Module 10 - Cardiovascular Flashcards
Exam 4
What are the 3 linings of the heart?
Endocardium
Myocardium
Epicardium
Which is the innermost layer of the heart? Which is the outermost?
Innermost - Endocardium
Outermost - Epicardium
In the epicardium, there are 2 important membranes called…
visceral and parietal
What are DHP receptors?
Specialized voltage receptors that are sensitive to changes in Ca and somewhat to changes in Na
What other receptor is related to the DHP?
RyR receptor
What is the purpose of the RyR receptor?
This is where the Ca moves out from the sarcoplasmic reticulum
Automaticity
Nodal cells can spontaneously depolarize when they reach RMP; this happens b/c of Na/K leak, which allows the cell to reach threshold
Rhythmicity
The consistency of the automaticity (is it regular?)
The pacemaker of the heart is what?
SA Node
If the SA node is not working, what is the next in line pacemaker?
AV Node
If the AV node AND the SA node are not working, what is the next pacemaker for the heart?
Purkinje Fibers
How many times per minute does the SA node depolarize?
60-100 (which is a normal RHR)
The AV node depolarizes ___ times per minute
40-60
The Purkinje Fibers depolarize ____ times per minute
20-30
What connects the SA and AV nodes?
Wenckebach’s Tract / middle tract AND the Thorel’s Tract / posterior tract
What connects the SA node to the L Atrium?
Bachmann’s Bundle / anterior tract
What is the main function of the AV node (when SA node is working)?
Pause the action potential for ~100 ms to allow for the ventricles to fill with blood
When the ___ ___ depolarize, the ventricles contract
Purkinje fibers
Semilunar valves
aortic, pulmonary
Atrioventricular (AV) valves
tricuspid and mitral / bicuspid
Tricuspid valve is on which side of the heart?
Right
Bicuspid / mitral valve is on which side of the heart?
Left
T/F: We should not have retrograde blood flow (from ventricles back to atria)
True
What is retrograde blood flow called?
Regurgitation
When we reach RMP, what happens to the nodal cell?
It becomes more permeable for cations to enter
What causes depolarization of the nodal cell?
The movement of Ca INTO the cell, particularly when Ca moves through the L-type Ca channel
Why are gap junctions important in the nodal cell AP?
They allow the ions to move through diffusion
What triggers myocyte action potential?
all the positive cations that are moving through the gap junctions
Which voltage-gated channel is fast vs. slow - Na and K?
Na is fast
K is slow
What happens with all the Ca that moves into the myocyte?
it triggers the calcium-triggered calcium release from the RYR receptors of the sarcoplasmic reticulum
What is the function of Ca in the cytoplasm of a muscle cell?
Muscle contraction
Repolarization of the nodal cell and myocyte is always due to what?
Movement of K+ OUT of the cell
(Slow voltage-gated K channels)
Chronotropic factors are related to ____ _____
Heart rate
Inotropic factors are related to _____
the heart’s ability to contract
Dromotropic factors are related to what?
the conduction speed
Epi/NE will generally cause the Nodal Cell curve to what?
Steepen - more APs, higher HR
ACh will generally ____ the depolarization curve.
Flatten; fewer APs, lower HR
During the P wave, what is happening in the heart?
Atrial depolarization
What is the PR interval?
Time from onset of the P wave to the QRS complex
What is happening during the PR interval?
AP at the AV node
T/F: There is NO electrical activity in the PR interval.
True.
What is happening in the heart during the QRS complex?
Ventricular depolarization
Atrial repolarization
What is happening during the T wave in the heart?
Ventricular repolarization
What ion is leaving the ICF of the myocyte during the T wave?
K
If P(atria) > P(ventricles), the ____ valves open.
AV
at the end of the atrium draining out of blood, what happens?
Atrial kick - actively contracts to get the remaining blood into the ventricles
After the atrial kick, what would you expect to see on the ECG?
P wave
If P(ventricles) < P(aorta / pulmonary), what happens to the semilunar valves?
They stay closed
If P(ventricles) > P(atria), the ____ valves _____.
AV, close.
The first heart sound - LUB - comes from what?
The closing of the AV valves
If P(ventricles) > P(aorta/pulmonary) what happens the semilunar valves?
They open
End-Systolic Volume
The amount of blood remaining in the ventricles at the end of systole
End-Diastolic Volume
The amount of blood in the ventricles at the end of diastole
What causes the semilunar valves to close in isovolumetric relaxation?
The contraction of the arteries (Retrograde / Pulse wave)
The second DUB heart sound comes from what?
The closing of the semilunar valves
Preload
amount of sarcomere stretch experienced by cardiac myocytes at the end of diastole
Contractility
Force of contraction at any given EDV (independent of Frank Starling Mechanism)
Afterload
The pressure that the LV must work against to eject blood during systole
What are positive influencer(s) of SV?
Preload and contractility
What is the negative influencer for SV?
Afterload
If we generate a greater P1 and P2 and Resistance stay constant, what happens to F?
Flow will increase
Chronic afterload is associated with what clinical condition?
LV hypertrophy