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20 Cards in this Set
- Front
- Back
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Purpose of Cardiovasc. System?
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O2 to muscles, remove waste
Nutrients to tissues Reg. of body temp |
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Blood flow of heart
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venous IN R. Atrium to R. Ventricle to lung (gas exchange) to L. Atrium to L. Ventricle OUT via arteries
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Explain Electrical Act. of heart
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starts @ SA node (on R atrium), depolarization spreads to L. Atrium + AV node then to R + L Ventricles (travels along His/Purkinje system)
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basic order of electrical/contraction in heart
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1 SA node (on R Atrium
2 L Atrium/AV node 3 L + R ventricles |
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Nervous system control of heart rate
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Parasympathetic NS = decrease HR
vagus nerve INHIBITS SA NODE Sympathetic NS = increase HR cardiac nerve STIMULATE SA NODE |
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Define Stroke Volume
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The volume of blood pumped by both ventricles per beat
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What 3 things affect Stroke Voume?
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1. EDV - end diastolic volume = preload
2. Afterload = MAP mean arterial pressure 3. Contractility - force produced by muscle |
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define EDV (preload) - end diastolic volume
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volume of blood in ventricles after relaxation/filling phase
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define afterload MAP - mean arterial pressure
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pressure the heart must pump against to eject blood
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define Contractility
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force of contraction of myocardium
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define/apply Frank - Starling effect.
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greater preload (EDV), amount of blood after filling phase, yields a greater stretch of ventricles (optimizes fiber length) and results in greater force/contraction
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what affects Frank - Starling effect?
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1. venoconstriction = inc venous returen
2. skeletal muscle pump = exercise causes muscle contraction to squeeze veins - inc venous return 3. respiratory pump - promotes return 4. slow HR - allows greater EDV (preload) |
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Formula for cardiac output + max cardiac output
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Q=cardiac rate (HR) x SV
max Q = max HR x max SV |
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factors that regulate cardiac output
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HR + SV
HR: inc parasym = dec HR inc symp = inc HR SV: EDV (preload) Afterload (MAP) inc=dec SV Contractility Frank Sterling |
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Composition of blood
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-Plasma - proteins, ions, hormones
-Cells - RBC + Buffy coat (WBC) -Hematocrit = % of blood that is cells - normal 42% increase to 50% w/ training |
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factors that affect Blood Flow
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pressure
resistance flow |
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blood pressure
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systolic/diastolic
systolic - pressure from contraction diastolic - pressure from relaxation/filling |
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what affects Resistance
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-length of vessel
-blood viscosity -radius of vessel radius probably most influential small change=huge impact |
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benefits of faucets/arteries in parallel vs series
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parallel allows for individual adj of pressure based on needs
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Control of -Blood Pressure
-Resistance |
Blood pressure controlled systemically
resistance controlled locally |
