Intro to Electrophysiology and Cardiac Mechanics Flashcards
Na+ channels open ____, K+ channels open ______
first, next
Action potential order
Depolarization, action potential, hyperpolarization, resting potential
Na+ is responsible for
the spike in voltage
K+ is responsible for
the hyperpolarization
During resting potential, Na+ channels are
closed
During depolarization, Na+ channels are
closed and inactivated
During action potential, Na+ channels are
open
During hyperpolarization, Na+ channels are
closed
Synapse
chemical connection from one cell to another
RA
right atria – systemic – blood from the body
LA
left atria – pulmonary – blood from the lungs
RV
right ventricle – pumps to the lungs (pulmonary artery)
LV
left ventricle – pumps to the body (aorta)
Heartbeat originates in the
sinoatrial (SA) node
Wave of depolarization spreads to the
atria and reaches the atroventricular (AV) node
Depolarization passes to the ventricles via the
Bundle of His
Depolarization is then conducted rapidly over the surface of the ventricles by
Purkinje fibers
Every single skeletal muscle fiber is innervated by a
motor neuron
Cardiac myocytes
don’t need innervation to fire
Skeletal muscles
Na+ and K+ channels
Cardiac muscles
Na+ K+ and Ca++ channels
Atrial depolarization
P wave
Ventricular depolarization
QRS wave
Ventricular repolarization
T wave
Depolarization causes
heart contraction
Repolarization causes
heart relaxation
E
End
D
Diastolic (rest/filling)
S
Systolic (contraction/ejection)
P
pressure
V
volume
L
left
R
right
EDP
end diastolic pressure
EDV
end diastolic volume
ESP
end systolic pressure
ESV
end systolic volume
LVP
left venous pressure
LVV
left venous volume
Preload
EDP, EDV, RAP
Afterload
ESP, ESV, MAP
SV
EDV - ESV
CO
HR*SV
Left Ventricular Pressure graph
A-V valve shuts, aortic valve opens, aortic valve shuts, A-V valve opens
Isovolumic
No change in blood volume in the ventricles
Stroke volume
amount of blood pumped during one heartbeat
