Anatomy- Unit 3 MCQB Chapter 21

The heart wall is composed of _____ layers of tissues.

3

The heart has the unique ability to change its workload. On average the heart can pump between ____ and _____ liters of blood per minute.

5; 30

Pacemaker cells depolarize about

60-70 times per minute.

During ventricular systole, the

AV valves are closed.

Which of the following is true of the contraction of the heart?

Cardiac contractions are coordinated by specialized conductive cardiac muscle fibers

Which of the following conditions would be caused if the amount of blood entering the ascending aorta with each contraction of the heart were increased?

The amount of blood entering the right atrium of the heart would be increased.

How would the activity of the heart be affected if there were a total blockage of the AV node

The electrical stimuli from the SA node would be normal, but the rate of contraction of the ventricles would slow or be irregular.

Which of the following is true of the coronary arteries?

They originate at the base of the aorta and are the first branch off this vessel.

In terms of time, at rest one cardiac cycle lasts

a little under 1 second.

The grooves on the outside of the heart contain

a) anastomoses. b) coronary arteries. c) fat. d) cardiac veins. ***e) all of the above. ***

Which of the following valves is assisted in functioning by the papillary muscles?

a) left atrioventricular valve b) right atrioventricular valve c) tricuspid valve d) bicuspid valve ***e) all of the above***

The fibrous skeleton of the heart functions to

a) maintain the shape of the heart. b) strengthen and help prevent overexpansion of the heart. c) help distribute the force of contraction of the heart. d) provide an anchor for the heart valves. ***e) do all of the above. ***

The first heart sound, otherwise called the "lubb," signals (the)

a) start of ventricular contraction and the closing of the atrioventricular valves and the opening of the semilunar valves. b) turbulence generated at the start of the filling of the atria. c) start of atrial contraction. d) start of ventricular filling, when the semilunar valves close. ***e) none of the above.***

Cardiac muscle cells obtain energy almost exclusively through

aerobic respiration.

Which of the following empties directly into the right atrium?

anterior cardiac veins

The inferior tip of the heart is the

apex

Which of the following is an incorrect association?

atrioventricular → aortic valve

Which of the following is a major component of the conduction system located in the interventricular septum?

bundle branches

ECG analysis is especially useful in detecting

cardiac arrhythmias.

Structures in the heart that establish the rate of contraction are called

conducting fibers

The superior end of the right ventricle near the pulmonary valve is called (the)

conus arteriosus.

Blood is supplied to the muscle of the heart through the

coronary arteries.

Functions of the endocardium include

covering the inner surfaces of the heart, including the valves.

At rest the heart rate is usually __________ by parasympathetic control

decreased

During their period of systole, the inner volume of the atrial chambers

decreases.

The QRS complex of the electrocardiogram occurs when

depolarization of the ventricles occurs.

Externally the posterior and inferior portions of the left ventricle form the

diaphragmatic surface.

During one cardiac cycle the heart spends most of its time in

diastole.

The chambers of the heart fill during

diastole.

Valves of the heart open and close due to

electrical signals.

The reinforcing layer of the pericardium is the __________ layer.

fibrous

The tough structure that surrounds the heart and helps prevent overfilling is

fibrous pericardium.

Cardiac muscle differs from other muscle tissue in

having fibers connected to one another at intercalated disks.

The main pacemaker region of the heart is

in the wall of the right atrium.

The parietal pericardium

is composed of dense irregular connective tissue.

The border between the atria and the ventricles is

marked by the coronary sulcus.

Papillary muscles receive a signal to contract from (the)

moderator band.

Which of the following is not typically supplied with blood by the right coronary artery?

most of the left atrium

Most of the thickness of the heart wall is the

myocardium.

One of the major differences between skeletal muscle and cardiac muscle is that cardiac muscle

needs Ca2+ to contract.

Cardiac muscle cells do not need ______________ to contract.

nervous stimulation

Prominent muscular ridges that run along the inner surface of the auricle and across the adjacent atrial wall are the

pectinate muscles.

The serous membrane lining the pericardial cavity is the

pericardium.

The coronary artery found in the coronary sulcus is (the)

posterior interventricular artery.

Grooves on the external surface of the heart that divide the right and left ventricles include the

posterior interventricular sulcus. and anterior interventricular sulcus.

The connective tissues of the heart

provide a strong fibrous cross-linkage system wrapping adjacent muscle cells together.

When a clot forms in a coronary vessel and obstructs blood flow to the muscle, the condition is referred to as a(n)

pulmonary embolism

The left ventricle is associated with all of the following except the

pulmonary trunk.

The left atrium receives blood from the

pulmonary veins.

The volume of blood pumped by the heart is

regulated by the nervous system.

The moderator band is located in the

right ventricle.

The left ventricle

sends blood out through the aortic semilunar valve to the systemic circulation.

Blood that is transported to and from all of the tissues of the body with the exception of the lungs is in the

systemic circulation.

The phase of the cardiac cycle during which each chamber contracts and pushes blood into an adjacent chamber is

systole.

The ability of the blood to supply oxygen and remove carbon dioxide from the tissues depends upon

the ability of the blood to remain in constant motion

If a small blood clot passes through the heart and heart vessels, where is it most likely to cause damage if it becomes immobilized?

the left coronary artery

The most serious place for a blockage of a coronary artery is

the left coronary artery.

Which of the chambers of the heart can generate the greatest pressure?

the left ventricle

Nodal activity of the heart may be influenced or modified by

the parasympathetic component of the autonomic nervous system. and hormones secreted by the lungs.

Analysis of an ECG can reveal

the sequence of the valves opening and closing

The most important factor in ensuring that blood moves in correct order through the heart is (the)

the timing of atrial and ventricular systole

Blood travels from the right atrium to the right ventricle through the

tricuspid valve.

The epicardium is also called the

visceral pericardium

The electrical activity of a cardiac muscle fiber

will cause contraction of that cell and several others.