The inner lining of the heart.

Endocardium

Heart muscle.

Myocardium

Serous layer covering the heart muscle.

Epicardium

17) The outermost layer of the serous pericardium.

Parietal layer

Heart rate at rest under both autonomic divisions signaling

Vagal tone

An abnormally fast heart rate

Tachycardia

An abnormally slow heart rate

Bradycardia

Difference between resting and maximal cardiac output

Cardiac reserve

Prevents backflow into the left ventricle.

Aortic valve

Prevents backflow into the right atrium.

Tricuspid valve

Prevents backflow into the left atrium.

Mitral valve

Prevents backflow into the right ventricle.

Pulmonary valve

AV valve with two flaps.

Mitral valve

AV valve with three flaps.

Tricuspid valve

Heart muscle is deprived of oxygen.

Ischemia

Death of heart muscle cells.

Infarction

A condition of rapid and irregular or out-of-phase contraction of heart muscle cells.

Fibrillation

An abnormal pacemaker.

Fibrillation

Total heart relaxation.

Quiescent period

The myocardium receives its blood supply from the coronary arteries.

true

Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle.

false

Anastomoses among coronary arterial branches provide collateral routes for blood delivery to the heart muscle.

true

Congestive heart failure means that the pumping efficiency of the heart is depressed so that there is inadequate delivery of blood to body tissues.

true

Tissues damaged by myocardial infarction are replaced by connective tissue.

true

The left side of the heart pumps the same volume of blood as the right.

true

Chronic release of excess thyroxine can cause a sustained increase in heart rate and a weakened heart.

true

Arterial blood supply to heart muscle is continuous whether the heart is in systole or diastole.

false

Auricles slightly increase blood volume in the ventricles.

false

The "lub" sounds of the heart are valuable in diagnosis because they provide information about the function of the heart's pulmonary and aortic valves.

false

Autonomic regulation of heart rate is via two reflex centers found in the pons.

false

The papillary muscles contract after the other ventricular muscles so that they can take up the slack on the chordae tendineae before the full force of ventricular contractions sends blood against the AV valve flaps.

false

An ECG provides direct information about valve function.

false

As pressure in the aorta rises due to atherosclerosis, more ventricular pressure is required to open the aortic valve.

true

Paroxysmal atrial tachycardia is characterized by bursts of atrial contractions with little pause between them.

true

Blood in the heart chambers provides some nutrients to the heart muscle cells.

true

Normal heart sounds are caused by which of the following events?

closure of the heart valves

Which of the events below does not occur when the semilunar valves are open?

Ventricles are in diastole.

Hemorrhage with a large loss of blood causes ________.

a lowering of blood pressure due to change in cardiac output

The left ventricular wall of the heart is thicker than the right wall in order to ________.

pump blood with greater pressure

Damage to the ________ is referred to as heart block.

AV node

The P wave of a normal electrocardiogram indicates ________.

atrial depolarization

Blood within the pulmonary veins returns to the ________.

left atrium

The condition where fluid compresses the heart and limits its ability to contract is called ________.

cardiac tamponade

The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is ________.

angina pectoris

To auscultate the aortic semilunar valve, you would place your stethoscope in the ________.

second intercostal space to the right of the sternum

The source of blood carried to capillaries in the myocardium would be the ________.

coronary arteries

The fact that the left ventricle of the heart is thicker than the right ventricle reveals that it ________.

pumps blood against a greater resistance

Which of the following factors does not influence heart rate?

skin color

Which of the following is not an age-related change affecting the heart?

thinning of the valve flaps

If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________.

decreased delivery of oxygen

If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells, ________.

tetanic contractions might occur, which would stop the heart's pumping action

Norepinephrine acts on the heart by ________.

causing threshold to be reached more quickly

If the vagal nerves to the heart were cut, the result would be that ________.

the heart rate would increase by about 25 beats per minute

A foramen ovale ________.

connects the two atria in the fetal heart

Which vessel(s) of the heart receive(s) blood during right ventricular systole?

pulmonary trunk

Which of these vessels receives blood during ventricular systole?

both the aorta and pulmonary trunk

Which of the following is not part of the conduction system of the heart?

AV valve

The tricuspid valve is closed ________.

when the ventricle is in systole

When viewing a dissected heart, it is easy to visually discern the right and left ventricles by ________.

noticing the thickness of the ventricle walls

Select the correct statement about the heart valves.

The AV valves are supported by chordae tendineae so that regurgitation of blood into the atria during ventricular contraction does not occur.

Select the correct statement about the function of myocardial cells.

The entire heart contracts as a unit or it does not contract at all

Select the correct statement about the structure of the heart wall.

The myocardium is the layer of the heart that actually contracts.

Compared to skeletal muscle, cardiac muscle ________.

has gap junctions that allow it to act as a functional syncytium

During the period of ventricular filling ________.

blood flows mostly passively through the atria and the open AV valves into the ventricles

The second heart sound is heard during which phase of the cardiac cycle?

isovolumetric relaxation

If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________.

threshold is reached more quickly and heart rate would increase

Select the correct statement about cardiac output.

A slow heart rate increases end diastolic volume, stroke volume, and force of contraction.

During contraction of heart muscle cells ________.

some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores

Isovolumetric contraction ________.

refers to the short period during ventricular systole when the ventricles are completely closed chambers

Commotio cordis is heart failure due to a ________.

relatively mild blow to the chest that occurs during a vulnerable interval (2 ms) when the heart is repolarizing

The pacemaker rhythm that determines heart rate is called ________ rhythm.

Sinus

The ECG ________ wave interval represents ventricular repolarization.

T

The ________ layer of the serous pericardium covers the heart.

visceral

The ________ valve of the heart has three valves with chordae tendineae.

tricuspid

When heart valve replacement is required, the ________ valve is the most likely valve that needs to be replaced.

mitral

Heart murmurs or rubs are considered to be ________ sounds.

abnormal

Define systole and diastole. Which heart chambers are usually referenced when these terms are used?

Systole is contraction of the muscle. Diastole is relaxation of the muscle. The contraction and relaxation of the ventricles are normally described with the terms systole and diastole

Define the terms end diastolic volume (EDV) and end systolic volume (ESV) and relate them to the calculation of stroke volume.

EDV is the amount of blood that collects in a ventricle during diastole. ESV is the volume of blood remaining in a ventricle after it has contracted. Stroke volume (ml/beat) equals EDV - ESV.

What is the difference between the auricles and the atria?

Auricles are the flaplike appendages attached to the atria that increase the atrial volume. The atria are receiving chambers for blood returning to the heart from the pulmonary and systemic circulation

What two important functions does the cardiac conduction system perform?

to initiate impulses (pacemaker) and to distribute impulses throughout the heart so that it depolarizes and contracts in an orderly, sequential manner.

Why is oxygen so much more critical to the heart muscle than to skeletal muscles?

Cardiac muscle cells are highly dependent on oxygen and rely almost exclusively on aerobic respiration

What is the functional importance of the intercalated discs of cardiac muscle?

Intercalated discs contain anchoring desmosomes that prevent cell separation, and gap junctions that allow ions to travel from cell to cell, transmitting current across the entire heart

What is the functional importance of the fibrous skeleton of the heart?

The fibrous skeleton acts as a tendon, an insertion and insulator, giving the cardiac cells something to pull or exert their force on and isolating atrial from ventricular contractions.