Unit 2 Exam Lab 8 Flashcards
The correct sequence of the wave of depolarization that passes through the heart is:
1 = atrioventricular (AV) node
2 = sinoatrial (SA) node
3 = Purkinje fibers
4 = bundle of His
5 = bundle branches
2,1,4,5,3
A resting membrane potential of -85 mV means that
the inside of the cell is more negative with respect to the outside of the cell.
During membrane depolarization, ______move _____ the cell through _____.
Na+, into, voltage gated channels
During membrane repolarization, _____ move _____ the cell through _____.
K+, out of, voltage gated channels
mass of cells that function as one
functional syncytium
cells capable of spontaneously depolarizing
pacemaker cell
pacemaker cell located in an unexpected site
ectopic pacemakers
baseline for ECG
isoelectric line
anatomical structure responsible for spread of wave of depolarization from cell to cell in cardiac tissue
intercalated dics
anatomical structure that prevents the spreading of action potentials directly from atrial myocardium to the ventricular myocardium
exoskeleton, fibrotendonous rings
which type of cardiac cells demonstrate slow response action potentials
SA node, AV node, ecotopic pacemaker cells
which type of cardiac cells demonstrate fast response action potentials
bundle of his, bundle of branches, purkinje fibers, atrial muscle cells, ventricular muscle cells
Which of the following can serve as pacemaker cells in the heart?
SA node, AV node, ecotopic pacemaker cells found in sites other than in the SA and AV nodes
The intracellular concentrations of _____ are greater than the extracellular concentrations in both pacemaker and non-pacemaker cells.
K+
The extracellular concentrations of _____ are greater than the intracellular concentrations in both pacemaker and non-pacemaker cells.
Na+ and Ca2+
Which of the following statements best describe the movement of Na+ across the membrane during the prepotential stage of slow response action potentials.
Na+ diffuses slowly from the outside to the inside through leakage channels.
Which of the following statements best describe the movement of K+ across the membrane during the prepotential stage of slow response action potentials?
K+ has reduced permeability for diffusing from the inside to the outside
Which of the following statements best describe the movement of Ca++ across the membrane during the prepotential stage of slow response action potentials?
Ca++ diffuses slowly from the outside to the inside through leakage channels.
During depolarization phase of slow response action potentials:, Na+:
is not involved in slow response action potential depolarization
During depolarization phase of slow response action potentials:, K+:
is not involved in slow response action potential depolarization
During depolarization phase of slow response action potentials:, Ca++:
diffuses rapidly from the outside to the inside of the cell
During repolarization of slow response action potentials, Na+:
is not involved in slow response action potential repolarization
During repolarization of slow response action potentials, K+:
diffuses rapidly from the inside to the outside of the cell
During repolarization of slow response action potentials, Ca++:
is not involved in slow response action potential repolarization
Which of the following best describes the role of Na+ movement through leakage channels at the resting membrane potential prior to a fast response action potential?
Na+ has limited permeability during resting membrane potential.
Which of the following best describes the role of K+ movement through leakage channels at the resting membrane potential prior to a fast response action potential?
K+ diffuses from the inside to the outside through leakage channels.
Which of the following best describes the role of Ca++ movement through leakage channels at the resting membrane potential prior to a fast response action potential?
Ca++ is not involved in development of the resting membrane potential.
During depolarization of fast response action potentials, Na+:
diffuses rapidly from the outside to the inside of the cell
During depolarization of fast response action potentials, K+:
is not involved in fast response action potential depolarization
During depolarization of fast response action potentials, Ca++:
is not involved in fast response action potential depolarization
During the plateau phase of fast response action potentials, Na+:
is not involved in fast response action potential plateau phase
During the plateau phase of fast response action potentials, K+:
diffuses from the inside to the outside of the cell
During the plateau phase of fast response action potentials, Ca++:
diffuses slowly from the outside to the inside of the cell
During repolarization of fast response action potentials, Na+:
is not involved in fast response action potential repolarization
During repolarization of fast response action potentials, K+:
diffuses rapidly from the inside to the outside of the cell
During repolarization of fast response action potentials, Ca++:
is not involved in fast response action potential repolarization
During the prepotential stage of slow response action potentials, the membrane potential becomes ____ negative on the inside with respect to the outside.
less
Increasing the prepotential slope _____ the rate of spontaneous depolarizations of pacemaker cells, while decreasing the prepotential slope _____the rate of spontaneous depolarizations of pacemaker cells.
increases; decreases
Distinguish between the steepness of the prepotential slope associated with pacemakers cells found in the the S-A node and the slope of the prepotential of pacemaker cells found in the the A-V node. Pacemaker cells in S-A node have a _______ slope than pacemaker cells in A-V node and therefore have a ______ rate of spontaneous depolarization.
steeper; faster
An electrocardiogram is a record of: (2)
-electrical impulse conduction through the heart.
-extracellular recording of the sum of all the electrical activity of the heart over time
P wave
atrial depolarization
T wave
ventricular repolarization
QRS complex
ventricular depolarization
Lead 1
Left arm and right arm
Lead 2
Right arm and left leg
Lead 3
Left arm and left leg
Einthoven’s Law
Lead II=Lead I+Lead III
Increased P wave
Damaged atrial cells
Increased PR interval
interference with conduction between SA node and purkinje fibers
Increased QRS duration
non-sinultaneous activation of ventricles
Decreasing the heart rate _____ QT interval.
increases
Increasing the heart rate _____ cycle length.
decreases
Which of the following conditions are or can be associated with a left mean electrical axis deviation?
-left ventricular hypertrophy
-systemic hypertension
-obesity
-pregnancy
Which of the following conditions are associated with a right mean electrical axis deviation?
-right ventricular hypertrophy
-pulmonary hypertension
impairment of conduction between the SA node and purkinje system
atrioventricular block
impairment of conduction through the bundle branches, ventricles activated at different times
bundle branch block
