Term
| can you describe the permaeability of the ions Ca++ and K+ during depolarization and repolarizationof the SA node cells |
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Definition
| during depol. calcium permaeaility is high and poatassuium is low. during ropol. calcim permeability is low and potassium permeablitiy is high |
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Term
| what is a "refractory period" and what causes it in the heart |
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Definition
| time in chich the cells cannot contract again until they repolarize. this keeps the cells from reaching tenanus. it is caused by the influx of calcium in the cell, which decreases potassium permeability and repolarization cannot occur until the ca+ is removed. |
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Term
| can you explain how the parasympathetic nercous system influences the hearts rate and contractility? |
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Definition
| Ach is released from parasympathetic fibers and binds to muscarinic receptors on the heart. this causes increased K+ permeability and repol. takes longer, thus slower heart rate |
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Term
| what are the chemicals that affect the heart's rate called? |
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Definition
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Term
| do you know what hyperkalemia is and why it is so dangerous |
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Definition
| it is increased levels of K+ in the ECF. this remoces the gradient from the cardiac cells and ECF and repolariztion cannot ve achieved. the heart will stop |
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Term
| can you explain what an electrocardiography is? |
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Definition
| electricall readings of the hearts activities. mesures depol and repol acticities of the nodes and cardiac tissues |
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Term
| can you list three deflection waves of an ecg/ekg trace and describe what is happening in each? |
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Definition
waves -P:artrial depol
QRS complex: ventricular depol
T: ventricular repol |
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Term
| what event of heart contraction is not visible in ECG trace and why |
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Definition
| Atrial repol, because it is shadowed by the huge depol event happening at the ventricles during the same time |
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Term
| can you describe the flow of the vessel types through the body starting with leaving the heart |
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Definition
| Arteries leave the heart and branch into smaller arteries and finally arterioles that lead blood into capillary beds. blood enters venules as it leaves the bed and anastomoses into larger and larger veins until it is returned to the heart |
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Term
| can you describe the structure and charactersistics of veins |
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Definition
| thin walls with very little smooth muscle or elastin. they have large lumen and valves |
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Term
| can you contrast the features that are different between arteris and veins? how do these contrasting features lend to the different functions of these vessels |
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Definition
| arteries have more smooth muscle and can be used as effector organs for regulation of blood pressure by the nervous system. arteries also have elastin to withstand pressure from the heart. veins hare large lumens to lessen resistance to blood flow as well as valeves to prevent backflow of blood |
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Term
| can you describe structure and characteristics of arteries |
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Definition
| they have thicker walls than veins with more tunica media (smooth muscle layer). they also have elastin in their walls to withstand fluctuations of pressure from the heart |
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Term
| if the blood loses most of its pressure i nthe capilaries, how does blood make it back up to the heart in the venous system |
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Definition
| muscular and respitory pumps |
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Term
| can you list five factors that influence blood pressure |
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Definition
| heart rate, stroke volume, peripheral resistance, blood viscosity and blood volume |
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Term
| can you describe how a myogenic response helps control blood pressure in a capillary bed? |
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Definition
| if blood pressure drops the arterioles will vasodilate to increase blood flow into the cap. bed and thus rasie blood pressure to ensure adequate exchange with the tissues. if blood pressure rises, the arterioles will vasoconstrict to reduce blood flow into the cap. bed and raise bp to preserve the integraty of the caps. |
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Term
what is the normal heart rate and blood pressure averges for humans?
- generally, how do the sympathetic and parasympathetic nervous systems affect these averages |
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Definition
BP- 120/80, HR 70 bpm
- sypathetic causes this to rise and parasympathetic casues these to drop. |
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Term
can you write the equation for cardiac output?
-if you can write the equation then you know the two factors that affect cardiac output. what are they |
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Definition
CO=HRxSV
-stroke volume: amount of blood pumped from the left ventricle in one stroke/contraction.
-Heart rate: number of beats per min.
-CO: cardiac volume |
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Term
| can you write the equation for stroke volume? |
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Definition
SV= EDV-ESV
EDV= end distolic volume
ESV= end systolic volume |
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Term
| what are the two factors in stroke volume |
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Definition
| End distolic volume EDV- amount of blood in the left ventricle after diastole (ventricular relaxation and the ventricle is filling). End systolic volume ESV- amount of blood remaining in the left ventircle after systole (venticular contraction and the blood is pumped from the chamber) |
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Term
| how does increase contractility of the ventricles affect stroke volume? what does this do to the ESV |
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Definition
| more blood is pumped out of the left ventricle. ESV is lowered |
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Term
| how would a decrease in ESV affec CO? can you show this in a drawing? |
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Definition
| if ESV is lowered then SV increases because a smaller number is subtracted from EDV |
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Term
| whats the equation for BP |
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Definition
BP=COxPR
CO= Cardiac output
PR= Periphery resitance |
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Term
| what are the two factors that affect blood pressure |
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Definition
Cardiac output: amount of blood pumped from the left ventricle in one min.
Periphery resistance: resistance to flow of blood in the periphery (blood vessesls) |
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Term
| can you explain how ESV,EDV,SV and CO would affect bp? |
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Definition
| If EDV increases and ESV decreases you get a significant rise in SV. if HR and SV siginificantly raise then you have a significant raise in CO. if CO raises then BP raises |
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Term
do you know what must happen to arteries fo PR to increase?
-how is this acomplished |
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Definition
| they must vasoconstrict. sympathetic nervous system- EPI/NE bind to alpha adrenergic receptors |
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Term
| can you define "venous return"? how can an increase in venous return affect EDV |
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Definition
| the amount of blood from venous supply returning to fill the chambers of the heart. if more blood returns to the heart, more blood fills the ventricle and EDV raises |
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Term
| how is the frank-starling law and venous return related? |
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Definition
| more venous return = more blood in the left ventricle = frank starling law |
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Term
| can you define blood viscosity? |
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Definition
|
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Term
| can you explain how blood vescosity influences BP? |
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Definition
| thicker blood exerts more presure on the walls of the vessels because there will be more resistance to flow in a thicker fluid |
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Term
| what is blood volume and how does it affect bp? |
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Definition
| it is the amount of blood in the vessels. more volume =more resistance to flow=increased PR= increased BP |
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Term
| can you explain the role of angiotensin II in vasoconstriction? |
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Definition
| it is a powerful vasoconstricter when it is present in the blood supply and causes increased PR and that causes increased BP |
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Term
do you know what detects a drop in blood pressure?
where are these structures located? |
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Definition
| Barroreceptors and they are found in the kidneys |
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Term
| do you know what the disorder for blood clotting is called? which factor is usually missing |
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Definition
| Hemophillia, and they are usually missing factor VIII |
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