Term
| what is the formula for mean arterial pressure? |
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Definition
mean arterial pressure = diastolic + 1/3 (pulse pressure)
or .33 |
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Term
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Definition
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Term
| what is the normal mean arterial pressure? |
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Definition
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Term
| Why is systolic BP 120mmHg? |
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Definition
when left ventricle pressure is greater than aortic pressure, the phase of ejection begins as the semilunar valves open
then aortic pressure increases to 120mmHg |
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Term
| why is diastolic BP 80mmHg? |
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Definition
as ventricular pressure falls below the aortic pressure, the back pressure causes the semilunar valves to close
then, the aortic pressure falls to about 80 mmHg while ventricular pressure falls to about 0mmHg |
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Term
| what three factors influence arterial BP? |
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Definition
cardiac output
vascular resistance
radius of vessel |
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Term
| describe phase 1 of the cardiac cycle. |
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Definition
as ventricles begin their contraction, ventricular pressure increases, causing the AV valves to close
isovolumetric contraction |
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Term
| what valves are open in phase 1 of the cardiac cycle? |
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Definition
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Term
| during phase 1 of the cardiac cycle do the muscle fibers lengthen or shorten? |
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Definition
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Term
| what factors effect vascular resistance? |
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Definition
diameter of vessel
length of vessel
viscosity of blood |
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Term
| describe phase 2 of the cardiac cycle. |
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Definition
when the left ventricle pressure is greater than aortic pressure, the phase of ejection begins as the semilunar valves open.
then ventricular and aortic pressure increases to 120mmHg |
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Term
| how much blood is ejected from the ventricles per beat? |
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Definition
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Term
| describe phase 3 of the cardiac cycle. |
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Definition
as ventricular pressure falls below the aortic pressure, the back pressure causes the semilunar valves to close
the aortic pressure falls to about 80mmHg while ventricular pressure falls to 0mmHg |
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|
Term
what is another name for phase 3 of the cardiac cycle?
why? |
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Definition
isvolumetric relaxation
all valves are closed
decrease in tension without lengthening, causes pressure to decrease
ventricular volume remains unchanged |
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Term
| describe phase 4 of the cardiac cycle. |
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Definition
when ventricular pressure falls below arterial pressure, the AV valves open and a phase of rapid filling in the ventricles occur
about 70% of the blood entering the atria during diastole in the ventricles |
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Term
| describe phase 5 of the cardiac cycle. |
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Definition
atrial contraction
empty the remaining 30% of atrial blooding ventricles before next phase (phase 1) |
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Term
| how is atrial blood pressure expressed? |
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Definition
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Term
| what is considered high BP? |
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Definition
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Term
| what is systolic pressure? |
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Definition
| pressure generated during ventricular contraction |
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Term
| what is diastolic pressure? |
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Definition
| pressure in the arteries during cardiac relaxation |
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Term
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Definition
| difference between systolic and diastolic |
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Term
| what is the formula for pulse pressure? |
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Definition
| pulse pressure = systolic - diastolic |
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Term
| what is mean arterial pressure? |
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Definition
| average pressure in the arteries |
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Term
| What is systolic blood pressure? |
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Definition
| the highest aortic pressure measured during the cardiac cycle |
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Term
| what is diastolic blood pressure? |
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Definition
| the aortic blood pressure during the diastole phase of the cardiac cycle |
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Term
| what is the formula for MAP in relation to cardiac output? |
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Definition
| MAP = cardiac output x vascular resistance |
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Term
| what is the formula for cardiac output? |
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Definition
| cardiac output = cardiac rate x stroke volume |
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Term
| what is total vascular resistance? |
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Definition
| the sum of resistance to blood flow provided by all systemic blood vessels |
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Term
| what are the two determinants of mean arterial pressure? |
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Definition
cardiac output
total vascular resistance |
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Term
| what is the formula for resistance? |
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Definition
| resistance = length x viscosity/ radius^4 |
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Term
| T/F increase length->increase resistance |
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Definition
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Term
| T/F increase hematocrit->increase viscosity->decrease resistance |
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Definition
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Term
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Definition
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Term
| what is the plasma in relation to blood? |
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Definition
liquid portion of blood
contains ions, proteins, hormones |
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Term
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Definition
| contain hemoglobin to carry oxygen |
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Term
| what is the role of WBCs? |
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Definition
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Term
| what is the role of platelets? |
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Definition
| important in blood clotting |
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Term
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Definition
| the portion of blood volume that is occupied by RBCs |
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Term
| T/F blood cells are more viscous than plasma |
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Definition
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Term
| T/F increase hematocrit->increase blood viscosity |
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Definition
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Term
| what is the most important variable in determining vascular resistance? |
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Definition
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Term
| T/F the resistance is inversely proportional to the fourth power of radius |
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Definition
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Term
| what causes a a change in diameter of the blood vessel? |
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Definition
| the contraction and relaxation of the vascular smooth muscle in the wall of the blood vessel. |
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Term
| T/F small changes in vessel diameter causes small changes in resistance. |
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Definition
false
large changes in resistance |
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Term
| If A and B vessels have the same radius and A vessel has twice the length compared to vessel B, which will have higher resistance? |
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Definition
| resistance will increase twice in vessel A |
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Term
| If the viscosity of the blood increases twice, how many folds does the resistance increase or decrease? |
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Definition
| resistance to flow will increase twice |
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Term
| If a 2-fold increase in radius, how many folds does the resistance increase or decrease? |
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Definition
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Term
| what system is in control of regulating arterial blood pressure in short-term regulation? |
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Definition
| sympathetic nervous system |
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Term
| what works in conjunction with the SNS in short-term regulation of arterial blood pressure? |
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Definition
| baroreceptors in the aorta and arteries |
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Term
| how does short-term regulation work when blood pressure is high? |
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Definition
when there is an increase in BP->
triggers barorecepotrs->
sends an impulse to cardiovascular control center (medulla) in the brain->
decreases SNS activity->
bring BP to normal |
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Term
| how does short-term regulation work when blood pressure is low? |
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Definition
when there is a decrease in BP->
reduce baroreceptor activity->
reduce impuse to cardiovascular control center to the brain->
increase SNS activity->
increase BP to normal |
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Term
| how does the body handle long-term regulation of arterial blood pressure? |
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Definition
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Term
| how does long-term regulation work when blood pressure is high? |
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Definition
increase in BP->
the kidneys increase their excretion rate of Na+ and water->
increase blood volume->
BP returns to normal |
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Term
| how does long-term regulation work when blood pressure is low? (hint: two ways) |
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Definition
one:
the kidneys decrease their excretion rate of Na+ and water->
increase in blood volume->
BP returns to normal
two:
increase renin released by kidneys |
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Term
| How does an increase in renin increase blood pressure when it is too low? |
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Definition
| renin results in the production of angiotensin 2 |
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Term
| what are the four ways angiotensin 2 increases blood pressure? |
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Definition
1) causes the arterioles to constrict
2) cause the cardiovascular control center in the brain to increase SNS activity
3) triggers the release of aldosterone
4) triggers the release of vasopressin |
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Term
| Renin triggers the release of aldosterone, how does this increase blood pressure when blood pressure is too low? |
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Definition
| causes the kidneys to increase the reabsorption of Na+ into the blood, this increase the blood volume, increasing BP |
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Term
| Renin triggers the release of vasopressin, how does this increase blood pressure when blood pressure is too low? |
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Definition
| causes the kidneys to increase water reabsorption into the blood, which increases the blood volume, which increases BP |
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Term
| during exercise does BP and HR increase? |
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Definition
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|
Term
| what kind of drug do people with hypertension take? |
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Definition
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Term
| what does an ACE inhibitor do? |
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Definition
| block the pathway to make angiotensin 2 |
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Term
| what layer of the heart does contraction depend on? |
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Definition
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Term
| what does contraction of the heart depend on? |
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Definition
| electrical stimulation of the myocardium |
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Term
| what are the four parts of the conduction system of the heart? |
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Definition
1) Sinoatrial (SA) node
2) Atrioventricular (AV) node
3) Bundle Branches
4) Purkinje Fibers |
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Term
|
Definition
the pacemaker
initiates depolarization |
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Term
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Definition
passes depolarization to ventricles
brief delay to allow for ventricular filling |
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Term
| where are the bundle branches located? |
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Definition
| to the left and right of the ventricles |
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Term
| where are the purkinje fibers located? |
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Definition
| throughout the ventricles |
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Term
| which chamber depolarizes 1st? |
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Definition
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|
Term
| which chamber depolarizes 2nd? |
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Definition
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|
Term
| when both atria depolarize what happens? |
|
Definition
AV valves open
70% of blood in atria will fill into the ventricles
then remaining 30% fill |
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Term
| what would happen if there was not a pause in depolarization? |
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Definition
the ventricles would not fill with enough blood
not enough blood would be pumped to the body
resulting in tissue damage |
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Term
| what happens in the first stage of the conduction system? |
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Definition
| action potentials originate in the SA node and travel across the walls of the atrium to the AV node. |
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Term
| what happens in the second stage of the conduction system? |
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Definition
| action potentials pass through the AV node and to the AV bundle. |
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Term
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Definition
| extends from the AV node, through the fibrous skeleton and into the inter ventricular septum |
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Term
| what happens in the third stage of the conduction system? |
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Definition
the AV bundle divides into the right and left bundle branches
the action potential descends to the apex of the ventricles |
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Term
| what happens in the fourth stage of the conduction system? |
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Definition
| purkinje fibers carry the action potentials along the ventricle walls |
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Term
| what is another name for the bundle branches? |
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Definition
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Term
| how does the sympathetic nervous system regulate heart rate? |
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Definition
| activates cardiac beta1 adrenergic receptors via cardiac accelerator nerves. |
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Term
| what are the cardiac excitatory effects? |
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Definition
increase the SA node pacing
increase rate of conduction
increase contractility |
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|
Term
| what do the cardiac beta1 receptors do? |
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Definition
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|
Term
| what does the right vagus nerve control? |
|
Definition
|
|
Term
| what does the left vagus nerve control? |
|
Definition
|
|
Term
| does heart rate increase or decrease with SNS stimulation? |
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Definition
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|
Term
| how does the parasympathetic nervous system regulate heart rate? |
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Definition
| activates muscarinic receptor via right vagus nerve |
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Term
| what are the cardiac inhibitory effects? |
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Definition
decrease SA node pacing
decrease rate of contraction
decrease for of contraction |
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|
Term
| does heart rate increase or decrease with PNS stimulation? |
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Definition
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|
Term
| T/F parasympathetic innervation of the heart is mediated by the left vagus nerve. |
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Definition
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|
Term
| what does the right vague nerve inhibit? |
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Definition
| directly inhibits the SA node of the right atrium |
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Term
| what is the normal heart rate? |
|
Definition
about 72 bpm
between 60-80bpm |
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Term
| if the SA node is damaged you should expect the heart rate to increase or decrease? |
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Definition
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|
Term
| T/F if the SA node and the AV node is damaged you should expect the expect the heart rate to be around 20-40 bpm |
|
Definition
|
|
Term
| how does a pacemaker work? |
|
Definition
when the SA node and the AV node are damaged, the pacemaker takes its place
when BP gets too low it causes the device to turn on to increase the HR |
|
|
Term
| what acts as the pacemaker if the SA node is damaged? |
|
Definition
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