ch 18 a&p 2

Which artery curves to the left around the coronary sulcus, eventually meeting and fusing with small branches of the right coronary artery

circumflex artery

The first blood vessels to branch from the aorta are the ________ arteries

coronary

The great and middle cardiac veins drain blood into the

coronary sinus

Which exterior heart structure returns "used" blood collected from the heart muscle itself (myocardium) back into the flow of blood to be delivered to the pulmonary circuit

coronary sinus

What causes the aortic semilunar valve to close?

greater pressure in the aorta than in the left ventricle Yes, backflow of blood in the aorta (towards the left ventricle) closes the aortic semilunar valve.

In an ECG recording, which of the following coincides with ventricular repolarization?

t wave

A faster-than-normal heart rate is calle

tachycardia

Blood is supplied to the myocardium by

the (Left and Right) coronary arteries.

The atrioventricular valves permit blood flow

in one direction only

Which description correctly describes the location of the heart

in the mediastinum, superior to the diaphragm

What factor would increase heart rate

increase in thyroxine (T4)

Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.

isovolumetric contraction, ventricular ejection, isovolumetric relaxation Yes, the ventricles must contract and eject blood before they relax and fill again.

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

left atrium

Which heart chamber receives blood from the lungs

left atrium

The circumflex branch and the anterior interventricular artery are branches of the

left coronary artery

Which vessel(s) supplies/supply the left ventricle, left atrium, and the interventricular septum

left coronary artery

Most of the mass of the heart lies to the ________ the midline

left of

The coronary sulcus is a groove that

marks the border between the atria and ventricles.

Cardiac muscle cells are __________.

mechanically, chemically, and electrically connected to one another

Which option describes the location of the heart

mediastinum

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

medulla oblongata

Which structure provides a rapid-conduction path that tenses the papillary muscles before the ventricular myocardium contracts, preventing "slamming" of the right AV cusps?

moderator band

Which phase of the cardiac cycle is the shortest

atrial systole

During the isovolumetric contraction phase of ventricular systole

atrioventricular valves and semilunar valves are closed.

The earlike extension of the atrium is the

auricle

the muscle layer of the heart is the

myocardium

The interventricular sulci and coronary sulcus contain all of the following except

nerves

What structure is immediately deep to the fibrous pericardium

parietal pericardium

from superficial to deep, name the layers of the heart wall

pericardium myocardium endocardium

Contractions of the papillary muscles

prevent the atrioventricular valves from reversing into the atria

Blood leaves the right ventricle by passing through the

pulmonary valve

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

right atrium

The marginal branch and posterior interventricular branch are branches of the

right coronary artery

Identify the correct sequence for blood flow through the heart

right ventricle, through pulmonary valve, pulmonary trunk, pulmonary arteries

The right ventricle pumps blood to the

the right and left lungs

Which event does NOT happen during ventricular diastole?

Atrioventricular valves close because of the contracting ventricles. During ventricular diastole, the ventricles are relaxed. The ventricles have ejected a good portion of their blood into the elastic arteries, and the pressure in the ventricles is now lower than the pressure in the atria and the arteries. This causes the atrioventricular valves to open and the semilunar valves to close.

Define autorhythmicity

Autorhythmicity is the ability of the heart to contract without neural or hormonal stimulation

Activation of which kind of receptor causes heart rate to increase

Beta-one receptor

Compare the base of the heart with the apex.

The base of the heart is the superior portion where the largest veins and arteries are attached. The apex of the heart is located on the inferior aspect of the heart.

What structure prevents the electrical signals generated in the SA node from passing directly from the atrium through to the ventricles below

The cardiac skeleton

In order to cause cardiac muscle contraction, the contractile cells must also depolarize. What causes the depolarization of the contractile cells

The flow of positive ions from adjacent cells

Describe the location and position of the heart

The heart is located near the anterior chest wall, directly behind the sternum.

Which statement is correct regarding the intrinsic heart rate?

During parasympathetic stimulation, acetylcholine released by parasympathetic neurons opens chemically gated potassium channels in the plasma membrane

Which heart chamber receives blood from the pulmonary veins?

Left atrium

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

Left ventricle

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

Most blood flows passively into the ventricles through open AV valves. Yes, most of the ventricular filling is passive; atrial contraction adds just a little more blood.

Contraction of the atria results from which wave of depolarization on the ECG tracing?

P wave

Which ECG event demonstrates the depolarization of the atria

P wave

List the important features of the ECG, and indicate what each represents.

P wave (atrial depolarization), QRS complex (ventricular depolarization), T wave (ventricular repolarization)

Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart

SA node

Which of the following is greater during left ventricular systole

The peak pressure in the ventricle.

What statement is true regarding pressures and volumes in the cardiac ventricles?

The pressure is greater in the left ventricle, but the volumes are equal in the two chambers

What superficial landmark identifies the boundary between the left and right ventricles

anterior interventricular sulcus

The left ventricle pumps blood to the

aorta

The inferior point of the heart is called the

apex

Which of the following descriptions matches the phrase "near the left fifth intercostal space

apex of the heart

Which pathology is described as a thickening and toughening of arterial walls

arteriosclerosis

What is the first phase of the cardiac cycle

artial systole

In the non-exercising heart, which event of the cardiac cycle lasts the longest?

atrial diastole There has to be adequate time during the cardiac cycle to provide enough blood return to the heart for adequate cardiac output to the lungs and body systems. Remember the path of blood through the heart

Which valve(s) close(s) during ventricular contraction

both AV valves

Compare the volume of blood each circuit receives from contraction of the ventricles.

both circuits receive the same volume of blood

The heart is innervated by ________ nerves

both parasympathetic and sympathetic

Which heart chamber pumps unoxygenated blood out the pulmonary trunk

Right ventricle

The heart pumps approximately ________ milliliters of blood each minute

6,000

Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles

AV node

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

AV valves only Yes, increased pressure in the ventricles would close the AV valves.

What factor would decrease stroke volume

An increase in afterload

Which of the following statements most accurately defines what is happening during the second phase of ventricular systole of the cardiac cycle?

Blood is being ejected from the ventricles through open semilunar valves. The electrical stimulation conducted through the heart causes contraction of the ventricles. During the second phase of ventricular systole, the heart is far enough along in the cycle that the pressure generated by the contracting ventricles has opened the semilunar valves silently and pushed the blood out into the aorta and pulmonary trunk.

What electrolyte (ion) is responsible for the plateau in the cardiac action potential

Calcium

Why is it important that cardiac tissue contain many mitochondria and capillaries

Cardiac tissue is metabolically active and dependent on mitochondrial activity to use aerobic respiration to generate ATP and capillaries provide the oxygen and nutrients for this process

Which statement regarding irreversible shock is true

Circulatory collapse occurs when arteriolar smooth muscles and precapillary sphincters become unable to contract

Which structures collect blood from the myocardium, and into which heart chamber does this blood flow?

Coronary veins collect blood from the myocardium and carry it to the right atrium

When threshold is reached at the SA node (an autorhythmic cell), what channels open causing further depolarization of the membrane

Fast calcium

Which of the following statements is correct concerning the cardiac cycle?

In late ventricular diastole, all chambers are relaxed and filling to about seventy percent of their capacity. The completion of the cardiac cycle occurs when all the chambers of the heart are relaxed which occurs during late ventricular diastole.

Which of the following would decrease heart rate

Increased parasympathetic stimulation of nodal fibers

One of the changes that occurs in the pacemaker potential (unstable resting membrane potential) in the SA node (an autorhythmic cell) is a decreased efflux of what ion

Potassium

Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.

Pressure in the atria would be greater than the pressure in the ventricles. Yes, higher pressure in the atria than in the ventricles forces the AV valves to open and blood moves into the ventricles.

What structure carries the electrical signal from the septum of the heart through the ventricular myocardium

Purkinje fibers

The portion of the tracing of an electrocardiogram, ECG, that represents ventricular depolarization is the

QRS complex

The portion of the tracing of an electrocardiogram, ECG, that represents ventricular depolarization is the __________.

QRS complex The QRS complex represents the entire events of ventricular depolarization.

List the three stages of an action potential in a cardiac muscle cell

Rapid depolarization, plateau, and repolarization

Which chamber receives blood from the superior and inferior vena cavae?

Right atrium

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

Two pumps

Veins are more prone to inappropriate stretching and twisting than arteries, because

Veins have thinner walls than arteries

What does the QRS complex represent in the ECG wave tracing

Ventricular depolarization

Why is ventricular fibrillation fatal?

Ventricular fibrillation is fatal because the ventricles quiver and do not pump blood to the systemic circulation.

What event causes the closing of the AV valves, which results in the first heart sound

Ventricular systole

Isovolumetric contraction is associated with which cardiac cycle phase

Ventricular systole - first phase

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

Voltage-gated potassium channels

The superior portion of the heart where major blood vessels enter and exit is the

base

What structure of the heart contains the largest veins and arteries

base

The term used to describe fluid collecting in the pericardial cavity that restricts the movement of the heart is known as

cardiac tamponade.

The cusps (leaflets) of atrioventricular valves attach directly to

chordae tendineae

What does the ECG wave tracing represent

electrical activity in the heart

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

gap junctions

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

ventricular diastole Yes, both occur during ventricular diastole when the ventricles are not actively contracting and ejecting blood.

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

ventricular ejection of ventricular systole

During which phase of the cardiac cycle is the blood pumped to the body

ventricular systole

The long plateau phase of the cardiac muscle action potential is due to

voltage-gated calcium channels remaining open

Intercalated discs serve to transfer all of the following from cell to cell except

z-lines