Physiology: The Cardiovascular System
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Questions and Answers

What is the relationship between KE and PE in the context of blood flow?

  • KE increases when PE decreases (correct)
  • KE decreases when PE increases
  • KE is independent of PE
  • KE is directly proportional to PE

    • What is the total peripheral resistance (TPR) in the body?

  • The site where blood pressure is measured
  • The collective designation for arterioles that vasoconstrict and vasodilate (correct)
  • The combination of all arterioles and arteries
  • The combination of all veins and venules

    • What happens to total pressure (TE) along the streamline according to Bernoulli?

  • It increases in one segment and decreases in another
  • It remains constant throughout the entire streamline (correct)
  • It is affected by viscosity and turbulence
  • It decreases in one segment and remains the same in another

    • What is the effect of vasoconstriction on blood flow and pressure?

    <p>It decreases blood flow and increases blood pressure</p> Signup and view all the answers

    What is the driving force for blood flow between two points?

    <p>Total energy (TE)</p> Signup and view all the answers

    What happens to pressure (PE) in the arteriole in the given diagram?

    <p>It decreases</p> Signup and view all the answers

    What is the flow (Q) in the arteriole affected by?

    <p>Both kinetic energy (KE) and potential energy (PE)</p> Signup and view all the answers

    What is the relationship between resistance (R) and vasoconstriction?

    <p>Vasoconstriction increases resistance</p> Signup and view all the answers

    What is not accounted for in Bernoulli's principle?

    <p>Viscosity and turbulence</p> Signup and view all the answers

    What is the upstream artery used for?

    <p>Measuring blood pressure</p> Signup and view all the answers

    What is the primary function of the reservoir of mercury in the blood pressure measurement device?

    <p>To display the pressure in the cuff</p> Signup and view all the answers

    What happens to blood flow through the brachial artery when the air is blown into the cuff?

    <p>It is cut off</p> Signup and view all the answers

    What is the primary factor that determines systolic pressure?

    <p>The force of the heart pumping blood</p> Signup and view all the answers

    What is the function of the stethoscope in the blood pressure measurement process?

    <p>To measure the pulse</p> Signup and view all the answers

    What is the effect of elastic recoil of the aorta on blood pressure?

    <p>It creates diastolic pressure</p> Signup and view all the answers

    What is the purpose of slowly letting the air out of the cuff during blood pressure measurement?

    <p>To decrease the pressure in the cuff</p> Signup and view all the answers

    What is the relationship between blood pressure and the size and flexibility of the arteries?

    <p>Blood pressure decreases as the arteries become larger and more flexible</p> Signup and view all the answers

    What is the effect of activity on blood pressure?

    <p>It can either increase or decrease blood pressure depending on the type and intensity of the activity</p> Signup and view all the answers

    What is the primary factor that determines diastolic pressure?

    <p>The elastic recoil of the aorta</p> Signup and view all the answers

    Why is it important to wrap the cuff around the upper arm during blood pressure measurement?

    <p>To ensure accurate measurement of blood pressure</p> Signup and view all the answers

    Alpha 1 receptors increase heart rate and contractility.

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

    Angiotensin II decreases blood pressure.

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

    Nitric oxide causes vasoconstriction.

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

    The sympathetic nervous system increases heart rate and contractility through beta 2 receptors.

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

    Atrial natriuretic peptide increases blood volume.

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

    Study Notes

    The Cardiovascular System

    • The ECG (Electrocardiogram) measures the electrical activity of the heart.

    ECG Components

    • P wave: Atrial activation
    • PR Interval: Onset of atrial activation to onset of ventricular activation
    • QRS Complex: Ventricular activation
    • QRS Duration: Duration of ventricular activation
    • ST-T Wave: Ventricular re-polarization
    • QT Interval: Duration of ventricular activation and recovery
    • U Wave: After-depolarizations in the ventricles

    Electrical and Mechanical Events

    • Atrial depolarization (electrical) → Atrial contraction (mechanical)
    • Ventricular depolarization (electrical) → Ventricular contraction (mechanical)
    • Ventricular re-polarization (electrical) → Ventricular relaxation (mechanical)

    ECG Leads

    • Standard leads: I, II, and III (bipolar, detect electrical potential change in frontal plane)
    • Augmented limb leads: aVR, aVL, and aVF (unipolar, detect electrical potential change in frontal plane)

    Cardiac Myocyte Cycle

    • Phase 0: Rapid influx of Na+ ions through "fast" channels
    • Phase 1: Closing of Na+ voltage-gated channels (VGCs)
    • Phase 2: Influx of Ca++ and slow efflux of K+
    • Phase 3: Rapid repolarization (closing of Ca++ VGCs, efflux of K+)
    • Phase 4: Unstable resting phase (influx of Na+, Ca++, and slow efflux of K+)

    Cardiac Output and Other Dynamics

    • Cardiac output (CO) = Heart rate (HR) x Stroke volume (SV)
    • Cardiac index (CI) = CO/m²
    • Starling's Law: Contractile force increases as the heart muscle stretches, but only to a point
    • Preload: Stretch on the heart muscle before contraction
    • Afterload: Resistance to blood flow after contraction

    Intrinsic and Extrinsic Factors

    • Intrinsic factors: Conduction system, functional syncytium, auto-regulation
    • Extrinsic factors: Parasympathetic and sympathetic nervous systems, vascular variables

    Cardiovascular Control Systems

    • Key variables: Blood pressure (BP), cardiac output (CO), heart rate (HR), stroke volume (SV)
    • Key equations: CO = HR x SV, CI = CO/m²
    • Bernoulli's equation: Does not account for factors such as viscosity, turbulence, or gravity

    Vasoconstriction, Blood Flow, and Blood Pressure

    • Total peripheral resistance (TPR) beds: Arterioles that vasoconstrict and vasodilate
    • Poiseuille and Bernoulli: Flow (Q), pressure (PE), and resistance (R) are related reciprocally
    • Vasoconstriction increases resistance (R), decreases flow (Q), and increases pressure (PE)

    Electrocardiography

    • aVF (left leg) records a change in electric potential in the frontal plane
    • Lead I is between the right arm and left arm electrodes, with the left arm being positive
    • Lead II is between the right arm and left leg electrodes, with the left leg being positive
    • Lead III is between the left arm and left leg electrodes, with the left leg being positive
    • Einthoven's Triangle is a diagrammatic representation of these three leads

    ECG Precordial Leads

    • These six unipolar leads are located on the chest and record electric potential changes in the heart in a cross-sectional plane
    • Each lead records electrical variations that occur directly under the electrode

    The Cardiac Myocyte Action Potential

    • Phase 0: rapid influx of Na+ via open Na+ VGCs and influx of Ca++ via Ca++ VGCs
    • Phase 1: closing of Na+ VGCs and small influx of Cl-, small efflux of K+
    • Phase 2: influx of Ca++ and efflux of K+ via open K+ VGCs
    • Phase 3: closing of Ca++ VGCs and efflux of K+ via open K+ VGCs
    • Phase 4: diastole, resting phase

    Cardiac Output and Other Dynamics

    • Cardiac Output (CO) = Heart Rate (HR) x Stroke Volume (SV)
    • CO can be modified by both intrinsic and extrinsic variables
    • Cardiac Index (CI) = CO/m2 (body surface area)

    Blood Flow and Resistance

    • Poiseuille's Equation: Q = ΔP/R, where Q is flow, ΔP is pressure difference, and R is resistance
    • Three primary factors that determine resistance: vessel diameter (or radius), vessel length, and viscosity of the blood
    • Vessel diameter is the most important factor quantitatively and physiologically

    Bernoulli's Principle

    • Kinetic energy and pressure energy can be interconverted, so total energy remains unchanged
    • Total pressure is constant along a streamline
    • Low pressure in one segment increases pressure in another connected segment
    • KE (kinetic energy) and PE (pressure energy) are related reciprocally: if one increases, the other must decrease

    Vasoconstriction, Blood Flow, and Blood Pressure

    • Total Peripheral Resistance (TPR) beds are arterioles of the body
    • Vasoconstriction increases resistance, decreases flow, and increases pressure
    • Vasodilation decreases resistance, increases flow, and decreases pressure

    Evaluating Blood Pressure

    • Blood pressure is measured using a cuff and mercury column
    • Systolic Pressure is measured when blood flow first returns (first heard pulse)
    • Diastolic Pressure is measured when the pulse sound disappears (elastic recoil of the Aorta)
    • Blood pressure is influenced by activity, temperature, diet, emotional state, posture, physical state, and medication use

    The Cardiovascular System Physiology

    ECG

    • The cardiovascular system consists of the aorta, systemic circulation, pulmonary circulation, and heart
    • The heart undergoes isovolumetric contraction, isovolumetric relaxation, ventricular ejection, and rapid inflow phases

    Phases of the Nodal Action Potential

    • Phase 4: unstable rest or pacemaker potential, caused by an influx of sodium (Na+) and calcium (Ca++) ions
    • Phase 0: rapid depolarization, caused by a large influx of Ca++ ions
    • Phase 3: repolarization, caused by a slow efflux of potassium (K+) ions

    Phases of the Cardiac Myocyte Action Potential

    • Phase 0: rapid depolarization, caused by an influx of Na+ ions
    • Phase 1: caused by the closure of "fast" Na+ channels and a small influx of chloride (Cl-) ions
    • Phase 2: plateau phase, caused by an influx of Ca++ and an efflux of K+ ions
    • Phase 3: repolarization, caused by a slow efflux of K+ ions

    Cardiac Output and Other Dynamics

    • Cardiac output (CO) = heart rate (HR) x stroke volume (SV)
    • CO can be modified by intrinsic and extrinsic factors
    • Starling's Law: contractile force increases as the heart muscle stretches, but only up to a point
    • Poiseuille's Equation: Q = ∆P/R, where Q is flow, ∆P is pressure difference, and R is resistance

    Autonomic Receptors

    • Alpha 1: vasoconstriction (VC) in total peripheral resistance (TPR) beds
    • Alpha 2: inhibits norepinephrine (NE) release
    • Beta 1: increases heart rate and contractility
    • Beta 2: vasodilation (VD) in TPR beds

    Key Biochemical Players in Cardiovascular Control

    • Acetylcholine (ACH): decreases heart rate
    • Aldosterone (ALD): increases sodium absorption and blood volume, leading to increased blood pressure
    • Angiotensin II (AGII): increases vasoconstriction and blood pressure
    • Atrial natriuretic peptide (ANP): increases sodium loss and decreases blood volume, leading to decreased blood pressure
    • Anti-diuretic hormone (ADH/AVP): increases water absorption and vasoconstriction
    • Epinephrine (EP): increases vasoconstriction, heart rate, and contractility
    • Nitric oxide (NO): vasodilation and increased tissue perfusion
    • Renin: increases conversion of angiotensinogen to AGII

    Cardiovascular Control Systems

    • Intrinsic factors that influence heart operation: SA node, contractility, and intercalated disks
    • Extrinsic factors that influence heart operation: parasympathetic nervous system (PNS), sympathetic nervous system (SNS), preload, and afterload
    • Intrinsic factors that influence vascular operation: endothelial cells, metabolic by-products, myogenic auto-regulation, and elasticity of great arteries
    • Extrinsic factors that influence vascular operation: neural and hormonal factors

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    Cardiovascular System Physiology PDF

    Description

    This quiz covers the principles of physiology related to the cardiovascular system, including ECG, atrial activation, and ventricular activation. It is part of Anatomy & Physiology II course, BIOL2220.

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