Chapter 21

Blood is supplied to the muscle of the heart through the A) coronary arteries. B) interventricular septum. C) pulmonary arteries. D) cardiac sinus. E) conus arteriosus.

A

Structures in the heart that carry electrical signals from the SA node to the AV node are called A) internodal pathways. B) bundle branches. C) Purkinje fibers. D) the chordae tendineae. E) None of the answers are correct.

A

The right ventricle A) has thinner muscular walls than does the left ventricle. B) receives blood from the left atrium through the tricuspid valve. C) pumps blood out of the heart to the systemic circuit. D) sends blood out through the aortic semilunar valve. E) is connected to the pulmonary veins.

A

The thick muscular partition that separates the two ventricles entire heart is the A) interventricular septum. B) right ventricle. C) left ventricle. D) right atrium. E) left atrium.

A

When a clot forms in a coronary vessel and obstructs blood flow to the muscle, the condition is referred to as a(n) A) coronary thrombosis. B) pulmonary embolism. C) angina pectoris. D) myocardial infarction. E) None of the answers are correct.

A

Which of the following is an incorrect association? A) atrioventricular—aortic valve B) atrioventricular—tricuspid valve C) atrioventricular—mitral valve D) semilunar—pulmonary valve E) None of the answers are correct.

A

At rest the heart rate is usually ________ by parasympathetic control. A) increased B) decreased C) unchanged D) shut down E) None of the answers are correct.

B

Cardiac muscle cells obtain energy almost exclusively through A) anaerobic pathways. B) aerobic respiration. C) glycolysis. D) the Krebs cycle. E) protein stores.

B

During their period of systole, the inner volume of the atrial chambers A) does not change. B) decreases. C) remains the same, but the auricles enlarge rapidly. D) increases, as does the volume in the auricles. E) None of the answers are correct.

B

Grooves on the external surface of the heart that divide the right and left ventricles include the A) lateral sulcus. B) anterior interventricular sulcus. C) coronary fissure. D) atrioventricular sulcus. E) interventricular septum.

B

If a small blood clot passes through the heart and heart vessels, where is it most likely to cause damage if it becomes immobilized? A) the right atrial chamber B) the left coronary artery C) the left ventricle D) the aorta E) Severe damage could occur if a small blood clot became immobilized at any of these positions.

B

In terms of time, at rest one cardiac cycle lasts A) about 1.5 seconds. B) a little under 1 second. C) 5 seconds. D) about a half second. E) None of the answers are correct.

B

Nodal activity of the heart may be influenced or modified by A) either the SA node or the AV node, but no other system. B) the autonomic nervous system. C) the somatomotor cortex. D) hormones secreted by the lungs. E) enzymes released from the kidney.

B

Papillary muscles of the right ventricle receive a signal to contract from (the) A) bundle branches. B) moderator band. C) AV node. D) Purkinje fibers. E) None of the answers are correct.

B

The broad, superior portion of the heart is the A) apex. B) base. C) sternocostal surface. D) pulmonary surface. E) anterior surface.

B

The connective tissues of the heart A) consist only of many dense collagen fibers. B) provide a strong fibrous cross-linkage system wrapping adjacent muscle cells together. C) do not join the muscle fibers to the fibrous skeleton of the heart. D) All of the answers are correct. E) None of the answers are correct.

B

The contraction of any one cardiac muscle fiber A) will immediately trigger an all-or-none response in all other cardiac fibers. B) will cause the contraction of several others. C) will cause the rate of heart muscle contraction to increase. D) will stimulate the electrical conduction system of the heart. E) None of the answers are correct.

B

The fibrous skeleton of the heart is located A) in the wall of the pericardial sac. B) surrounding the heart valves. C) covering the outer surface of the heart. D) forming the atria and ventricles of the heart. E) All of the answers are correct.

B

The innermost layer of the heart wall is the A) parietal and visceral layers of the epicardium. B) endocardium C) myocardium. D) fibrous pericardium. E) connective tissue.

B

The most serious place for a blockage of a coronary artery is A) the circumflex branch of the left coronary artery. B) the left coronary artery. C) the right marginal branch of the right coronary artery. D) the posterior interventricular artery. E) left anterior descending artery.

B

The superior end of the right ventricle near the pulmonary valve is called (the) A) auricle. B) conus arteriosus. C) pulmonary trunk. D) ligamentum arteriosum. E) All of the answers are correct.

B

The tough structure that surrounds the heart and helps reinforce and maintain position of the heart is the A) mediastinum. B) pericardial sac. C) pleural cavity. D) aorta. E) epicardium.

B

Which of the chambers of the heart can generate the greatest pressure? A) the left atrium B) the left ventricle C) the right atrium D) the right ventricle E) Both ventricles create greater pressures simultaneously than do the atria

B

Which of the following is a major component of the conduction system located in the interventricular septum? A) SA node B) bundle branches C) AV node D) Purkinje fibers E) None of the answers are correct.

B

Blood that is transported to and from all of the tissues of the body with the exception of the lungs is in the A) arterial circuit. B) pulmonary circuit. C) systemic circuit. D) portal circuit. E) venous circuit.

C

Blood travels from the left atrium to the left ventricle through the A) semilunar valve. B) fossa ovalis. C) mitral valve. D) tricuspid valve. E) conus arteriosus.

C

Cardiac muscle differs from other muscle tissue in A) no ways; it is not unusual. B) having striations. C) having fibers connected to one another at intercalated discs. D) having fewer mitochondria. E) having larger sized fibers than other striated muscles.

C

One of the major differences between skeletal muscle and cardiac muscle is that cardiac muscle A) is striated. B) has myosin and actin. C) lacks triads. D) needs Ca2+ to contract. E) has a very large sarcoplasmic reticulum.

C

Pacemaker cells of the SA node depolarize about A) 60-70 times per minute. B) 120-140 times per minute. C) 80-100 times per minute. D) 40-50 times per minute. E) None of the answers are correct.

C

The ability of the blood to supply oxygen and remove carbon dioxide from the tissues depends upon A) the diameter of the capillaries. B) the number of white blood cells in the circulation. C) the ability of the blood to remain in constant motion. D) the rate at which platelets are manufactured. E) the osmotic balance, as controlled by the kidneys.

C

The chambers of the heart empty during A) maximum contraction. B) diastole. C) ventricular systole. D) atrial systole. E) None of the answers are correct.

C

The coronary artery found under the right atrium is (the) A) LAD. B) circumflex artery. C) right coronary artery. D) posterior interventricular artery. E) None of the answers are correct.

C

The heart wall is composed of ________ layers of tissues. A) 1 B) 2 C) 3 D) 4 E) 5

C

The left atrium receives blood from the A) coronary arteries. B) mitral valve. C) pulmonary veins. D) aorta. E) pulmonary trunk.

C

The moderator band is located in the A) left ventricle. B) right atrium. C) right ventricle. D) left atrium. E) interventricular sulcus.

C

The phase of the cardiac cycle during which each chamber contracts and pushes blood into the next structure is A) diastole. B) relaxation. C) systole. D) ejection. E) None of the answers are correct.

C

The serous membrane lining the pericardial cavity is the A) pleura. B) mediastinum. C) pericardium. D) myocardium. E) endocardium.

C

The visceral pericardium is also called the A) pericardial cavity. B) parietal pericardium. C) epicardium. D) pericardial sac. E) fibrous pericardium.

C

The wall between the atria is called the A) interchamber septum. B) cardiac septum. C) interatrial septum. D) interventricular septum. E) coronary sulcus.

C

Which of the following conditions would cause the amount of blood entering the ascending aorta with each contraction of the heart to increase? A) The heartbeat would be speeded up by the parasympathetic nervous system. B) Stimulation by the sympathetic nervous system would accompany this change. C) The amount of blood entering the right atrium of the heart was increased. D) The atrioventricular valves would not close. E) The amount of blood sent to the lungs for oxygenation would decrease.

C

Which of the following empty directly into the right atrium? A) middle cardiac vein B) great cardiac vein C) anterior cardiac veins D) small cardiac vein E) None of the answers are correct.

C

Which of the following is true of the contraction of the heart? A) The ventricles contract first, followed by the atria. B) The contractions do not occur in any specific repeatable sequence each time. C) Cardiac contractions are coordinated by specialized conductive cardiac muscle fibers. D) The muscle obtains the beat from the pacemaker region exclusively. E) None of the answers are correct.

C

Which of the following is true of the coronary arteries? A) They branch off the pulmonary veins. B) Together they supply part of the heart muscle with oxygen. C) They originate at the base of the aorta and are the first branches off this vessel. D) They open and close in pulsation with the contraction and relaxation of the heart ventricles. E) None of the answers are correct.

C

Blood vessels traveling away from the heart are A) arterioles. B) venules. C) capillaries. D) arteries. E) All of the answers are correct.

D

During one cardiac cycle the ventricles spend most of their time in A) systole. B) contraction. C) fibrillation. D) diastole. E) None of the answers are correct.

D

Externally the posterior and inferior portions of the left ventricle form the A) sternocostal surface. B) right border. C) left border. D) diaphragmatic surface. E) superior border.

D

How would the heart rate be affected if there were a blockage of the AV node? A) The heart rate would be unaffected. B) The heart rate would increase. C) The heart would cease to contract. D) The electrical stimuli from the SA node would be normal, but the rate of contraction would slow or be irregular. E) The heart rate would slow dramatically, and become extremely irregular, contracting only when the ventricles became overfilled.

D

Prominent muscular ridges that run along the inner surface of the auricle and across the adjacent atrial wall are the A) chordae tendineae. B) foramen ovale. C) papillary muscles. D) pectinate muscles. E) trabeculae carneae.

D

The left ventricle pumps blood into the A) pulmonary semilunar valves. B) pulmonary veins. C) pulmonary arteries. D) aorta. E) vena cava.

D

The most important factor in ensuring that blood moves in correct order through the heart is (the) A) location of the main electrical conduction node. B) coordination of the timing of atrial and ventricular systole. C) strength of the contraction of the different parts of the myocardium. D) pressure of blood in each of the chambers at any given time. E) None of the answers are correct.

D

The reinforcing layer of the pericardium is the ________ layer. A) visceral B) parietal C) sutural D) fibrous E) epicardial

D

The right ventricle is associated exclusively with which of the following? A) mitral valve B) papillary muscles C) aorta D) pulmonary trunk E) trabeculae carneae

D

Valves of the heart open and close due to A) contraction of papillary muscles. B) timing sequences. C) electrical signals. D) pressure changes. E) None of the answers are correct.

D

Which of the following is supplied with blood by the left anterior descending artery? A) right atrium B) right ventricle C) the conducting system D) left ventricle E) posterior heart wall

D

Cardiac muscle cells do not need ________ to contract. A) ATP B) sodium C) potassium D) calcium E) nervous stimulation

E

During most of ventricular diastole, the A) atria are contracting. B) AV valves are closed. C) ventricles are contracting. D) pressure in the ventricles does not change. E) the ventricles are filling.

E

The anterior and posterior interventricular sulci on the outside of the heart contain A) coronary arteries. B) fat. C) cardiac veins. D) grooves. E) All of the answers are correct.

E

The fibrous skeleton of the heart functions to A) maintain the shape of the heart. B) physically isolating the atrial muscle cells from the ventricular muscle cells. C) help distribute the force of contraction of the heart. D) reinforcing the heart valves. E) All of the answers are correct.

E

The heart has the unique ability to change its workload. On average the heart can pump between ________ and ________ liters of blood per minute. A) 2; 20 B) 1; 3 C) 10; 20 D) 5; 50 E) 5; 30

E

The main pacemaker region of the heart is A) electrically active nodal tissue located in the wall of the left ventricle. B) in the interventricular septum. C) able to cause the atria and ventricles to contract simultaneously. D) able to cause the muscle to begin to contract at the apex. E) in the wall of the right atrium.

E

Which of the following valves is assisted in functioning by the papillary muscles? A) right atrioventricular valve B) tricuspid valve C) mitral valve D) bicuspid valve E) All of the answers are correct.

E