What ensures the unidirectional flow of blood through both the heart and the blood vessels?
C) valves within the heart that prevent backflow of blood
The ____________ carries blood throughout the body; the ____________ carries blood only to and from the lungs.
D) systemic circuit; pulmonary circuit
What are the three layers of the heart wall, in order from external to internal?
B) epicardium, myocardium, endocardium
The epicardium is also called the
B) visceral layer of the serous pericardium
The myocardium is composed of
B) cardiac muscle tissue
In which of the following ways does cardiac muscle tissue differ from skeletal muscle tissue?
D) all of the above
The fibrous skeleton of the heart does not
B) promote random impulse conduction throughout the heart wall
The heart is rotated such that the ____________ are located more anteriorly, while the other chambers are located more posteriorly.
A) right atrium and ventricle
Externally, the atria and ventricles are separated by a relatively deep groove called the
D) coronary sulcus
The inferior, conical end of the heart is called the
A) apex
What are the prominent ridges on the internal surfaces of the auricles and the anterior atrial walls?
C) pectinate muscles
As their name implies, the heart chambers that receive blood returning through both circulatory circuits are called
D) atria
All of the following are true of the left ventricle except
C) receives deoxygenated venous blood from the left atrium
Blood from the systemic circuit returns directly into which heart chamber?
D) right atrium
The pulmonary trunk carries blood from which heart chamber into the pulmonary circuit?
B) right ventricle
Oxygenated blood returning from the lungs enters the left atrium through
B) the pulmonary veins
From the right atrium, blood passes through the right AV (tricuspid) valve into the
B) right ventricle
When closed, the left atrioventricular valve prevents backflow of blood into the
A) left atrium
Which structures prevent the AV valves from everting and flipping into the atria when the ventricles contract?
A)chordae tendineae and pectinate muscles
B)chordae tendineae and papillary muscles
C)conus arteriosus and interventricular septum
D)foramen ovale and fossa ovalis
B)chordae tendineae and papillary muscles
As the ventricles start to contract, the first heart sound ("lubb") signifies the
D) closing of the AV valves
Specialized cardiac muscle fibers that transmit muscle impulses to the contractile muscle cells of the myocardium are an important part of the heart’s
C) conduction system
The cardiac muscle fibers of the ____________ act as the pacemaker, the rhythmic center that initiates the heartbeat.
A) sinoatrial node
The inclusive period of time from the beginning of one heartbeat to the next is called
C) a cardiac cycle
Regardless of the heart chamber, contraction is called ____________ and relaxation, ____________.
C) systole, diastole
The QRS complex of a typical electrocardiogram (ECG) tracing denotes the beginning of
B) depolarization of the ventricles
An ECG produces a composite tracing of all ____________ generated by myocardial cells.
B) muscle impulses
The right coronary artery typically branches into which two vessels?
D) right marginal artery and posterior interventricular artery
Sympathetic and parasympathetic components of the autonomic nervous system that innervate the heart are collectively called the
D) coronary plexus
Autonomic innervation of the heart does which of the following?
D) both b and c
After birth, the foramen ovale of the fetal heart is replaced by a small depression in the interatrial septum called the
C) fossa ovalis
Which of the following is not true of a normal adult heart?
D) the left ventricle pumps at a faster rate than the right
The serous pericardium does not
B) form a mucous membrane lining the pericardial cavity
Oxygenated blood flows through ____________ in the systemic circuit but through ____________ and the opposite heart chambers in the pulmonary circuit.
A) arteries and the left atrium and ventricle; veins
Blood from the systemic circuit returns to the right atrium through
D) all of the above
In terms of oxygen content of the blood they transmit, left atrioventricular is to aortic semilunar as ____________ is to pulmonary semilunar.
C) tricuspid
A type of heart murmur called mitral valve prolapse would most likely involve a defect in
A) the left chordae tendineae or papillary muscles
The left and right coronary arteries
D) all of the above
In the coronary circulation, all venous blood returns to the heart through the
C) coronary sinus
Although the valve itself is located elsewhere, the best auscultation site for the left AV valve is
A) near the apex of the heart in the fifth intercostal space
Just before leaving the heart to go to the lungs, blood must pass through a smooth-walled region called the
B) conus arteriosus
What would happen if the papillary muscles could not contract?
D) the atrioventricular valves would not seal tightly
Which set correctly lists the sequence in which events in the cardiac cycle begin?
A) atrial systole, atrial diastole, ventricular systole, ventricular diastole
Rank the following in order from the longest lasting to the shortest-lived condition in a normal cardiac cycle: (1) atria relaxed (2) ventricles contracting (3) AV valves open (4) semilunar valves closed
D) 1, 4, 3, 2
What happens during ventricular diastole?
D) both ventricles fill with blood
Under normal conditions, only two heart chambers are ever concurrently in ____________, but all four are ____________ together for the last half of the cardiac cycle.
C) systole; relaxing
In which of the following pairs do the events start almost simultaneously?
D) all of the above
Tachycardia predisposes a person to inadequate coronary blood flow because
C) it reduces the time that the myocardium is relaxed enough to permit blood flow
Arrange these components of the heart's conduction system in their sequence of activity, beginning with the pacemaker: (1) Purkinje fibers (2) AV node (3) SA node (4) AV bundle
C) 3, 2, 4, 1
In an ECG tracing, what might an unusually strong QRS complex indicate?
B) hypertrophy of the ventricular myocardium
When a person's heart "skips a beat," what has most likely occurred?
D) premature ventricular contraction
All of the following accurately characterize heart development except
D) the heart starts beating as soon as development is complete, by week 8
If the fetal septum primum and septum secundum fail to fuse properly at birth, the newborn has a congenital heart malformation called
A) an atrial septal defect
Which potentially fatal heart problem is most like a stroke, or cerebrovascular accident?
A) myocardial infarction
What heart problem may be caused, ironically, by the body's attempt to protect itself from a streptococcal throat infection?
