Heart

In an adult at rest, the end-diastolic volume is typically

130 mL

The following is a list of vessels and structures that are associated with the heart. What is the correct order for the flow of blood entering from the systemic circulation? 1. right atrium 2. left atrium 3. right ventricle 4. left ventricle 5. venae cavae 6. aorta 7. pulmonary trunk 8. pulmonary veins

5, 1, 3, 7, 8, 2, 4, 6

Figure 20-2 Cardiac CycleUse Figure 20-2 to answer the following question: What occurs at the area labeled "C" on the graph?

AV valve closes.

During ventricular systole, the

AV valves are closed

Considering the left ventricle, why does isovolumetric ventricular contraction occur during ventricular systole?

Aortic pressure is higher than ventricular pressure and the ventricle must pressurize the blood to open the aortic valve.

Identify the ear like flaps that are attached to the top chambers of the heart.

Auricle

When heart rate increases, the time spent in

all phases decreases but most of the decrease is during diastole.

The __________ valve prevents backward flow of blood into the left ventricle.

aortic

The ________ carry blood away from the heart.

arteries

Figure 20-2 Cardiac CycleUse Figure 20-2 to answer the following question: What occurs at the circle labeled "3" on the graph?

atrial diastole and ventricle systole

The earlike extension of the atrium is the

auricle

The property of heart muscle to contract in the absence of neural or hormonal stimulation is called

automaticity.

Oxygenated blood flows through the right side of the heart.

False

The base of the heart is located at the bottom of the heart.

False

The moderator band is found on both the right and left side of the heart.

False

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.

What happens to the electrical impulse when it reaches the AV node? (Figure 20-11)

It gets delayed.

Figure 20-2 Cardiac CycleUse Figure 20-2 to answer the following question: What is occurring in the left atrium at the circle labeled "2" on the graph?

Left atrium is in systole.

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

Pectinate muscles

What is the function of the coronary circulation?

Provide a blood supply to the heart

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

Pulmonary semilunar valve

Depolarization of the ventricles is represented on an electrocardiogram by the

QRS Complex

What part of the ECG tracing occurs just as ventricular volume reaches 130 mL?

QRS Complex

Into which chamber of the heart will blood flow next after the vessel indicated by the red arrow?

Right atrium

Which chamber of the heart exits into the pulmonary trunk?

Right ventricle

Figure 20-2 Cardiac CycleUse Figure 20-2 to answer the following question: What occurs at the area labeled "B" on the graph?

Semilunar valve closes.

Figure 20-2 Cardiac CycleUse Figure 20-2 to answer the following question: What occurs at "A" on the graph?

Semilunar valve opens.

Figure 20-22 (b) A normal heart is fully repolarized at -60mV. Using the diagram, describe what has occurred in this heart.

The heart rate has decreased as the heart experiences greater hyperpolarization and slower depolarization.

Name the irregular ridges of muscle lining the ventricles.

Trabeculae carneae

Identify the right atrioventricular valve.

Tricuspid valve

The first branch off the arch of the aorta is the brachiocephalic artery in both the sheep and the human.

True

The backward flow of blood from a ventricle to its atrium or from a outflow vessel to its ventricle is called

regurgitation.

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

right atrium.

Which of the following are involved in the pulmonary circuit?

right ventricle, pulmonary trunk, left atrium

The pulmonary valve prevents backward flow into the

right ventricle.

The endocardium consists of this type of tissue.

simple squamous epithelium

The normal pacemaker of the heart is located in

sinoatrial node

Which ion's entry causes rapid depolarization? Which ion's entry causes the plateau? Which ion's exit causes repolarization? (Figure 20-15)

sodium; calcium; potassium

Figure 20-2 Cardiac CycleUse Figure 20-2 to answer the following question: What volume is labeled "E" on the graph?

stroke volume

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

systolic ejection phase.

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

the refractory period lasts until the muscle relaxes.

Which of the labeled valves will open during ventricular systole to allow the flow of blood to the lungs?

the semilunar valve labeled B

Beginning with the right atrium, what is the order of the valves through which blood will pass? (Figure 20-5)

tricuspid valve, pulmonary valve, mitral valve, aortic valve

Blood on the right never mixes with blood on the left, once the heart is fully developed.

true

The ________ carry blood toward the heart.

veins

The heart spends most of the cardiac cycle in which phase?

ventricular diastole

The T wave on an ECG tracing represents

ventricular repolarization

Identify the specific serous membrane layer at the end of the arrow.

visceral pericardium

During the beginning of ventricular systole when the muscle is contracting but not enough pressure has built up to open the semilunar valves the heart is said to be in

isovolumetric contraction.

Figure 20-2 Cardiac CycleUse Figure 20-2 to answer the following question: What occurs at the circle labeled "4" on the graph?

isovolumetric ventricular contraction

Figure 20-2 Cardiac CycleUse Figure 20-2 to answer the following question: What occurs at the circle labeled "7" on the graph?

isovolumetric ventricular relaxation

The AV node delay is beneficial because

it allows time for the atria to contract.

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

left atrium.

In mitral valve prolapse, the cusps of the mitral valve are pushed into the

left atrium.

Identify the most muscular chamber.

left ventricle

What heart chamber pushes blood through the aortic semilunar valve?

left ventricle

Which chamber has the thickest wall?

left ventricle

An MI that affects the ________ side of the heart is more severe because it has to pump blood with ________ force.

left; more

The ________ side of the heart supplies blood to the systemic circuit, while the ________ side of the heart supplies blood to the pulmonary circuit. (Figure 20-1)

left; right

In the middle of the thoracic cavity is a region occupied by the heart, great vessels, thymus, esophagus, and trachea called the

mediastinum.

Which of the following events occurs at the red arrow?

opening the AV valves

Gradual drifting of membrane potential toward threshold in autorhythmic cells is termed a

pacemaker potential.

Figure 20-2 Cardiac CycleUse Figure 20-2 to answer the following question: What occurs at the circle labeled "5" on the graph?

peak systolic pressure

Contractions of the papillary muscles

prevent the atrioventricular valves from reversing into the atria.

What is the function of the gap junction within this structure indicated by the red arrow?

propagate action potentials from cell to cell

Oxygen is added to blood as it flows through the ________ circuit.

pulmonary

Blood leaves the right ventricle by passing through the

pulmonary valve

The right atrium receives blood from all of the following structures except the

pulmonary veins.

Compared to the right ventricle, the left ventricle has all the following characteristics except

pumps a greater volume.

The following are structural components of the conducting system of the heart. 1. Purkinje fibers 2. AV bundle 3. AV node 4. SA node 5. bundle branches The sequence in which excitation would move through this system is

4, 3, 2, 5, 1.

At rest, the end-systolic volume (ESV) is what percent of the end-diastolic volume (EDV)?

40%

Which of the following will receive electrical impulses next, after the structure indicated by the red arrow?

interventricular septum

What is the ligamentum arteriosum?

A remnant of the ductus arteriosus

Identify the valve found between the left atrium and left ventricle.

Bicuspid (mitral) valve

________ is to slow heart rate as ________ is to fast heart rate.

Bradycardia; tachycardia

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

Calcium

The arrow indicates the point of transition from the absolute refractory period to the relative refractory period. Which of the following occurs just before this point?

Cardiac muscle begins to relax.

What fibrous structure functions to anchor the atrioventricular valves in a closed position?

Chordae tendineae

The ________ valve prevents backward flow into the left atrium.

bicuspid

With each ventricular systole,

blood pressure increases

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

calcium channels remaining open

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

cardiac muscle cells.

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

cardiac tamponade.

The coronary sinus drains the ________ into the ________.

cardiac veins; right atrium

The cusps (leaflets) of atrioventricular valves attach directly to

chordae tendineae.

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

closing of the atrioventricular valves

The structures responsible for distributing excitation to the contractile cells are

conducting cells

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

coronary

The term ________ refers to blockage in the coronary circulation.

coronary artery disease

The P wave of the electrocardiogram is a signal from

depolarization of the atria

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

end-diastole volume

Figure 20-2 Cardiac CycleUse Figure 20-2 to answer the following question: What volume is labeled "F" on the graph?

end-diastolic volume

Figure 20-2 Cardiac CycleUse Figure 20-2 to answer the following question: What volume is labeled "G" on the graph?

end-systolic volume

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

end-systolic volume

The amount of blood remaining in the ventricle when the semilunar valve closes is the

end-systolic volume.

Name the inner lining of the heart.

endocardium

The visceral pericardium is the same as the

epicardium

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

foramen ovale.

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

heart rate will decrease and cells will hyperpolarize

The ________ is shared by the two ventricles.

interventricular septum