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