ch 18 practice test mybradylabs

The P wave of an electrocardiogram represents __________. atrial depolarization ventricular repolarization ventricular depolarization atrial repolarization

atrial depolarization

Which of the following factors gives the myocardium its high resistance to fatigue? the presence of intercalated discs gap junctions the coronary circulation a very large number of mitochondria in the cytoplasm

a very large number of mitochondria in the cytoplasm

An enlarged R wave on an ECG would indicate __________. repolarization abnormalities an enlarged ventricle a myocardial infarction cardiac ischemia

an enlarged ventricle

The coronary arteries arise from the __________. inferior vena cava pulmonary trunk superior vena cava aorta right atrium

aorta

The superior chambers of the heart are called the __________. ventricles cavae coronary chambers atria

atria

Which of the following is NOT a role of the fibrous pericardium? It prevents the heart from overfilling with blood. It anchors the heart to surrounding structures. It facilitates heart contraction. It protects the heart.

It facilitates heart contraction.

The normal pacemaker of the heart is the __________. subendocardial conducting network (Purkinje fibers) SA node bundle branches AV bundle AV node

SA node

Choose the correct sequence of electrical current flow through the heart wall. 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 subendocardial conducting network, AV node, AV bundle, right and left bundle branches, SA node AV node, SA node, subendocardial conducting network, AV bundle, right and left bundle branches

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. The heart is shaped like a cone with the base facing the right shoulder. 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 enclosed in a double-layered sac called the pleural membrane.

In the fetus, blood from the left and right sides of the heart normally mix. True False

True

Which of the following is a difference between cardiac muscle and skeletal muscle? 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 do not rely on calcium ions for contraction. Unlike skeletal muscle cells, cardiac muscle cells can be autorhythmic.

Unlike skeletal muscle cells, cardiac muscle cells can be autorhythmic.

The __________ are attached to the AV valve flaps. pectinate muscles chordae tendineae papillary muscles trabeculae carneae

chordae tendineae

The second heart sound (the "dup" of "lub-dup") is caused by the __________. closure of the atrioventricular valves closure of the semilunar valves opening of the semilunar valves opening of the atrioventricular valves

closure of the semilunar valves

systole

contraction

The vessels that carry oxygen to the myocardium are called __________. coronary arteries aortic arteries pulmonary arteries coronary veins pulmonary veins

coronary arteries

The lining of the heart chambers is called the __________. pericardium epicardium myocardium endocardium

endocardium

Which of the following are correctly paired? ectopic focus: an abnormal pacemaker heart block: uncoordinated atrial and ventricular contraction fibrillation: premature contraction arrhythmia: atrioventricular (AV) node failure

ectopic focus: an abnormal pacemaker

Which is the correct sequence of layers in the heart wall, starting with the outer layer? parietal pericardium, myocardium, endocardium epicardium, myocardium, endocardium endocardium, epicardium, myocardium endocardium, smooth muscle, epicardium myocardium, pericardium, endocardium

epicardium, myocardium, endocardium

The contractile cardiac muscle fibers of the myocardium behave as a single, coordinated unit called a __________. pacemaker cardiac cycle functional syncytium sarcomere contractile unit

functional syncytium

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? incompetent cardiac valve myocardial infarction angina pectoris cardiac tamponade

incompetent cardiac valve

The interventricular septum forms a dividing wall between the __________. right atrium and right ventricle left and right ventricles left and right atria left atrium and left ventricle right ventricle and left atrium

left and right ventricles

Into which chamber of the heart do the pulmonary veins deliver blood? left ventricle right ventricle right atrium left atrium

left atrium

Freshly oxygenated blood is delivered to the __________, and then it passes into the __________ to be pumped to the body tissues (systemic circuit). right ventricle; right atrium right atrium; right ventricle left ventricle; left atrium left atrium; left ventricle

left atrium; left ventricle

The most muscular chamber of the heart is the __________. left ventricle right atrium left atrium right ventricle

left ventricle

During systemic circulation, blood leaves the __________. right ventricle and flows directly to the aorta left ventricle and flows directly to the aorta right ventricle and flows directly to the lungs right atrium and flows directly to the lungs lungs and flows directly to the left atrium

left ventricle and flows directly to the aorta

When the mitral valve closes, it prevents the backflow of blood from the __________. right atrium into the right ventricle left ventricle into the aorta right ventricle into the pulmonary trunk left atrium into the left ventricle left ventricle into the left atrium

left ventricle into the left atrium

Guided by powerful signaling molecules, the human heart develops from __________. endoderm cardioderm ectoderm mesoderm

mesoderm

The noncontractile cardiac muscle cells that initiate their own depolarization and cause depolarization of the rest of the heart are called __________. gap junctions pacemaker cells desmosomes intercalated discs cardioinhibitory centers

pacemaker cells

Which of the following would lead to a decrease in heart rate? parasympathetic stimulation norepinephrine sharply decreased blood volume exercise

parasympathetic stimulation

The structure just deep to the fibrous pericardium is the __________. diaphragm visceral layer of the serous pericardium endocardium myocardium epicardium parietal layer of the serous pericardium

parietal layer of the serous pericardium

aortic semilunar valve

prevents backflow of blood into the left ventricle

pulmonary semilunar valve

prevents backflow of blood into the right ventricle

diastole

relaxation

The inferior vena cava brings blood from the lower regions of the body and empties into the __________. left ventricle left atrium right ventricle right atrium aorta

right atrium

The tricuspid valve is located between the __________. left atrium and left ventricle right ventricle and the aorta right atrium and right ventricle right and left atria right and left ventricles

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. right ventricle, left ventricle, left atrium, lungs, right atrium right atrium, right ventricle, lungs, left atrium, left ventricle 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 atrium, right ventricle, lungs, left atrium, left ventricle

During pulmonary circulation, blood leaves the __________. left ventricle and flows directly to the lungs right ventricle and flows directly to the aorta right atrium and flows directly to the lungs right ventricle and flows directly to the lungs right atrium and flows directly to the left ventricle

right ventricle and flows directly to the lungs

posterior interventricular artery

runs to the apex of the heart

The role of the atrioventricular node (AV node) is to __________. conduct impulses to the sinoatrial node (SA node) initiate ventricular depolarization initiate a sinus rhythm slow down impulses so that the atria can contract to fill the adjacent ventricles with blood

slow down impulses so that the atria can contract to fill the adjacent ventricles with blood

The endocardium is composed of __________. columnar epithelium cuboidal epithelium cardiac muscle cells squamous epithelium elastic cartilage

squamous epithelium

anterior interventricular artery

supplies blood to the interventricular septum and anterior walls of both ventricles

right marginal artery

supplies blood to the lateral right side of the myocardium

circumflex artery

supplies blood to the left atrium and posterior walls of the left ventricle

cardiac output

the amount of blood pumped by each ventricle in one minute

Cardiac output is __________. the number of times the heart beats in one minute the amount of blood filling each ventricle at the end of diastole the amount of blood pumped out of each ventricle in one minute the amount of blood pumped out of the heart during every ventricular contraction the number of impulses fired by the SA node in one minute

the amount of blood pumped out of each ventricle in one minute

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 fibrous pericardium the pericardial sac the epicardium the parietal layer of serous pericardium

the epicardium

cardiac cycle

the events associated with blood flow through the heart during one complete heartbeat

What part of the heart is considered the systemic circuit pump? the left ventricle the right ventricle the right atrium the pericardium

the left ventricle

Which of the following valves is most often faulty in the heart? the pulmonary semilunar valve the tricuspid valve the mitral, or bicuspid, valve the aortic semilunar valve

the mitral, or bicuspid, valve

The absolute refractory period refers to the time during which __________. the muscle cell is ready to respond to any stimulus the muscle cell will respond only to a sub-threshold stimulus the muscle cell is ready to respond to a threshold stimulus the muscle cell will not respond to a stimulus of any strength the muscle cell will respond only to an exceptionally strong stimulus

the muscle cell will not respond to a stimulus of any strength

The cardiac cycle includes all of the following events EXCEPT __________. 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 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 number of times the heart beats in one minute

stroke volume

the volume of blood pumped by one ventricle with each heartbeat

The __________ nerve carries parasympathetic fibers to the sinoatrial (SA) node. hypoglossal vagus accessory facial

vagus

mitral (bicuspid) valve

valve between the left atrium and left ventricle

tricuspid valve

valve between the right atrium and right ventricle

The trabeculae carneae are located in the __________. epicardium atria ventricles endocardium

ventricles