Week 4 Pre-Learning: Perfusion Properties Flashcards
What are the 5 mechanical properties affecting cardiac output?
- Cardiac contractility
- Heart rate
- Preload (stretch)
- Afterload (squeeze)
- Blood volume
What is the formula for cardiac output? What is the normal CO in an adult?
CO = (HR)(SV)
3-6L/min in adults
What is cardiac output?
- amount of blood pumped out of the left ventricle each minute
What is preload? (2)
- volume of blood in ventricles at the end of diastole
- aka end diastolic pressure (pre-systole, amount of blood returning to heart)
Preload is increased in what instances? (3)
- Hypervolemia
- Regurgitation of cardiac valves
- Heart failure
What is afterload?
- Resistance that the left ventricle must overcome to circulate blood
What is afterload affected by? (3)
- arteriole BP
- diameter of blood vessels
- pressure in ventricles must be greater than systemic and pulmonic pressures to open aortic + pulmonary valves
When would afterload be increased? (2)
- Hypertension
- vasoconstriction
An increase in afterload means an increase in _____ _____.
cardiac workload
What do electrical properties of the heart regulate? (2)
- HR and rhythm
What properties do cardiac muscle cells have? (4)
- excitability
- Conductivity
- Contractility
- Refractoriness
What are the important electrolytes for the electrical properties of the heart? (3)
- Na+
- K+
- Ca2+
Coronary circulation involves what 3 coronary arteries?
- Right coronary artery (RCA)
- Left anterior descending (LAD)
- Circumflex
The right coronary artery supplies blood to what structures? (6)
- Right atrium
- Right ventricle
- part of left ventricle (inferior)
- SA node (50%)
- AV node
- Bundle of His
What can occur if the RCA is blocked? (2)
- RV failure
- bradycardia heart block