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85 Cards in this Set
- Front
- Back
Which contains more blood, the veins or the arteries?
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Veins
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Which vessels are elastic and which are resistance?
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Veins are elastic, and arteries are resistance.
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What is EDV determined by?
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Preload, filling pressure, filling time, ventricular dispensability.
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What is ESV determined by?
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Afterload (aortic/pulmonary pressure), contractility, and preload.
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Which curve defines changes in central venous pressure (right atrial pressure) that occur due to changes in cardiac output?
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Vascular function curve
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What determines the level of central venous pressure?
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The heart (the pump)
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If compliances are equal then pressure will stabilize at what?
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The mean of arterial pressure and central venous pressure.
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T/F
Arterial and venous compliances are equal. |
False!
However, arterial and venous compliances are very different. |
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Why is the the mean pressure in the system at equilibrum reduced to 7 mmHg?
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Because venous compliance is so great.
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What effects do step-down changes in flow (cardiac output) have on arterial and venous pressures?
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Arterial pressure - pressure decreases and pulsations get closer and closer together
Venous pressure - increases and at very low pressure the graph shows small pulsations |
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The mean circulatory pressure (or static pressure), Pmc, is what?
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The equilibrium pressure (7mmHg) throughout the cardiovascular system when cardiac output is 0.
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What is the value for normal venous pressure and normal cardiac output?
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Vvenous pressure (2mmHg) at normal cardiac output of 5 L/min.
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T/F
On the vascular function curve, the point at which CVP = 0 changes with changes in blood volume. |
True!
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When there is more volume in the closed system, pressure (decreases/increases), and when there is less volume, pressure (decreases/increases).
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Increases, decreases
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Why is one of the first goals during a hemorrhage (during significant blood loss) to increase blood volume?
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Cardiac output of 5 L/min cannot be maintained at this time.
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T/F
Central venous pressure at a cardiac output of 0 changes with changes in peripheral resistance. |
False!
In all cases CVP = 7 mmHg when cardiac output is 0. This is because we have not changed volume in the system. |
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Which curve represents the Frank-Starling mechanism?
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Cardiac output curve
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In the cardiac output curve, as the independent variable is increased the heart contracts (less/more) forcefully.
This can be represent by any of what 3 variables? |
More
Stroke volume, pressure (in ventricles), or cardiac output. |
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T/F
Things that affect HR will change the cardiac output curve. |
True!
The cardiac output curve is SV and HR, so while the curve represents F-S mechanism, it includes HR. So things that affect HR change the curve. |
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Which curve will parasympathetic stimulation change, the SV vs. EDV curve ot the CO curve?
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CO curve
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What does the intersection of the cardiac and vascular function curves represent?
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The stable values of CO and CVP at which the system tends to operate.
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An increase in CVP causes a(n) (decrease/increase) in CO.
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Increase
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In a vascular function curve, a rise in CO causes a(n) (decrease/increase) in CVP.
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Decrease
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How does sympathetic stimulation of the heart shift the cardiac output curve?
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Up and left
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What determines the level of central venous pressure?
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The heart (the pump)
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If compliances are equal then pressure will stabilize at what?
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The mean of arterial pressure and central venous pressure.
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T/F
Arterial and venous compliances are equal. |
False!
However, arterial and venous compliances are very different. |
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Why is the the mean pressure in the system at equilibrum reduced to 7 mmHg?
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Because venous compliance is so great.
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What are the values for normal venous pressure and normal cardiac output?
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Venous pressure (2mmHg) at normal cardiac output of 5 L/min
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T/F
The point at which CVP = 0 changes with changes in blood volume. |
True!
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When there is more volume in the closed system pressure (decreases/increases), and when there is less volume, pressure (decreases/increases).
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Increases, decreases
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During hemorrhage (significant blood loss), why is one of the first goals to increase blood volume?
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Cardiac output of 5L/min cannot be maintained with significant blood loss.
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T/F
Changes in peripheral resistance cause changes in CVP at a cardiac output of 0. |
False!
In all cases CVP = 7 mmHg when cardiac output is 0. This is because we have not changed volume in the system. |
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Which curve represents the Frank-Starling mechanism?
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Cardiac output curve
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In cardiac output curves, as the independent variable is increased, the heart contracts (less/more) forcefully.
What 3 variables is this represented by? |
More
Stroke volume, pressure (in ventricles), or cardiac output. |
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T/F
CO curve is unaffected by heartrate. |
CO curve is SV and HR, so while the curve represents F-S mechanism, it includes HR. Therefore, things that affect HR change the curve.
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Which curve will parasympathetic stimulation change - the SV vs. EDV curve or CO curve?
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CO curve
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What does the intersection of the cardiac and vascular function curves represent?
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The stable values of CO and CVP at which the system tends to operate.
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In the cardiac output curve, an increase in CVP = a(n) (decrease/increase) in CO.
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Increase
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In the vascular function curve, a rise in CO causes a(n) (decrease/increase) in CVP.
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Decrease
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How does sympathetic stimulation of the heart shift the cardiac output curve?
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Up and left
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With sympathetic stimulation of the heart:
a) Increased myocardial contractility suddenly (decreases/increases) CO. b) Shifting blood from venous to arterial side of circuit causes what? c) CO would continue to fall until when? |
a) Increases
b) CVP begins to fall c) Until reaching a new equilibrium |
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What factors would cause the cardiac output curve to shift upwards?
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↓ Parasympathetic
↑ Sympathetic ↑ contractility Heart hypertrophy |
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What factors would shift the cardiac output curve downwards/right?
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↑ Parasympathetic
↓ Sympathetic ↓ contractility Heart failure |
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What does blood transfusion shift in order to enhance cardiac output?
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Vascular function curve
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What effect does increased resistance have on both the vascular function curve and cardiac output curve?
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Vascular function - Increased resistance decreases the volume held in the arterial vessels so the vascular curve is depressed.
CO - Increased resistance also increases afterload so that ESV is increased, SV is decreased therefore CO is decreased. |
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What aspect of sympathetic stimulation affects the venous return curve?
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Vasoconstriction of veins and arteries
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What aspects of sympathetic stimulation affects the cardiac output curve?
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↑ heart rate
↑ contractility |
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What are 4 intrinsic causes of heart failure?
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Coronary artery disease: ↓flow to heart tissue
Myocardial infarct: tissue damaged, so healthy tissue has extra work. Also leads to functional changes Valvular disease and congenital defects Cardiomyopathies; usually causes loss of inotropy |
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What are 3 extrinsic causes of heart failure?
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↑afterload (hypertension)
↑ stroke volume (volume load, preload) ↑ body demands |
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What is impaired in systolic vs diastolic problems?
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Systolic – impaired contraction
Diastolic – impaired filling can be vascular side or heart |
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Systolic impairment causes what 3 things?
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Altered signal transduction
Altered excitation/contraction coupling Decreases in Frank starling mechanism (this can cause a compensatory increase in preload) |
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Diastolic impairment causes what 2 things?
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Decreased ventricular compliance
Impaired relaxation |
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What are the normal pressures in each of the following:
a) Aorta b) Right atrium c) Right ventricle d) Pulmonary artery e) Left atrium f) Left ventricle |
a) 120/80
b) 0-4 c) 25/4 d) 25/10 e) 8-10 f) 120/10 |
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What could cause the F-S curve to decrease significantly in amplitude and slope?
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Systolic failure
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Loss of inotropy and a normal ejection graction <20% (normal is >55%) is likely caused by what?
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Systolic failure
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How will systolic failure affect EDV, ESV and SV?
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↑ EDV
↑ESV ↓SV |
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How does an upward shift in the EDPVR in diastolic failure affect filling and end-diastolic pressure?
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↓filling and ↑end-diastolic pressure (usually <10mmHg)
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a) In diastolic failure, what can cause an increase in left atrial pressure and pulmonary pressure?
b) What does this lead to? c) If this occurs on right side, what can it lead to? |
a) The increase in end-diastolic pressure (can be as high as 30 mmHg).
b) Pulmonary edema c) Systemic edema |
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What do systolic and diastolic failure together cause?
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Less filling
Less emptying Great reduction in stroke volume High end-diastolic pressure leads to pulmonary edema |
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↑sympathetic reflexes, baroreceptor reflex,chemoreceptors, and ischemic response are (short/long) term responses to heart failure.
How does this affect the heart and the vasculature? |
Short
Heart - ↑HR, ↑contractility Vasculature - ↑ venous return, ↑ total peripheral resistance |
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What happens to the CO curve during heart failure?
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It shifts down.
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Stimulation of adrenal medulla, release of circulating hormones, fluid retention at kidney, and remodeling of heart tissue are all (short/long) term responses to heart failure.
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Long
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Which long term responses to heart failure serve to increase pressure, and how?
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Stimulation of adrenal medulla:
Release of epi/norepi Release of circulating hormones: ADH (vasopressin) Renin-angiotensin-aldosterone Angiotensin potent vasoconstrictor |
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Which long term response to heart failure serves to increase volume, and how?
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Fluid retention at kidney:
ADH – fluid retention Aldosterone – Na+ retention |
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Which long term response to heart failure serves to increase pumping?
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Remodeling of heart tissue
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What is the term for the amount that CO can ↑ above normal?
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Cardiac reserve
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What will the patient experience if cardiac reserve is low?
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Shortness of breath
Muscle fatigue Excessive in ↑HR |
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What type of receptor are bare ends of myelinated nerve fibers located at the ends of afferent axons that join the vagus?
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Atrial baroreceptors
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Atrial baroreceptors:
a) Gradual (decrease/increase) in firing as atria fill b) Monitor rising _______ volume c) Detect changes in _____________. d) Effectively monitor circulating volume and _____________. |
a) Increase
b) Atrial c) Central venous pressure d) Venous return |
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When blood volume is low or hypotension occurs, what happens to CVP and what is the nervous response?
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There is a fall in CVP (central venous pressure) that will elicit a sympathetic response.
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What does angiotensin II stimulate release of?
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Stimulates release of vasopressin (ADH) from post-pituitary and aldosterone from adrenal cortex.
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How does angiotensin II affect resistance vessels? What does this do to PR and BP?
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Constrict resistance vessels
↑PR and ↑ BP |
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T/F
Angiotensin II inhibits thirst centers. |
False!
Angiotensin II stimulates thirst centers. |
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T/F
Angiotensin II stimulates cardiac and vascular hypertrophy. |
True!
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How does angiotensin II affect blood volume, CO, and BP?
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Results in ↑ volume ↑ CO ↑ BP
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ACE inhibitors and AT receptor blockers affect what 4 things?
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BP, afterload, blood volume, hence preload.
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Some afferent fibers of artial receptors go to the location of ADH (vasopressin), which is where?
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Hypothalamus
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Vasopressin mostly stimulated by a)_____________ and is involved in regulation of b)________ and c)__________.
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a) plasma osmolarity
b) osmolarity c) BV |
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T/F
A fluid loss of 5-10% leads to a sharp rise in vasopressin. |
True!
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Clinically, what causes a sharp increase in ADH release?
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Hemorrhagic and hypovolemic shock
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Atrial myocytes become over stretched when what is high?
Then, what do they release? |
CVP
Atrial natriuretic peptide (ANP) |
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galabia
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جَلاّبيّة جَلاليب
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What does ANP stimulate at the kidney?
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Na+ and water excretion.
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What does ANP do to blood volume, CO and BP?
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Results in ↓blood volume ↓CO and ↓BP.
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