Chapter 20 STUDY

increasing ejection fraction. increasing heart rate. decreasing end-systolic volume. increasing stroke volume.

Cardiac output can be increased by

pacemaker

Cells that spontaneously make action potentials make up ________ tissue.

prevent the atrioventricular valves from reversing into the atria.

Contractions of the papillary muscles

right atrium.

Coronary veins empty into the

QRS complex

Depolarization of the ventricles is represented on an electrocardiogram by the

decrease blood pressure. decrease the force of cardiac contraction. produce a negative inotropic effect. dilate the coronary arteries.

Drugs known as calcium channel blockers such as nifedipine can be used to

both repolarizing and relaxing.

During the T wave of the electrocardiogram, the ventricles are

calcium

During the plateau phase of the cardiac action potential, which ion is entering the cardiac muscle cell?

increases; decreases

During ventricular systole, the blood pressure __________ and ventricular volume __________.

amount of blood remaining in a ventricle after contraction

End-systolic volume is defined as the

medulla oblongata.

Heart rate is controlled by neurons of the cardiovascular center located in the

The AV valves and semilunar valves are closed.

Heart valves are in what state during isovolumetric contraction?

decreased stroke volume and no change in cardiac output

How would a decrease in blood volume affect both stroke volume and cardiac output?

increased contractility

How would an increase in the sympathetic nervous system increase stroke volume?

Pulmonary semilunar valve

Identfiy the valve located at the exit of the right ventricle.

Tricuspid valve

Identify the right atrioventricular valve.

the ventricles will beat more slowly.

If the connection between the SA node and AV node becomes blocked,

decrease

If the force of ventricular contraction increases, what will happen to the end-systolic volume?

heart rate will decrease and cells will hyperpolarize.

If the pacemaker cells in the SA node become more permeable to potassium ions, the

The rate of P waves will be faster than the rate of QRS complexes

If there is a complete block between the SA node and the AV node, how would the ECG be affected?

cardiac output

If you know both the heart rate and stroke volume, you can calculate the __________.

AV valves only

Increased pressure in the ventricles would close what valve(s)?

electrical signals the force of contraction action potentials ionic currents

Intercalated discs serve to transfer ________ from cell to cell.

ventricular diastole

Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.

while the AV valve is open

Left ventricular filling occurs __________.

left of midline.

Most of the mass of the heart lies

cardiac muscle cells.

Most of the middle layer in the heart wall is composed of

trabeculae carneae

Muscular ridges on the inner surface of the ventricles are called

Pectinate muscles

Name the ridged bundles of muscle found projecting inside the right atrium.

voltage-gated potassium channels

Repolarization of an autorhythmic cell is due to the opening of which channels?

end-diastolic volume. the contractility of the ventricle. venous return of blood to the heart. the pressure required to pump blood into the aorta.

Stroke volume depends on

the refractory period lasts until the muscle relaxes.

Tetanic muscle contractions don't occur in a normal cardiac muscle because

depolarization of the atria.

The P wave of the electrocardiogram is a signal from

contraction of both atria

The P wave of the electrocardiogram is closely followed by __________.

ventricular repolarization.

The T wave on an ECG tracing represents

arteries

The ________ carry blood away from the heart.

veins

The ________ carry blood toward the heart.

systemic

The ________ circuit carries blood from the aorta to the right ventricle

pulmonary

The ________ circuit carries blood to and from the lungs.

end-systolic volume

The ________ is the amount of blood in a ventricle after it has contracted and before it begins to refill.

end-diastolic volume

The ________ is the volume of blood in a ventricle at the beginning of systole.

venous return.

The amount of blood returning to the heart is the

in one direction only.

The atrioventricular valves permit blood flow

between the left atrium and left ventricle.

The bicuspid or mitral valve is located

ventricular systole

The closing of the left AV valve occurs near the beginning of __________.

add strength and prevent overexpansion of the heart. provide physical support for cardiac muscle. provide elasticity to help return the heart to its normal size. help distribute the forces of contraction.

The connective tissue fibers of the myocardium

systole.

The contraction phase of the cardiac cycle is called

cardiac veins; right atrium

The coronary sinus drains the ________ into the ________.

marks the border between the atria and ventricles.

The coronary sulcus is a groove that

the semilunar valve to close

The decrease in left ventricular pressure at the end of ventricular systole causes __________.

closing of the atrioventricular valves.

The first heart sound ("lubb") is associated with

collect blood then pump it to the ventricle.

The function of an atrium is to

two pumps

The heart is actually (one, two, or three) pumps?

both parasympathetic and sympathetic

The heart is innervated by ________ nerves.

pericardial

The heart lies within the ________ cavity.

aorta

The left ventricle pumps blood to the

ventricular and atrial diastole

The majority of ventricular filling occurs while the ventricles and atria are in what state(s)?

the sinoatrial node.

The normal pacemaker of the heart is located in

the left ventricle to the left atrium

The one-way nature of the left AV valve prevents blood flow from _________.

prevent the AV valves from reversing into the atria

The papillary muscles function to __________.

systolic ejection phase

The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the

lungs.

The pulmonary arteries carry blood to the

heart.

The pulmonary veins carry blood to the

increased levels of circulating epinephrine. faster rise of the pacemaker potential increased sympathetic stimulation of the SA node

what will increase the heart rate?

Starling's

"An increase in end-diastolic volume increases the stroke volume" is a way of stating ________ law of the heart.

tachycardia.

A faster-than-normal heart rate is called

stent

A fine tubular wire mesh called a(n) ________ may be inserted into a coronary vessel, holding it open.

coronary arterial bypass graft.

A procedure in which a length of the patient's vein or artery is used to create a detour around an obstruction in a coronary artery is called

bradycardia.

A slower-than-normal heart rate is called

murmurs.

Abnormal heart sounds caused by turbulent flow through faulty valves are called

gap junctions

Action potentials generated by the autorhythmic cells spread to the contractile cells through what structures in the membrane?

the duration of the ventricular action potential. the condition of the conducting system. the effects of drugs and poisons. heart rate.

Analysis of the electrocardiogram can reveal all of the following

right atrium

Blood flowing in the vena cava will next enter the __________.

left atrium.

Blood returning to the heart from the pulmonary circuit first enters the

increased end diastolic volume

By what mechanism would an increase in venous return increase stroke volume?

oxygenated; left atrium

The right pulmonary veins carry ________ blood to the ________.

right and left lungs.

The right ventricle pumps blood to the

mediastinum.

The space between the pleural cavities is called the

foramen ovale.

The structure that permits blood flow from the right atrium to the left atrium in the fetal circulation is the

isovolumetric relaxation

Ventricular diastole begins with the closing of the semilunar valves. What phase of the cardiac cycle happens between this event and the later opening of the AV valves?

greater pressure in the aorta than in the left ventricle

What causes the aortic semilunar valve to close?

diastole

What is the relaxed state of the ventricle called?

open.

When the semilunar valves close, the AV valves then

left ventricle

Which chamber pumps oxygenated blood out the aorta to the systemic circuit?

right ventricle

Which heart chamber pumps unoxygenated blood out the pulmonary trunk?

left atrium

Which heart chamber receives blood from the pulmonary veins?

right ventricle, pulmonary trunk, left atrium

Which of the following are involved in the pulmonary circuit?

Most blood flows passively into the ventricles through open AV valves.

Which of the following is correct about the filling of the ventricles?

AV node

Which of these structures conduct(s) action potentials the slowest?

SA node

Which part of the intrinsic conduction system normally initiates the depolarizing impulse that causes a heartbeat?

blood pressure increases

With each ventricular systole,