Cardiovascular 3 Flashcards
(50 cards)
What is the primary function of the SA node?
It serves as the pacemaker of the heart.
What are the four special conducting bundles in atrial conduction?
SA node, AV node, Bachmann’s bundle, and internodal pathways.
What does Bachmann’s bundle do?
Conducts action potentials from the SA pacemaker into the left atrium.
What are the three types of internodal pathways?
Anterior, middle, and posterior internodal pathways.
What is the role of the internodal pathways?
Conduct the action potential from the SA node to the AV node.
How does atrial conduction compare to ventricular conduction?
Atrial conduction is relatively slow.
What is the typical time for atrial conduction?
80-100 ms.
Fill in the blank: The action potentials from the SA node depolarize the _______ muscle.
right atrial
True or False: Atrial conduction is faster than ventricular conduction.
False
Ventricular Ring
a layer of connective tissue that prevents conduction directly from atria to ventricle
-conduction slow down through the AV node to allow blood from atria to empty into ventricles
Ventricular conduction Depolarization
-process through the septum to the apex (bundle of his followed by bundle branches)
-then spreads up the walls of the ventricles from apex to Purkinje fibers, or the base
Ventricular conduction occurs
More rapidly, about 60-100ms
Pathway of ventricular conduction
SA node, AV node, Bundle of His, Bundle branches, Purkinje fibres
Ventricular muscles have what arrangement that does what?
They have spiral arrangement that ensures blood is squeezed UP from the apex (bottom left) of the heart
What happens if electrical activity cannot be transferred from the atria into the ventricles?
A complete conduction block is caused by damage in conduction pathway
-block at bundle of his fresults in complete dissasociation between the atria and ventricles
What happens during a complete conduction block?
The SA node continues to be the pacemaker, but the electrical activity doesn’t make it to the ventricles
-Purkinje fibres take over as pacemaker for the ventricles
-requires an artificial pacemaker
ECG
Electrocardiogram
-place electrodes on the skins surface and record the electrical activity of all the cells of the heart
Einthovens triangle for ECG
Right arm negative, left arm positive on top negative on bottom, legs are both positive
-creates a triangle of positive to negative attachments
If the electrical activity of the heart is moving towards the positive electrode of the lead, what kind of deflection happens
An upward direction comes from electrical activity moving upwards
-current flow vector is pointed towards the positive electrode
Electrical activity moving AWAY from a positive electrode is
A downward reflection
-current flow vector is pointed towards the negative electrode
Electrical activity moving perpendicular to the axis of the electrodes causes
No deflection
-across the lead
-vector that is pointed perpendicular to the axis of the electrode
ECG waves
Appear as deflections above or below the baseline
ECG Segments
Are the sections of baseline between 2 waves
ECG Intervals
Are the combination of waves and segments
