Human A & P Cardiovascular System
Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart? AV node AV bundle (bundle of His) Purkinje fibers SA node
SA node
Which part of the intrinsic conduction system normally initiates the depolarizing impulse that causes a heartbeat? AV nodeI nternodal pathway AV bundle SA node
SA node
which sets the pace for the entire heart Bundle branches AV bundle internodal pathways AV node SA node purkinje fibers
SA node
Which of these structures conduct(s) action potentials the slowest? Bundle branches Purkinje fibers AV node AV bundle
AV node
Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles? AV bundle (bundle of His) SA node bundle branches Purkinje fibers AV node
AV node
Select the correct statement about the heart valves. The mitral (bicuspid) valve separates the right atrium from the right ventricle. The atrioventricular (AV) valves prevent backflow of blood added into the atria during ventricular contraction. Aortic and pulmonary semilunar valves control the flow of blood into the heart. The tricuspid valve divides the left atrium from the left ventricle.
The atrioventricular (AV) valves prevent backflow of blood added into the atria during ventricular contraction.
Which portion of the electrocardiogram represents the time during which the ventricles are in systole? Q-T interval P wave T wave QRS complex
Q-T interval
The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is ________. A) ischemia B) pericarditis C) myocardial infarct D) angina pectoris
angina pectoris
Blood enters the left and right coronary arteries directly from which vessel or chamber? left ventricle circumflex artery pulmonary trunk aorta
aorta
The vessel that carries oxygen-rich blood to tissues is the mitral valve aorta systemic capillaries aortic semilunar valve pulmonary trunk pulmonary semilunar valve tricupsid valve pulmonary capillaries
aorta
Pectinate muscles are found in the ________. atria and ventricles right atrium and right ventricle only ventricles only atria only
atria only
Convey(s) the impulse down the interventricular septum Bundle branches AV bundle internodal pathways AV node SA node purkinje fibers
bundle branches
SA nodes directly trigger atria to contract and activate
cardiac muscle fibers AV nodes, bundles and purkinje fibers
Stroke volume and Heart rate are multiplied which calculates
cardiac output
The condition where fluid compresses the heart and limits its ability to contract is called ________. pericarditis cardiac tamponade myocardial infarction angina pectoris
cardiac tamponade
Auricles slightly increase blood volume in the ventricles. True False
false
Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle. True False
false
Heart tissue is supplied with nutrients primarily by diffusion from the heart chambers through the myocardium. True False
false
The moderator band is found on both the right and left side of the heart. True False
false
What are SA nodes made of
pacemaker cells
The heart is actually (one, two, or three) pumps?
two pumps
fear and anxiety may stretch cardiac muscle which increases
venous return
What does the QRS complex represent in the ECG wave tracing?
ventricular depolarization
semilunar valves are closed
diastole
ventricles are relaxed
diastole
Arrange these elements of the intrinsic conduction system in the order that a depolarizing impulse travels during a normal heartbeat Purkinje fibers, AV bundle, SA node, AV node, bundle branches, internodal pathways
1) SA node 2) Internodal pathways 3) AV node 4) AV bundle 5) Bundle branches 6) Purkinje fibers
How does heart rate affect stroke volume? A low heart rate reduces the end diastolic volume (EDV) and stroke volume (SV), because an inadequate supply of blood is pumped into the ventricles. A high heart rate reduces the end diastolic volume (EDV) and stroke volume (SV), because there is less time for ventricular filling. A high heart rate decreases venous return, which increases end systolic volume (ESV) and stroke volume (SV). A high heart rate increases venous return, which increases end diastolic volume (EDV) and stroke volume (SV).
A high heart rate reduces the end diastolic volume (EDV) and stroke volume (SV), because there is less time for ventricular filling.
What is the ligamentum arteriosum? A remnant of the ductus arteriosus A ligament attaching the aorta to the superior vena cava A remnant of the foramen ovale A ligament securing the aorta
A remnant of the ductus arteriosus
What does the ECG wave tracing represent? A) electrical activity in the heart B) contraction of the heart
A) electrical activity in the heart
Electrical link(s) between atria and ventricles Bundle branches AV bundle internodal pathways AV node SA node purkinje fibers
AV bundle
Delay(s) occurs here while atria contract Bundle branches AV bundle internodal pathways AV node SA node purkinje fibers
AV node
Trace the pathway of stimulation through the heart. Which of these pathways shows stimulation in the correct order? subendocardial conducting network, interventricular septum, AV bundle, AV node AV bundle, subendocardial conducting network, interventricular septum, SA node SA node, interventricular septum, AV node, papillary muscles AV node, AV bundle, interventricular septum, subendocardial conducting network
AV node, AV bundle, interventricular septum, subendocardial conducting network
Identify the ear like flaps that are attached to the top chambers of the heart. Atrium Pectinate muscles Coronary sinus Auricle
Auricle
Select the correct partial path. This path is part of the complete blood flow pathway. Blood moves from the aorta, through smaller systemic arteries, and into systemic capillaries. From there it moves through systemic veins, into the right atrium, and through the tricuspid valve. Blood moves from the pulmonary trunk, through the pulmonary arteries, and into the pulmonary capillaries. From there it moves through the pulmonary veins into the right atrium. Blood moves from the pulmonary artery into the left atrium. From there, it passes through the mitral valve into the left ventricle. Blood from the systemic veins returns to the heart through the left atrium. Blood then passes through the mitral valve.
Blood moves from the aorta, through smaller systemic arteries, and into systemic capillaries. From there it moves through systemic veins, into the right atrium, and through the tricuspid valve.
pace maker cells and cardiac muscle fibers enter the plateau phase due to the influx of
Ca+2 ions
In contrast to a skeletal muscle cell action potential, why does the action potential for a cardiac muscle cell contain a "plateau" phase? Cardiac muscle cells lack the gap junctions found in skeletal muscle tissue, resulting in action potentials that "plateau." Cardiac muscle cells are depolarized by the influx of Ca2+ ions rather than by Na+ ions, and cardiac muscle cells contain few pumps to return Ca2+ ions to the extracellular fluid. Cardiac muscle cells contain slow Ca2+ channels in their sarcolemma that continue to allow influx of Ca2+ ions after Na+ channels are inactivated. Cardiac muscle cells contain slow voltage-gated Na+ channels instead of the typical fast Na+ channels found in skeletal muscle cells.
Cardiac muscle cells contain slow Ca2+ channels in their sarcolemma that continue to allow influx of Ca2+ ions after Na+ channels are inactivated.
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. Cardiac muscle does not use the sliding filament mechanism for contraction; skeletal muscle does. 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.
The base of the heart is located at the bottom of the heart. True or False
False
Why are gap junctions a vital part of the intercellular connection of cardiac muscles? Gap junctions contract when stimulated, strengthening the force of cardiac cell contraction. Gap junctions form strong intercellular connections. Gap junctions allow calcium to enter the cell, triggering calcium release from the SR. Gap junctions allow action potentials to spread to connected cells.
Gap junctions allow action potentials to spread to connected cells.
What is the effect of high blood pressure on cardiac output? High blood pressure increases preload and ventricular filling, thereby increasing cardiac output (CO). High blood pressure occurs only when the cardiac output is already very high. High blood pressure reduces afterload, thereby increasing cardiac output (CO). High blood pressure increases afterload and reduces cardiac output (CO).
High blood pressure increases afterload and reduces cardiac output (CO).
Why does a graph of the membrane potential of living pacemaker cells never demonstrate a flat line? As pacemaker cells hyperpolarize, the excessive influx of K+K+ ions increases the membrane potential. Repolarization of pacemaker cells triggers the opening of fast Ca2+ channels, triggering another rapid depolarization. The vagus nerve continually stimulates the pacemaker cells. Hyperpolarization of pacemaker cells triggers the opening of slow Na+ channels and starts a new slow depolarization phase.
Hyperpolarization of pacemaker cells triggers the opening of slow Na+ channels and starts a new slow depolarization phase.
pace maker cells and cardiac muscle fibers repolarize due to the influx of
K+ ions
Which statement regarding cardiac muscle structure is accurate? Cardiac cells possess fewer mitochondria than other types of muscle cells. Cardiac muscle cells are independent of one another both structurally and functionally. Cardiac cells are long, cylindrical, and multinucleate. Myofibrils of cardiac muscle tissue vary in diameter and branch extensively.
Myofibrils of cardiac muscle tissue vary in diameter and branch extensively.
pace maker cells and cardiac muscle fibers rapid depolarize due to the efflux of
Na + ions
Contraction of the atria results from which wave of depolarization on the ECG tracing?
P wave
Name the ridged bundles of muscle found projecting inside the right atrium. Intercalated discs Pectinate muscles Papillary muscles Trabeculae carneae
Pectinate muscles
What is the function of the coronary circulation? Provide a blood supply to the heart Provide a blood supply to the lungs Provide a blood supply to the aortic arch Provide a blood supply to the pericardium
Provide a blood supply to the heart
What is the role of the atrioventricular bundle? The atrioventricular bundle is what brings parasympathetic signals from the autonomic nervous system to the heart to regulate heart rate and contractility. The atrioventricular bundle provides the only pathway for electrical signals to pass from the atria to the ventricles. The atrioventricular bundle is the only structure that allows blood to pass from the atria to the ventricles. The atrioventricular bundle is responsible for initiating the heartbeat and setting the sinus rhythm.
The atrioventricular bundle provides the only pathway for electrical signals to pass from the atria to the ventricles.
Select the correct statement about the function of myocardial cells. Cardiac muscle cells are innervated by sympathetic, parasympathetic, and somatic nerve fibers so that the nervous system can increase heart rate. The entire heart contracts as a unit or it does not contract at all. The influx of potassium ions from extracellular sources is the initiating event in cardiac muscle contraction. The refractory period in skeletal muscle is much longer than that in cardiac muscle.
The entire heart contracts as a unit or it does not contract at all.
Now that you have reviewed normal blood flow, why does a patient with left-sided heart failure have a low systolic blood pressure? The left side of the heart receives blood from the body, so when it fails, blood will build up in the blood vessels. The left side of the heart does not directly move blood into the body, but when it fails, the right side will also fail, and that will decrease blood pressure out in the body. The left side of the heart pumps blood into the body, so when it fails, less blood will be pumped into the arteries. The left side of the heart contains the ventricles, so it controls blood pressure.
The left side of the heart pumps blood into the body, so when it fails, less blood will be pumped into the arteries.
Mr. G talks in short bursts with frequent breaths. He tells you he used to feel breathless when he was walking, but now he has been having more and more trouble breathing even when he is lying down at night.When you listened to his lungs you heard fluid in them. Could this be due to his heart failure, or is it another problem? The left side of the heart does not have anything to do with the lungs, but if it fails, the right side is going to fail too, and then circulation through the lungs will decrease. If the left side of the heart fails, it will not pump enough blood to the body, and that means less blood will reach the right side of the heart and be sent to the lungs. The left side of the heart receives blood from the lungs and pumps it out to the body, so if it fails, blood will remain in the lungs. The left side of the heart pumps blood to the lungs, so if it fails, circulation in the lungs will decrease. The left side of the heart receives blood from the lungs and pumps it out to the body, so if it fails, blood will remain in the lungs.
The left side of the heart receives blood from the lungs and pumps it out to the body, so if it fails, blood will remain in the lungs.
Select the correct statement about the structure of the heart wall. The fibrous cardiac skeleton forms the bulk of the heart. The myocardium is the layer of the heart that actually contracts. Connective tissue in the heart wall aids in the conduction of the action potential. The heart chambers are lined by the endomysium.
The myocardium is the layer of the heart that actually contracts.
Which statement best describes the autonomic nervous system's role in regulating heart rate? The parasympathetic division does not innervate the heart at all, and the sympathetic division innervates it only slightly. The parasympathetic division normally inhibits the heart, keeping it beating at a slower rate than it would be on its own. The sympathetic division continually stimulates the heart to keep it from slowing to an inadequate rate for oxygenating the body. The parasympathetic division increases the heart rate during strenuous exercise or conditions of fright or anxiety.
The parasympathetic division normally inhibits the heart, keeping it beating at a slower rate than it would be on its own.
Which description of the heart or its coverings is INCORRECT? The endocardium lines the inside of the heart. The parietal layer of the serous pericardium is also known as the epicardium of the heart wall. The parietal pericardium lines the internal (deep) surface of the fibrous pericardium. The fibrous pericardium prevents overfilling of the ventricles.
The parietal layer of the serous pericardium is also known as the epicardium of the heart wall.
Which statement is correct regarding the ventricles? The right ventricle forms a complete circle in cross section. The left ventricle has a thinner wall than the right ventricle. The right ventricle empties into the pulmonary trunk. The left ventricle empties into the pulmonary circuit.
The right ventricle empties into the pulmonary trunk.
The first branch off the arch of the aorta is the brachiocephalic artery in both the sheep and the human. True or False
True
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 the atria. b.) Yes, because the ventricles will depolarize on their own without nodal stimulation at a rate of 50 times per minute. c.) No, because there would be no more connection between the atrioventricular node and the bundle branches. d.) Yes, because the atrioventricular node will still stimulate ventricular systole.
Yes, because the atrioventricular node will still stimulate ventricular systole.
Which coronary artery is most responsible for supplying blood to the myocardial tissue of the left atrium? right marginal artery circumflex artery posterior interventricular artery anterior interventricular artery
circumflex artery
Which vessel carries blood from the anterior surface of the left ventricle to its posterior surface? left coronary artery marginal artery circumflex artery posterior interventricular artery
circumflex artery
The foramen ovale ________. connected the two atria in the fetal heart is a connection between the pulmonary trunk and the aorta in the fetus is a condition in which the heart valves do not completely close is a shallow depression in the interventricular septum
connects the two atria in the fetal heart
fear and anxiety sends impulses that directly increase
contracility and heart rate
The source of blood carried to capillaries in the myocardium would be the ________. A) coronary sinus B) fossa ovalis C) coronary arteries D) coronary veins
coronary arteries
carries oxygen-poor venous blood of the coronary circulation into the right atrium. Pulmonary veins superior vena cava inferior vena cava pulmonary trunk aorta coronary sinus
coronary sinus
If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________. decreased delivery of oxygen a lack of nutrients to feed into metabolic pathways a decrease in the number of available mitochondria for energy production an inadequate supply of lactic acid
decreased delivery of oxygen
AV valves are open
diastole
blood is entering the heart
diastole
blood is flowing through the AV valves
diastole
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 atrioventricular (AV) valve flaps. True False
false
The right side of the heart is considered the systemic circuit pump. True false
false
Which of the following descriptions does not describe atrioventricular (AV) valves? anchored inferiorly by specialized connective tissue open based on pressure changes in the atria versus the ventricles formed from pocket-like cusps flap-like
formed from pocket-like cusps
Which is most responsible for the synchronized contraction of cardiac muscle tissue? desmosomes small motor units branching cells gap junctions
gap junctions
Compared to skeletal muscle, cardiac muscle ________. has more nuclei per cell has gap junctions that allow it to act as a functional syncytium lacks striations cells are larger than skeletal muscle cells
has gap junctions that allow it to act as a functional syncytium
Which of the following is an effect of epinephrine, norepinephrine, and thyroxine? increase contractility decrease cardiac output increase end systolic volume decrease heart rate
increase contractility
carries oxygen-poor venous blood from below the diaphragm from the areas of the lower body and extremities into the right atrium Pulmonary veins superior vena cava inferior vena cava pulmonary trunk aorta coronary sinus
inferior vena cava
What structures connect the individual heart muscle cells?' chordae tendineae anastomoses trabaculae carneae intercalated discs
intercalated discs
Link(s) between the SA node and AV node Bundle branches AV bundle internodal pathways AV node SA node purkinje fibers
internodal pathways
The parietal pericardium ________. lines the internal surface of the fibrous pericardium is also called the epicardium is separated from the fibrous pericardium by serous fluid is found within the pericardial cavity
lines the internal surface of the fibrous pericardium
Which of the following is a branch of the right coronary artery? anterior interventricular artery circumflex artery coronary sinus posterior interventricular artery
posterior interventricular artery
The left ventricular wall of the heart is thicker than the right wall in order to ________. pump blood through a smaller valve pump blood with greater pressure expand the thoracic cage during diastole accommodate a greater volume of blood
pump blood with greater pressure
The fact that the left ventricle of the heart is thicker than the right ventricle reveals that it ________. A) pumps a greater volume of blood B) pumps blood against a greater resistance C) expands the thoracic cage D) sends blood through a smaller valve
pumps blood against a greater resistance
Convey(s) the impulse throughout the ventricular walls Bundle branches AV bundle internodal pathways AV node SA node purkinje fibers
purkinje fibers
A blockage in which of these vessels would most likely cause a myocardial infarction in the lateral right side of the heart? circumflex artery posterior interventricular artery anterior interventricular artery right marginal artery
right marginal artery
Which chamber of the heart exits into the pulmonary trunk?
right ventricle
Specifically, what part of the intrinsic conduction system stimulates the atrioventricular (AV) node to conduct impulses to the atrioventricular bundle? a.) subendocardial conducting network (Purkinje fibers) b.) sinoatrial (SA) node c.) bundle branches d.) interventricular septum
sinoatrial (SA) node
The anatomy of the intrinsic conduction system causes contraction of the ventricles to begin at the apex and move superiorly. Why is this important? because the AV bundle is the only electrical connection between the atria and the ventricles so the atria can finish contracting before the ventricles contract because the Purkinje fibers conduct action potentials away from the heart apex so blood is forced upward, toward the semilunar valves
so blood is forced upward, toward the semilunar valves
Consider the following characteristics of the cells found in muscle tissue. Which feature is shared by both cardiac muscle and skeletal muscle? striations intercalated discs triads branched cells
striations
When venous return is increased, the EDV increases
stroke volume
when contractility is high, ESV is reduces which increases
stroke volume
The _______ carries oxygen-poor venous blood from above the diaphragm from areas of the upper body and extremities into the right atrium. Pulmonary veins superior vena cava inferior vena cava pulmonary trunk aorta coronary sinus
superior vena cava
The capillaries receiving blood flow from the left side of the heart are the mitral valve aorta systemic capillaries aortic semilunar valve pulmonary trunk pulmonary semilunar valve tricupsid valve pulmonary capillaries
systemic capillaries
AV valves are closed
systole
blood is flowing through semilunar valves
systole
blood is leaving heart
systole
semilunar valves are open
systole
ventricles are contracting
systole
What structure in the intrinsic cardiac conduction system determines heart rate? the vagus nerve the cardiac nerve the sinoatrial (SA) node the atrioventricular (AV) node
the sinoatrial (SA) node
If the aorta and pulmonary trunk were switched, oxygen rich blood would be pumped from the left ventricle to the lungs. True False
true
The left side of the heart pumps the same volume of blood as the right. True False
true
The myocardium receives its blood supply from the coronary arteries. True False
true
Tissues damaged by myocardial infarction are replaced by fibrous connective tissue. True False
true