Test 4 - 10/25 Flashcards
What is the tough outer layer of the pericardium?
Fibrous pericardium
What is immediately under the fibrous pericardium (attached)
Serous pericardium, parietal layer
Parietal pain is more ____ pain
tissue
Clear, stretchy, super thin layer that sits between the serous parietal layer and the actual heart tissue
Serous pericardium, visceral layer.
The serous pericardium visceral layer allows for the heart to ____
slide around easily within the pericardium
In the AP’s in the heart, where would we see lots of fast Na channels?
- ventricular muscle
- purkinje fibers
If something happens to the fast Na channels in our heart AP, what can happen?
it can turn out fast AP into slow AP and that can affect our HR and strength of contraction
Action potential propogation through two cells is only via
gap junctions
How are neurotransmitters used in the heart?
They aren’t, dumbass. its only gap junctions. this isn’t a neuron.
What fits through gap junctions?
Na fits best. Ca is big and clunky.
If we are relying on Ca to get us an AP what would we see?
It would still get us an AP but it is big and clunky and doesn’t move through the gap junctions very well
Since we are using gap junctions in the heart as a synapse it can be _____
a bidirectional synapse
Synaptic connections are ____
One way
Why can gap junctions being bidirectional be a negative thing?
If a part of the heart depolarizes spontaneously it can have retrograde movement and travel backward
What is protecting us from retrograde movement through the gap junctions
the absolute refractory period
What might happen if there is retrograde movement during the relative refractory period
might fire an odd AP. force generation wont look great.
What is the 3 lead EKG also called?
frontal or coronal plane
What are augmented leads?
3 extra leads if 3 isnt enough
What is the eyeball in terms of the EKG leads?
The positive lead, we can see if the AP is moving towards it (positive deflection) or away from it (negative deflection)
If there is current moving towards the eyeball that will show up as a ______ deflection
positive
For lead placement where will the negatives and positives always be?
L foot - 2 positives
R arm - 2 negatives
L arm - 1 positive and 1 negative
The equilateral triangle for the lead placements is called what?
Einthovens Triangle (Dutch..somewhere from europe)
Need _____ to turn the EKG signals into something that the machine can process
amplifier.
What is a left axis deviation
anything less than 59 degrees. If the depolarization is headed more superior towards the left arm.
Heart rotated left
If the heart is turned towards the left that would give us a _____ deviation and it would be ______ degrees
left axis;
less than 59
A bundle branch block might do what?
swing the electrical axis one way or another
what can cause the heart to be pointed straight up and down instead of pointed towards the left foot?
Inflated lungs or COPD
If we deflate the lungs the heart will be more oriented towards _____
L arm. kinda on its side
If we take a really big deep breath that will turn the heart towards _____
the right
anything greater than ____ degrees is considered a right axis deviation
59
Anything less than _____ degrees is a left axis deviation
59
The wall of the right ventricle is ______ compared to the left
thinner
The main bundle branches are located in the _____
interventricular septum
The atrial P wave is pointed towards _____
L foot.
If we have repolarization for the atria it will be pointed towards _____ and will be a ______ deflection.
L foot.
negative
Where do we see the atrial repolarization on the EKG?
We don’t, it is hidden by the QRS complex
What do the wall size of the atria and the wall size of the ventricles have to do with the fact that we cant see the repolarization of the atria
The walls of the atria are super thin compared to the ventricles so its not powerful enough to obscure the QRS complex.
Atrial depolarization and repolarization go in _______(same/opposite) direction
same
If we had an atrial T wave it would be a _____ deflection
negative
Which one is lead 1
green. 0 degrees
which one is lead 2
pink. 60 degrees
which one is lead 3. what is the axis for this lead
Blue. 120 degrees
In a normal EKG if we are looking at the different readings for leads 1,2 and 3 what would we expect to see from lead 2.
the biggest magnitude of deflection.
Why does lead 2 show the biggest magnitude of deflection?
Because everything is headed straight towards that lead (the eyeball)
Why does lead one have a much smaller magnitude of deflection
Because lead one only picks up a portion of the current
How would we figure out how much of a positive deflection we would see in lead 1?
Draw in the line L and the length of line A would be the positive deflection we would see in lead 1 vs lead 2.
it is much smaller.
If the heart is positioned straight up and down and the mean electrical axis is now 90 degrees, what would we expect to see from lead 1? Why?
Should show zero because there is no left to right movement. The vector is perpendicular to lead 1.
If the heart is pointed towards the right foot and this is our new mean electrical axis, what would we expect to see in lead 1
This should show a negative deflection
What would this show in lead one?
Huge negative deflection
What would this show in lead one?
Huge positive deflection
What would we use 3 vs 6 leads for?
3: figure out what the problem is
6: figure out where the problem is
What is Einthovens Law?
Lead 1 + Lead 3 = Lead 2
How would we calculate einthovens law?
lead 1 + 3 = 2
Difference in peak positive deflection minus peak negative deflection
