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12 Cards in this Set
- Front
- Back
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Electrical conduction of the heart |
SA node AV node Bundle of his Purkinje fibers |
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ECG Wave values |
P - atrium contracts (atrial depolarization) QRS - Ventricles contract, atrium repolarize (ventricular depolarization) T - ventricles relax (ventricular repolarization) |
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Heart sounds |
Systolic = lub, caused by contraction if the ventricles and the vibrations of the closing AV valves Diastolic = dub, caused by vibrations of the closing SL valves |
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Perfusion pressure |
The pressure gradient needed to maintain blood flow through local tissue Blood going back to the heart has the least amt of pressure |
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Arterial blood pressure |
Primary determinant is the volume of blood in the arteries A direct relationship between the arterial blood pressure and arterial blood volume Increases stroke volume, increased HR, increased blood viscosity, and a decrease in diameter of arterioles ALL INCREASE arterial blood pressure and volume |
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Cardiac output |
Volume of blood pumped out of the heart per unit of time. CO = SV x HR |
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Stroke volume |
Volume of blood that leaves the ventricles in a heartbeat |
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Starlings law of the heart |
The greater the stretch on a muscle, the greater the contraction and vice versa Contraction also altered by chemical factors (epinephrine) |
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Vasomotor pressorreflexes |
Change the ratio of sympathetic and parasympathetic output Carotid sinus baroreceptors - measures pressure out of heart and into the veins |
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Vasomotor chemoreflexes |
Change ratio of sympathetic and parasympathetic output based on chemicals in the blood. I.e. An increase in co2 wold cause an increase in HR |
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The 4 major influences on venous return to the heart |
1. Stress-relaxation: occurs when a change in BP causes a change in vessel diameter that accommodates the new pressure and thereby keeps blood flowing. 2. Gravity - causes a decrease in venous return (orthodontic effect) (laying down would cause no effect of gravity) 3. Venous pumps (only in veins) - work to overcome gravity in legs 4. Total blood volume
Expiration pushes venous blood into heart Inspiration pulls blood into the central veins |
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Hormone effects on total blood volume |
Changes in total blood volume changes the amt of total blood to the heart ADH increases blood vol (stops urine production) Aldosterone increases blood vol (stops urine production) ANH decreases blood vol (produced in atria, causes Na+ to be released in urine) |
