A&P 3
Depolarization of the atria corresponds to the ECG's
P wave.
Cardiac output is increased by
A) more sympathetic stimulation. B) increased end-diastolic volume. C) increased stroke volume. D) all of the above
The wall of the left ventricle is thicker than the right because
A) the left ventricle does more work than the right ventricle. B) the left ventricle pumps against greater resistance than the right ventricle. C) the left ventricle produces a higher pressure than the right. D) all of the above
The AV node delivers the stimulus to the AV bundle, located within the interventricular septum.
Both parts of the statement are true.
The main control of peripheral resistance by the vasomotor centers occurs in the
arteriole.
The function of the atrium is to
collect blood and pump blood to the ventricle.
The pulmonary veins carry blood to the
heart.
Heart rate is controlled by neurons of the cardiovascular center located in the
medulla oblongata.
There are ________ pulmonary veins.
4
Abnormally slow depolarization of the ventricles would most change the shape of the ________ in an ECG tracing.
QRS complex
What effect would compressing the inferior vena cava just below the diaphragm have on cardiac function?
Sympathetic stimulation of the heart would increase.
________ is to contraction as ________ is to relaxation.
Systole; diastole or Ejection; filling
Complications related to arteriosclerosis account for roughly ________ percent of deaths in the United States.
50
The visceral pericardium is the same as the
epicardium
The first heart sound ("lubb")
is associated with closing of the mitral valve.
The ________ ventricle has a greater workload than the ________. A
left; right ventricle
When the semilunar valves close, the AV valves then
open.
The volume of blood ejected from each ventricle during a contraction is called the
stroke volume.
As a result of the long refractory period in the cardiac action potential, cardiac muscle cannot exhibit
tetany.
Which of the following is greater during left ventricular systole?
the peak pressure in the ventricle
Each of the following factors would increase peripheral resistance, except
vasodilation.
The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the
ventricular ejection of ventricular systole.
The right atrium receives blood from the
A) coronary sinus. B) superior vena cava. C) inferior vena cava. D) all of the above
Stroke volume depends on
A) end-diastolic volume. B) the contractility of the ventricle. C) the pressure required to pump blood into the aorta. D) ALL OF THE ABOVE
The interventricular sulci and coronary sulcus contain
A) fat. B) arteries. C) veins. D) all of the above
Averaged over a few heartbeats, venous return is ________ cardiac output.
equal to
The foramen ovale in the fetal heart is located in the
interatrial septum.
Rupture of the papillary muscles in the left ventricle may result in
mitral regurgitation. mitral valve prolapse. bicuspid regurgitation. bicuspid prolapse. ALL OF THE ABOVE
During the cardiac cycle, the
both QRS complex of the ECG precedes the increase in ventricular pressure and first heart sound coincides with the QRS complex of the ECG.
If the pacemaker cells in the SA node become more permeable to potassium ions, the
both heart rate will decrease and membrane will hyperpolarize.
The heart is innervated by ________ nerves.
both parasympathetic and sympathetic
Blood returning to the heart from the pulmonary circuit first enters the
left atrium
If a patient's tricuspid valve was leaking during systole, what would happen?
regurgitation into the left atrium
The right ventricle pumps blood to the
right and left lungs.
The normal pacemaker of the heart is located in the
sinoatrial node.
The heart pumps approximately ________ milliliters of blood each minute.
6,000
The following are structural components of the conducting system of the heart. 1. Purkinje fibers 2. AV bundle 3. AV node 4. SA node 5. bundle branches
D) 4, 3, 2, 5, 1.
The pulmonary arteries carry blood to the
lungs.
Acetylcholine slows the heart because it
opens potassium ion channels in SA node cells and causes the pacemaker potential to depolarize more slowly.
Total peripheral resistance is related to all of the following, except the
osmolarity of interstitial fluids.
The pulmonary semilunar valve prevents backward flow into the
right ventricle.
Which of the following would be greater?
the end-diastolic volume when the heart rate is 60 beats/minute Answer: B
Tetanic muscle contractions don't occur in a normal cardiac muscle because
the refractory period lasts until the muscle relaxes.
If the connection between the SA node and AV node becomes blocked,
the ventricles will beat more slowly.
Blood flowing into the heart from the venae cavae flows next through the ________ valve.
tricuspid
Blood pressure is lowest in the
veins.
The T wave on an ECG tracing represents
ventricular repolarization.
During ventricular systole, the
AV valves are closed.
The first heart sound is heard when the
AV valves close.
The long plateau phase of the cardiac muscle action potential is due to
calcium channels remaining open.
In cardiac muscle
calcium ions enter the cell through slow ion channels.
The term used to describe fluid collecting in the pericardial cavity that restricts the movement of the heart is known as
cardiac tamponade
Drugs that block the beta-one adrenergic receptors will
decrease heart rate.
Drugs known as calcium channel blockers such as nifedipine can be used to
decrease the force of cardiac contraction.
When the left ventricle contracts, the diameter of the ventricular chamber
decreases
When the left ventricle contracts, the distance from the apex to the base
decreases.
Cardiac output can be increased by all of the following except one. Choose the exception.
decreasing ejection fraction
Which of the following would have the greater effect on vascular resistance?
decreasing the diameter of a blood vessel by ½
The P wave of the electrocardiogram is a signal from
depolarization of the atria.
In the middle of the thoracic cavity is a region occupied by the heart, great vessels, thymus, esophagus, and trachea called the
mediastinum
Analysis of the electrocardiogram can reveal all of the following, except the
stroke volume.
The following is a list of vessels and structures that are associated with the heart. 1. right atrium 2. left atrium 3. right ventricle 4. left ventricle 5. venae cavae 6. aorta 7. pulmonary trunk 8. pulmonary veins
) 5, 1, 3, 7, 8, 2, 4, 6
At a heart rate of 60 beats/minute, a cardiac cycle lasts
1 second.
The heart beats approximately ________ times each day.
100,000
Pacemaker cells isolated from the SA node generate action potentials at ________ beats per minute.
80-100
Which of the following affects blood flow through the body?
A) blood viscosity B) vessel diameter C) turbulence D) vascular resistance E) all of the above
The cardioacceleratory center activates sympathetic neurons and the cardioinhibitory center controls parasympathetic neurons.
Both parts of the statement are true and relate to brainstem control of heart rate.
If there is a complete block between the SA node and the AV node, how would the ECG be affected?
The rate of P waves will be faster than the rate of QRS complexes.
Which of these would cause stroke volume to increase?
both when venous return is increased and when diastolic blood pressure is decreased
In which of the following would the blood flow be highest?
a vessel 1.0 cm in diameter and 2 meters long
In which of the following would the resistance be greater?
a vessel 10 microns in diameter
The left ventricle pumps blood to the
aorta.
Blood pressure is highest here.
artery
During the isovolumetric contraction phase of ventricular systole, the
atrioventricular valves and semilunar valves are closed.
The earlike extension of the atrium is the
auricle
Activation of which kind of receptor causes heart rate to increase?
beta-one receptor
The bicuspid or mitral valve is located
between the left atrium and left ventricle.
The ________ valve prevents backward flow into the left atrium.
bicuspid
The cusps (leaflets) of atrioventricular valves attach directly to
chordae tendineae.
Each of the following factors will increase cardiac output, except
increased parasympathetic stimulation.
Pacemaker cells in the SA node
generate action potentials that spread to the myocardium.
The atrioventricular valves permit blood flow
in one direction only.
David suffers from a prolapsed mitral valve. This condition would cause
increased effort by the left ventricle and regurgitation.
Each of the following changes will result in increased blood flow to a tissue, except
increased hematocrit.
As blood travels from arteries to veins,
pressure drops.
Contractions of the papillary muscles
prevent the atrioventricular valves from reversing into the atria.
As blood leaves the right ventricle it passes through the ________ and then into the pulmonary trunk.
pulmonary valve
Blood leaves the right ventricle by passing through the
pulmonary valve.
The difference between the systolic and diastolic pressures is called the ________ pressure.
pulse
Compared to the right ventricle, the left ventricle has all the following characteristics, except that it
pumps a greater volume.
The mitral valve closes
A) when left ventricular pressure exceeds left atrial pressure. B) at the beginning of ventricular systole. C) at the same time at the tricuspid valve. ALL OF THE ABOVE
Turbulent blood flow occurs
A) when there are irregularities in the vessel wall. B) at high flow rates. C) when there are sudden changes in vessel diameter. D) all of the above
If blood pressure doubled, the blood flow through a vessel would be
doubled.
If the connection between the vagus nerve and the heart is cut, which of these changes will occur?
A) heart will beat slower B) stroke volume will decrease C) cardiac output will decrease D) nodal fibers will depolarize more slowly E) NONE OF THE ABOVE
Arteriosclerosis can lead to
A) hypertension. B) stroke. C) coronary artery disease. D) ALL OF THE ABOVE
Which of the following would increase heart rate?
A) increased sympathetic stimulation of SA node B) decreased parasympathetic stimulation of nodal fibers C) increased levels of norepinephrine and/or epinephrine D) faster depolarization of the pacemaker potential E) ALL OF THE ABOVE
Depolarization of the ventricles is represented on an electrocardiogram by the
QRS complex.
During the T wave of the electrocardiogram, the ventricles are
both repolarizing and relaxing.
In cardiac muscle, the fast depolarization phase of the action potential is the result of
increased membrane permeability to sodium ions.
________ is to slow heart rate as ________ is to fast heart rate.
Bradycardia; tachycardia
