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37 Cards in this Set

  • Front
  • Back
Cardiovascular disease
What is the number one cause of death in the US?
drugs (majority)
mechanical devices
How is cardiovascular disease treated?
Cardiac electrical conduction system
What is the name of the system that is ablility to set its own rate?
Heart strength is important to be able to have enough strength to push the blood around and able to get to the organs or destinations that it needs to go to.
Why is heart strength so important?
capillary beds
Where does the site of exchange of O2 leave the blood and CO2 is picked up?
Our tissues have a constant need or continuous supply of O2, so therefore, the heart must have a continuous pump or reg. rhythm.
Why is heart rate and rhythm so important?
SA node

in charge of setting the rate or how fast the depolarizes
AV node
The SA node leaks Na+ which leads to depolarization. Once depolarization reaches threshold, which happens about 72 times per minute, a pacemaker potential is propagated down to the ___ _____ through the internodal pathway. The __ ____ is located in the bottom right of the atria.
only electrical connection btwn the atria and the ventricles
Why is the Bundle of His so important?
self depolarize or self excite
What does the cardiac electrical conduction system have the ability to do?
Congestive heart failure
Heart cannot adequately pump to meet needs of body. Has many causes including heart attacks, faulty valves, and rate/conduction issues.
heart pain
disorders of rate, abnormal impulse formation, and abnormal electrical conduction in the heart.

(abnormalities related to the "impulse")
capacity for spontaneous, repetitive self-excitation usually only found in the SA and AV nodes and in the Bundle of His and purkinje system. Due in part, to a slow influx of sodium and calcium ions, but ultimately triggered by a time-dependent "pacemaker" current that opens the sodium ion channels.

capacity for spontaneous, repetitive ______________ usually only found in the SA and AV nodes and in the Bundle of His and _________ system.

Due in part, to a slow influx of ______ and ______ ions(drift in and trigger action potential), but ultimately triggered by a time-dependent "pacemaker" current that opens the _______ ion channels.
B1 adrenergic
muscarinic cholinergic
Adrenergic (symp)
Vagal (parasymp)

Rate may be modified by nerves and hormones or chemicals. Both SA and AV nodes have ___ _________ and _________ _________ receptors. _________ stimulation increases the background influx of sodium ion and calcium ion and seems to increase the rate of the "pacemaker" current. ________ (______________) stimulation seems to increase potassium efflux and hyperpolarize the cells.
Ectopic foci
out of place pacemakers

impulses beginning other than in SA node.
Circus movements
Damaged heart does not depolarize efficiently so the same impulse keeps "circling" the heart muscle. This abnormal movement is caused by reentry.
most common causes of arrythmias.

The same impulse reactivates tissue that it has already stimulated.
1. normal conduction to be slowed

2. refractoriness to be shortened

3. both
What is required for "reentry" or circus movements to occur?
slow arrythmias

50-60 bpms
100-200 bpm

fast arrythmias
200-300 bpm

some beats are usually ectopic
probably over 300 bpm

can't measure pulse b/c contraction non-effective. Many ectopic sites are active.
Ventricular fibrillation
What is the worst abnormal impulse formation?
Functional refractory period
1. AV node limited to about 200 bpm

2. Explains use of electroshock for ectopic foci, circus movements, and fibrillations.
Any drug that effects the electrical conduction system is going to effect the heart.

T or F
Any drug that effects the muscular part of the heart is going to effect the ___________.
electrical conduction system
Any drug that effects the rate of the heart is going to effect the ________ _________ _______.
A-V block
from tissue damage, coronary infarction, vagal stimulation, ventricles contract on own - usually less than 50 - 60 bpm - a major reason for bradycardia.
1' A-V block
slow conduction (rate ok)
2' A-V block
type 1

slower until skip
2' A-V block
Type II
just skips
3' A-V block
complete blockage
Circus movements
would not occur without damaged areas preventing proper depolarization of entire muscle mass in unison.
A-V block
Circus movements
What are the 2 conduction issues?