chapter 18 homework
Compare the volume of blood each circuit receives from contraction of the ventricles.
Both circuits receive the same volume of blood
Which parts of the following statement are true? The AV node delivers the stimulus to the AV bundle, located within the interventricular septum.
Both parts of the statement are true
Veins are more prone to inappropriate stretching and twisting than arteries, because
Veins have thinner walls than arteries
What is coronary ischemia?
a condition in which the blood supply of the coronary arteries is reduced
Which of the following does NOT contribute to the partial or complete blockage of the coronary arteries that causes coronary ischemia?
a stent
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 valve(s) close(s) during ventricular contraction?
both AV valves
The ________ separate(s) the two ventricles.
interventricular septum
Define cardiac regurgitation
is the backflow of blood into the atria when the ventricles contract
Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.
isovolumetric contraction, ventricular ejection, isovolumetric relaxation
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
Which chamber pumps oxygenated blood out the aorta to the systemic circuit?
left ventricle
The ________ has a greater workload than the ________.
left ventricle; right ventricle
The pulmonary arteries carry blood to the
lungs
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
The muscle layer of the heart is the
myocardium
The interventricular sulci and coronary sulcus contain all of the following except
nerves
When the semilunar valves close, the AV valves then
open
The right atrium receives blood from all of the following except the
pulmonary veins
Compared to the right ventricle, the left ventricle has all the following characteristics except that it
pumps a greater volume
If a patient's tricuspid valve was leaking during systole, what would happen?
regurgitation back into the right atrium
During the T wave of the electrocardiogram, the ventricles are electrically ________ and functionally ________.
repolarizing; relaxing
The right ventricle pumps blood to the
right and left lungs
Blood returning to the heart from the systemic circuit first enters the
right atrium
Which chamber receives blood from the superior and inferior vena cavae?
right atrium
The marginal branch and posterior interventricular branch are branches of the
right coronary artery
The ________ deliver(s) blood to the myocardium.
right coronary artery and left coronary artery
The pulmonary semilunar valve prevents backward flow into the
right ventricle
Which heart chamber pumps unoxygenated blood out the pulmonary trunk?
right ventricle
Identify the correct sequence for blood flow through the heart.
right ventricle, through pulmonary valve, pulmonary trunk, pulmonary arteries
The cavity that contains the lungs, the heart, great vessels, thymus, esophagus, and trachea is called the
thoracic cavity
Blood flowing into the heart from the venae cavae flows next through the ________ valve.
tricuspid
The heart is actually (one, two, or three) pumps?
two pumps
The pulmonary veins carry blood to the
heart
David suffers from a prolapsed mitral valve. This condition would cause
increased effort by the left ventricle and regurgitation
The ________ separate(s) the two atria.
interatrial septum
Blood returning to the heart from the pulmonary circuit first enters the
left atrium
Which heart chamber receives blood from the lungs?
left atrium
Which heart chamber receives blood from the pulmonary veins?
left atrium
Name the four chambers of the heart.
left atrium, left ventricle, right atrium, right ventricle
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
The earlike extension of the atrium is the
auricle
From superficial to deep, name the layers of the heart wall.
pericardium, myocardium, endocardium
What do semilunar valves prevent?
prevent backflow of blood into the ventricles
Damage to the semilunar valve on the right side of the heart would affect blood flow to which vessel?
pulmonary trunk
As blood leaves the right ventricle, it passes through the ________ and then into the pulmonary trunk.
pulmonary valve
Blood leaves the right ventricle by passing through the
pulmonary valve
Muscular ridges on the inner surface of the ventricles are called
trabeculae carneae
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
In an ECG recording, which of the following coincides with ventricular repolarization?
T-wave
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.
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
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 of the following is correct about the filling of the ventricles?
Most blood flows passively into the ventricles through open AV valves
Depolarization of the atria corresponds to the ECG's
P wave
In the non-exercising heart, which event of the cardiac cycle lasts the longest?
atrial diastole
When the ventricles contract, what pushes the cusps of the AV together, closing them to prevent backflow from the ventricles into the atria?
blood from inside the ventricles
There are ________ pulmonary veins.
4
Complications related to arteriosclerosis account for roughly ________ percent of deaths in the United States.
50
The first heart sound is heard when the
AV valves close
How would properly functioning valves prevent varicose veins?
Valves prevent backward flow of blood
The bicuspid, or mitral, valve is located
between the left atrium and left ventricle
The ________ valve prevents backward flow into the left atrium.
bicuspid
The P wave of the electrocardiogram is a signal from
depolarization of the atria
Arteriosclerosis can lead to all of the following except
diabetes
What causes the aortic semilunar valve to close?
greater pressure in the aorta than in the left ventricle
Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.
ventricular diastole
The mitral valve closing is associated with all of the following except
when the left atrial pressure exceeds the left ventricular pressure
intercalated discs serve to transfer all of the following from cell to cell except
z-lines
Increased pressure in the ventricles would close what valve(s)?
AV valves only
Compare arteriosclerosis with atherosclerosis
Arteriosclerosis is any thickening and toughening of arterial walls; atherosclerosis is a type of arteriosclerosis characterized by changes in the endothelial lining and the formation of fatty deposits (plaque) in the tunica media
Which event does NOT happen during ventricular diastole?
Atrioventricular valves close because of the contracting ventricles
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
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
Abnormally slow depolarization of the ventricles would most change the shape of the ________ in an ECG tracing.
QRS complex
Depolarization of the ventricles is represented on an electrocardiogram by the
QRS complex
Comparing the left ventricle with the right ventricle, which of the following is true?
The left ventricle does more work than the right ventricle
Why is the left ventricle more muscular than the right ventricle?
The left ventricle must generate enough force to propel blood through the systemic circuit, whereas the right ventricle must generate only enough force to propel blood the short distance from the heart to the lungs in the pulmonary circuit
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
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 heart sound ("lubb") is associated with
closing of the mitral valve
The function of the atrium is to
collect blood and pump blood to the ventricle
The first blood vessels to branch from the aorta are the ________ arteries.
coronary
Blood is supplied to the myocardium by
coronary arteries
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
Given the description of Tran's varicose veins, what is the name of one of the affected vessels in his legs?
great saphenous vein
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