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23 Cards in this Set
- Front
- Back
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Normal Hemodynamic Pressure value: RA
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1-5mmHg
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Normal Hemodynamic Pressure values: RV
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15-30/2-5 mmHg
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Normal Hemodynamic Pressure values: PCWP
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5-12 mmHg
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Normal Hemodynamic Pressure values: LA
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5-10 mmHg
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Normal Hemodynamic Pressure values: LV
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120/0-10 mmHg
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Normal Hemodynamic Pressure Value: Aorta
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115/8 mmHg
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Systolic Pressure
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Contraction (ejection)
1/3 cardiac cycle Isovolumetric: During fulling increased pressure in chambers- mitral tricuspid values close. increased pressure in the ventricles. Isotonic: Pulmonic and aortic valves open and blood is ejected into aorta- to all other parts of the body. |
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Diastolic Pressure
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Relaxation (filling)
2/3 cardiac cycle (with increased HR there is decreased filling) Perfusion of coronary vessels occurs |
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Cardiac Output
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HR x Stroke Volume
Amount of blood pumped from the heart per minute. Normal is 4-8L per minute. |
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Heart Rate
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Stress in any form stimulates the CNS, increasing cardiac rate. This increased rate leads to increased cardiac output, and ventricular contractility. Rate changes are referred to as chronotropic effect (both positive and negative).
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Stroke Volume
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Amount of blood ejected from each ventricle beat; this is not all the blood in each ventricle; but about 60-75% of the volume, and is called the ejection fraction.
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Pre-load
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Pre-load to the degree of stretch (myocardial muscle length) before contraction. Pre-load is provided by venous return and refers to the volume that causes a degree of stretch in the ventricles.
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After load
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After load refers to the resistance that the aortic and pulmonary valves normally maintain, the condition and tone of the aorta, and the resistance that the systemic and pulmonary arterioles offer. It is the net force per unit cross-sectional area across the myocardial wall during ejection and is estimated using Laplace's law. After load is measured by the SVR. MAP may be used to approximate after load.
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Contractility
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Refers to teh force of contraction, also expressed as inotropic state and inotropy means contraction is increased, whereas inotropy means contraction is decreased.
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Automiticity
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A property of conductive tissue where spontaneous APs are generated within the tissue. This phase occurs through slow diastolic depolarization during phase 4 is more rapid in the SA node. The spread occurs throughout atria to ventricles.
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Rhythmicity
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An important property of conductive tissue which is characteristic of all potential pacemakers o the heart. It refers to the rhythmic or regular generatio of an AP. The CNS and the PNS may influence rhythmicity. CNS stimulation may increase irritability and promote ectopic beats. PNS influence with the vagus nerve influences heart rate.
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Excitability
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Refers to the ability of the cardiac cells to respond to stimulation. This property means that the threshold impulse generated in one muscle cell can be readily transmitted to the next until the entire muscle unit is depolarized and contracts. Influences alterations in the cardiac cycle, especially with dysrhythmias.
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Conductivity
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Allowing the stimlus to be passed from one cell to the next.
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Mixed Venous Oxygen Saturation
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Reflects the balance between oxygen supply and demand.
Normal: 65-75%. |
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Fall in SvO2
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Increased oxygen consumption- shivering, seizures, hyperthermia.
Decreased oxygen delivery- decreased CO, hypoxemia, and anemia. |
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Rise in SvO2 Reflects
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Increased oxygen delivery- reflects increase CO and increased arterial oxygenation.
Reduced oxygen consumption- caused by hypothermia, induced musclar paralysis. Presence of L-R intracardia shut. Mechanical interference. |
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Sympathetic Autonomic Nervous System
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Description- influences mediated through nerve fibers or hormones (fight/flight)
Neurotransmitters: E and NE Adrenergic Receptors Catecholamines: Stimulate heart by binding to receptors- alpha, beta, and dopa. |
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Parasympathetic Autonomic Nervous System
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75% vagus nerve (CN-X)
Rest and Repair |
