Term
| What are the 4 main factors that directly affect cardiac output? |
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Definition
| Level of basal metabolic activity, level of exercise, person's age, person's size |
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Term
| What is the normal cardiac output for men? For women? |
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Definition
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Term
| What is the Frank Starling intrinsic mechanism? |
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Definition
| If more blood is delivered, more blood will automatically be pumped out of the aorta, increasing cardiac output |
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Term
| What effect does stretching of the SA node in the wall of the right atrium have on the rhythmicity of the node and the heart rate? |
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Definition
| Increases heart rate by 10-15% |
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Term
| What reflex is initiated by stretching of the right atrium? |
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Definition
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Term
| Change in blood flow to local tissues is proportional to what? |
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Definition
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Term
| Cardiac output is inversely proportional to what? |
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Definition
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Term
| How is cardiac output related to arterial pressure and total peripheral resistance? |
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Definition
| Arterial pressure/total peripheral resistance |
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Term
| What four properties of heart function directly affect cardiac output? |
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Definition
| Heart rate, myocardial contractility, preload, afterload |
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Term
| The cardiac output curve are associated directly with heart rate and myocardial contractility and are directly related to what mechanism? |
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Definition
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Term
| What factors contribute to a hyper-effective heart? |
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Definition
| Nervous system stimulation, hypertrophy of heart muscles |
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Term
| What factors contribute to a hypo-effective heart? |
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Definition
| Increased arterial pressure, inhibition of nervous input, coronary blockage, valvular heart disease, congenital heart disease, myocarditis (inflammation of heart muscle), cardiac hypoxia |
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Term
| What does the vascular curve describe? |
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Definition
| Changes in central venous pressure (right atrial pressure) that occur due to changes in cardiac output |
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Term
| What determines central venous pressure? |
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Definition
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Term
| What is the mean circulatory pressure at equilibrium? |
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Definition
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Term
| What is venous pressure at normal cardiac output? |
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Definition
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Term
| In all cases, central venous pressure is 7mmHg when cardiac output is what? |
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Definition
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Term
| The intersection of the vascular function and cardiac function curves represents what? |
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Definition
| Stable values of cardiac output and central venous pressure at which the system tends to operate |
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Term
| While a cardiac function curve supports the Frank-starling mechanism of increased CVP = increased CO, what inverse relationship does the vascular function curve describe? |
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Definition
| A rise in CO = reduction of CVP |
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Term
| An increase in myocardial contractility results in an increase in cardiac output. What effect does this have on central venous pressure? |
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Definition
| Shifts blood from venous to arterial side of the circuit, lowering central venous pressure |
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Term
| What effect does a blood transfusion have on cardiac output? |
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Definition
| Shifts vascular function curve, enhances cardiac output to compensate |
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Term
| What effect does increased resistance have on central venous pressure? |
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Definition
| Decreases the volume in arterial vessels causing vascular curve to be depressed. |
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Term
| What effect does increased resistance have on cardiac output? |
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Definition
| Increases afterload, decreases cardiac output |
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Term
| What autonomic effects increase cardiac output and shift the curve left (up)? |
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Definition
| Decreased parasympathetic, increased sympathetic, heart hypertrophy |
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Term
| What autonomic effects decrease cardiac output and shift the curve right (down)? |
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Definition
| Increased parasympathetic, decreased sympathetic, heart failure |
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Term
| Systolic failure is associated with loss of inotropy which means a loss in what? |
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Definition
| Force of muscle contraction |
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Term
| Pulmonary edema and decreased compliance is associated to what aspect of heart failure? |
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Definition
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Term
| What are short term responses to heart failure (dramatic decrease in cardiac output)? |
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Definition
| Increased sympathetic reflexes via baroreceptors, chemoreceptors, and ischemic response, increased heart rate and contractility, increased venous return to arterioles, increased total peripheral resistance |
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Term
| What are long term responses to heart failure? |
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Definition
| Stimulation of adrenal medulla to release epi/norepi, release circulating hormones, increased fluid retention in the kidneys, remodeling of heart tissue |
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Term
| The amount cardiac output can increase above normal is known as what? |
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Definition
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Term
| Low cardiac reserve manifests as what symptoms? |
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Definition
| Shortness of breath, muscle fatigue, excessive increase in heart rate |
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Term
| Atrial baroreceptors detect what? |
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Definition
| Changes in central venous pressure |
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Term
| Angiotensin II stimulates the release of what? |
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Definition
| Vasopressin (ADH) from the posterior pituitary, aldosterone from the adrenal cortex, constricts resistance vessels, stimulates thirst centers, cardiac vascular hypertrophy, increases volume, cardiac output, blood pressure |
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Term
| What effect does hemorrhages and hypovolemic shock have on ADH levels? |
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Definition
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Term
| Central venous pressure increase causing stretching of atrial myocytes causes release of what? |
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Definition
| Atrial natriuretic peptide (ANP) |
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Term
| Atrial natriuretic peptide has what effects? |
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Definition
At kidney stimulates Na+ and water excretion
Results in ↓blood volume ↓CO and ↓BP |
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