Term
| what are the 2 circuits of the CV? |
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Definition
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Term
| since capillary beds are different and blood flow needs to be controlled, how is this done? |
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Definition
| heart rate can be sped up/slowed down, vessels can be constricted/dialated, etc |
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Term
| where does the P wave come from? |
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Definition
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Term
| what are myocardial properties? |
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Definition
| automaticity, contractility, excitability, and conductivity of impulses |
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Term
| what does the aorta have a lot of structurally? |
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Definition
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Term
| how thick are capillaries? how does laplace's law affect them? |
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Definition
| capillaries are one cell thick, and have only a small amount of tension b/c laplace's law states less radius = less tension |
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Term
| what does the vena cava have a lot of structurally? |
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Definition
| fibrous tissue for holding large vascular volume |
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Term
| where does all the blood leaving the LV go? RV? |
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Definition
| LV -> aorta, RV -> pulmonary artery |
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Term
| how does vascular smooth muscle regulate flow? |
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Definition
| vascular smooth muscle tone affects the radius and of the arterioles and precapillary sphincters to regulate flow (contraction = resistance) |
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Term
| where is the greatest vascular cross sectional area? |
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Definition
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Term
| where is the greatest % blood volume? |
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Definition
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Term
| where is central venous pressure measured? |
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Definition
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Term
| what happens if pressure is increased in the RA? |
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Definition
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Term
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Definition
| CO x TPR OR diastolic + 1/3(systolic - diastolic) |
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Term
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Definition
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Term
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Definition
| SV, the stroke volume is the difference between the end diastolic (full heart) and end systolic volumes |
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Term
| what is an important indicator of heart function? |
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Definition
| ejection fraction = SV/EDV (should be around 60-70%) |
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Term
| why would BP drop if HR was suddenly increased? |
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Definition
| less time for heart to fill (CO = HR x SV) |
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Term
| when should you worry about bringing up a slow HR? |
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Definition
| when it starts to affect MABP |
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Term
| how would slowing HR a little affect force of contraction? |
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Definition
| decreasing HR increases time in diastole, which stretches the sarcomeres a little - increasing EDV, and preload, thus enhancing the force of contraction |
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Term
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Definition
| blocks Ach from the vagus, speeds the heart up (muscarinic effect). conversely, beta blockers will slow HR |
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Term
| how does increased SV affect CO? |
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Definition
| increase SV and increase CO |
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Term
| how does increased HR affect CO? |
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Definition
| increase HR and increase CO |
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Term
| what happens if you increase both SV and HR? |
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Definition
| CO should increase considerably, but too much, and it will start to go down |
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Term
| what can bradycardia cause? tachycardia? |
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Definition
bradycardia: low BP
tachycardia: high BP |
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Term
| what predominately controls TPR? |
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Definition
| the ANS, which can raise TPR or lower it depending on the area: vasoconstriction/vasodilation |
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Term
| is SV affected by preload? how can you increase preload? |
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Definition
| SV is affected by preload, which can be increased by giving the pt fluids |
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Term
| how can you decrease preload? when would you do this? |
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Definition
| 80 mg lasix, have a pt keep peeing, diruetics. this might be done if pt has a gram - infection (sepsis (remember LPS), precapillary sphincters dilate and TPR goes down and HR goes up, SV goes down, patient can pass out) |
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Term
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Definition
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Term
| do preload and afterload affect SV? |
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Definition
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Term
| what are all factors that can contribute to afterload? |
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Definition
| the elastic tissue, volume of blood vs. volume of blood in the ventricle (80 vs 120 ml), stretch, myocardial contractility |
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Term
| how can you lower afterload? why would you want to do this? |
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Definition
| drugs can vause vasodilation in the venous compartment, decreasing preload. this is important in helping the heart not work as hard |
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Term
| when do the coronaries get the most blood flow? |
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Definition
| during diastole when the heart is at rest - which tachycardia can present problems with |
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Term
| if you drop diastolic pressure to decrease the workload of the heart due you risk becomine ischemic due to lack of coronary circulation? |
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Definition
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Term
| what does the ANS affect? |
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Definition
| afterload (arterial), TPR, and preload (venous) |
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Term
| does preload affect blood volume? |
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Definition
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Term
| can renal function affect preload? |
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Definition
| yes, which decreases SV and thus CO |
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Term
| how long should the BP cuff be? what is the actual pressure being taken? |
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Definition
| 2/3 the length of the humerus. the pressure being taken is the pressure in the cuff |
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Term
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Definition
| diuresis is increased production of urine by kidneys, which drugs like lasix/bumax do. increased urine production = lowering blood volume which decreases sarcomeric stress, the preload, and SV. this will cause the CO to go down and even tually MABP |
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Term
| why might protein be found in the urine? |
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Definition
| if the glomerular capillary beds are damaged |
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Term
| giving blood to increase volume solves that problem, but what other factor needs to be addressed? |
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Definition
| giving blood may increase BP and lower HR, but need to replace oxygen carrying capacity -> get CBC |
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Term
| how does peripheral circulation work with central circulation and the heart, arteries, capillaries, and veins? |
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Definition
| through the nervous system (parasympathetics, vagus, sympathetic, ANS, fight or flight vs. vegetative) or hormonal release (epinephrine, norepinephrine, vasopressin, angiotensin – can activate or constrict vessels and make kidneys pump or keep more fluid) |
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Term
| where are capillaries tight? |
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Definition
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Term
| where are capillaries leaky? |
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Definition
| nephron/kidney and the liver to a lesser extent (sinusoids) |
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Term
| what can cause cardiac dysrhythmia? |
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Definition
| coronary circulation problems |
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Term
| what needs to happen in the even of a ventricular fibrillation? |
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Definition
| electro-shock, SV will be 0 |
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Term
| what information can you gain from an ECHO? |
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Definition
| whether chambers are filling, color (w/doppler), thickness of walls, SV guestimation from end diastolic volume-end systolic volume |
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Term
| what does a swan gatz catheter do? |
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Definition
| helps get readings for different values in the heart |
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Term
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Definition
| the body's control over itself to keep pressure from damaging the tissue blood vessels serve - *blood flow is constant, velocity/pressure is different |
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Term
| can different capillaries within the kidney be controlled separately? |
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Definition
| yes, for example afferent and efferent arteries will respond differently to pharmacological agents |
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Term
| what can be controlled in the skin by dialation of its blood vessels? |
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Definition
| heat can be dissapated by dialation or conserved with constriction |
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Term
| how do histamines affect capillaries? |
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Definition
| they cause them to leak = edema w/anaphylaxis |
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Term
| how does coronary circulation happen? |
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Definition
| coronary vessels come off at the root of the aorta and are open to blood flow mainly during diastole |
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Term
| how does a faster HR affect coronary circulation? |
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Definition
| the heart spends less time in diastole, and coronary perfusion is lessened |
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Term
| do different parts of the body have different blood flow at different times, depending on their functional needs? |
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Definition
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Term
| what does adenosine do to HR? |
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Definition
| adenosine (ATP metabolite) can slow HR |
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Term
| can tissues and metablic factors control bloof flow? |
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Definition
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Term
| what does renal profusion do? |
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Definition
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Term
| what are precapillary sphincters regionally controlled by? |
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Definition
| metabolites, (K+, adenosine) |
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