Arteries and Veins
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Questions and Answers

Which of the following is NOT one of the pacemakers that control the pace of the heart according to the text?

  • SA node
  • Purkinje fibers
  • Brain (correct)
  • AV node

    • Which system can influence heart rate according to the text?

  • Respiratory system
  • Nervous system (correct)
  • Endocrine system
  • Digestive system

    • Which of the following is NOT a pacemaker involved in controlling the pace of the heart according to the text?

  • Purkinje fibers
  • AV node
  • SA node
  • Ventricles (correct)

    • Which system can influence heart rate through the release of hormones according to the text?

    <p>Endocrine system</p> Signup and view all the answers

    Which cells in the heart are responsible for spontaneously firing electrical commands to tell the cardiomyocytes to contract?

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

    What is the role of the AV node in the conduction system of the heart?

    <p>To delay the electrical signal before it reaches the ventricles</p> Signup and view all the answers

    Which of the following is responsible for the contraction of cardiac muscle cells?

    <p>Ca2+</p> Signup and view all the answers

    What is the function of intercalated discs and gap junctions in cardiac muscle?

    <p>To allow for synchronized contraction of all cardiac muscle cells</p> Signup and view all the answers

    Which of the following is the correct definition of Mobitz Type 1 (Wenckebach)?

    <p>Lengthening of PR interval followed by a dropped beat</p> Signup and view all the answers

    Which of the following is a cause of tachycardia?

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

    Which of the following is true about veins?

    <p>They have thin walls and can contract or expand</p> Signup and view all the answers

    Which of the following is true about laminar flow?

    <p>It has a steady rate and the fastest velocity in the center of the vessel</p> Signup and view all the answers

    Which of the following factors can increase the right atrial pressure?

    <p>Increased blood volume</p> Signup and view all the answers

    What is the formula for calculating mean arterial pressure (MAP)?

    <p>MAP = DBP + 1/3 (SBP - DBP)</p> Signup and view all the answers

    Which of the following statements about venous pressures is true?

    <p>Venous pressure can be estimated by observing distention in the neck</p> Signup and view all the answers

    What are the four primary forces (Starling forces) that determine fluid movement in and out of capillaries?

    Signup and view all the answers

    Which of the following is true about the interstitial fluid hydrostatic pressure (Pif)?

    <p>Pif force fluid inward through the capillary membrane</p> Signup and view all the answers

    What is the role of the lymphatic system in fluid balance?

    <p>It picks up excess water and protein and returns them to the bloodstream</p> Signup and view all the answers

    What is the main function of precapillary sphincters?

    <p>To contract and decrease blood flow to capillaries</p> Signup and view all the answers

    Which plasma protein is responsible for 80% of the oncotic pressure?

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

    What happens when capillary pressure increases too much?

    <p>Edema occurs as fluids are forced out of the capillaries</p> Signup and view all the answers

    What is the main theory behind autoregulation of blood flow in specific tissues?

    <p>Myogenic theory</p> Signup and view all the answers

    Which of the following is NOT a characteristic of the action potential in cardiac muscle cells compared to skeletal muscle cells?

    <p>Cardiac muscle cells use Na+ to repolarize</p> Signup and view all the answers

    Which of the following is NOT a cause of cardiac arrhythmias?

    <p>High levels of potassium in the blood</p> Signup and view all the answers

    Which of the following is NOT an effect of parasympathetic stimulation on the SA node?

    <p>Decreased stroke volume</p> Signup and view all the answers

    What is the purpose of the AV bundle delay in the conduction system of the heart?

    <p>To synchronize the contraction of the atria and ventricles</p> Signup and view all the answers

    According to Ohm's Law, which of the following equations correctly represents the relationship between flow (F), pressure gradient (∆P), and resistance (R)?

    <p>F = ∆P/R</p> Signup and view all the answers

    Which of the following statements accurately describes the relationship between total peripheral resistance (TPR) and blood vessel constriction/dilation?

    <p>TPR increases with blood vessel constriction and decreases with blood vessel dilation.</p> Signup and view all the answers

    What is the relationship between conductance and resistance in a blood vessel?

    <p>Conductance is inversely proportional to resistance.</p> Signup and view all the answers

    What effect does an increased hematocrit have on blood viscosity?

    <p>Increased hematocrit increases blood viscosity.</p> Signup and view all the answers

    Study Notes

    Pacemakers and Heart Control

    • Main pacemakers include SA node, AV node, and Purkinje fibers; non-pacemaker options not specified.
    • Nervous system influences heart rate through autonomic nervous pathways.
    • Hormonal influence on heart rate is primarily through the release of epinephrine and norepinephrine.

    Electrical Activity in the Heart

    • Sinoatrial (SA) node cells spontaneously fire electrical impulses, triggering contractions in cardiomyocytes.
    • The AV node's role is to delay electrical signals, allowing the atria to contract before the ventricles.

    Cardiac Muscle Structure

    • Intercalated discs and gap junctions enable rapid electrical communication and coordinated contractions between cardiac muscle cells.

    Cardiac Arrhythmias

    • Mobitz Type 1 (Wenckebach) is characterized by a progressive lengthening of the PR interval until a heartbeat is dropped.
    • Causes of tachycardia may include stress, fever, and certain medications.
    • Notable arrhythmia causes can include structural abnormalities, electrolyte imbalances, and ischemic heart disease.

    Vascular System Insights

    • Veins are typically compliant structures that can accommodate varying volumes of blood.
    • Laminar flow describes a streamlined flow pattern that reduces turbulence and improves blood flow efficiency.
    • Factors increasing right atrial pressure include increased blood volume or obstruction to venous return.

    Hemodynamics and Fluid Movement

    • Mean arterial pressure (MAP) is calculated using the formula: MAP = DBP + 1/3(SBP - DBP).
    • Venous pressures are influenced by gravity, volume changes, and compliance of veins.
    • Starling forces determine transcapillary fluid movement, including hydrostatic pressure and oncotic pressure differences.

    Fluid Dynamics

    • The interstitial fluid hydrostatic pressure (Pif) participates in opposing filtration in capillaries.
    • The lymphatic system maintains fluid balance by draining excess interstitial fluid and returning it to the bloodstream.
    • Precapillary sphincters control blood flow into capillary beds, regulating nutrient delivery and waste removal.

    Plasma Proteins and Capillary Pressure

    • Albumin is the primary plasma protein responsible for approximately 80% of oncotic pressure.
    • Excessive capillary pressure can lead to edema due to increased filtration of fluid into interstitial spaces.

    Autoregulation and Blood Flow

    • Autoregulation theory acts on the premise that tissues can self-regulate blood flow based on metabolic needs.
    • Characteristics of cardiac muscle action potentials differ significantly from those of skeletal muscle, particularly in duration and refractory periods.

    Neural and Hormonal Regulation

    • Parasympathetic stimulation affects the SA node by slowing down heart rate; effects contrary to this statement are to be noted.
    • AV bundle delay is critical for synchronized contraction, ensuring efficient blood ejection from the heart.

    Principles of Circulatory Dynamics

    • According to Ohm's Law, Flow (F) = Pressure Gradient (ΔP) / Resistance (R), illustrating fundamental hemodynamic principles.
    • Total peripheral resistance (TPR) inversely relates to vessel diameter; constriction increases resistance while dilation decreases it.
    • Increased hematocrit elevates blood viscosity, affecting overall blood flow resistance and circulatory efficiency.

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    Physio II Exam 2 Review.docx

    Description

    Quiz: Understanding the Distensibility of Arteries and Veins Test your knowledge on the distensibility of arteries and veins with this quiz. Explore the differences between the two and how they function as blood reservoirs. Learn how sympathetic stimulation affects the pressure at different volumes in both arteries and veins.

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