Mastering A&P Chapter 18 Heart

Which of these structures conduct(s) action potentials the slowest? A. AV node B. Purkinje fibers C. AV bundle D. Bundle branches

A. AV node Action potentials slow down as they pass through the AV node. This gives the atria time to finish contracting before the ventricles are depolarized.

Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles? A. AV node B. AV bundle (bundle of His) C. bundle branches D. Purkinjie fibers E. SA node

A. AV node Yes, the AV node slows down the impulse giving the atria time to contract before the ventricles contract.

Increased pressure in the ventricles would close what valve(s)? A. AV valves only B. semilunar valves only C. both semilunar and AV valves

A. AV valves only Yes, increased pressure in the ventricles would close the AV valves.

What heart chamber pushes blood through the aortic semilunar valve? A. Left ventricle B. Left atrium C. Right atrium D. Right ventricle

A. 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 relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________. A. ventricular diastole B. ventricular systole

A. ventricular diastole Yes, both occur during ventricular diastole when the ventricles are not actively contracting and ejecting blood.

Repolarization of an autorhythmic cell is due to the opening of which channels? A. voltage-gated potassium channels B. chemically gated calcium channels C. Chemically gated potassium channels D. voltage-gated sodium channels

A. voltage-gated potassium channels Yes, 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.

Calculate the stroke volume if the end diastolic volume (EDV) is 135 mL and the end systolic volume (ESV) is 60 mL. A. 60 mL B. 75 mL C. 205 mL D. 8100 mL

B. 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.

What fibrous structure functions to anchor the atrioventricular valves in a closed position? A. Trabeculae carneae B. Chordae tendineae C. Moderator band D. Papillary muscle

B. Chordae tendineae Chordae tendineae are the fibrous cords that attach the atrioventricular valves to papillary muscles. They help anchor the atrioventricular valves in a closed position during ventricular contraction.

Name the inner lining of the heart. A. Pericardium B. Endocardium C. Myocardium D. Epicardium

B. 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.

Which of the following is correct about the filling of the ventricles? A. The majority of ventricular filling is caused by contraction of the atria. B. Most blood flows passively into the ventricles through open AV valves.

B. 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.

Contraction of the atria results from which wave of depolarization on the ECG tracing? A. T wave B. P wave C. QRS comples

B. P wave Yes, the P wave represents atrial depolarization, which leads to atrial contraction.

Name the ridged bundles of muscle found projecting inside the right atrium. A. Intercalated discs B. Pectinate muscles C. Papillary muscles D. Trabeculae cameae

B. Pectinate muscles 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.

Describe the pressures in the atria and ventricles that would cause the opening of the AV valves. A. Pressures in the atria and ventricles would be equal. B. Pressure in the atria would be greater than the pressure in the ventricles. C. Pressure in the ventricles would be greater than in the atria.

B. 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.

Which portion of the electrocardiogram represents the time during which the ventricles are in systole? A. T wave B. Q-T interval C. P wave D. QRS complex

B. Q-T interval The Q-T interval is the period from the beginning of ventricular depolarization through ventricular repolarization, during which the ventricles are in systole.

Identify the ear like flaps that are attached to the top chambers of the heart. A. Coronary sinus B. Pectinate muscles C. Auricle D. Atrium

C. Auricle The auricles are flap like extensions of the atria that are observed on the external surface of the heart.

Identify the most muscular chamber. A. Right ventricle B. Right atrium C. Left ventricle D. Left atrium

C. Left ventricle the left ventricle is responsible for pumping blood out of the body. This requires a lot of force. The left ventricle is the most muscular in order to pump the blood with adequate force.

Identify the right atrioventricular valve. A. Aortic semilunar valve B. Bicuspid valve C. Tricuspid valve D. Pulmonary valve

C. Tricuspid valve The tricuspid valve is the atrioventricular valve located on the right side of the heart. It separates the right atrium from the right ventricle.

The moderator band is found on both the right and left side of the heart. False True

False The moderator band is a cord like structure found in the right ventricle. It contains portions of the cardiac conduction system that help convey the electrical message for the ventricles to contract. It works as a shortcut within the cardiac conduction system.

Oxygenated blood flows through the right side of the heart. False True

False Oxygenated blood returning from the lungs is received by the left atrium, then to the left ventricle before being pumped out to the body. This pathway of blood flow is known as the systemic circulation.

The base of the heart is located at the bottom of the heart. False True

False The base is located at the top of the heart. It is unusual to see the largest portion of an organ at the top. Typically, the base is at the bottom of an organ, as in the lungs.

What is the ligamentum arteriosum? A. A remnant of the ductus arteriosus B. A ligament attaching the aorta to the superior vena cava C. A remnant of the foramen ovale D. A ligament securing the aorta

A. 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.

Which portion of the electrocardiogram represents the depolarization wave received by the atria from the sinoatrial (SA) node? A. P wave B. T wave C. S-T segment D. QRS complex

A. P wave The P wave represents the depolarization of the left and right atria and the beginning of atrial systole.

What causes the abnormal swishing or whooshing sound that is heard as blood regurgitates back into an atrium from its associated ventricle? A. blood turbulence B. aortic recoil C. semilunar valve closure D. pulmonary trunk expansion

A. blood turbulence

Which of the following would increase cardiac output? A. epinephrine B. high blood pressure C. parasympathetic stimulation D. decreased calcium during contraction

A. epinephrine Sympathetic 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 of the following is NOT a factor that increases stroke volume? A. increasing afterload B. increasing contractility C. increasing sympathetic stimulation D. increasing preload

A. increasing afterload Increasing afterload decreases stroke volume.

What separates the parietal and visceral pericardium? A. pericardial cavity B. myocardium C. epicardium D. fibrous pericardium

A. pericardial cavity The pericardial cavity separates the parietal and visceral pericardium. This cavity contains serous fluid that lubricates the visceral and parietal membranes.

In order to cause cardiac muscle contraction, the contractile cells must also depolarize. What causes the depolarization of the contractile cells? A. the flow of positive ions from adjacent cells B. the flow of negative ions from adjacent cells C. an unstable resting membrane potential in the contractile cells

A. the flow of positive ions from adjacent cells Yes, the flow of positive ions from the autorhythmic cells (or adjacent cells) brings the membrane to threshold initiating depolarization of the contractile cell.

Name the irregular ridges of muscle lining the ventricles. A. Pectinate muscles B. Trabeculae carnae C. Papillary muscles D. Chardae tendineae

B. Trabeculae carnae Trabeculae carneae are the small elevated ridges of muscle arranged in a web type fashion found in both the right and left ventricles.

What does the ECG wave tracing represent? A. contraction of the heart B. electrical activity in the heart

B. electrical activity in the heart Yes, the ECG waves show the depolarization and repolarization in various areas of the heart.

When threshold is reached at the SA node (an autorhythmic cell), what channels open causing further depolarization of the membrane? A. potassium B. fast calcium C. fast sodium D. slow calcium

B. fast calcium Yes, 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 structures connect the individual heart muscle cells? A. trabaculae carneae B. intercalated discs C. anastomoses D. chordae tendineae

B. intercalated discs Intercalated discs connect the heart muscle cells. They include desmosomes (anchoring junctions) and gap junctions (communicating junctions).

Which of the following does NOT deliver deoxygenated blood to the heart? A. coronary sinus B. pulmonary veins C. inferior vena cava D. superior vena cava

B. pulmonary veins The pulmonary veins deliver oxygenated blood to the left atrium.

Identify the valve found between the left atrium and the left ventricle. A. Tricuspid valve B. Pulmonary valve C. Bicuspid (mitral) valve D. Aortic valve

C. Bicuspid (mitral) valve The atrioventricular valve on the left is the bicuspid valve. The bicuspid valve is also called the mitral valve.

Which part of the conduction system initiates the depolarization impulse, which spreads throughout the heart? A. Purkinjie fibers B. AV bundle (bundle of His) C. SA node D. AV node

C. SA node Yes, the SA Node spontaneously depolarizes, causing the wave of depolarization that spreads through the rest of the conduction system and heart.

Blood enters the left and right coronary arteries directly from which vessel or chamber? A. left ventricle B. circumflex artery C. aorta D. pulmonary trunk

C. aorta Blood flows to the right and left coronary arteries directly from the aorta.

Which of these vessels returns blood to the left atrium of the heart? A. coronary sinus B. superior vena cava C. pulmonary veins D. pulmonary trunk

C. pulmonary veins The pulmonary veins transport oxygen-enriched blood from the lungs to the left atrium.

Specifically, what part of the intrinsic conduction system generates the original stimulus that reaches the atrioventricular (AV) node, allowing it to conduct impulses to the atrioventricular bundle? A. subendoardial conducting network (Purkinje fibers) B. bundle branches C. sinoatrial (SA) node D. interventricular septum

C. sinoatrial (SA) node The sinoatrial node, by spontaneously depolarizing faster than the atrioventricular node, initiates heart contraction.

The _____ valve is located between the right atrium and the right ventricle. A. mitral B. pulmonary semilunar C. tricuspid D. aortic semilunar

C. tricuspid The tricuspid valve is located between the right atrium and right ventricle.

Superior Vena Cava

Carries oxygen-poor venous blood from above the diaphragm from areas of the upper body and extremities into the right atrium.

Inferior Vena Cava

Carries oxygen-poor venous blood from below the diaphragm from the areas of the lower body and extremities into the right atrium.

Coronary Sinus

Carries oxygen-poor venous blood of the coronary circulation into the right atrium.

Bundle branches

Convey(s) the impulse down the interventricular septum

Purkinje fibers

Convey(s) the impulse throughout the ventricular walls

What is the function of the coronary system? A. Provide a blood supply to the pericardium B. Provide a blood supply to the aortic arch C. Provide a blood supply to the lungs D. Provide a blood supply to the heart

D. Provide a blood supply to the heart The coronary circulation provides oxygenated blood to the heart through coronary arteries. Coronary veins return the deoxygenated from the heart to 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 directly from the body.

Which of the following is the innermost layer of the heart? A. visceral layer B. epicardium C. parietal layer D. endocardium

D. endocardium The endocardium lines the inside of the heart. Its surface is composed of simple squamous epithelium.

Which heart chamber receives blood from the pulmonary veins? A. right atrium B. left ventricle C. right ventricle D. left atrium

D. left atrium The left atrium receives oxygenated blood from the pulmonary veins.

The right atrioventricular valve prevents backflow of blood from the right ventricle into the __________. A. left atrium B. left ventricle C. pulmonary trunk D. right atrium

D. right atrium Flow from the right ventricle to the right atrium is prevented by the right atrioventricular valve.

What does the QRS complex represent in the ECG wave tracing? A. atrial repolarization B. atrial depolarization C. ventricular repolarization D. ventricular depolarization

D. ventricular depolarization Yes, the QRS complex represents depolarization in the ventricles, which have greater mass than the atria.

AV node

Delay(s) occurs here while atria contract

AV bundle

Electrical link(s) between atria and ventricles

SA node

Set(s) the pace for the entire heart

Systemic Capillaries

The capillaries receiving blood flow from the left side of the heart.

Aorta

The vessel that carries oxygen-rich blood to tissues.

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? A. potassium B. sodium C. calcium

A. Potassium Yes, 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.

Identify the valve located at the exit of the right ventricle. A. Pulmonary semilunar valve B. Tricuspid valve C. Bicuspid valve D. Aortic semilunar valve

A. Pulmonary semilunar valve The pulmonary semilunar 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.

A person notices his or her heart beat because he or she senses blood being pumped by the heart. Excessive caffeine intake can lead to irregular heart rhythms (arrhythmias) that patients perceive as "skipped beats." Given that caffeine is a stimulant, which of the following mechanisms best explains the reason for the feeling that the heart skipped a beat? A. Action potentials are not delayed sufficiently at the AV node. B. Purkinje fibers initiate spontaneous action potentials, which cause the ventricles to contract early. C. Spontaneous action potentials in the SA node overlap such that the repolarizing phase of one action potential cancels out the depolarizing phase of the next. D. Action potentials propagate into the ventricles before the contractile cells have repolarized from the previous heartbeat.

A. Purkinje fibers initiate spontaneous action potentials, which cause the ventricles to contract early. Action potentials normally originate in the SA node because the pacemaker cells there depolarize faster than pacemaker cells located elsewhere in the heart. However, certain drugs, such as caffeine, nicotine, or cocaine, can stimulate other pacemaker cells to speed up and temporarily "escape" the SA node rhythm. If this ectopic focus consists of Purkinje fibers then ventricular contraction will occur prematurely, prior to ventricular filling. Without proper filling, this abnormal contraction pumps little blood and is not sensed. However, the following normal beat generated from the SA node has augmented filling and is sensed, resulting in the missed beat sensation.

Which statement is correct regarding the ventricles? A. The right ventricle empties into the pulmonary trunk.. B. The left ventricle empties into the pulmonary circuit. C. The left ventricle has a thinner wall than the right ventricle. D. The right ventricle forms a complete circle in cross section.

A. The right ventricle empties into the pulmonary trunk. The right ventricle empties into the pulmonary trunk and the pulmonary circuit.

What is happening during the "pause" phase when the heart is resting (relaxing)? A. Ventricles are filling. B. Valves are closing. C. Ventricles are contracting. D. Atria are contracting.

A. Ventricles are filling.

Which layer of the heart wall contracts and is composed primarily of cardiac muscle tissue? A. myocardium B. endocardium C. epicardium D. visceral layer of the serous pericardium

A. myocardium The myocardium is composed of cardiac muscle and a dense network of connective tissue.

Into which chamber of the heart do the superior vena cava, inferior vena cava, and coronary sinus return deoxygenated blood? A. right atrium B. left ventricle C. right ventricle D. left atrium

A. right atrium All of these vessels deliver blood to the right atrium.

Which chamber receives blood from the superior and inferior vena cavae? A. right atrium B. left atrium C. left ventricle D. right ventricle

A. right atrium The right atrium receives unoxygenated blood from the systemic circuit.

Which heart chamber pumps unoxygenated blood out the pulmonary trunk? A. right ventricle B. right atrium C. left ventricle D. left atrium

A. right ventricle The right ventricle pumps unoxygenated blood out the pulmonary trunk to the lungs.

What does the QRS wave of the electrocardiogram (ECG) represent? A. ventricular depolarization B. atrial repolarization C. atrial depolarization D. ventricular repolarization

A. ventricular depolarization Ventricular depolarization is represented by the QRS complex of an ECG.

Put the phases of the cardiac cycle in the correct order, starting after ventricular filling. A. ventricular ejection, ventricular relaxation, isovolumetric contraction B. isovolumetric contraction, ventricular ejection, isovolumetric relaxation C. ventricular ejection, isovolumetric contraction, isovolumetric relaxtion D. isovolumetric relaxation, ventricular ejection, isovolumetric contraction

B. isovolumetric contraction, ventricular ejection, isovolumetric relaxation Yes, the ventricles must contract and eject blood before they relax and fill again.

Which heart chamber receives oxygenated blood from the lungs? A. right ventricle B. left atrium C. left ventricle D. right atrium

B. left atrium Oxygenated blood from the lungs returns to the left atrium of the heart.

Which of these muscles is particularly associated with anchoring the right and left atrioventricular valves? A. trabeculae carneae B. papillary muscles C. pectinate muscles D. myocardium

B. papillary muscles Papillary muscles contract to tense the right and left atrioventricular valves via the chordae tendineae just before ventricular systole.

Cadiac tamponade results in ineffective pumping of blood by the heart because the excessive amount of fluid in the pericardial cavity will __________. A. prevent the visceral layer of the serous pericardium from properly surrounding the heart B. prevent the heart from filling properly with blood C. prevent proper oxygenation of the blood D. interfere with the ability of this fluid to lubricate the serous membranes

B. prevent the heart from filling properly with blood The heart is wrapped by a double-walled sac called the pericardium. The pericardial cavity lies between the parietal and visceral layers of the serous pericardium. It is filled with a very small amount of serous fluid. If additional fluid fills the pericardial space, it adds pressure on the outside of the heart, preventing it from filling normally.

Besides cardiac muscle, what other tissue type possesses pacemaker cells? A. nervous tissue B. smooth muscle C. skeletal muscle D. connective tissue

B. smooth muscle

The anatomy of the intrinsic conduction system causes contraction of the ventricles to begin at the apex and move superiorly. Why is this important? A. so the atria can finish contracting before the ventricles contract B. so blood is forced upward, toward the semilunar valves C. because the AV bundle is the only electrical connection between the atria and the ventricles D. because the Purkinje fibers conduct action potentials away from the heart apex

B. so blood is forced upward, toward the semilunar valves Beginning contraction at the apex causes blood to be forced upward, through the semilunar valves, and into the aorta and pulmonary trunk. This makes ventricular ejection more efficient, much like squeezing a tube of toothpaste up from the bottom is more efficient at dispensing the toothpaste than is squeezing from the top.

Suppose a patient develops a myocardial infarction that disables the sinoatrial node. Would the heart still pump blood to the aorta and the pulmonary trunk? A. No, because there will be no contraction of atria. B. Yes, because the ventricles will depolarize on their own at a rate of 50 times per minute. C. Yes, because the atrioventricular node will still stimulate ventricular systole. D. No, because there would be no more connection between the atrioventricular node and the bundle branches.

C. Yes, because the atrioventricular node will still stimulate ventricular systole. The atrioventricular node spontaneously depolarizes similarly to the sinoatrial node, but more slowly. It can lead to the ventricles pumping blood to the aorta and pulmonary trunk around 50 times per minute.

Which blood vessel carries blood from the anterior to the posterior of the heart? A. posterior interventricular artery B. left coronary artery C. circumflex artery D. marginal artery

C. circumflex artery The circumflex artery is a branch of the left coronary artery that carries blood towards the back of the heart.

Action potentials generated by the autorhythmic cells spread to the contractile cells through what structures in the mebrane? A. desmosomes B. tight junctions C. gap junctions D. intercalated discs

C. gap junctions Yes, 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.

What causes the aortic semilunar valve to close? A. higher ventricular pressure than aortic pressure B. equal ventricular and aortic pressures C. greater pressure in the aorta than in the left ventricle

C. greater pressure in the aorta than in the left ventricle Yes, backflow of blood in the aorta (towards the left ventricle) closes the aortic semilunar valve.

Failure in a particular chamber of the heart tends to cause a backup of blood in the lungs, known as pulmonary congestive heart failure. Failure of which chamber of the heart would lead to such a backup? A. right ventricle B. right atrium C. left ventricle D. left atrium

C. left ventricle Failure in the left ventricle can cause increased blood hydrostatic pressure in the lungs, causing fluid buildup in the alveoli.

Which chamber of the heart has the highest probability of being the site of a myocardial infarction? A. left atrium B. right atrium C. left ventricle D. right ventricle

C. left ventricle The left ventricle has to pump blood around the entire body and overcome the largest pressures (120/80 mm Hg). This is the largest chamber in the heart and has the most muscle around it compared to the other chambers.

Which chamber pumps oxygenated blood out the aorta to the systemic circuit? A. right atrium B. left atrium C. left ventricle D. right ventricle

C. left ventricle The left ventricle pumps oxygenated blood out the aorta to the entire body (systemic circuit).

Which chamber of the heart sends oxygenated blood to the systemic circuit via the aorta? A. left atrium B. right ventricle C. left ventricle D. right atrium

C. left ventricle The left ventricle sends blood to the systemic circuit via the aorta and its branches.

Which of the following is a branch of the right coronary artery? A. anterior interventricular artery B. circumflex artery C. posterior interventricular artery D. coronary sinus

C. posterior interventricular artery The posterior interventricular artery is a branch of the right coronary artery, although an anastomosis with the circumflex artery meets with it near its origin.

Which valve is located between the right atrium and ventricle? A. bicuspid valve B. pulmonary semilunar valve C. tricuspid valve D. mitral valve

C. tricuspid valve The tricuspid valve separates the right atrium and ventricle.

At what rate does the sinoatrial (SA) node depolarize? A. 30 times per minute B. 40 times per minute C. 50 times per minute D. 75 times per minute

D. 75 times per minute The sinoatrial node typically depolarizes spontaneously about 75 times per minute, although this can vary in different individuals. This rate is directly modulated by the autonomic nervous system.

Which statement regarding cardiac muscle structure is accurate? A. Cardiac cells possess few mitochondria. B. Cardiac muscle cells are independent of one another both structurally and functionally. C. Cardiac cells are long, cylindrical, and multinucleate. D. Myofibrils of cardiac muscle tissue vary in diameter and branch extensively.

D. 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.

Which chamber of the heart exists into the pulmonary trunk? A. Left ventricle B. Left atrium C. Right atrium D. Right ventricle

D. Right Ventricle The right ventricle pumps deoxygenated blood through the pulmonary semilunar valve into the pulmonary trunk to be distributed to the lungs.

Which part of the intrinsic conduction system normally initiates the depolarizing impulse that causes a heartbeat? A. AV node B. Internodal pathway C. AV bundle D. SA node

D. SA node Like the rest of the intrinsic conduction system, the SA node contains pacemaker cells that spontaneously depolarize. The cells within the SA node, however, depolarize faster than the other cells within the system. This causes action potentials to initiate in the SA node rather than in any of the other structures.

Select the correct partial path. This path is part of the complete blood flow pathway. You should be able to trace flow starting in any location. A. pulmonary artery into left atrium through mitral valve to left ventricle B. systemic veins returning to the left atrium and forward through the mitral valve C. pulmonary trunk to pulmonary arteries to pulmonary capillaries to pulmonary veins returning to the right atrium D. aorta to smaller systemic arteries to systemic capillaries to systemic veins to right atrium, and then through the tricuspid valve

D. aorta to smaller systemic arteries to systemic capillaries to systemic veins to right atrium, and then through the tricuspid valve All systemic veins return oxygen-poor venous flow to the right atrium, through the tricuspid to the right ventricle, and up and out the pulmonary semilunar valve to the pulmonary trunk and pulmonary arteries to the capillaries of the lungs. Returning oxygen-rich blood flowing through pulmonary veins enters the left atrium, passes through the mitral valve to the left ventricle, and flows out through the aortic semilunar valve into the aorta and on to systemic capillaries.

A blockage in which of these vessels could cause a myocardial infarction in the lateral right side of the heart? A. anterior interventricular artery B. posterior interventricular artery C. circumflex artery D. right marginal artery

D. right marginal artery The right marginal artery branches from the right coronary artery to nourish the lateral areas of the right ventricle. A blockage in this vessel could damage this area.

The right side of the heart is considered the systemic circuit pump. True False

False The right side of the heart pumps oxygen-poor blood to the lungs to be re-oxygenated. For this reason, the right side of the heart is considered the pulmonary circuit pump. The left side of the heart pumps blood to the body, and is therefore considered the systemic circuit pump.

The role of the chordae tendineae is to open the AV valves at the appropriate time. True False

False The role of the chordae tendineae is to anchor the AV valves against the large pressure changes that occur as the ventricles contract.

Arrange these elements of the intrinsic conduction system in the order that a depolarizing impulse travels during a normal heartbeat. AV node Internodal pathways AV bundle Bundle branches SA node Purkinje fibers

SA node, Internodal pathways, AV node, AV bundle, Bundle branches, Purkinje fibers

Aortic Semilunar Valve

The structure that is located anatomically between the aorta and the left ventricle.

Mitral (bicuspid) Valve

The structure that prevents backflow of blood into the left atrium.

The first branch off the arch of the aorta is the brachiocephalic artery in both the sheep and the human. True False

True In both the sheep and human, the brachiocephalic artery is the first major vessel to exit the arch of the aorta. Further branching of the brachiocephalic artery and the arch of the aorta differs between a sheep and a human.

Blood on the right never mixes with blood on the left, once the heart is fully developed. True False

True Once fetal modifications (i.e. foramen ovale, ductus arteriosus) close following delivery of the infant, blood on the right side of the heart should not mix with blood on the left side of the heart.

The heart is actually (one, two, or three) pumps?

Two pumps. The right side of the heart pumps to/from the lungs (pulmonary circuit) and the left side of the heart pumps to/from the rest of the body (the systemic circuit)