CVR2

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What are the 4 properties of the heart?
- autorythmicity
- contractility
- excitability
- conductivity
What are the parts of the electrical conducting system?
- SA node
- AV node
- Purkinje's fibers
- HIS bundle
- Right and left bundle branches
What 2 kinds of cells make up the heart?
- Mechanical cells
- Cells of electrical system
The cells of electrical system are actually these

Modified cardiac muscle cells
What 2 things do interclated discs contain?
- Desmosomes - attach cells together
- Gap junctions - spread action potentials
What is the resting membrane potential in cardiac cells?

-80 to -90 mv
This ion generates resting membrane potential

K+
What is the Nernst equation?

61.5 log10 (Xo / Xi)
These are 2 types of action potentials in the heart
- Fast
- Slow
Which cells have fast response action potentials?
- atrial cells
- ventricular cells
- His cells
- Purkinje cells
Which cells have slow action potentials?
- AV node
- SA node
Fast AP:
- 0= Na influx
- 1= Na close and open specific K+ channels
- 2= open calcium channels
- 3= close calcium open K+
- 4= rest
The refractory period spans this time

depolarization half way down repolarization
Pacemaker Potential:
- 1. K+ close, Na_f open
- 2. Na_f close, T-calcium open
- 3. T-calcium close, L-calcium open
- 4. L-calcium close, K+ open
The suppression of all other pacemakers by the SA node is called this

overdrive suppression
Conduction of AP
- 1. AP made in SA node
- 2. Rapid spread through atria
- 3. Delay
- 4. Goes through His bundle
- 5. Goes through ventricles
- 6. Rest
These cells have the largest diameter with most of gap junctions

Purkinje cells
These cells have small diameter and less gap junctions

AV node cells
Intercalated Disc between cells

Author

Bobopudge

64636

Card Set

CVR2

Description

Autorhytmicity and Conduction in the Heart

Updated

2011-03-31T10:09:22Z