Term
| 1. Describe the structure and location of the heart. |
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Definition
| The heart has four chambers and is made of cardiac muscle. |
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Term
| 3. Describe the differences between the pulmonary and systemic circulation and relate the differences in the structure of the right and left ventricles to the distinctions between these circuits. |
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Definition
Pulmonary:
Low Pressure System
Rt. Ventricle Pumps De-Oxygenated Blood to Lungs
Systemic: High Pressure System
Left Ventricle Pumps Oxygenated Blood to All Tissues. Left ventricle has thicker muscle because it has to pump blood to more places. |
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Term
| 4. Describe the basic structure and function of cardiac muscle. (4) |
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Definition
1.Highly Oxidative Tissue (prefers lipids as energy source but can use a wide variety of energy sources)
2. Mature Cardiac Muscle cells don’t divide by mitosis: instead hypertrophy occurs when cardiac muscle is damaged.
3. Striated Muscle (sarcomeres found in cardiac muscle) (also short and are capable of branching unlike skeletal muscle, also another difference is they only have one nucleus. They are also interconnected muscle cells which include gap junction which means they communicate and share action potentials)
4. Works as Functional Unit (Syncytium)
Atrial Unit
Ventricular Unit |
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Term
| 7. Describe the conduction system of the heart and the functional role of the sinoatrial node as the pacemaker of the heart.(2) |
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Definition
Sinoatrial Node (SA-Node): Pacemaker Located in the Posterior Wall of the Right Atrium, normally action potential starts here.
Normal path of action potential conduction: SA node→ atrial muscle → AV node→ bundles of His → purkinje fibers → ventricular muscle (contracts from apex to base) |
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Term
| Physiological Properties of Myociardial Cells (6 facts 4 general features) |
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Definition
1. Contractility: The force of contraction of the heart is dependent on the number of myosin crossbridges bound to actin, and is varied by changing the amount of calcium available to bind to troponin.
2. Excitability (fig 18-12): Heart muscle generates action potentials. The action potential has is longer in duration due to the opening of voltage-gated Ca+2 channels after the opening of voltage gated Na+ channels and prior to opening of voltage gated K+ channels. This longer action potential results in a longer refractory period and prevents the heart from contracting tetanically.
The SA node and conduction tissues each have different action potentials, than cardiac muscle, that are initiated by pacemaker potentials.
3. Automaticity (figure 18-13) Normally only the SA node and the conduction tissues have the ability to depolarize automatically.
4. Conductivity (figures 18.11 and 18.14)
Cardiac muscle cells are connected via gap junctions in the intercalated disks. These gap junctions allow the action potential to move from myocardial cell to myocardial cell in the heart.
Conducting fibers in the heart direct and provide the appropriate timing for the conduction of the action potential in the heart.
Heart is more sensitive to Ca2+ concentration due to Ca2+ being brought in cell from outside of cell and not just from sarcoplasmic reticulum. Due to voltage gated Ca++ channels. |
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Term
| Cardiac Conduction System Features (3) and the normal path of action potential conduction. |
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Definition
Tissues in the Heart Specialized To Conduct Electrical Impulse (Action Potential) Across the Heart
Sinoatrial Node (SA-Node): Pacemaker Located in the Posterior Wall of the Right Atrium
Atrioventricular Node (AV-Node): Mass of Conducting Fibers Between The Atria And Ventricles
Normal path of action potential conduction: SA node→ atrial muscle → AV node→ bundles of His → purkinje fibers → ventricular muscle |
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Term
| What are ECGs used for? (3) |
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Definition
| Diagnosis of Pacemaker or Conduction Defects; Useful in suggesting Changes in The Muscle Mass of The Heart; Used To Indicate Areas of Ischemia That Occur With Coronary Disease |
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Term
| Numerically Define Brachycardia |
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Definition
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Term
| Numerically Define Tachycardia |
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Definition
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Term
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Definition
| Beats That Originate From a Site Other Than the SA-Node |
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Term
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Definition
| Very Rapid Uncoordinated Depolarizations that Produce Uncoordinated Contractions |
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Term
| Which two valves is the second heart sound associated with? |
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Definition
| Pulmonary And Aortic Valves |
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Term
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Definition
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Term
| Define systole and list its two phases |
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Definition
Heart Cycle portion where muscle is contracting
Isovolumetric contraction
Ejection Phase |
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Term
| Define Isovolumetric contraction phase |
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Definition
| Systole Phase: Pressure increases but volume is constant. All valves are closed until ventricular pressures exceed the pressures in the arteries leaving the heart. |
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Term
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Definition
| Begins when the pressures in the arteries increase slightly above the pressures in the aorta and pulmonary artery and the aortic and pulmonary semilunar valves open. Volume in the ventricles decreases during this phase |
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Term
| Diastole definition and two phases |
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Definition
Heart cycle portion where muscle is relaxed or relaxing
isovolumetric relaxation
filling phase |
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Term
| Define isovolumetric relaxation phase |
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Definition
| begins when pressures in the ventricles decrease below the pressures in the arteries leaving the heart (and the aortic and pulmonary semilunar valves close) This phase continues until the pressures in the ventricles decrease below the atrial pressures. Pressure decreases but volume is constant |
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Term
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Definition
| Begins when the atrioventricular valves open and continues until the next ventricular contraction (and the atrioventricular valves close). Ventricular volume increases. |
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Term
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Definition
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Term
Define Cardiac Output (CO)
And write the formula for it |
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Definition
Amount Of Blood Pumped by Each Ventricle Per Minute (liters/minute)
Stroke Volume (mls/beat) X Heart Rate (beats/min) |
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Term
What is the formula for MAP?
What is the formula for Estimated MAP? |
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Definition
(Cardiac Output)(Total Peripheral Resistance)
Diastolic Pressure + 1/3(Pulse Pressure) |
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Term
| What are the three aspects of neuronal control for HR? |
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Definition
Cardiovascular center in the Medulla Oblongata is the integrating center
Autonomic Nervous System innervates the SA node and AV node (Mechanism of changing HR: Change in Slope of Pacemaker Potential by changing permeability of SA node to ions)
Sympathetic Nervous System (Increases Intrinsic heart rate)
Parasympathetic Nervous System Decreases Intrinsic heart rate (via vagus nerve) |
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Term
| Local Factors that affect HR (3) |
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Definition
| physical fitness, Ions: Ca+2, Na+, and K+ in extracellular fluid, CO2, O2, [H+] also influence smooth muscle in arterioles and change vascular resistance and blood pressure |
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Term
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Definition
| The Stretch on the Muscle Fibers before Contraction (Proportional to End Diastolic Volume) The length tension relationship is critical in adjusting the contraction force in the heart with changes in ventricular filling |
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Term
| What is the Frank-Starling Law of the Heart? |
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Definition
| The Greater the End Diastolic Volume the Greater the Force of Contraction (Within Normal Physiological Range) |
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Term
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Definition
| The Pressure that the Ventricle Must Exceed Prior To Ejection (Proportional To Aortic Pressure) Increased afterload tends to decrease stoke volume, but other changes compensate for the effects of afterload in a healthy heart |
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Term
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Definition
| The Driving Force for Tissue Perfusion also the homeostatically controlled variable for the cardiovascular system |
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Term
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Definition
| (Arterial Pressure- Venous Press) / Resistance |
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Term
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Definition
| Systolic Pressure - Diastolic Pressure |
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Term
| What are the three vessel layers and what do they consist of? |
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Definition
Vessel Layers
1. Tunica Externa
Connective Tissue
2. Tunica Media
Smooth Muscle
Elastic Tissue
3. Tunica Intima
Elastic Fibers
Basement Membrane
Endothelium |
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Term
| What are arteries, and what is their function? |
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Definition
Strong Elastic Vessels that Carry Blood Away From the Ventricles at High Pressure
(Pressure Reservoir) Primary function is dependent on the presence of a large amount of elastic tissue. Function to store pressure and maintain blood flow throughout the cardiac cycle |
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Term
| What are arterioles and what are their two functions? |
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Definition
| Small Branches of Arteries that lead into Capillaries and Actively Change Diameter: Primary function is dependent on the presence of a lot of smooth muscle which allows the diameter to be varied significantly (Vasoconstriction or Vasodilation). Arterioles Function to 1. Control Blood flow to specific regions by varying the radius and 2. collectively determine the vascular resistance and the MAP |
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Term
| What are capillaries and what is their function? |
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Definition
Microscopic, Thin Walled Vessels that are Specialized for Exchange between the Blood and Tissues.
Function is related to the presence of only a single layer of cells (endothelium) and a small amount of connective tissue |
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Term
| What determines capillary density? |
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Definition
| Capillary Density Is Proportional To Metabolic Activity of Tissue |
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Term
| What four ways do substances pass through capillary walls? |
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Definition
Diffusion (lipid soluble substances)
Filtration:
Movement through intercellular clefts (water soluble substances)
Movement through fenestrations (water soluble substances)
Transport via vesicles or caveolae (large substances) |
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Term
| Define venule & give function |
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Definition
| Small Vessel; Transport Blood From Capillaries To Veins |
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Term
| Define vein & give function |
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Definition
| Low Pressure, Thin-Walled Vessels; Function is dependent on the presence of relatively less elastic tissue which makes veins very compliant. Also contain some smooth muscle so that the diameter can be varied somewhat |
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Term
| What are the two functions of the venous system? |
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Definition
Veins Function to Return Blood to the Heart at low pressure Veins are
Very Compliant (Hold ~70% of Blood Volume at Low Pressure) |
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Term
| What is central venous pressure? |
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Definition
| Pressure in Right Atrium (0-2mmhg) |
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Term
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Definition
| Amount of Blood Returned to the Right Atrium; Directly Effects End Diastolic Volum |
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Term
| What 5 factors determine venous return? |
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Definition
Blood Volume
Valves
Skeletal Muscle Contraction
Respiratory Movements
Increased Smooth Muscle Tone in Veins (promoted by the Sympathetic Nervous System) |
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Term
| What are the three determinants of total peripheral resistance? |
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Definition
Length of Blood Vessels: resistance is directly proportional to length
Viscosity of Blood: resistance is directly proportional to viscosity
Radius of Vessels (Arterioles vasoconstrict or vasodilate to change the radius): ! Resistance is proportional to 1/(radius)4 ! |
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Term
| What two areas have barorecetpors? |
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Definition
| The aortic arch, the carotid arteries |
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Term
| What are the two hormones used to control bp short term? |
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Definition
Epinephrine: extension of sympathetic effects
Angiotensin II is a vasoconstrictor which increases resistance or arterioles |
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Term
| 4 long term ways of controlling bp |
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Definition
Increasing Blood Volume → Increases Blood Pressure
Control of Blood Volume (neuroendocrine mechanisms that affect kidney function)
Antidiuretic Hormone (ADH): increases blood volume
Renin Angiotensin System: increases blood volume
Atrial Natriuretic Factor: decreases blood volume |
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Term
| What does the sympathetic nervous system do to affect bloodflow? (2) |
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Definition
Increase Muscle Blood Flow
Decreases Blood Flow to Skin and Gastrointestinal (GI) Tract |
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Term
| 8. Briefly describe the cardiac muscle action potential with respect to the changes in membrane potential |
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Definition
Na+ comes in, Ca++ comes in, then K+ out
Ca++ voltage gated channels |
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Term
| 9. Describe how the atria and ventricles act as functional units (2) |
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Definition
They both have separate nodes, atria pump first
Atrium cells and Ventricle cells do not have gap junctions between them and do not communicate with each other |
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Term
| List the events of the cardiac cycle and describe how these events are related (8) |
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Definition
Blood in from vena cavae
P-Wave: Atrial Depolarization
Atria pump
Blood to right and left ventricles
QRS-Complex: Ventricular Depolarization
Atria relax, but masked by QRS
Blood pumped to lungs and rest of the body from ventricles
T-Wave: Ventricular Repolarization
Ventricles relax |
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Term
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Definition
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Term
| Describe how mean arterial pressure is homeostatically controlled to regulate the overall function of the cardiovascular system |
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Definition
| When blood pressure is increased or decreased, tissue perfusion is affected relatively, and heart rate is adjusted inversely |
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Term
| Describe how blood pressure generally changes as the blood moves from the ventricle through capillaries and into veins (2) |
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Definition
Ventricle pressure increases to just above aortic pressure
Pressure decreases with each decrease in size of arteries or veins |
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Term
What does increased venous pressure lead to?
What does a lower number of plasma proteins lead to? |
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Definition
Increase in [lymph] fluid accumulation
Less osmotic pressure which leads to edema |
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Term
| What causes for the Net Movement of fluid from the Blood into the Interstitial Fluid? |
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Definition
| a Balance of Hydrostatic Pressures and Osmotic Pressures between the capillary and intercellular space |
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Term
| Why is low pressure in the veins a good thing? |
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Definition
| So that capillary flow moves from arteries to veins, also why venous system has more blood (60%) |
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Term
| Explain how vascular resistance is regulated by the autonomic nervous system (5) |
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Definition
Baroreceptors sense pressure, send signals to
Medulla Oblongata - integrating center, interprets baroreceptor signals
Effectors: Heart, Arterioles and Veins
Sympathetic Nervous System: Promotes Vasoconstriction of arterioles in most areas; increases heart function and increases venomotor tone (venous stiffness)
Parasympathetic Nervous System: Promotes Vasodilation in a Few Areas but is not important in influencing total peripheral resistance; reduces heart rate |
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Term
| Describe the baroreceptor reflex and explain its significance in blood pressure regulation (5) |
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Definition
Mechanoreceptor measures stretch of arteries
Stimulates cardioacceleeratory center, inhibit cardioinhibitory center, and stimulate vasomotor center.
This results in vasomotor constriction increasing peripheral resistance, sympathetic impulses lead to heart rate increase, contractility and cardiac output increase. |
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Term
| Describe how cardiac output, vascular resistance, MAP and blood flow change during exercise |
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Definition
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