge of muscle contraction and Purkinje fibers with this quiz. Learn about the process of actin and myosin attachment, cross bridge formation, and the role of SA nodes in regulating heartbeats.

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