The heart is located in a subdivision of the thorax called the ________.
The major pumping chambers of the heart are ________.
The shapes and the thickness of the walls of the right ventricle compared to the left are ________.
different: L ventricle is egg-shaped (round in cross section) with thicker walls
How many heart valves are there?
What is true of the mitral and tricuspid heart valves?
They lie between the atria and the ventricular chambers on each side of the heart.
What is true about heart valves?
They enforce a one-way blood flow through the heart, operate passively (no active contraction required), and separate atria from ventricles, and ventricles from the large arteries that leave them.
Which side of the heart receives blood from the body and pumps it to the lungs?
The pulmonary trunk and arteries are color-coded ________ on models and in pictures, because they carry ________ blood.
In the coronary circulation oxygenated blood is provided to the heart muscle by the ________.
right and left coronary arteries
Cardiac muscle tissue ________.
is striated, like skeletal muscle tissue
Blood arriving in the right atrium has just come from the ________.
vena cava and coronary sinus
Blood has just been discharged into the pulmonary trunk: from which chamber did it exit?
the right ventricle
The heart is called a double pump because ________.
it is two separate side-by-side pumps serving different circulations, it simultaneously pumps blood to the lungs (right side) and to all the other organs of the body (left side), and blood flows into and out of each side of the heart, but not from one side to the other
These vessels carry oxygenated blood.
aorta and pulmonary veins
What is the name of the circuit that supplies blood to the brain, heart, and gastrointestinal tract?
Which artery supplies the anterior ventricular walls and laterodorsal part of the left side of the heart?
left coronary artery
Which of the veins listed here drains directly into the right atrium?
anterior cardiac vein
The intercalated discs in cardiac muscle tissue ________.
mark the junction between two cardiac cells
This structure is a remnant of a fetal vessel that connected the pulmonary trunk and the aorta.
________ is/are found in the ventricles, and attach the flaps of the AV valves to papillary muscle.
What is the function of the coronary circulation?
Provide a blood supply to the heart
What is the ligamentum arteriosum?
A remnant of the ductus arteriosus
Which chamber of the heart exits into the pulmonary trunk?
Identify the ear like flaps that are attached to the top chambers of the heart.
T OR F: The first branch off the arch of the aorta is the brachiocephalic artery in both the sheep and the human.
T OR F: The base of the heart is located at the bottom of the heart.
Name the ridged bundles of muscle found projecting inside the right atrium.
Identify the right atrioventricular valve.
Identfiy the valve located at the exit of the right ventricle.
pulmonary semilunar valve
T OR F: The moderator band is found on both the right and left side of the heart.
T OR F: Oxygenated blood flows through the right side of the heart.
Identify the most muscular chamber.
Name the inner lining of the heart.
Identify the valve found between the left atrium and left ventricle.
bicuspid (mitral) valve
What heart chamber pushes blood through the aortic semilunar valve?
Name the needle like ridges of muscle lining the ventricles.
What fibrous structure functions to anchor the atrioventricular valves in a closed position?
T OR F: Blood on the right never mixes with blood on the left, once the heart is fully developed.
T OR F: The myocardium receives its blood supply from the coronary arteries.
T OR F: Anastomoses among coronary arterial branches provide collateral routes for blood delivery to the heart muscle.
T OR F: The left side of the heart pumps the same volume of blood as the right.
T OR F: Arterial blood supply to heart muscle is continuous whether the heart is in systole or diastole.
T OR F: Trabeculae carneae are found in the ventricles and never the atria.
T OR F: The papillary muscles contract after the other ventricular muscles so that they can take up the slack on the chordae tendineae before the full force of ventricular contractions sends blood against the AV valve flaps.
Which of the events below does not occur when the semilunar valves are open?
AV valves are closed.
Ventricles are in systole.
VENTRICLES ARE IN DIASTOLE.
Blood enters pulmonary arteries and the aorta.
The left ventricular wall of the heart is thicker than the right wall in order to ________.
pump blood with greater pressure
Blood within the pulmonary veins returns to the ________.
Small muscle masses attached to the chordae tendineae are the ________.
The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is ________.
The source of blood carried to capillaries in the myocardium would be the ________.
The fact that the left ventricle of the heart is thicker than the right ventricle reveals that it ________.
pumps blood against a greater resistance
When viewing a dissected heart, it is easy to visually discern the right and left ventricles by ________.
noticing the thickness of the ventricle walls
Select the correct statement about the heart valves.
The AV valves are supported by chordae tendineae so that regurgitation of blood into the atria during ventricular contraction does not occur.
Select the correct statement about the structure of the heart wall.
The myocardium is the layer of the heart that actually contracts.
The ________ and ________ valves of the heart have no chordae tendineae attached.
aortic and pulmonary
The enlarged coronary vessel outside the heart that empties blood into the right atrium is the ________.
The ________ valve of the heart has three flaps with chordae tendineae.
The layers of the heart wall from superficial to deep are:
epicardium, myocardium, and endocardium.
The heart has _____ chambers and _____ valves.
Which of the following does not deliver blood to the right atrium?
Inferior vena cava
Superior vena cava
The role of the coronary arteries is to:
supply blood to the heart tissue
Which of the following is not a difference between the left and right ventricles?
THE LEFT VENTRICLE RECEIVES A SMALLER PERCENTAGE OF CORONARY BLOOD SUPPLY THAN THE RIGHT VENTRICLE.
The left ventricle is a more powerful pump than the right ventricle.
The left ventricle pumps blood to the systemic circuit, while the right ventricle pumps blood to the pulmonary circuit.
The walls of the left ventricle are thicker than the walls of the right ventricle.
The ________ valve is located between the right atrium and the right ventricle.
Which of the following is not a difference between cardiac and skeletal muscle?
Cardiac muscle cells contain more mitochondria than do skeletal muscle cells.
Cardiac muscle cells quickly die in the absence of oxygen; skeletal muscle cells are better able to adapt to oxygen deficiency.
The plasma membranes of cardiac muscle cells interlock, but skeletal muscle fibers are independent.
CARDIAC MUSCLE DOES NOT USE THE SLIDING FILAMENT MECHANISM FOR CONTRACTION; SKELETAL MUSCLE DOES.
Which heart chamber sends deoxygenated blood to the lungs?
Which valve is located between the right atrium and ventricle?
What structures connect the individual heart muscle cells?
Which of the following terms refers to a lack of oxygen supply to heart muscle cells?
The heart is actually (one, two, or three) pumps?
Which chamber receives blood from the superior and inferior vena cavae?
Which heart chamber receives blood from the pulmonary veins?
Which heart chamber pumps unoxygenated blood out the pulmonary trunk?
Which chamber pumps oxygenated blood out the aorta to the systemic circuit?
A man enters the hospital complaining of chest pain. His history includes smoking, a stressful job, a diet heavy in saturated fats, lack of exercise, and high blood pressure. Although he is not suffering from a heart attack, his doctor explains to him that a heart attack is quite possible. What did the chest pain indicate? Why is this man a prime candidate for further complications?
Angina pectoris. If the coronary arteries are occluded (atherosclerosis), the heart muscle could be deprived of oxygen, resulting in a heart attack.
A patient takes a nitroglycerin tablet sublingually for chest pain. Nitroglycerin acts directly on smooth muscle, producing relaxation and vessel dilation. What is the name for chest pain, and how does nitroglycerin relieve chest pain?
Angina pectoris is thoracic pain caused by a fleeting deficiency in oxygen delivery to the myocardium. Because nitroglycerin acts as a vasodilator, blood flow to the heart is increased, promoting the delivery of oxygen to the cells.
T OR F: Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle.
If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________.
decreased delivery of oxygen
If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells ________.
tetanic contractions might occur, which would stop the heart's pumping action
Select the correct statement about the function of myocardial cells in a healthy, normally functioning heart.
The atria, followed by the ventricles, contract as a unit or they do not contract at all.
Compared to skeletal muscle, cardiac muscle ________.
has gap junctions that allow it to act as a functional syncytium
During contraction of heart muscle cells ________.
some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores
The heart's pacemaker is the:
What is the source of ATP for cardiac muscle contraction?
T OR F: Congestive heart failure means that the pumping efficiency of the heart is depressed so that there is inadequate delivery of blood to body tissues.
T OR F: Tissues damaged by myocardial infarction are replaced by connective tissue.
T OR F: Chronic release of excess thyroxine can cause a sustained increase in heart rate and a weakened heart.
T OR F: The "lub" sounds of the heart are valuable in diagnosis because they provide information about the function of the heart's pulmonary and aortic valves.
T OR F: Autonomic regulation of heart rate is via two reflex centers found in the pons.
T OR F: An ECG provides direct information about valve function.
T OR F: As pressure in the aorta rises due to atherosclerosis, more ventricular pressure is required to open the aortic valve.
Normal heart sounds are caused by which of the following events?
closure of the heart valves
Hemorrhage with a large loss of blood causes ________.
a lowering of blood pressure due to change in cardiac output
Damage to the ________ is referred to as heart block.
The P wave of a normal electrocardiogram indicates ________.
To auscultate the aortic semilunar valve, you would place your stethoscope in the ________.
second intercostal space to the right of the sternum
Which of the following factors does not influence heart rate?
Norepinephrine acts on the heart by ________.
causing threshold to be reached more quickly
If the vagal nerves to the heart were cut, the result would be that ________.
the heart rate would increase by about 25 beats per minute
Which vessel of the heart receives blood during right ventricular systole?
Which of these vessels receives blood during ventricular systole?
both the aorta and pulmonary trunk
Which of the following is not part of the conduction system of the heart?
bundle of His
The tricuspid valve is closed ________.
when the ventricle is in systole
During the period of ventricular filling ________.
blood flows passively through the atria and the open AV valves into the ventricles
The second heart sound is heard during which phase of the cardiac cycle?
The time of day most hazardous for heart attacks is ________.
If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________.
threshold is reached more quickly and heart rate would increase
Select the correct statement about cardiac output.
A slow heart rate increases end diastolic volume, stroke volume, and force of contraction.
Isovolumetric contraction ________.
refers to the short period during ventricular systole when the ventricles are completely closed chambers
The ECG T wave interval represents ________.
CO = ________ × SV.
The order of impulse conduction in the heart, from beginning to end, is:
SA node, AV node, bundle of His, bundle branches, and Purkinje fibers.
A premature ventricular contraction is classified as a(n):
The QRS complex on an electrocardiogram represents:
The first heart sound (the 'lub' of 'lub-dup') is caused by:
closure of the atrioventricular valves
Which is correctly matched?
Quiescent period: total heart relaxation between heartbeats
In a healthy individual which of the following would be low?
Which of the following would increase heart rate?
T OR F: The left side of the heart is considered the systemic circuit pump.
Which of the following structures sets the pace of heart contraction?
What does the T wave of the electrocardiogram represent?
Which of the following is NOT a factor that regulates stroke volume?
ALL OF THE FACTORS ABOVE REGULATE STROKE VOLUME
What is afterload?
back pressure exerted by arterial blood
What causes heart sounds?
heart valve closure
Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart?
What does the ECG wave tracing represent?
electrical activity of the heart
What does the QRS complex represent in the ECG wave tracing?
Contraction of the atria results from which wave of depolarization on the ECG tracing?
Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?
Which of the following would increase cardiac output to the greatest extent?
increased heart rate and increased stroke volume
Which of the following would increase heart rate?
epinephrine and norepinephrine
How would an increase in the sympathetic nervous system increase stroke volume?
By what mechanism would an increase in venous return increase stroke volume?
increased end diastolic volume
How would a decrease in blood volume affect both stroke volume and cardiac output?
decreased stroke volume and no change in cardiac output
Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.
Which of the following is correct about the filling of the ventricles?
Most blood flows passively into the ventricles through open AV valves.
Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.
Pressure in the atria would be greater than the pressure in the ventricles.
What causes the aortic semilunar valve to close?
greater pressure in the aorta than in the left ventricle
Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.
isovolumetric contraction, ventricular ejection, isovolumetric relaxation
Increased pressure in the ventricles would close what valve(s)?
AV valves only
A 14-year-old girl undergoing a physical examination prior to being admitted to summer camp was found to have a loud heart diastolic murmur at the second intercostal space to the left side of the sternum. What is the reason for the loud heart murmur associated with this girl's condition?
The heart murmur is due to incomplete closing of the pulmonary valve.
An older woman complains of shortness of breath and intermittent fainting spells. Her doctor runs various tests and finds that the AV node is not functioning properly. What is the suggested treatment?
Surgery to implant an artificial pacemaker
A patient was admitted to the hospital with chest pains. On admission, his pulse was 110 and blood pressure was 96/64. According to his history, his normal pulse rate is usually between 80 and 88 and his blood pressure runs from 120/70 to 130/80. Why did these changes in BP and HR occur?
To maintain the same cardiac output, the heart rate would need to increase to compensate for a decreased stroke volume.
A 55-year-old male was admitted to the hospital with heart failure. He complains of increasing shortness of breath on exertion, and of needing to sleep on three pillows at night. On physical assessment, the nurse determines that his ankles and feet are very swollen. Which of these symptoms either reflect left-sided and/or right-sided heart failure?
Left side failure results in shortness of breath. Right side failure results in edema in the extremities.
Asystole is the total absence of ventricular electrical activity. Would defibrillation be effective in this situation?
Defibrillation would not be effective: it interrupts chaotic electrical activity in the heart, and if there is no electrical activity, then there is nothing to interrupt.
A patient is prescribed a calcium channel blocker to prevent angina (chest pain) by decreasing the demand for oxygen. What is the explanation for this pharmacological effect?
A drug that inhibits the entry of calcium ions into the cytoplasm of cardiac cells decreases the force of myocardial contractility, thereby decreasing the oxygen demand, relieving the chest pain.
What is the main function of heart valves?
to prevent backward flow of blood
When the atria contract, which of the following is true?
The ventricles are in diastole
Which of the following is equivalent to the ventricular volume during isovolumetric contraction?
The end diastolic volume (EDV)
Which of the following is true during ventricular systole?
The AV valves are closed.
During the ventricular ejection phase of the cardiac cycle, which of the following is true?
The semilunar valves are open.
Most of the decrease in ventricular volume takes place during which phase of the cardiac cycle?
Which of the following is equivalent to the ventricular volume during isovolumetric relaxation?
end systolic volume (ESV)
Most of the increase in left ventricular volume takes place during what phase of the cardiac cycle?
In what direction does blood flow through the heart?
from a region of high pressure to a region of low pressure
Atrial pressure is greater than ventricular pressure during which phase of the cardiac cycle?
At what point during the cardiac cycle does the AV valve close?
when ventricular pressure becomes greater than atrial pressure
At what point in the cardiac cycle does the semilunar valve open?
when ventricular pressure becomes greater than aortic pressure
Ventricular pressure is greater than aortic pressure during which phase of the cardiac cycle?
At what point in the cardiac cycle does the semilunar valve close?
when pressure in the ventricle becomes less than aortic pressure
Isovolumetric relaxation is characterized by which of the following?
The semilunar and AV valves are closed.
At what point in the cardiac cycle does the AV valve open?
when atrial pressure becomes greater than ventricular pressure
T OR F: Proxysmal atrial tachycardia is characterized by bursts of atrial contractions with little pause between them.
Which of the following is not an age-related change affecting the heart?
fibrosis of cardiac muscle
THINNING OF THE VALVE FLAPS
decline in cardiac reserve
Foramen ovale ________.
connects the two atria in the fetal heart
Commotio cordis is heart failure due to a ________.
relatively mild blow to the chest that occurs during a vulnerable interval (2 ms) when the heart is repolarizing
What structure in the fetal heart allows blood to flow from the right atrium directly to the left atrium?
T OR F: The pulmonary circuit is not active in the developing fetus.
An angiocardiogram was performed on an infant who had symptoms of breathlessness, and it was found that he had a patent ductus arteriosus. What is the location and function of the ductus arteriosus in the fetus, and how does it relate to the reason for the infant's breathlessness?
Ductus arteriosus is a shunt between the pulmonary trunk and the aorta in the fetus. Breathlessness is due to the mixing of oxygenated and deoxygenated blood.
The principle of complementary structure and function is evident when examining the coverings of the heart. In what way is this relationship evident?
The visceral and parietal membranes of the pericardium are smooth and slide past each other, providing a low-friction environment for heart movement.
Of the following layers of the heart wall, which consumes the most energy?
WHich of the following structures is an exception to the general principle surrounding blood vessel oxygenation levels?
pulmonary artery and pulmonary veins
What purpose does the coronary circuit serve?
It delivers 1/20 of the body's blood supply to the heart muscle itself
A heart murmur would be detected when blood is heard flowing from the ____ to the ____ through the ____.
left ventricle; left atrium; mitral valve
The presence of intercalated discs between adjacent cardiac muscle cells causes the heart to behave as a _____.
Cardiac muscle cells have several similarities with skeletal muscle cells. Which of the following is not a similarity?
THE CELLS ARE EACH INNERVATED BY A NERVE ENDING.
The cells store calcium ions in the sarcoplasmic retiuculum.
The cells contain sarcomeres.
The cells become depolarized when sodium ions enter the cytoplasm.
The plateau portion of the action potential in contractile cardiac muscle cells is due to:
an influx of calcium ions.
The stimulus for the heart's rhythmic contractions comes from _____.
a pacemaker potential
The major ionic change that initiates the rising phase of the autorhythmic cell action potential is _____.
calcium ion entry
For which type of heart condition might a doctor prescribe calcium channel blockers?
In a normal heart, which of the following structures is responsible for setting the heart's pace?
Predict the nature of an ECG recording when the atrioventricular node becomes the pacemaker.
The rhythm would be slower.
The primary input ot the heart by the cardioinhibitory center is primarily found in the _____.
sinoatrial node and atrioventricular node
The "lub-dub" heart sounds are produced by:
the closing of the atrioventricular valves ("lub") and the the closing of the semilunar valves ("dup").
Atrial systole occurs ____ the firing of the sinoatyrial node.
The majority (80%) of ventricular filling occurs _____.
during late ventricular systole; passively through blood flow alone
In terms of blood flow, why is it important that atrial diastole occurs just as ventricular systole begins?
Blood is continually propelled in a forward motion down its pressure gradient.
Cardiac output is determined by _____.
heart rate; stroke volume
Predict what would happen to the end systolic volume (ESV) if contraction force were to increase.
It would decrease.
The Frank-Starling law of the heart can be demonstrated when an individual takes a deep breath. This is because:
the negative intrathoracic pressure induces a larger than normal venous return to the right atrium, thereby stretching the wall of the right ventricle.
Your heart seems to "pound" after you hear a sudden, loud noise. This increase contractility is:
due to norepinephrine causing threshold to be reached more quickly.
Predict what happens to end diastolic volume when an increase in heart rate is not accompanied by an increase in contractility.
End diastolic volume is decreased.
WHat is the nature of acetylcholine's inhibitory effect on heart rate?
Acetylcholine causes opening of potassium channels in the sinoatrial node, thereby hyperpolarizing it.
Why is high blood pressure damaging to the heart?
Due to increased afterload, the left ventricle must contract more forefully to expel the same amount of blood.
The cardiac cycle ________.
represents all of the events of the heart during one heartbeat
The QRS complex of the electrocardiogram begins ________.
just prior to ventricular contraction
Heart sounds are associated with ________.
turbulent blood flow, closure of the AV valves, and closure of the semilunar valves
The semilunar valves are forced open when ________.
ventricular pressure exceeds the pressure in the large arteries leaving the heart
Is it possible to determine blood pressure from a cardiac cycle graph? Why or why not?
Yes, both systolic and diastolic pressures can be read.
Which phase of the cardiac cycle is longest?
Pulse pressure ________.
is the difference between systolic and diastolic pressure
By taking a pulse you can determine ________.
pulse rate, regularity of the pulse, and strength of the pulse
Blood pressure is ________.
the pressure of the blood against the blood vessel walls
If you cut yourself and blood spurts rhythmically from the injury, you have probably cut ________.
By convention, the cardiac cycle graphs the events of the left side of the heart. How would the graphs change if we looked, instead, at the right side of the heart?
Pressure in the right ventricle would be much less, and all other events would be about the same.
What does the cardiac cycle reveal about the opening and closing of the heart valves?
The AV valves close first, then the semilunars open and close, then the AV valves open.
The first heart sound heard during the cardiac cycle is associated with ________.
closure of the AV valves
In comparing the volume of blood moved from atria to ventricles when the atria contract with the volume of blood ejected from the heart when the ventricles contract, we observe that ________.
atrial contractions move less blood into the ventricles than ventricles eject
Heart murmurs ________.
often indicate problems with heart valves, can be used to diagnose failure of the heart valves to close tightly, and can be used to diagnose constricted heart valves
The first heart sounds are best heard ________.
in the 5th intercostal spaces, at various distances from the sternal margins
The first of the two numbers measured when taking the blood pressure represents ________.
The mean arterial pressure for a patient whose blood pressure is 110/80 is ________.
90 mm Hg
Venous pressure ________.
is much lower than arterial pressure
During moderate exercise, ________.
heart rate and blood pressure increase