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Cardiology (IV)
Heart Physiology
30
Physiology
Undergraduate 2
04/02/2013

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Cards

Term
What does an EKG do?
Definition
Maps electricity of the heart.
Term
What are the three main types of cardiac arrhythmias?
Definition
Atrial flutter, premature ventricular contractions and Ventricular fibrillation
Term
What is an Atrial flutter?
Definition
Ectopic foci in atria, beats 200-400 times/min.
Term
what is a premature ventricular contraction?
Definition
Early firing of ectopic focus.
Term
What are some causes of PVCs?
Definition
stimulants, emotional stress, lack of sleep.
Term
Can PVCs sometimes be serious?
Definition
Yes
Term
What is Vfib?
Definition
Electrical signals arriving at different regions of myocardium at very different times.
Term
Out of atrial flutters, PVCs and Vfib, which one is the most serious and life threatening?
Definition
Ventricular fibrillation
Term
What does ectopic mean?
Definition
Out of place
Term
Why is the SA node the "pacemaker" of the heart?
Definition
It spontaneously depolarizes FASTER
Term
spontaneous depolarization is also known as...?
Definition
pacemaker potential
Term
What causes spontaneous depolarization in the SA node?
Definition
Na
Term
What makes the pacemaker potential different from other membrane potentials?
Definition
Since Na causes the spontaneous depolarization, the cells DO NOT need innervation. The cells are depolarizing themselves.
Term
What lets the Na into the cells?
Definition
Na channels.
Term
What can abnormal pacemakers do?
Definition
cause bradycardia and tachycardia
Term
Step one in cardiac impulse conduction is...?
Definition
SA node spontaneous depolarization.
Term
Step two in cardiac impulse conduction...?
Definition
Stimulus reaches AV node.
Term
Step three in cardiac impulse conduction...?
Definition
Delay at AV node while atria contract.
Term
Step four in cardiac impulse conduction...?
Definition
Travels down AV bundles branches to purkinje fibers and to papillary muscles.
Term
Step five in cardiac impulse conduction...?
Definition
Impulse distributed by purkinje fibers and sent through ventricular myocardium.
Term
During what step of the impulse conduction through the heart does atrial contraction end and ventricular contraction begin?
Definition
Step 5
Term
What does a cardiac cycle consist of?
Definition
one complete contraction and relaxation of all four heart chambers.
Term
What is systole and what is happening within the chamber during this?
Definition
Contraction, chamber pushes blood into next section.
Term
What is diastole and what is happening within the chamber during this?
Definition
Relaxation, chamber fills with blood
Term
What is responsible for the absolute refractory period in cardiac muscles?
Definition
Ca channels open
Term
What is another phrase for aortic systole?
Definition
Isovolumic pressure
Term
what are myocytes connected by?
Definition
intercalated discs
Term
intercalated discs connections contain ____ and _____.
Definition
multiple gap junctions and desmosomes
Term
in the intercalated discs what do the multiple gap junctions allow to happen?
Definition
The spreading of action potentials.
Term
in the intercalated discs what do the desmosomes do?
Definition
give structural integrity to the muscle sheet.
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