Week 4 Pre-Learning: Perfusion Properties Flashcards

1
Q

What are the 5 mechanical properties affecting cardiac output?

A
  1. Cardiac contractility
  2. Heart rate
  3. Preload (stretch)
  4. Afterload (squeeze)
  5. Blood volume
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2
Q

What is the formula for cardiac output? What is the normal CO in an adult?

A

CO = (HR)(SV)

3-6L/min in adults

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3
Q

What is cardiac output?

A
  • amount of blood pumped out of the left ventricle each minute
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4
Q

What is preload? (2)

A
  • volume of blood in ventricles at the end of diastole
  • aka end diastolic pressure (pre-systole, amount of blood returning to heart)
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5
Q

Preload is increased in what instances? (3)

A
  • Hypervolemia
  • Regurgitation of cardiac valves
  • Heart failure
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6
Q

What is afterload?

A
  • Resistance that the left ventricle must overcome to circulate blood
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7
Q

What is afterload affected by? (3)

A
  • arteriole BP
  • diameter of blood vessels
  • pressure in ventricles must be greater than systemic and pulmonic pressures to open aortic + pulmonary valves
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8
Q

When would afterload be increased? (2)

A
  • Hypertension
  • vasoconstriction
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9
Q

An increase in afterload means an increase in _____ _____.

A

cardiac workload

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10
Q

What do electrical properties of the heart regulate? (2)

A
  • HR and rhythm
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11
Q

What properties do cardiac muscle cells have? (4)

A
  • excitability
  • Conductivity
  • Contractility
  • Refractoriness
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12
Q

What are the important electrolytes for the electrical properties of the heart? (3)

A
  • Na+
  • K+
  • Ca2+
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13
Q

Coronary circulation involves what 3 coronary arteries?

A
  • Right coronary artery (RCA)
  • Left anterior descending (LAD)
  • Circumflex
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14
Q

The right coronary artery supplies blood to what structures? (6)

A
  • Right atrium
  • Right ventricle
  • part of left ventricle (inferior)
  • SA node (50%)
  • AV node
  • Bundle of His
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15
Q

What can occur if the RCA is blocked? (2)

A
  • RV failure
  • bradycardia heart block
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16
Q

Where does the left anterior descending artery supply blood to? (2)

A
  • Anterior wall of LV
  • Heart valves
17
Q

What may occur with blockage of LAD? (3)

A
  • LV failure (main powerhouse perfusion)
  • Dysrhythmias (life-threatening)
  • Highest mortality rate (most lethal)
18
Q

Where does the circumflex artery supply blood to? (3)

A
  • Left atrium
  • Lateral and posterior walls of left ventricle
  • SA node (50%)
19
Q

What may occur with blockage of the circumflex artery? (2)

A
  • Left ventricle failure
  • Dysrhythmias
20
Q

What is collateral circulation?

A
  • Additional arterial connections found around areas of increasing occlusion

think of it as arteries are highways, and construction develops

21
Q

Why does collateral circulation occur?

A
  • Body’s response to chronic, long-standing ischemia
22
Q

Does collateral circulation always occur with occlusion?

A
  • When arterial occlusion is rapid, there is no time for collateral circulation
23
Q

What are factors that determine collateral circulation?

A
  • Genetic predisposition
  • Chronic ischemia

if Hx of hypercholesterolemia, it does not allow collaterals to develop