Chapter 18: The Cardiovascular System: The Heart
The __________ nerve carries parasympathetic fibers to the sinoatrial (SA) node.
vagus.
Choose the correct sequence of current flow through the heart wall.
SA node, AV node, AV bundle, right and left bundle branches, Purkinje fibers.
The normal pacemaker of the heart is the __________.
SA node.
Which of the following statements is NOT true about the shape, position, and location of the heart?
The heart is enclosed in a double-layered sac called the pleural membrane.
Which of the following factors gives the myocardium its high resistance to fatigue?
a very large number of mitochondria in the cytoplasm.
An enlarged R wave on an ECG would indicate __________.
an enlarged ventricle.
The coronary arteries arise from the __________.
aorta.
The ability of some cardiac muscle cells to initiate their own depolarization and cause depolarization of the rest of the heart is called __________.
automaticity.
The __________ are attached to the AV valve flaps.
chordae tendineae
The vessels that carry oxygen to the myocardium are called __________.
coronary arteries.
Which is the correct sequence of layers in the heart wall, starting with the outer layer?
epicardium, myocardium, endocardium.
The cells of the myocardium behave as a single, coordinated unit called a __________.
functional syncytium.
A doctor puts his stethoscope on a patient's chest over the location of the heart and hears a swishing sound. Which of the following conditions is the best diagnosis for the patient's condition?
incompetent cardiac valve.
The interventricular septum forms a dividing wall between the __________.
left and right ventricles.
During systemic circulation, blood leaves the __________.
left ventricle and goes 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.
The inner lining of the fibrous pericardium is formed by the __________.
parietal layer of serous pericardium.
The tricuspid valve is located between the __________.
right atrium and right ventricle.
Identify the correct sequence of blood flow through the chambers of the heart.
right atrium, right ventricle, lungs, left atrium, left ventricle.
The inferior vena cava brings blood from the lower regions of the body and empties into the __________.
right atrium.
During pulmonary circulation, blood leaves the __________.
right ventricle and moves to the lungs.
The endocardium is composed of __________.
simple squamous epithelium.
Cardiac output is __________.
the amount of blood pumped out of each ventricle in one minute. cardiac output = heart rate × stroke volume.
Which of the following structures lies on the outside surface of the heart and is an integral part of the cardiac wall?
the epicardium.
What part of the heart is considered the systemic circuit pump?
the left ventricle.
Which of the following valves is most often faulty in the heart?
the mitral, or bicuspid, valve.
The absolute refractory period refers to the time during which __________.
the muscle cell is not in a position to respond to a stimulus of any strength.
The cardiac cycle includes all of the following events EXCEPT __________.
the number of times the heart beats in one minute.
The trabeculae carneae are located in the __________.
ventricles.
