A&P II: chapter 18

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

increased contractility (an increase in sympathetic nervous system activity would increase contractility (by increasing available calcium), thus increasing stroke volume. Contractility causes an increase in stroke volume by decreasing end systolic volume; it does not change end diastolic volume.))

Which of the following would increase heart rate? 1)low metabolic rate 2)cold temperature 3)parasympathetic stimulation 4)epinephrine

epinephrine (Sympathetic stimulation (i.e., exercise) can lead to the release of epinephrine and norepinephrine, both of which increase heart rate.)

Which of the following is the outermost covering of the heart? 1)epicardium 2)visceral layer 3)parietal layer 4)fibrous pericardium

fibrous pericardium

Which of the following does NOT deliver blood to the right atrium? 1)pulmonary veins 2)coronary sinus 3)superior vena cava 4)inferior vena cava

pulmonary veins (The pulmonary veins deliver blood to the left atrium, not the right atrium.)

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

two pumps (Yes, the right side of the heart pumps to/from the lungs (pulmonary circuit) and the left side of the heart pumps to/from the rest of the body (the systemic circuit))

Which portion of the electrocardiogram represents the time during which the atria repolarize?

QRS complex

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

SA node ( the SA Node spontaneously depolarizes, causing the wave of depolarization that spreads through the rest of the conduction system and heart.)

Which of the following is NOT a factor that regulates stroke volume? 1)afterload 2)heart rate 3)contractility 4)preload

heart rate (Heart rate does not affect stroke volume. Heart rate and stroke volume determine cardiac output.)

Which layer of the heart wall contracts and is composed primarily of cardiac muscle tissue?

myocardium

Which heart chamber sends deoxygenated blood to the lungs?

right ventricle (The right ventricle sends the deoxygenated blood to the lungs via the pulmonary trunk.)

Which heart chamber pumps unoxygenated blood out the pulmonary trunk?

right ventricle (the right ventricle pumps unoxygenated blood out the pulmonary trunk to the lungs)

Specifically, what part of the intrinsic conduction system stimulates the atrioventricular (AV) node to conduct impulses to the atrioventricular bundle?

sinoatrial (SA) node

At what rate does the sinoatrial (SA) node ensure depolarization in the heart?

75 beats of the heart per minute

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

P wave (the P wave represents atrial depolarization, which leads to atrial contraction.)

During which portion of the electrocardiogram do the atria contract?

P-R interval

The QRS complex represents __________.

ventricular depolarization (The QRS complex shows ventricular depolarization.)

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

AV node (the AV node slows down the impulse giving the atria time to contract before the ventricles contract.)

Which of the following is NOT a difference between the left and right ventricles? 1)The left ventricle is a more powerful pump than the right ventricle. 2)The walls of the left ventricle are thicker than the walls of the right ventricle. 3)The left ventricle receives a smaller percentage of coronary blood supply than the right ventricle. 4)The left ventricle pumps blood to the systemic circuit, while the right ventricle pumps blood to the pulmonary circuit.

The left ventricle receives a smaller percentage of coronary blood supply than the right ventricle. (Since the demands on the left ventricle are so great, it receives the highest percentage of the coronary blood supply.)

Which of the events below does not occur when the semilunar valves are open? 1)Ventricles are in diastole. 2)Ventricles are in systole. 3)Blood enters pulmonary arteries and the aorta. 4)AV valves are closed.

Ventricles are in diastole.

Hemorrhage with a large loss of blood causes ________.

a lowering of blood pressure due to change in cardiac output

The first heart sound (the "lub" of the "lub-dup") is caused by __________.

closure of the atrioventricular valves (The first heart sound (the "lub" of the "lub-dup") is generated by the closure of the atrioventricular valves.)

Normal heart sounds are caused by which of the following events? 1)closure of the heart valves 2)excitation of the SA node 3)friction of blood against the chamber walls 4)opening and closing of the heart valves

closure of the heart valves

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

decreased stroke volume and no change in cardiac output (a decreased blood volume would decrease the end diastolic volume, thus lowering the stroke volume. Although this would initially lead to a decrease in the cardiac output, heart rate would increase because of increased activity of the sympathetic nervous system in an effort to maintain cardiac output.)

What does the ECG wave tracing represent?

electrical activity in the heart (the ECG waves show the depolarization and repolarization in various areas of the heart.)

Which of the following would increase heart rate? 1)decreased activity of the sympathetic nervous system 2)increased activity of the parasympathetic nervous system 3)epinephrine and norepinephrine 4)acetylcholine

epinephrine and norepinephrine (secreted by the adrenal medulla as a result of sympathetic stimulation, these hormones act as part of the sympathetic response, increasing heart rate.)

Which of the following increases stroke volume? 1)exercise 2)decrease in preload 3)severe blood loss 4)decrease in end diastolic volume (EDV)

exercise

true or false:Autonomic regulation of heart rate is via two reflex centers found in the pons.

false

Which of the following terms refers to a lack of oxygen supply to heart muscle cells?

ischemia (Ischemia refers to a lack of oxygen supply to heart muscle cells.)

Blood within the pulmonary veins returns to the ________.

left atrium

Which heart chamber receives blood from the pulmonary veins?

left atrium (the left atrium receives oxygenated blood from the pulmonary veins.)

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

left ventricle (the left ventricle pumps oxygenated blood out the aorta to the entire body (systemic circuit))

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

right atrium ( the right atrium receives unoxygenated blood from the systemic circuit)

The heart's pacemaker is the..........

sinoatrial node (The sinoatrial node (SA node), which is in the right atrial wall, is the heart's pacemaker. The autorhythmic cells of this node generate the sinus rhythm that determines heart rate.)

Which of the following factors does not influence heart rate? 1)gender 2)skin color 3)body temperature 4)age

skin color

The __________ valve is located between the right atrium and the right ventricle.

tricuspid (The tricuspid valve is located between the right atrium and right ventricle.)

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

true

What does the QRS complex represent in the ECG wave tracing?

ventricular depolarization (the QRS complex represents depolarization in the ventricles, which have greater mass than the atria.)

What does the T wave of the electrocardiogram (ECG) represent?

ventricular repolarization (The T wave of the ECG represents ventricular repolarization as the heart rests and prepares to contract again.)

A foramen ovale ________. 1)is a connection between the pulmonary trunk and the aorta in the fetus 2)connects the two atria in the fetal heart 3)is a shallow depression in the interventricular septum 4)is a condition in which the heart valves do not completely close

connects the two atria in the fetal heart

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

increased end diastolic volume (an increase in venous return increases the end diastolic volume. The fibers are stretched more, resulting in an increase in the force of contraction (preload, or the Frank-Starling Mechanism).)

Which of the following would increase cardiac output to the greatest extent? 1)decreased heart rate and increased stroke volume 2)increased heart rate and increased stroke volume 3)increased heart rate and decreased stroke volume 4)decreased heart rate and decreased stroke volume

increased heart rate and increased stroke volume (cardiac output = heart rate x stroke volume)

What structures connect the individual heart muscle cells?

intercalated discs (Intercalated discs connect the heart muscle cells. They include desmosomes (anchoring junctions) and gap junctions (communicating junctions).)

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

pump blood with greater pressure