ECG Flashcards
the general line of ECG
ECG stands for
electrocardiogram
P wave
atrial depolarization
QRS complex
ventricular depolarization (contracting)
T wave
ventricular repolarization (ventricles relax)
where is atrial repolarization?
with QRS complex (covered)
define ECG
assesses the NET cardiac electrical activity measured between two points on the body’s surface
ECG: Cell-to-cell propagation of cardiac AP occur because of the ability of _______ to provide extremely efficient electrical connectivity between cardiac muscle cells that allow them to beat in a functional _________
Cell-to-cell propagation of cardiac AP occur because of the ability of GAP JUNCTIONS to provide extremely efficient electrical connectivity between cardiac muscle cells that allow them to beat in a functional SYNCYNCTIUM
ECG is the primary clinical tool for the diagnosis of: 2
— cardiac arrhythmias (abnormal electrical patterns in the heart)
— myocardial injuries that cause disturbances in heart rate (HR), rhythm, and/or wave-front propagation
ECG: strength of cardiac muscle contraction is _____ _______ to the intracellular Ca2+ concentration
directly proportional
ECG: after action potential, ________ Ca2+ channels opening causing a 1000-fold rise in the intracellular free Ca2+
L-type slow Ca2+ channels
ECG: sliding filament theory
- Depolarization conducts along membrane to T- tubules
- Calcium influx induces more Ca2+ release from the SR stores into intracellular fluid
- Ca2+ binds with troponin causing shift to reveals the binding site for myosin heads
- Cross-bridge formation between the actin and myosin filaments of the sarcomere
study heart (no question)
Trace blood flow from SVC/IVC (in words)
Order of Valves opening in heart: Tiny Penguins Marching Along
tricuspid, pulmonary, mitral, aortic
normal blood pressure
systolic: <120
diastolic: <80
elevated blood pressure
systolic: 120-129
diastolic: <80
High blood pressure (hypertension) Stage 1
systolic: 130-139
diastolic: 80-89
High blood pressure (hypertension) Stage 2
systolic: >140
diastolic: >90
Hypertensive crisis
systolic: >180
diastolic: >120
ECG: systole
during ventricular contraction to pump blood flow
ECG: diastole
occurs after contraction when the heart relaxes (ventricles fill with blood)
study
ECG: “lub”
S1
First heart sound “Lub, dub”
Closure of the tricuspid and mitral valves
Beginning of ventricular systole (ventricular contraction)
ECG: “dub”
S2
Second heart sound “lub, dub”
Closure of the aortic and pulmonary valves
beginning of ventricular diastole
ECG: heart cells
Pacemaker cells:
- SA node
- AV node
- His bundle
- Bundle branches
- Purkinjie fibers
working myocardial cells
ECG: what do pacemaker cells do in the heart?
responsible for the initiation & conduction of electrical signaling through the heart
ECG: electrical conduction sequence
SA node
Atria
AV node
His bundle
Bundle branches
Purkinjie fibers
Ventricles
ECG: what is the fastest conduction cell?
SA node
ECG: what does the AV node do?
create a slight delay between atrial contraction and ventricular contraction
ECG: what do Purkinje fibers do?
ensure that all ventricular cells contract at nearly the same instant (rapid conduction)
ECG: what cell is the Heart Rate (HR) normally controlled by?
SA nodal cells
ECG: Automaticity
property of the specialized cardiac cells to
spontaneously fire APs
o SA node has fastest rate (dominant pacemaker)
o Sinoatrial rhythm is 60-100 bpm
o latent pacemakers (all other cells)
ECG: what is the AV rhythm range
Atrioventricular (AV) rhythm is only 40-60 beats per minute.