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Cardiovascular #2-4 // Physiology term 1 Flashcards | StudBud
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Cardiovascular #2-4 // Physiology term 1
Cardiovascular #2-4 // Physiology term 1
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1
Heart failure can be caused by
Electrolyte imbalance
Valve defects
Cardiac hypoxia
An increased length-tension relationship in cardiomyocytes
2
How does the AV node slow the conduction?
Small diameter of the AV node
Poor expression of Na+ voltage channels leading to low upstroke velocity
Complex arrangement of cardiomyocytes separated by CT
Large diameter of the AV node
3
If the depolarization vector is moving towards the electrode, the deflexion is...
Positive
Negative
4
The atrioventricular valves
Guide blood from ventricle to large arteries during diastole
Guide blood from atrium to ventricles during diastole
Guide blood from atrium to ventricles during systole
Guide blood from ventricle to large arteries during systole
5
What happens at phase 0 of the generation of a pacemaker potential?
An unstable membrane potential
Prepotentials
Depolarization, due to a slow Ca2+ current and long lasting Ca2+ channels
Repolarization, due to opening of K+ voltage channels
6
How does the SA node determine heart-rate?
Generates stronger action potentials
Generates action potentials at a higher rate
Generates longer action potentials
Generates action potentials at a lower rate
7
The purkinje fibers in the hearts of which species do not penetrate the entire thickness of the myocardium (group 1)?
Cats
Whales
Dogs
Pigs
8
Where is the primary pacemaker of the heart?
Bundle of His
AV node
SA node
Purkinje fibers
9
Purkinje fibers can be a source of arrhythmia
False
True
10
The electrical heart axis...
Show the depolarizations only in the ventricles
Refers to the general direction of the depolarization vector front
Refers to the general direction of the repolarization vector front
Is an average of all depolarizations in the heart
11
What happens at phase 4 of the generation of a pacemaker potential?
An unstable membrane potential
Depolarization, due to a slow Ca2+ current and long lasting Ca2+ channels
Repolarization, due to opening of K+ voltage channels
Prepotentials
12
In an ECG, the P wave represents
Depolarization of the atria
Atrial repolarization
Ventricular Repolarization
Depolarization of the ventricles
13
In a clinical setting, the amplification of the ECG recorder should be set to
12 mm/mV
5-10 mm/mV
20-25 mm/mV
2-3 mm/mV
14
Under parasympathetic stimulation, ___ causes hyperpolarization and bradycardia
Epinephrine acting on a beta adrenoreceptor
Epinephrine acting on an alpha adrenoreceptor
Acetylcholine acting on muscarinic receptor
Acetylcholine acting on cholinergic receptor
15
Characteristics of the AV node
Amplifies the electrical impulse from the atria to the ventricles
Delays the electrical impulse speed between atria and ventricles
Contracts the ventricles
Is the gatekeeper between the atria and the ventricles
16
The left ventricle generates the strongest signal, regarding the electrical heart axis
False
True
17
The semilunar valves
Guide blood from ventricle to large arteries during diastole
Guide blood from atrium to large arteries during diastole
Guide blood from ventricle to large arteries during systole
Guide blood from atrium to large arteries during systole
18
A steeper pacemaker slope leads to
A slower heart rate
A faster heart rate
19
In Einthoven's triangle, lead III connects
The negative electrode to right hindlimb, positive to left hindlimb
The negative electrode to right forelimb, positive to left hindlimb
The positive electrode to right forelimb, negative to left hindlimb
The negative electrode to left forelimb, positive to left hindlimb
20
When the SA node triggers an action potential, it brings the auxiliary pacemakers to threshold as well
False
True
21
Which of the following could increase stroke volume by affecting contractility?
Propanolol, a beta-adrenoreceptor antagonist
Propofol
Isoproternol, a beta-adrenoreceptor agonist
Pimobendane, by inhibiting phosphodiesterase 3
22
Under sympathetic stimulation, ___ causes more rapid depolarization and tachycardia
Acetylcholine acting on muscarinic receptor
Acetylcholine acting on cholinergic receptor
Epinephrine acting on an alpha adrenoreceptor
Epinephrine acting on a beta adrenoreceptor
23
What happens at phase 3 of the generation of a pacemaker potential?
Prepotentials
Depolarization, due to a slow Ca2+ current and long lasting Ca2+ channels
An unstable membrane potential
Repolarization, due to opening of K+ voltage channels
24
Characteristics of the Goldberger ECG method
Use unipolar leads
Uses bipolar leads
Generates larger signals
Electrodes are in mirror arrangement
25
Heart activity can also be effected by humoral controls, such as
Hormones like catecholamines
Electrolytes (Na, K, Ca)
Drugs
Temperature
26
In a clinical setting, a typical paper speed is
50-60 mm/sec
25-50 mm/sec
2-3 mm/sec
100 mm/sec
27
A low paper speed
Shows more detail
Shows more cardiac events
Reveals random events such as extra systoles
Gives a better view of rhythmic events (HR)
28
The Bundle of His penetrates the fibrous tissue isolating the atria and ventricles to deliver the signal from AV node
True
False
29
What are the auxiliary pacemakers?
They take over if the SA node is too busy
The AV node and Bundle of His
The AV node, Bundle of His, and purkinje fibers
They take over if the SA node fails
30
In an ECG, the QRS interval represents
Atrial repolarization
Depolarization of the atria
Depolarization of the ventricles
Ventricular Repolarization
31
The parasympathetic innervation
reaches the ventricles and myocardium
Originates from a chain of ganglia
Originates from the vagus nerve
has limited reach of the ventricles and myocardium
32
In an ECG, the t wave represents
Depolarization of the ventricles
Depolarization of AV node and BOH
Atrial repolarization
Ventricular Repolarization
33
Where do the pacemaker potentials occur?
Purkinje node
Semilunar node
Sinoatrial node
Atrioventricular node
34
In Einthoven's triangle, lead II connects
The negative electrode to left forelimb, positive to left hindlimb
The negative electrode to right hindlimb, positive to left hindlimb
The negative electrode to right forelimb, positive to left hindlimb
The positive electrode to right forelimb, negative to left hindlimb
35
The maximum recorded potential in an ECG can exceed the maximum generated potential
True
False
36
Which of the following could decrease stroke volume by affecting contractility?
Pimobendane, by inhibiting phosphodiesterase 3
Propanolol, a beta-adrenoreceptor antagonist
Propofol
Isoproternol, a beta-adrenoreceptor agonist
37
Bathmotropic refers to
Force of contraction
Excitability
Heart rate
Conduction speed
38
Inotropic refers to
Heart rate
Conduction speed
Force of contraction
Excitability
39
Heart rate frequency is under ANS regulation
False
True
40
Dromotropic refers to
Conduction speed
Excitability
Heart rate
Force of contraction
41
Effects of Acetylcholine on the heart
Steeper depolarizations
Increases Na+ and Ca2+ influx
Increases K+ efflux
Flatter prepotentials
42
Effects of norepinephrine on the heart
Steeper depolarizations
Flatter prepotentials
Increases K+ efflux
Increases Na+ and Ca2+ influx
43
Classification of cardiomyocytes
Contractile cardiomyocytes display a stable resting membrane potential
Autorhythmic cells represent 99% of cardiomyocytes
Contractile represent 99% of cardiomyocytes
Autorhythmic cells generate APs spontaneously by slow depolarization
44
In an ECG, the PQ segment represents
Depolarization of AV node and BOH
Ventricular Repolarization
Atrial repolarization
Depolarization of the ventricles
45
In Einthoven's triangle, lead I connects
The negative electrode to right hindlimb, positive to left hindlimb
The positive electrode to right forelimb, negative to left hindlimb
The negative electrode to right forelimb, positive to left forelimb
The negative electrode to left forelimb, positive to left hindlimb
46
The sympathetic innervation
Originates from a chain of ganglia
has limited reach of the ventricles and myocardium
reaches the ventricles and myocardium
Originates from the vagus nerve
