Cardiovascular Physiology Quiz
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Questions and Answers

What calculation determines the stroke volume (SV)?

  • End-diastolic volume (EDV) minus end-systolic volume (ESV) (correct)
  • End-diastolic volume (EDV) plus end-systolic volume (ESV)
  • End-systolic volume (ESV) minus end-diastolic volume (EDV)
  • End-diastolic volume (EDV) multiplied by end-systolic volume (ESV)

    • If the end-diastolic volume (EDV) is 130 ml and the end-systolic volume (ESV) is 60 ml, what is the stroke volume (SV)?

  • 130 ml
  • 200 ml
  • 60 ml
  • 70 ml (correct)

    • What is the approximate cardiac output (CO) for a person with a heart rate (HR) of 75 beats per minute and a stroke volume (SV) of 80 ml?

  • 5.0 liters/min
  • 7.5 liters/min
  • 6.0 liters/min (correct)
  • 4.0 liters/min

    • Which of the following statement correctly describes ejection fraction?

    <p>The percentage of blood ejected from the ventricle with each contraction. (B)</p> Signup and view all the answers

    If a person has an end-diastolic volume (EDV) of 140 ml and a stroke volume (SV) of 70 ml, what is the ejection fraction?

    <p>50% (A)</p> Signup and view all the answers

    What is primarily responsible for the initial slow depolarization phase of the pacemaker potential?

    <p>Leakage of sodium ions into the cell and potassium ions out through nonspecific cation channels. (D)</p> Signup and view all the answers

    Which event causes the full depolarization phase in pacemaker cells?

    <p>Opening of voltage-gated calcium channels. (D)</p> Signup and view all the answers

    What triggers the repolarization phase in pacemaker cells?

    <p>The closure of calcium channels and opening of potassium channels. (B)</p> Signup and view all the answers

    What causes the minimum potential phase (hyperpolarization) in pacemaker cells?

    <p>The sustained opening of voltage-gated potassium channels. (A)</p> Signup and view all the answers

    Where is the sinoatrial (SA) node located?

    <p>In the upper right atrium, slightly inferior and lateral to the opening of the superior vena cava. (A)</p> Signup and view all the answers

    What is the intrinsic rate of depolarization of the SA node?

    <p>About 60 or more times per minute (A)</p> Signup and view all the answers

    Which of the following systems can influence the rate of depolarization of the SA node?

    <p>The sympathetic and parasympathetic nervous systems. (B)</p> Signup and view all the answers

    Which of the following best describes the effect of bundle branch blocks on the QRS complex?

    <p>The QRS complex is widened. (D)</p> Signup and view all the answers

    The calcium ion channels in pacemaker cells are which type of gated channels?

    <p>Time-gated (B)</p> Signup and view all the answers

    During ventricular filling, what is the relationship between the pressures in the ventricles and atria?

    <p>Ventricular pressures are lower than atrial pressures. (B)</p> Signup and view all the answers

    What is the main characteristic of atrial fibrillation on an ECG tracing?

    <p>Irregularly irregular rhythm with absent P waves. (D)</p> Signup and view all the answers

    What is the immediate treatment for ventricular fibrillation?

    <p>Defibrillation. (A)</p> Signup and view all the answers

    What prevents the backflow of blood from the pulmonary trunk and aorta into the ventricles during ventricular filling?

    <p>The closure of the semilunar valves. (B)</p> Signup and view all the answers

    What causes the atrioventricular valves to open during the ventricular filling phase?

    <p>Higher atrial pressure compared to ventricular pressure. (C)</p> Signup and view all the answers

    Why is defibrillation ineffective in cases of asystole?

    <p>There is no electrical activity to reset in asystole. (D)</p> Signup and view all the answers

    Approximately what percentage of the total atrial blood volume drains passively into the ventricles?

    <p>80% (B)</p> Signup and view all the answers

    Which condition is described as chaotic electrical activity in the ventricles, resulting in the heart’s inability to effectively pump blood?

    <p>Ventricular fibrillation. (C)</p> Signup and view all the answers

    What is a common visual comparison used to describe the movement of a fibrillating muscle?

    <p>A plastic bag full of writhing earthworms. (A)</p> Signup and view all the answers

    What event immediately follows the end of the passive filling of the ventricles?

    <p>Atrial systole. (A)</p> Signup and view all the answers

    What is the approximate volume of blood in each ventricle at the end of atrial systole, also known as the End-Diastolic Volume (EDV)?

    <p>120 ml (A)</p> Signup and view all the answers

    What is the typical treatment for asystole, given that defibrillation is not appropriate?

    <p>CPR combined with medications like atropine and epinephrine. (B)</p> Signup and view all the answers

    Which of the following is TRUE about atrial fibrillation?

    <p>It is generally not life-threatening because it does not affect ventricular filling. (A)</p> Signup and view all the answers

    What causes the S1 heart sound at the beginning of ventricular systole?

    <p>The closure of the atrioventricular valves. (A)</p> Signup and view all the answers

    What characterizes the isovolumetric contraction phase?

    <p>Both AV and semilunar valves are closed, ventricular volume does not change. (A)</p> Signup and view all the answers

    What event is primarily responsible for the opening of the semilunar valves?

    <p>Increased pressure in the ventricles. (D)</p> Signup and view all the answers

    What is the approximate volume of blood remaining in each ventricle at the end of the ventricular ejection phase, also known as end-systolic volume (ESV)?

    <p>50 ml (D)</p> Signup and view all the answers

    During the isovolumetric relaxation phase, what action causes the second heart sound (S2)?

    <p>Closing of the semilunar valves. (A)</p> Signup and view all the answers

    What is the state of the ventricles during the isovolumetric relaxation phase, in relation to blood volume?

    <p>No blood is entering or leaving them, so the volume stays constant. (A)</p> Signup and view all the answers

    If a person has a heart rate (HR) of 75 beats per minute and a stroke volume (SV) of 70 ml, what is their cardiac output (CO) in ml/min?

    <p>5250 ml/min (D)</p> Signup and view all the answers

    What is the term for the amount of blood pumped by the ventricle in one heartbeat?

    <p>Stroke Volume (C)</p> Signup and view all the answers

    What is the average range for the number of cardiac cycles (beats) per minute?

    <p>60-80 cycles per minute (A)</p> Signup and view all the answers

    Why does the ejection of blood from the ventricles decrease as the ventricular ejection phase continues?

    <p>The pressure in the pulmonary trunk and aorta approaches that in ventricles. (C)</p> Signup and view all the answers

    What is the primary effect of acetylcholine release on the heart?

    <p>Decrease in the rate of action potential generation. (B)</p> Signup and view all the answers

    Which of the following has the strongest negative inotropic effect on the heart?

    <p>Parasympathetic Vagus nerve stimulation (B)</p> Signup and view all the answers

    What is the effect of epinephrine and norepinephrine on the heart?

    <p>They have similar effect to the sympathetic nervous system and longer-lasting effects. (C)</p> Signup and view all the answers

    Which hormone decreases blood volume and preload, thereby reducing cardiac output?

    <p>Atrial natriuretic peptide (D)</p> Signup and view all the answers

    How does an increase in body temperature affect the heart's sinoatrial (SA) node?

    <p>The SA node fires more rapidly. (B)</p> Signup and view all the answers

    What effect does increasing blood volume have on cardiac output?

    <p>It increases preload and increases cardiac output. (A)</p> Signup and view all the answers

    Which of the following is a positive chronotropic agent?

    <p>Adrenaline (A)</p> Signup and view all the answers

    What is the effect of increased extracellular electrolyte concentration on cardiac output?

    <p>Affects the length and magnitude of action potential (B)</p> Signup and view all the answers

    Study Notes

    Human Anatomy & Physiology, Chapter 17: The Cardiovascular System I: The Heart

    • The cardiovascular system comprises the heart, blood vessels, and blood.
    • The heart is a cone-shaped organ situated slightly left of the center in the thoracic cavity; it rests on the diaphragm and its apex points towards the left hip.
    • The heart is roughly the size of a fist and weighs approximately 250-350 grams.
    • The heart's superior chambers are the atria, and the inferior chambers are the ventricles.
    • The atrioventricular sulcus is an indentation externally marking the boundary between the atria and ventricles.
    • The interventricular sulcus is an externally visible depression separating the right and left ventricles.
    • Blood enters the atria from veins and is pumped into arteries from ventricles.
    • The heart has two main circuits; the pulmonary circuit, which carries blood to and from the lungs, and the systemic circuit, which carries blood to the rest of the body.
    • In the pulmonary circuit, the right side of the heart pumps oxygen-poor blood to the lungs where it becomes oxygenated.
    • The pulmonary arteries transfer deoxygenated blood.
    • In the systemic circuit, the left side of the heart receives this oxygenated blood from the lungs and pumps it throughout the body.
    • Oxygen-rich blood is carried in arteries to the tissues and oxygen-poor blood is collected in veins and returned to the heart.
    • The heart has four chambers and valves that assure blood flow in only one direction.

    Heart Chambers and Valves

    • The heart has four chambers: two atria and two ventricles.
    • The atria receive blood; the ventricles pump blood.
    • The atria contract to pump blood into the ventricles, where the ventricles contract to pump blood into the arteries.
    • Heart valves ensure blood flows in one direction.
    • The tricuspid valve is the right AV valve; the bicuspid (mitral) valve is the left AV valve.
    • Each valve has flaps called cusps that close when ventricles contract, preventing backflow.
    • Semilunar valves (pulmonary valve & aortic valve) are found near where the heart pumps blood out; they prevent backflow from the arteries into the ventricles.

    Blood Vessels

    • Blood vessels, including arteries, veins, and capillaries, form a network to transport blood throughout the body.
    • Major systemic veins include the superior and inferior vena cava, which drain blood into the right atrium.
    • The pulmonary trunk receives blood from the right ventricle and branches into right and left pulmonary arteries.
    • These arteries carry blood to the lungs for oxygenation.
    • Oxygenated blood returns to the heart via pulmonary veins to the left atrium.
    • The aorta, the largest artery in the body, receives blood from the left ventricle and distributes it to the rest of the body's systemic circuit.

    The Heart's Great Vessels

    • The superior vena cava (SVC) drains deoxygenated blood from the upper body.
    • The inferior vena cava (IVC) drains blood from the lower body.
    • The pulmonary trunk is the main vessel carrying blood from the right ventricle to the lungs.
    • It branches to the right and left pulmonary arteries.
    • Pulmonary veins return oxygenated blood from the lungs to the left atrium.
    • The aorta receives oxygenated blood from the left ventricle and distributes it throughout the body.

    The Coronary Circulation

    • The heart receives blood from coronary arteries, which branch from the aorta.
    • The network of channels facilitates adequate oxygen and nutrient supply to all parts of the heart tissue.
    • Coronary veins collect deoxygenated blood and return it to the right atrium through the coronary sinus.
    • Blockage in the coronary arteries can lead to heart attack.

    Cardiac Muscle Tissue Anatomy and Electrophysiology

    • The heart's rhythmic contraction arises from specialized cardiac muscle cells' autorhythmicity.
    • Cardiac muscle cells exhibit unique structures called intercalated discs (desmosomes and gap junctions), contributing to coordinated contraction.
    • The heart's electrical activity, orchestrated by specialized pacemaker cells, creates the heartbeat.
    • The SA and AV nodes are two significant pacemaker regions, establishing the heart's rhythm.
    • The Purkinje fibers disseminate the electrical signal to ensure coordinated ventricular contractions.
    • An electrocardiogram (ECG) is a diagnostic tool to visualize the heart's electrical activity.

    Cardiac Output and Regulation

    • Cardiac output (CO) is the total blood volume pumped into circulation by the heart in one minute, determined by heart rate and stroke volume.
    • Stroke volume (SV) is the amount of blood ejected by one ventricle during a contraction, dependent on preload, contractility, and afterload.
    • The body regulates CO via both nervous and hormonal systems.

    Heart Failure

    • Heart failure is an inability for the heart to pump adequately.
    • Reduced contractility, valve disease, and electrolyte imbalances contribute to heart failure.

    Dysrhythmias

    • Dysrhythmias or arrhythmias involve irregularities in the heart's electrical activity.
    • Bradycardia denotes a slow heart rate, while tachycardia denotes a rapid heartbeat.
    • Heart blocks are conduction disturbances, frequently involving the AV node, often resulting in abnormal ECG patterns
    • Fibrillation, a chaotic, uncoordinated contraction of the heart muscle, may also be life threatening.

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    Human Anatomy & Physiology - Chapter 17 - PDF

    Description

    Test your knowledge on stroke volume, cardiac output, and pacemaker potentials with this quiz. Questions cover essential calculations and physiological concepts related to heart function and the electrical conduction system. Perfect for students of cardiovascular physiology.

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