Ch. 18 The Cardiovascular System: The Heart
The coronary arteries arise from the
aorta
prevents backflow of blood into the left ventricle
aortic semilunar valve
The most muscular chamber of the heart is the
left ventricle
Which of the following would lead to a decrease in heart rate? norepinephrine parasympathetic stimulation sharply decreased blood volume exercise
parasympathetic stimulation
During systemic circulation, blood leaves the
left ventricle and flows directly to the aorta
When the mitral valve closes, it prevents the backflow of blood from the
left ventricle into the left atrium
Guided by powerful signaling molecules, the human heart develops from
mesoderm
valve between the left atrium and left ventricle
mitral (bicuspid) valve
The noncontractile cardiac muscle cells that initiate their own depolarization and cause depolarization of the rest of the heart are called
pacemaker cells
The tricuspid valve is located between the
right atrium and right ventricle
From the perspective of blood returning from the systemic circuit, identify the correct sequence of blood flow through the chambers of the heart: lungs, right ventricle, left ventricle, right atrium, left atrium left ventricle, left atrium, lungs, right ventricle, right atrium left atrium, left ventricle, right ventricle, right atrium, lungs right ventricle, left ventricle, left atrium, lungs, right atrium right atrium, right ventricle, lungs, left atrium, left ventricle
right atrium, right ventricle, lungs, left atrium, left ventricle
supplies blood to the lateral right side of the myocardium
right marginal artery
The role of the atrioventricular node (AV node) is to
slow down impulses so that the atria can contract to fill the adjacent ventricles with blood
The __________ nerve carries parasympathetic fibers to the sinoatrial (SA) node.
vagus
cardiac output = __________ x _________
heart rate x stroke volume
The inferior vena cava brings blood from the lower regions of the body and empties into the
right atrium
An enlarged R wave on an ECG would indicate
an enlarged ventricle
supplies blood to the interventricular septum and anterior walls of both ventricles
anterior interventricular artery
The contractile cardiac muscle fibers of the myocardium behave as a single, coordinated unit called a
functional syncytium
The vessels that carry oxygen to the myocardium are called
coronary arteries
The superior chambers of the heart are called the
atria
relaxation
diastole
The trabeculae carneae are located in the
ventricles
The normal pacemaker of the heart is the
SA node
Choose the correct sequence of electrical current flow through the heart wall. AV node, SA node, subendocardial conducting network, AV bundle, right and left bundle branches subendocardial conducting network, AV node, AV bundle, right and left bundle branches, SA node AV node, subendocardial conducting network, AV node, AV bundle, right and left bundle branches SA node, subendocardial conducting network, AV node, AV bundle, right and left bundle branches SA node, AV node, AV bundle, right and left bundle branches, subendocardial conducting network
SA node, AV node, AV bundle, right and left bundle branches, subendocardial conducting network
Which of the following statements is NOT true about the shape, position, and location of the heart? The heart is located between the two lungs within the mediastinum. Approximately two-thirds of the heart is found to the left of the midline. The heart is enclosed in a double-layered sac called the pleural membrane. The heart is shaped like a cone with the base facing the right shoulder.
The heart is enclosed in a double-layered sac called the pleural membrane.
The P wave of an electrocardiogram represents
atrial depolarization
the events associated with blood flow through the heart during one complete heartbeat
cardiac cycle
An elevated S-T segment on an ECG indicates
cardiac ischemia
the amount of blood pumped by each ventricle in one minute
cardiac output
the amount of blood pumped out of each ventricle in one minute
cardiac output
Which of the following are correctly paired? arrhythmia: atrioventricular (AV) node failure heart block: uncoordinated atrial and ventricular contraction fibrillation: premature contraction ectopic focus: an abnormal pacemaker
ectopic focus: an abnormal pacemaker
The lining of the heart chambers is called the
endocardium
A doctor puts his stethoscope on a patient's chest over the location of the heart and hears an abnormal swishing sound. Which of the following conditions is the best diagnosis for the patient's condition? cardiac tamponade myocardial infarction angina pectoris incompetent cardiac valve
incompetent cardiac valve
The interventricular septum forms a dividing wall between the
left and right ventricles
lines the internal surface of the fibrous pericardium
parietal layer of serous pericardium
The structure just deep to the fibrous pericardium is the
parietal layer of the serous pericardium
runs to the apex of the heart
posterior interventricular artery
prevents backflow of blood into the right ventricle
pulmonary semilunar valve
the volume of blood pumped by one ventricle with each heartbeat
stroke volume
contraction
systole
Which of the following structures is superficial to the heart wall and serves to protect the heart, anchor the heart, and prevent the heart from overfilling? the epicardium the parietal layer of serous pericardium the fibrous pericardium the pericardial sac
the epicardium
Which of the following is NOT a role of the fibrous pericardium? It prevents the heart from overfilling with blood. It facilitates heart contraction. It protects the heart. It anchors the heart to surrounding structures.
It facilitates heart contraction
Which of the following is a difference between cardiac muscle and skeletal muscle? Unlike skeletal muscle cells, cardiac muscle cells do not rely on calcium ions for contraction. Unlike skeletal muscle cells, cardiac muscle cells can be autorhythmic. Unlike skeletal muscle, cardiac muscle is not striated. Unlike skeletal muscle, cardiac muscle does not use a sliding filament mechanism for contraction.
Unlike skeletal muscle cells, cardiac muscle cells can be autorhythmic.
Which of the following factors gives the myocardium its high resistance to fatigue? the presence of intercalated discs a very large number of mitochondria in the cytoplasm the coronary circulation gap junctions
a very large number of mitochondria in the cytoplasm
often muffles cardiac sound so that no heart sounds can be heard
cardiac tamponade
The __________ are attached to the AV valve flaps
chordae tendineae
supplies blood to the left atrium and posterior walls of the left ventricle
circumflex artery
The second heart sound (the "dup" of "lub-dup") is caused by the
closure of the semilunar valves
Which is the correct sequence of layers in the heart wall, starting with the outer layer? epicardium, myocardium, endocardium parietal pericardium, myocardium, endocardium endocardium, smooth muscle, epicardium endocardium, epicardium, myocardium myocardium, pericardium, endocardium
epicardium, myocardium, endocardium
Into which chamber of the heart do the pulmonary veins deliver blood?
left atrium
Freshly oxygenated blood is delivered to the __________, and then it passes into the __________ to be pumped to the body tissues (systemic circuit).
left atrium; left ventricle
During pulmonary circulation, blood leaves the
right ventricle and flows directly to the lungs
The endocardium is composed of
simple squamous epithelium
What part of the heart is considered the systemic circuit pump
the left ventricle
The absolute refractory period refers to the time during which
the muscle cell will not respond to a stimulus of any strength
The cardiac cycle includes all of the following events EXCEPT __________. the changes in pressure gradients in all chambers of the heart the closing and opening of the heart valves during each heartbeat the number of times the heart beats in one minute the movement of impulse from the SA node to all regions of the heart wall the changes in blood volume in all chambers of the heart
the number of times the heart beats in one minute
valve between the right atrium and right ventricle
tricuspid valve
Which valve is most often faulty in the heart?
the mitral, or bicuspid, valve
T/F: In the fetus, blood from the left and right sides of the heart normally mix.
true
