What heart chamber pushes blood through the aortic semilunar valve?
  • Pectinate musclesCorrect. The pectinate muscles are ridge like elevations of muscle. They are parallel to each other and resemble teeth of a comb. They are easily observed inside the right atrium.
  • Left ventricle;The aortic valve is located between the left ventricle and the aorta. The left ventricle pumps oxygenated blood out of the heart through the aortic valve to the body.
  • left ventricle;The left ventricle is responsible for pumping blood out to the body. This requires a lot of force. The left ventricle is the most muscular in order to pump the blood with adequate force
  • Most blood flows passively into the ventricles through open AV valves.Yes, most of the ventricular filling is passive; atrial contraction adds just a little more blood.
Name the ridged bundles of muscle found projecting inside the right atrium.
  • Pectinate musclesCorrect. The pectinate muscles are ridge like elevations of muscle. They are parallel to each other and resemble teeth of a comb. They are easily observed inside the right atrium.
  • Left ventricle;The aortic valve is located between the left ventricle and the aorta. The left ventricle pumps oxygenated blood out of the heart through the aortic valve to the body.
  • Pulmonary semilunar valveCorrect. The pulmonary valve is the semilunar valve found between the right ventricle and the pulmonary trunk. Deoxygenated blood travels through the pulmonary valve as it exits the right side of the heart on its way to the lungs.
  • Trabeculae carneae;Correct. Trabeculae carneae are the small elevated ridges of muscle arranged in a web type fashion found in both the right and left ventricles.
carries oxygen-poor venous blood of the coronary circulation into the right atrium.
  • coronary sinus
  • inferior vena cava
  • mitral (bicuspid) valve
  • systemic capillaries
oxygen-poor
  • superior vena cava, right ventricle, pulmonary arteries, right atrium
  • superior vena cava
  • inferior vena cava
  • AV valves onlyYes, increased pressure in the ventricles would close the AV valves.
Name the inner lining of the heart.
  • Endocardium;The endocardium is the smooth, slick lining of the chambers of the heart. Endocardium is a continuation of endothelium that lines blood vessels. Both endocardium and endothelium are composed of simple squamous epithelial tissue, which minimizes friction between the wall of the chamber/vessel and the blood.
  • Trabeculae carneae;Correct. Trabeculae carneae are the small elevated ridges of muscle arranged in a web type fashion found in both the right and left ventricles.
  • Pectinate musclesCorrect. The pectinate muscles are ridge like elevations of muscle. They are parallel to each other and resemble teeth of a comb. They are easily observed inside the right atrium.
  • fast calciumYes, unlike nerve cells or cardiac muscle cells, fast calcium channels are responsible for the depolarization phase of the autorhythmic cell action potential. When the fast calcium channels open, calcium rushes into the cell making it less negative (or more positive).
Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.
  • Pressure in the atria would be greater than the pressure in the ventricles.Yes, higher pressure in the atria than in the ventricles forces the AV valves to open and blood moves into the ventricles.
  • Trabeculae carneae;Correct. Trabeculae carneae are the small elevated ridges of muscle arranged in a web type fashion found in both the right and left ventricles.
  • ventricular diastoleYes, both occur during ventricular diastole when the ventricles are not actively contracting and ejecting blood.
  • intercalated discsIntercalated discs connect the heart muscle cells. They include desmosomes (anchoring junctions) and gap junctions (communicating junctions).
One of the changes that occurs in the pacemaker potential (unstable resting membrane potential) in the SA node (an autorhythmic cell) is a decreased efflux of what ion?
  • Provide a blood supply to the heart;Correct. The coronary circulation provides oxygenated blood to the heart through coronary arteries. Coronary veins return the deoxygenated from the heart to the coronary sinus on the posterior surface of the heart. The coronary sinus empties the deoxygenated blood directly into the right atrium where it joins deoxygenated from the body.
  • potassiumYes, if there is a decreased efflux of potassium while there is a normal influx of sodium, the inside of the cell would become less negative. Thus, threshold would be reached. The ability of these autorhythmic cells to spontaneously depolarize is what results in the pacemaker potential.
  • Pressure in the atria would be greater than the pressure in the ventricles.Yes, higher pressure in the atria than in the ventricles forces the AV valves to open and blood moves into the ventricles.
  • voltage-gated potassium channelsYes, opening of voltage-gated potassium channels causes positive potassium ions to move out of the cell. This efflux of potassium causes the cell to become more negative inside thus, repolarizing the cell.
Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart?
  • P waveYes, the P wave represents atrial depolarization, which leads to atrial contraction.
  • SA nodeYes, the SA Node spontaneously depolarizes, causing the wave of depolarization that spreads through the rest of the conduction system and heart.
  • the flow of positive ions from adjacent cellsYes, the flow of positive ions from the autorhythmic cells (or adjacent cells) brings the membrane to threshold initiating depolarization of the contractile cell.
  • AV nodeYes, the AV node slows down the impulse giving the atria time to contract before the ventricles contract.
Identfiy the valve located at the exit of the right ventricle.
  • Tricuspid valveCorrect. The tricuspid valve is the atrioventricular valve located on the right side of the heart. It separates the right atrium from the right ventricle.
  • Pulmonary semilunar valveCorrect. The pulmonary valve is the semilunar valve found between the right ventricle and the pulmonary trunk. Deoxygenated blood travels through the pulmonary valve as it exits the right side of the heart on its way to the lungs.
  • Pectinate musclesCorrect. The pectinate muscles are ridge like elevations of muscle. They are parallel to each other and resemble teeth of a comb. They are easily observed inside the right atrium.
  • Bicuspid (mitral) valve;The atrioventricular valve on the left is the bicuspid valve. The mitral valve is also called the mitral valve.
When threshold is reached at the SA node (an autorhythmic cell), what channels open causing further depolarization of the membrane?
  • gap junctionsYes, action potentials generated by the autorhythmic cells spread waves of depolarization to contractile cells through gap junctions. If the depolarization causes the contractile cells to reach threshold, they will in turn generate an action potential.
  • fast calciumYes, unlike nerve cells or cardiac muscle cells, fast calcium channels are responsible for the depolarization phase of the autorhythmic cell action potential. When the fast calcium channels open, calcium rushes into the cell making it less negative (or more positive).
  • potassiumYes, if there is a decreased efflux of potassium while there is a normal influx of sodium, the inside of the cell would become less negative. Thus, threshold would be reached. The ability of these autorhythmic cells to spontaneously depolarize is what results in the pacemaker potential.
  • Endocardium;The endocardium is the smooth, slick lining of the chambers of the heart. Endocardium is a continuation of endothelium that lines blood vessels. Both endocardium and endothelium are composed of simple squamous epithelial tissue, which minimizes friction between the wall of the chamber/vessel and the blood.
In order to cause cardiac muscle contraction, the contractile cells must also depolarize. What causes the depolarization of the contractile cells?
  • the flow of positive ions from adjacent cellsYes, the flow of positive ions from the autorhythmic cells (or adjacent cells) brings the membrane to threshold initiating depolarization of the contractile cell.
  • potassiumYes, if there is a decreased efflux of potassium while there is a normal influx of sodium, the inside of the cell would become less negative. Thus, threshold would be reached. The ability of these autorhythmic cells to spontaneously depolarize is what results in the pacemaker potential.
  • Pressure in the atria would be greater than the pressure in the ventricles.Yes, higher pressure in the atria than in the ventricles forces the AV valves to open and blood moves into the ventricles.
  • SA nodeYes, the SA Node spontaneously depolarizes, causing the wave of depolarization that spreads through the rest of the conduction system and heart.
carries oxygen-poor venous blood from below the diaphragm from the areas of the lower body and extremities into the right atrium
  • superior vena cava
  • coronary sinus
  • mitral (bicuspid) valve
  • inferior vena cava
Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.
  • Bicuspid (mitral) valve;The atrioventricular valve on the left is the bicuspid valve. The mitral valve is also called the mitral valve.
  • A remnant of the ductus arteriosus;The ligamentum arteriosum is a remnant of the ductus arteriosus. The ductus arteriosus is a fetal shunt that connects the pulmonary trunk to the aorta.
  • Pulmonary semilunar valveCorrect. The pulmonary valve is the semilunar valve found between the right ventricle and the pulmonary trunk. Deoxygenated blood travels through the pulmonary valve as it exits the right side of the heart on its way to the lungs.
  • Pressure in the atria would be greater than the pressure in the ventricles.Yes, higher pressure in the atria than in the ventricles forces the AV valves to open and blood moves into the ventricles.
Action potentials generated by the autorhythmic cells spread to the contractile cells through what structures in the membrane?
  • gap junctionsYes, action potentials generated by the autorhythmic cells spread waves of depolarization to contractile cells through gap junctions. If the depolarization causes the contractile cells to reach threshold, they will in turn generate an action potential.
  • AV nodeYes, the AV node slows down the impulse giving the atria time to contract before the ventricles contract.
  • potassiumYes, if there is a decreased efflux of potassium while there is a normal influx of sodium, the inside of the cell would become less negative. Thus, threshold would be reached. The ability of these autorhythmic cells to spontaneously depolarize is what results in the pacemaker potential.
  • fast calciumYes, unlike nerve cells or cardiac muscle cells, fast calcium channels are responsible for the depolarization phase of the autorhythmic cell action potential. When the fast calcium channels open, calcium rushes into the cell making it less negative (or more positive).
What causes the aortic semilunar valve to close?
  • electrical activity in the heartYes, the ECG waves show the depolarization and repolarization in various areas of the heart.
  • ventricular depolarizationYes, the QRS complex represents depolarization in the ventricles, which have greater mass than the atria.
  • right ventricle;The right ventricle pumps deoxygenated blood through the pulmonary semilunar valve into the pulmonary trunk to be distributed to the lungs.
  • greater pressure in the aorta than in the left ventricleYes, backflow of blood in the aorta (towards the left ventricle) closes the aortic semilunar valve.
What does the ECG wave tracing represent?
  • electrical activity in the heartYes, the ECG waves show the depolarization and repolarization in various areas of the heart.
  • greater pressure in the aorta than in the left ventricleYes, backflow of blood in the aorta (towards the left ventricle) closes the aortic semilunar valve.
  • A remnant of the ductus arteriosus;The ligamentum arteriosum is a remnant of the ductus arteriosus. The ductus arteriosus is a fetal shunt that connects the pulmonary trunk to the aorta.
  • Tricuspid valveCorrect. The tricuspid valve is the atrioventricular valve located on the right side of the heart. It separates the right atrium from the right ventricle.
Increased pressure in the ventricles would close what valve(s)?
  • P waveYes, the P wave represents atrial depolarization, which leads to atrial contraction.
  • Trabeculae carneae;Correct. Trabeculae carneae are the small elevated ridges of muscle arranged in a web type fashion found in both the right and left ventricles.
  • auricles;The auricles are flap like extensions of the atria that are observed on the external surface of the heart
  • AV valves onlyYes, increased pressure in the ventricles would close the AV valves.
What structures connect the individual heart muscle cells?
  • right ventricle;The right ventricle pumps deoxygenated blood through the pulmonary semilunar valve into the pulmonary trunk to be distributed to the lungs.
  • intercalated discsIntercalated discs connect the heart muscle cells. They include desmosomes (anchoring junctions) and gap junctions (communicating junctions).
  • ventricular depolarizationYes, the QRS complex represents depolarization in the ventricles, which have greater mass than the atria.
  • Trabeculae carneae;Correct. Trabeculae carneae are the small elevated ridges of muscle arranged in a web type fashion found in both the right and left ventricles.
Which of the following is NOT a factor that increases stroke volume?
  • Most blood flows passively into the ventricles through open AV valves.Yes, most of the ventricular filling is passive; atrial contraction adds just a little more blood.
  • ventricular depolarizationYes, the QRS complex represents depolarization in the ventricles, which have greater mass than the atria.
  • increasing afterloadIncreasing afterload decreases stroke volume.
  • epinephrineSympathetic stimulation leads to the release of epinephrine and norepinephrine, both of which increase heart rate and increase contractility, which increases stroke volume. Increasing heart rate and stroke volume increases cardiac output.
Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?
  • Most blood flows passively into the ventricles through open AV valves.Yes, most of the ventricular filling is passive; atrial contraction adds just a little more blood.
  • 75 mL The SV is calculated by subtracting the ESV from the EDV. You are comparing the volume of the ventricle at its fullest to its emptiest.
  • AV nodeYes, the AV node slows down the impulse giving the atria time to contract before the ventricles contract.
  • auricles;The auricles are flap like extensions of the atria that are observed on the external surface of the heart
Identify the valve found between the left atrium and left ventricle.
  • Bicuspid (mitral) valve;The atrioventricular valve on the left is the bicuspid valve. The mitral valve is also called the mitral valve.
  • auricles;The auricles are flap like extensions of the atria that are observed on the external surface of the heart
  • Pulmonary semilunar valveCorrect. The pulmonary valve is the semilunar valve found between the right ventricle and the pulmonary trunk. Deoxygenated blood travels through the pulmonary valve as it exits the right side of the heart on its way to the lungs.
  • ventricular depolarizationYes, the QRS complex represents depolarization in the ventricles, which have greater mass than the atria.
oxygen-rich
  • pulmonary veins, left ventricle, aorta, left atrium
  • AV valves onlyYes, increased pressure in the ventricles would close the AV valves.
  • Pulmonary semilunar valveCorrect. The pulmonary valve is the semilunar valve found between the right ventricle and the pulmonary trunk. Deoxygenated blood travels through the pulmonary valve as it exits the right side of the heart on its way to the lungs.
  • coronary sinus
Which chamber of the heart exits into the pulmonary trunk?
  • Most blood flows passively into the ventricles through open AV valves.Yes, most of the ventricular filling is passive; atrial contraction adds just a little more blood.
  • Left ventricle;The aortic valve is located between the left ventricle and the aorta. The left ventricle pumps oxygenated blood out of the heart through the aortic valve to the body.
  • isovolumetric contraction, ventricular ejection, isovolumetric relaxationYes, the ventricles must contract and eject blood before they relax and fill again.
  • right ventricle;The right ventricle pumps deoxygenated blood through the pulmonary semilunar valve into the pulmonary trunk to be distributed to the lungs.
The structure that is located anatomically between the aorta and the left ventricle is the
  • aortic semilunar valve
  • mitral (bicuspid) valve
  • systemic capillaries
  • intercalated discsIntercalated discs connect the heart muscle cells. They include desmosomes (anchoring junctions) and gap junctions (communicating junctions).
Calculate the stroke volume if the end diastolic volume (EDV) is 135 mL and the end systolic volume (ESV) is 60 mL.
  • 75 mL The SV is calculated by subtracting the ESV from the EDV. You are comparing the volume of the ventricle at its fullest to its emptiest.
  • auricles;The auricles are flap like extensions of the atria that are observed on the external surface of the heart
  • AV nodeYes, the AV node slows down the impulse giving the atria time to contract before the ventricles contract.
  • ventricular diastoleYes, both occur during ventricular diastole when the ventricles are not actively contracting and ejecting blood.
What is the function of the coronary circulation
  • Provide a blood supply to the heart;Correct. The coronary circulation provides oxygenated blood to the heart through coronary arteries. Coronary veins return the deoxygenated from the heart to the coronary sinus on the posterior surface of the heart. The coronary sinus empties the deoxygenated blood directly into the right atrium where it joins deoxygenated from the body.
  • epinephrineSympathetic stimulation leads to the release of epinephrine and norepinephrine, both of which increase heart rate and increase contractility, which increases stroke volume. Increasing heart rate and stroke volume increases cardiac output.
  • Pulmonary semilunar valveCorrect. The pulmonary valve is the semilunar valve found between the right ventricle and the pulmonary trunk. Deoxygenated blood travels through the pulmonary valve as it exits the right side of the heart on its way to the lungs.
  • electrical activity in the heartYes, the ECG waves show the depolarization and repolarization in various areas of the heart.
Which of the following would increase cardiac output?
  • epinephrineSympathetic stimulation leads to the release of epinephrine and norepinephrine, both of which increase heart rate and increase contractility, which increases stroke volume. Increasing heart rate and stroke volume increases cardiac output.
  • Myofibrils of cardiac muscle tissue vary in diameter and branch extensively. The myofibrils of cardiac muscle have various diameters; they also branch in order to maintain connections, via intercalated discs, with other muscle cells.
  • increasing afterloadIncreasing afterload decreases stroke volume.
  • Most blood flows passively into the ventricles through open AV valves.Yes, most of the ventricular filling is passive; atrial contraction adds just a little more blood.
The capillaries receiving blood flow from the left side of the heart are the
  • superior vena cava
  • True
  • inferior vena cava
  • systemic capillaries
______ carries oxygen-poor venous blood from above the diaphragm from areas of the upper body and extremities into the right atrium
  • AV nodeYes, the AV node slows down the impulse giving the atria time to contract before the ventricles contract.
  • aortic semilunar valve
  • superior vena cava
  • mitral (bicuspid) valve
Identify the right atrioventricular valve.
  • Trabeculae carneae;Correct. Trabeculae carneae are the small elevated ridges of muscle arranged in a web type fashion found in both the right and left ventricles.
  • left ventricle;The left ventricle is responsible for pumping blood out to the body. This requires a lot of force. The left ventricle is the most muscular in order to pump the blood with adequate force
  • electrical activity in the heartYes, the ECG waves show the depolarization and repolarization in various areas of the heart.
  • Tricuspid valveCorrect. The tricuspid valve is the atrioventricular valve located on the right side of the heart. It separates the right atrium from the right ventricle.
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