Chapter 20 Heart 3rd version
Depolarization of the atria corresponds to the EKG's
P wave
Which of the following would be greater? A) the end-diastolic volume when the heart rate is 150 beats/minute B) the end-diastolic volume when the heart rate is 60 beats/minute
B) the end-diastolic volume when the heart rate is 60 beats/minute
________ is to slow heart rate as ________ is to fast heart rate.
Bradycardia; tachycardia
The right ventricle pumps blood to the
right and left lungs
coronary veins empty into the
right atrium
The ________ deliver(s) blood to the myocardium.
right coronary artery and left coronary artery
The pulmonary semilunar valve prevents backward flow into the
right ventricle
The T wave on an ECG tracing represents
ventricular contraction
in cardiac muscle
at least half of the calcium ion required for contraction comes from outside the cell.
The cusps (leaflets) of atrioventricular valves attach directly to
chordae tendineae
The function of the atrium is to
collect blood and pump blood to the ventricle
As blood leaves the right ventricle it passes through the ________ and then into the pulmonary trunk.
conus arteriosus
The great and middle cardiac veins drain blood into the
coronary sinus
Artery is to ________ as vein is to ________.
efferent;afferent
The pulmonary veins carry blood to the
heart
The atrioventricular valves permit blood flow
in one direction only
In cardiac muscle, the fast depolarization phase of the action potential is the result of
increased membrane permeability to sodium ions.
Each of the following factors will increase cardiac output, except
increased parasympathetic stimulation.
The first heart sound ("lub")
is associated with closing of the mitral valve
The ________ ventricle has a greater workload than the ________.
left;right ventricle
The pulmonary arteries carry blood to the
lungs
Rupture of the papillary muscles in the left ventricle may result in
mitral regurgitation. mitral valve prolapse. bicuspid regurgitation. bicuspid prolapse.
Cardiac output is increased by
more sympathetic stimulation. increased stroke volume.
When the semilunar valves close, the AV valves then
open
Acetylcholine slows the heart because it
opens potassium ion channels in SA node cells. causes the pacemaker potential to depolarize more quickly.
Contractions of the papillary muscles
prevent the atrioventricular valves from reversing into the atria.
Blood leaves the right ventricle by passing through the
pulmonary valve
When a blood clot forms on a ruptured plaque in a coronary artery, the condition is referred to as a(n)
coronary thrombosis
The visceral pericardium is the same as the
epicardium
Which of the following would increase heart rate?
increased sympathetic stimulation of SA node decreased parasympathetic stimulation of nodal fibers increased levels of epinephrine faster depolarization of the pacemaker potential
The foramen ovale in the fetal heart is located in the
intertribal septum
Intercalated discs serve to transfer ________ from cell to cell.
ionic current, action potentials, the force of contraction
Blood is supplied to the left atrium by the
left coronary artery
The circumflex branch and the anterior interventricular artery are branches of the
left coronary artery
The coronary sulcus is a groove that
marks the border between the atria and ventricles.
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
none of the above
Excess fluid in the ________ causes cardiac tamponade
pericardial cavity
Compared to the right ventricle, the left ventricle has all the following characteristics, except that it
pumps a greater volume
During the T wave of the electrocardiogram, the ventricles are
repolarizing, relaxing
During ventricular systole, the
AV valves are closed.
The first heart sound is heard when the
AV valves close
The structure that permits blood flow from the right atrium to the left atrium in the fetal circulation is the
Foramen ovale
The long plateau phase of the cardiac muscle action potential is due to
calcium channels remaining open.
Most of the middle layer in the heart wall is composed of
cardiac myocytes
The term used to describe fluid collecting in the pericardial cavity that restricts the movement of the heart is known as
cardiac tamponade
The right atrium receives blood from the
coronary, superior vena cava and inferior vena cava
Drugs that block the beta-one adrenergic receptors will
decrease heart rate
An increase in the rate of action potentials from baroreceptors will reflexly lead to
decrease in heart rate. decrease in blood pressure.
Drugs known as calcium channel blockers such as nifedipine can be used to
decrease the force of cardiac contraction. decrease blood pressure. dilate the coronary arteries. produce a negative inotropic effect.
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
The P wave of the electrocardiogram is a signal from
depolarization of the atria.
Stroke volume depends on
end diastolic volume. the contractility of the ventricle. the pressure required to pump blood into the aorta.
The interventricular sulci and coronary sulcus contain
fat, arteries, veins
Heart rate is controlled by neurons of the cardiovascular center located in the
medulla oblongata
Pacemaker cells in the SA node
show a slow spontaneous depolarization. are connected by gap junctions to atrial myocytes.
A heartbeat lasts
370 msec.
At a heart rate of 60 beats/minute, a cardiac cycle lasts
1 sec
________ is to contraction as ________ is to relaxation
Systole;diastole ejection;filling
The heart beats approximately ________ times each day.
100,000
there are ______ pulmonary veins
4
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 The sequence in which excitation would move through this system is
4, 3, 2, 5, 1.
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
The heart pumps approximately ________ liters of blood each day
8,000
Pacemaker cells isolated from the SA node generate action potentials at ________ beats per minute.
80-100
The earlike extension of the atrium is the
Auricle
Cardiac muscle cells and skeletal muscle cells differ in a few ways. Which of the following is not one of them?
Cardiac muscle cells lack transverse tubules
The first blood vessels to branch from the aorta are the ________ arteries
Coronary
Abnormally slow depolarization of the ventricles would most change the shape of the ________ in an ECG tracing.
QRS complex
Depolarization of the ventricles is represented on an electrocardiogram by the
QRS complex
During the cardiac cycle, the
QRS complex of the ECG precedes the increase in ventricular pressure. First heart sound coincides with the QRS complex of the ECG
Blood returning to the heart from the systemic circuit first enters the
Right Atrium
The marginal branch and posterior interventricular branch are branches of the
Right Coronary artery
"An increase in end-diastolic volume increases the stroke volume" is a way of stating
Starling's law of the heart.
The heart is roughly the size of
a man's clenched fist
The connective tissue fibers of the myocardium
add strength and prevent overexpansion of the heart. help distribute the forces of contraction. provide elasticity to help return the heart to its normal size. provide physical support for cardiac muscle.
The left ventricle pumps blood to the
aorta
A heart murmur might be caused by
aortic valve stenosis. or mitral valve insufficiency. or pulmonic valve insufficiency.
Which of the following descriptions matches the term near the left fifth intercostal space?
apex of the heart
During the isovolumetric phase of ventricular systole, the
atrioventricular valves and semilunar valves are closed.
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 heart is innervated by ________ nerves
both parasympathetic and sympathetic
Which of these comparisons between skeletal and heart muscle is false?
both rely entirely on oxidative metabolism for energy.
The normal pacemaker of the heart is located in the
sinoatrial node
Analysis of the electrocardiogram can reveal all of the following, except the
stroke volume
The volume of blood ejected from each ventricle during a contraction is called the
stroke volume
Cardiac cells damaged by infarction will show which of the following?
switch to anaerobic metabolism. release of enzymes into the circulation. release of troponin T and I into the circulation. release of MB-CK into the circulation
The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the
systolic ejection phase
As a result of the long refractory period in the cardiac action potential, cardiac muscle cannot exhibit
tetany
Blood is supplied to the myocardium by
the coronary arteries.
The wall of the left ventricle is thicker than the right because
the left ventricle does more work than the right ventricle. the left ventricle produces a higher pressure than the right.
Which of the following is greater during left ventricular systole?
the peak pressure in the ventricle
Tetanic muscle contractions don't occur in a normal cardiac muscle because
the refractory period lasts until the muscle relaxes.
Blood flowing into the heart from the venae cavae flows next through the ________ valve.
tricuspid
Blood returning to the heart from the pulmonary circuit first enters the
Left Atrium
In the middle of the thoracic cavity is a region occupied by the heart, great vessels, thymus, esophagus, and trachea called the
Mediastinum
AV nodal cells are poorly interconnected compared to contractile cells but they have bigger diameters.
The first part of the statement is true but the second part is false