Chapter 12

When the heart rate is 70 beats per minute and the stroke volume is 80 mL, what is cardiac output?

5600 mL/min

What heart valve prevents backflow of blood into the left atrium during ventricular contraction?

Bicuspid valve (left atrioventricular valve)

What are the functions of the chordae tendineae and the papillary muscles?

During ventricular contraction, they prevent the AV valves from swinging up into the atria.

A recording of the electrical events in the heart is a(n)

ECG.

What is the relationship between heart rate, stroke volume, and cardiac output?

Heart rate times stroke volume equals cardiac output.

Which of the following is the term for the structures that connect cardiac muscle cells and creates a direct electrical connection between them?

Intercalated discs

Which chamber of the heart receives oxygenated blood from the right and left pulmonary veins?

Left atrium

What effect would raising blood pressure have on capillary exchange?

More fluid would leave the capillary on the arteriole end because of increased hydrostatic pressure

Which structure of the conducting system propagates action potentials through the ventricular myocardial cells?

Purkinje fibers

Which part of the ECG appears as the ventricles depolarize?

QRS complex

The pacemaker of the heart is normally the

SA node.

Under heavy exercise, which of the following organs receives a massive increase in blood flow?

Skeletal muscles

What is systolic pressure?

The peak blood pressure in an artery measured during ventricular systole

The direction of blood flow through the chambers of the heart is maintained by the internal heart valves. Which of these statements below regarding blood flow and the placement of heart valves within the heart is INCORRECT?

Valves are placed where blood flows into the heart and between the atria and ventricles on each side of the heart.

Cardiac muscle differs from skeletal muscle in that cardiac cells

are chemically and functionally connected into a single functional unit.

Expandable extensions of the atrium are called

auricles

A common technique to improve blood flow and remove plaque in coronary vessels is

balloon angioplasty and stent placement.

Low pressure and slow flow rates are characteristics of favorable

capillary exchange

When the ventricles are relaxed the semilunar valves are ________ and the atrioventricular valves are ________.

closed; open

In the normal, healthy adult two heart sounds, S1 and S2 are heard upon cardiac auscultation (listening with a stethoscope to sounds made by the heart.). These sounds are caused by ________.

closure of the heart valves. S1 signifies closure of the AV valves and S2 results from closure of the semilunar (pulmonary and aortic) valves.

The vessels that supply blood to the heart are called the

coronary arteries.

The right atrium receives

deoxygenated blood from the vena cava.

The apex of the heart lies superior to the

diaphragm.

The size-selective exchange of materials across endothelial walls of capillaries is

filtration.

During light exercise, the increase in cardiac output is mostly due to

increased venous return.

As vessels become smaller, peripheral resistance

increases.

The layer of the heart containing cardiac muscle is the

myocardium.

The thickest layer of the heart is the

myocardium.

Which of the following will NOT increase heart rate?

parasympathetic stimulation

The intrinsic conduction system of the heart allows the heart to contract in a rhythmic way without input from the nervous or endocrine systems. Several groups of non-contractile cells are able to initiate and distribute depolarization across the walls of the heart leading to contraction. Which of the following is the correct sequence of excitation of these autorhythmic cardiac cells?

sinoatrial node → internodal pathway → atrioventricular node → AV bundle → bundle branches → Purkinje fibers

An intercalated disc is a

specialized cardiac muscle intercellular connection.

The bone lying anterior to the heart is the

sternum.

The base of the heart is the portion that is most

superior

An accelerated heart rate above 100 beats per minute is called

tachycardia.

Which of these features differentiate cardiac muscle from skeletal muscle?

the presence of intercalated discs

Which of the following structures is NOT contained in the mediastinum?

thyroid

The right atrioventricular valve is the

tricuspid.

A midsagittal section through the trunk would divide the heart

unequally, with most lying on the left side.

The membrane covering the heart is the

visceral pericardium.