56 Questions
Which of the following is responsible for initiating the electrical impulses that cause the heart to beat?
Sinoatrial (SA) node
Which part of the nervous system increases heart rate by releasing norepinephrine?
Sympathetic nervous system
Which ions are responsible for initiating action potentials in the heart?
Calcium ions
Which part of the heart conducts the electrical impulse rapidly through the ventricular septum?
Bundle of His
What causes the SA node action potential graph to shoot up?
Activation of Ca2+ channels
Which nervous system releases acetylcholine to slow down the heart rate?
Parasympathetic nervous system
What can cause tachycardia?
Exercise
Which of the following is a cause of bradycardia?
Excessive vagal stimulation
What is paroxysmal atrial tachycardia characterized by?
A series of rapid heartbeats that suddenly start and then suddenly stop
What is the cause of ventricular tachycardia (V-tach)?
Ischemic damage
What is the effect of atrial fibrillation (AFib) on heart pumping efficiency?
Decreases efficiency by 20-30%
Which of the following factors can increase right atrial pressure?
All of the above
What are Korotkoff's sounds?
Sounds produced by the turbulent flow of blood through the compressed artery
Which factor is defined by Poiseuille's law and directly proportional to the fourth power of the vessel radius?
Vessel length
Which structure in the heart is responsible for generating and conducting electrical impulses throughout the heart?
Purkinje fibers
During which phase of the cardiac muscle action potential does rapid depolarization occur?
Phase 0
What is the function of intercalated discs in the heart?
All of the above
Which of the following is true about the refractory periods in the cardiac muscle action potential?
The relative refractory period lasts from the middle of phase 2 to the end of phase 3
Which of the following is the primary pacemaker of the heart?
Sinoatrial (SA) node
What is the main function of the Atrioventricular (AV) node?
To serve as a gateway for the electrical impulses to pass from the atria to the ventricles
What is the role of troponin in the contraction of cardiac muscle fibers?
To trigger a conformational change in the tropomyosin-troponin complex
What is the function of the Purkinje fibers?
To spread the electrical impulses throughout the ventricles
Which one of these is the correct relationship between resistance and flow in a circuit, according to Ohm's law?
Flow rate is equal to the pressure difference divided by the total resistance.
Which one of these is the correct relationship between conductance and resistance?
Conductance is the reciprocal of resistance.
Which one of these is the correct relationship between conductance and diameter?
Conductance increases in proportion to the fourth power of the diameter.
What is the advantage of vascular compliance?
Allows the arterial tree to normally reduce pressure pulsations.
Which of the following organs can influence the heart rate?
Lungs
What is the effect of the sympathetic nervous system on heart rate?
Increases heart rate
Which of the following hormones can increase heart rate?
Epinephrine
What initiates the electrical impulses that cause the heart to beat?
Sinoatrial (SA) node
Which of the following is responsible for conducting the electrical impulse rapidly through the ventricular septum?
bundle of His
What is the cause of an ectopic pacemaker?
A shift of pacemaker from the sinus node
Which part of the nervous system releases acetylcholine to slow down the heart rate?
Parasympathetic nervous system
What is the effect of sympathetic stimulation on the heart rate?
Increases the heart rate
Which of the following is the correct order of electrical signal transmission through the conduction system of the heart?
SA node -> AV node -> bundle of His -> Purkinje fibers
Which of the following is responsible for initiating each heartbeat and setting the heart rate?
SA node
Which of the following is a characteristic of muscle cells in the heart?
Striated appearance
Which of the following is a function of the atrioventricular (AV) node?
Acts as a gateway for electrical impulses to pass from the atria to the ventricles
Which of the following is responsible for the rapid depolarization of the cardiac muscle cell membrane during Phase 0 of the action potential?
Voltage-gated Na+ channels
Which of the following channels are responsible for the plateau phase in Phase 2 of the cardiac muscle action potential?
L-type Ca2+ channels
Which of the following is true about the refractory periods in the cardiac muscle action potential?
The absolute refractory period is the period during which the cardiac muscle cell cannot be stimulated to depolarize again.
Which of the following is true about the pressures and volumes during ventricular systole?
Ventricular pressure increases and volume decreases.
According to the text, what is the relationship between the Reynolds number and the flow of blood in a vessel?
All of the above.
What is the formula for the Reynolds number (Re) in terms of velocity (V), diameter (D), density (P) of blood, and viscosity (N)?
$Re = \frac{V \cdot D \cdot P}{N}$
What is the relationship between conductance and resistance in a blood vessel?
Conductance is the reciprocal of resistance.
What is the relationship between the diameter of a blood vessel and its ability to conduct blood flow?
Small changes in diameter cause significant changes in blood flow.
Which of the following is true about ventricular tachycardia (V-tach) and ventricular fibrillation (V-fib)?
V-tach may lead to V-fib
What is the effect of atrial fibrillation (AFib) on heart pumping efficiency?
Decreases heart pumping efficiency by 20-30%
What are the physical characteristics of arteries, veins, and capillaries?
Arteries have strong vascular walls, capillaries have thin walls, and veins have thin and muscular walls
What is the relationship between pressure, flow, and resistance in blood circulation?
Flow is determined by the pressure gradient and vascular resistance
Which of the following factors can decrease right atrial pressure?
Decreased blood volume
Which one of the following is responsible for regulating right atrial pressure?
The heart's ability to pump blood out of the right atrium and ventricle into the lungs
Which one of the following is defined by Poiseuille's law and is directly proportional to the fourth power of the vessel radius?
The pressure gradient driving blood flow
Which one of the following physical properties of blood vessels and blood determine hemodynamics?
All of the above
Which one of the following is NOT a factor that can increase right atrial pressure?
Constriction of the arterioles
Which one of the following is NOT a factor that can decrease right atrial pressure?
Increased blood flow from the peripheral veins into the right atrium
Test your knowledge on the total resistance to blood flow in series and parallel vascular circuits in this quiz. Explore the relationship between Reynolds' number and flow characteristics, and understand how velocity, diameter, density, and viscosity affect blood flow.
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