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19 Cards in this Set
- Front
- Back
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Systolic pressure |
Before the left ventricle ejects blood into the aorta, pressure rises~ systolic pressure - pressure decreases after left ventricle relaxes |
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Pulse |
Net pressure generated with each cardiac contraction that propels the blood throughout the body -Difference between systolic and diastolic pressure determines blood flow |
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Aorta |
Has elastic fibers that that allows it to expand and compress - The expansion is called compliance (aorta has high compliance) |
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Stroke volume |
Amount of blood ejected per heart contraction (directly related to pulse pressure) |
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Cardiac output |
amount of blood that leaves the heart to supply metabolic demands of the body - determined by heart rate and stroke volume CO= SV x HR |
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Stroke volume is determined by three factors: |
Preload Afterload Contractility |
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Preload |
volume of blood in ventricle before contraction - the more the cardiac muscle is stretched, the greater its contraction -determined by the amount of blood that enters the right atrium |
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Afterload |
pressure the ventricle blood faces before ejection - occurs at two sites: 1. right ventricle must generate pressure to overcome pulmonary artery pressure 2. left ventricle must overcome aortic pressure |
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Contractility |
the force that muscles generate at a given muscle length |
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Baroreceptors |
pressure receptors in the carotid arteries that supply the brain -sense a change in blood pressure very fast and notice subtle changes |
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Control of blood pressure (brain) |
If pressure becomes too great, signal is sent to ParaSNS to lower blood pressure by decreasing heart rate If pressure becomes to little, signal is sent to SympatheticNS to raise blood pressure by increasing heart rate |
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Example: ER patient |
As blood pressure decreases in ER patient, the pressure reflexes relay this info to the Medulla which causes an inhibition of the ParaSNS and an excitation of the sympatheticNS |
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Hypertension |
Elevated diastolic pressure and/or systolic pressure |
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How hypertension can kill |
1. if there is not a great difference between diastolic and systolic pressure (no blood flow) 2. high pressure causes damage to blood vessels leading to hemorrhage |
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Types of HTN |
Essential HTN (95%) : cause of hypertension is unknown Secondary HTN (5-10%): if it is due to renal or endocrine disorders (result of a disease) |
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Treating essential HTN |
Decrease amount of pressure generated by the heart - this is because with more fluid entering the heart, the stronger the heart has to beat - drugs (diuretics) cause patients to lose fluid |
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Hypertension dangers |
cause of 50% of the cases of stroke, dementia, heart attacks, and heart failure - extreme pressures will eventually wear away the arterial response to the bombardment of pressure~blood vessels springing a leak OR - huge after load that weakens cardiac muscle overtime leads to heart failure |
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Hypotension |
not enough of a pressure differential between systolic and diastolic pressures~ leading to low blood flow - not as life threatening as hypertension |
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Pressor drugs |
agents that increase blood pressure -given to patients with hypotension - the increase in heart rate and and stronger muscle contraction will increase cardiac output |
