EKG Tech Cardiac Anatomy And Physiology
Chapter 1 (Based on textbook ECG Interpretation Made Incredibly Easy, 4th Edition)
Questions and Answers
- 1.
The heart is located in the ___________ cavity.
- A.
Dorsal
- B.
Cardiac
- C.
Mediastinal
- D.
Thorasic
Correct Answer
C. MediastinalExplanation
The heart is located in the mediastinal cavity. The mediastinal cavity is the central compartment of the thoracic cavity, which is located between the lungs. It contains various structures including the heart, thymus gland, esophagus, and major blood vessels. The heart is specifically situated in the mediastinum, which is the central part of the mediastinal cavity.Rate this question:
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- 2.
The top of the heart, or its base, lies just below the _____ rib.
- A.
Second
- B.
Third
- C.
First
- D.
None of the above.
Correct Answer
A. SecondExplanation
The top of the heart, or its base, lies just below the second rib.Rate this question:
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- 3.
The bottom of the heart is known as the ____.
- A.
Base
- B.
Apex
- C.
Anchor
- D.
Case
Correct Answer
B. ApexExplanation
The bottom of the heart is known as the apex. The apex refers to the pointed tip or lowest part of the heart, which is located at the bottom and slightly to the left. It is where the heartbeat can be felt most strongly and is an important landmark in cardiac examinations and procedures. The term "apex" is commonly used in medical terminology to describe the lowest or most inferior part of an organ or structure.Rate this question:
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- 4.
An athlete's heart usually weighs more than that of the average person while an elderly person's weighs less.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because athletes often have larger hearts due to their rigorous training and exercise routines. Regular exercise increases the size and strength of the heart muscle, allowing it to pump more blood efficiently. This results in an increase in the overall weight of the heart. On the other hand, as people age, their heart muscles tend to weaken, leading to a decrease in the size and weight of the heart. Therefore, an athlete's heart usually weighs more than that of an average person, while an elderly person's heart weighs less.Rate this question:
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- 5.
The heart is made up of three layers: the epicardium, myocardium and the _____
- A.
Echocardium
- B.
Aortic lining
- C.
Endocardium
Correct Answer
C. EndocardiumExplanation
The heart is made up of three layers: the epicardium, myocardium, and the endocardium. The endocardium is the innermost layer of the heart and lines the chambers and valves. It is composed of endothelial cells and connective tissue, providing a smooth surface for blood flow and preventing clot formation. The endocardium also plays a role in regulating the contraction and relaxation of the heart muscle.Rate this question:
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- 6.
The myocardium makes up the smallest portion of the hearts wall.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The myocardium does not make up the smallest portion of the heart's wall. The myocardium is the middle layer of the heart's wall and is responsible for the contraction of the heart muscle. It is thicker than the other two layers, the epicardium and the endocardium. Therefore, the statement is false.Rate this question:
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- 7.
The layer of connective tissue that surrounds the heart is called _______
- A.
Adipose
- B.
Myocardium
- C.
Visceral layer
- D.
Ventricular Septum
Correct Answer
B. MyocardiumExplanation
The correct answer is Myocardium. The myocardium is the middle layer of the heart wall and is composed of cardiac muscle tissue. It is responsible for the contraction and relaxation of the heart, allowing it to pump blood throughout the body. The myocardium is surrounded by other layers, including the epicardium (visceral layer) and the endocardium. Adipose refers to fatty tissue, while the ventricular septum is a wall that separates the two ventricles of the heart.Rate this question:
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- 8.
The fibrous and serous pericardium layers are seperated by a thin, clear liquid called pericardial fluid.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The fibrous and serous pericardium layers are indeed separated by a thin, clear liquid called pericardial fluid. This fluid acts as a lubricant, reducing friction between the layers of the pericardium as the heart beats and moves. It also helps to cushion and protect the heart from external forces. Therefore, the statement is true.Rate this question:
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- 9.
Pericardial effusion, a condition of having excess pericardial fluid, can _________
- A.
Compromise the lung's ability to receive oxygen.
- B.
Block the the SA node from firing.
- C.
Cause over production of red blood cells.
- D.
Compromise the heart's ability to pump blood.
Correct Answer
D. Compromise the heart's ability to pump blood.Explanation
Pericardial effusion is the accumulation of excess fluid in the pericardial sac surrounding the heart. This can lead to increased pressure on the heart, which in turn compromises its ability to pump blood effectively. As the fluid builds up, it compresses the heart, reducing its ability to expand and contract properly. This compromises the heart's ability to pump blood efficiently, leading to decreased cardiac output and potential complications.Rate this question:
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- 10.
The heart contains four chambers - two atria and two ventricles.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The heart is divided into four chambers - two atria and two ventricles. The atria receive blood from the body and lungs, while the ventricles pump the blood out to the rest of the body. This division of chambers allows for efficient circulation of oxygenated and deoxygenated blood throughout the body. Therefore, the statement that the heart contains four chambers - two atria and two ventricles - is true.Rate this question:
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- 11.
The right atria receives
- A.
Oxygenated blood.
- B.
Deoxygenated blood.
- C.
Oxygen from the pulmonary artery.
- D.
None. It acts as a reservoir.
Correct Answer
B. Deoxygenated blood.Explanation
The right atria receives deoxygenated blood. This is because the right atrium receives blood from the body through the superior and inferior vena cava, which carries deoxygenated blood from the systemic circulation. The deoxygenated blood then flows into the right ventricle and is pumped to the lungs to be oxygenated. Therefore, the right atrium acts as a receiving chamber for deoxygenated blood.Rate this question:
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- 12.
The ___________ divides the right and left atrium and helps them contract.
- A.
AV node.
- B.
Cardiac septum.
- C.
Interatrial septum.
- D.
Bundle of His.
Correct Answer
C. Interatrial septum.Explanation
The interatrial septum is the correct answer because it is the structure that divides the right and left atrium of the heart. It helps to separate the oxygenated blood in the left atrium from the deoxygenated blood in the right atrium. This division allows for more efficient contraction of the atria, ensuring that blood is properly pumped through the heart. The AV node, cardiac septum, and bundle of His are not involved in dividing the right and left atrium.Rate this question:
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- 13.
The ______________ septum seperates the left and right ventricles.
Correct Answer
interventricularExplanation
The interventricular septum is the correct answer because it is the structure that separates the left and right ventricles of the heart. This septum plays a crucial role in preventing the mixing of oxygenated and deoxygenated blood in the heart, ensuring that the blood flows in the correct direction and is properly distributed to the body.Rate this question:
- 14.
Because the atria collect blood, their walls are thicker than the ventricles.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Since the atria doesn't have to pump the deoxygenated blood far, the chamber walls are thinner. Likewise, the left ventricle has a much thicker wall than the right because it pumps blood against the higher pressures in the body's arterial circulation.Rate this question:
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- 15.
The atrioventricular valves are:
- A.
Aortic and pulmonic.
- B.
Aortic and tricuspid.
- C.
Pulmonic and mitral.
- D.
Tricuspid and mitral.
Correct Answer
D. Tricuspid and mitral.Explanation
The correct answer is tricuspid and mitral. The atrioventricular valves are located between the atria and ventricles of the heart and prevent the backflow of blood. The tricuspid valve is located on the right side of the heart, between the right atrium and right ventricle. The mitral valve, also known as the bicuspid valve, is located on the left side of the heart, between the left atrium and left ventricle. Together, these valves ensure that blood flows in the correct direction through the heart.Rate this question:
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- 16.
Give the names of the two atrioventricular (AV) valves.
Correct Answer
tricuspid and mitral
tricuspid, mitral
mitral, tricuspid
mitral and tricuspidExplanation
The correct answer is tricuspid and mitral. The two atrioventricular (AV) valves in the heart are named the tricuspid valve and the mitral valve. The tricuspid valve is located between the right atrium and the right ventricle, while the mitral valve is located between the left atrium and the left ventricle. These valves prevent the backflow of blood from the ventricles into the atria during the pumping action of the heart.Rate this question:
- 17.
The semilunar valves include the aortic and the _______.
Correct Answer
pulmonic
pulmonary
pulmonaryExplanation
*The correct term is pulmonic however, for the purpose of this quiz, pulmonary will be accepted.*Rate this question:
- 18.
What age does a child have to reach before his/ her heart is located in the same position as an adults?
- A.
4
- B.
5
- C.
6
- D.
7
Correct Answer
D. 7Explanation
As a child grows, their organs gradually shift into their adult positions. The heart is located in the same position as an adult's by the time they reach the age of 7.Rate this question:
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- 19.
The mitral valve is located between the
- A.
Right atrium and right ventricle.
- B.
The left atrium and left ventricle.
- C.
The right ventricle and pulmonary artery.
- D.
The superior vena cava and right atrium.
Correct Answer
B. The left atrium and left ventricle.Explanation
The mitral valve is located between the left atrium and left ventricle. This valve prevents the backflow of blood from the left ventricle to the left atrium during ventricular contraction. It ensures that blood flows in one direction, from the left atrium to the left ventricle, allowing for efficient oxygenation of the body's tissues.Rate this question:
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- 20.
The mitral valve has two cusps and the tricuspid valve has three.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because the mitral valve, also known as the bicuspid valve, has two cusps, while the tricuspid valve has three cusps. The cusps are the flaps of tissue that open and close to allow blood flow through the valves.Rate this question:
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- 21.
The right ventricle pumps blood through the pulmonic valve into the pulmonary arteries and then into the lungs. From the lungs, blood flows through the pulmonary veins and empties into the left atrium. What is this cycle called?
- A.
Cardiac cycle.
- B.
Pulmonary circulation.
- C.
Systemic circulation.
- D.
Rapid circulation.
Correct Answer
B. Pulmonary circulation.Explanation
The cycle described in the question, where blood is pumped from the right ventricle through the pulmonic valve into the pulmonary arteries and then into the lungs, and then flows back through the pulmonary veins into the left atrium, is known as pulmonary circulation. This is the specific circulation pathway that involves the lungs, where oxygen is taken up and carbon dioxide is released. It is distinct from systemic circulation, which involves the rest of the body, and rapid circulation is not a recognized term in this context.Rate this question:
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- 22.
When the left ventricle pumps blood through the aortic valve into the aorta and then throughout the body, this is referred to as _________.
- A.
Pulmonary circulation.
- B.
Contractility.
- C.
Isovolumetric relaxation.
- D.
Systemic circulation.
Correct Answer
D. Systemic circulation.Explanation
When the left ventricle pumps blood through the aortic valve into the aorta and then throughout the body, it is referred to as systemic circulation. Systemic circulation involves the transportation of oxygenated blood from the heart to the various organs and tissues of the body, delivering nutrients and removing waste products. This process ensures that oxygen and nutrients are distributed to all the cells in the body and plays a crucial role in maintaining overall bodily functions.Rate this question:
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- 23.
The ________ arteries supply the heart muscle with blood and oxygen.
Correct Answer
coronaryExplanation
The answer "coronary" is correct because the coronary arteries are responsible for supplying the heart muscle with blood and oxygen. These arteries branch off from the aorta and wrap around the heart, ensuring that the heart receives the necessary nutrients and oxygen to function properly. Without the coronary arteries, the heart would not be able to receive the blood supply it needs, leading to various heart conditions and potentially a heart attack.Rate this question:
- 24.
The coronary ostium is _________
- A.
An opening in the aorta.
- B.
A coronary artery disease.
- C.
Located in the left atria.
- D.
A corrective surgery.
Correct Answer
A. An opening in the aorta.Explanation
The coronary ostium refers to an opening in the aorta. This opening allows blood to flow into the coronary arteries, which supply oxygen and nutrients to the heart muscle. It is an essential pathway for the circulation of blood to the heart.Rate this question:
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- 25.
The __________ artery supplies oxygenated blood to the lateral walls of the left ventricle, left atrium and sometimes the SA node.
Correct Answer
circumflexExplanation
The circumflex artery is responsible for supplying oxygenated blood to the lateral walls of the left ventricle, left atrium, and sometimes the SA node. This artery plays a crucial role in delivering the necessary nutrients and oxygen to these areas of the heart, ensuring their proper functioning.Rate this question:
- 26.
A network of anastomoses is called __________.
- A.
Cardiac byways.
- B.
Collateral cirulation.
- C.
Cluster veins.
- D.
Arterial webs.
Correct Answer
B. Collateral cirulation.Explanation
A network of anastomoses refers to a system of interconnected blood vessels that provide alternate pathways for blood flow in the event of a blockage or restriction in a main vessel. This network is known as collateral circulation. It helps to maintain blood supply to tissues and organs, ensuring their proper functioning even when there is a disruption in the normal blood flow. The other options, such as cardiac byways, cluster veins, and arterial webs, do not accurately describe this specific network of interconnected vessels.Rate this question:
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- 27.
Cardiac veins collect deoxygenated blood from the capillaries of the myocardium.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because cardiac veins do indeed collect deoxygenated blood from the capillaries of the myocardium. The myocardium is the muscular tissue of the heart, and like any other tissue, it requires a blood supply to deliver oxygen and nutrients. The capillaries in the myocardium exchange oxygen and nutrients for waste products, resulting in deoxygenated blood. This deoxygenated blood is then collected by the cardiac veins and eventually returned to the right atrium of the heart.Rate this question:
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- 28.
The cardiac veins join to form an enlarged vessel called the ________, which returns blood to the right atrium where it continues through the circulation.
Correct Answer
coronary sinusExplanation
The cardiac veins collect deoxygenated blood from the heart muscle and merge together to form a larger vessel known as the coronary sinus. The coronary sinus then transports this blood back to the right atrium of the heart, where it can be pumped into the pulmonary circulation to receive oxygen and continue its journey throughout the body.Rate this question:
- 29.
____________ is the reconnection of two streams that previously branched out, such as blood vessels.
Correct Answer
AnastomosesExplanation
Anastomoses refers to the reconnection of two streams or pathways that had previously branched out. In the context of blood vessels, anastomoses occur when two or more blood vessels merge or join together, allowing for blood flow to be redirected or shared between them. This can happen naturally in the body or can be surgically created to bypass blockages or restore blood flow in certain conditions. Anastomoses are important for maintaining proper circulation and ensuring that vital organs receive an adequate blood supply.Rate this question:
- 30.
Circulation of blood through a network of minor vessels that become enlarged and joined with adjacent vessels when a major vein or artery is impaired is called: _____________
- A.
Restricted circulation
- B.
Conjoined circulation
- C.
Collateral circulation
- D.
Fused circulation
Correct Answer
C. Collateral circulationExplanation
Collateral circulation refers to the circulation of blood through a network of minor vessels that become enlarged and joined with adjacent vessels when a major vein or artery is impaired. This allows for an alternative route for blood flow, bypassing the blocked or damaged vessel and ensuring that tissues receive adequate blood supply.Rate this question:
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- 31.
Backflow of blood from one chamber to another is known as __________.
Correct Answer
regurgitationExplanation
The backflow of blood from one chamber to another is known as regurgitation. This occurs when the valves between the chambers do not close properly, allowing blood to flow in the wrong direction. Regurgitation can occur in various parts of the heart, such as the mitral valve or the aortic valve. It can be caused by conditions such as valve damage, congenital heart defects, or heart disease. Regurgitation can lead to symptoms like heart murmur, fatigue, and shortness of breath, and may require medical intervention depending on its severity.Rate this question:
- 32.
_________ are cord-like tendons that connect the papillary muscles to the tricuspid valve and mitral valve in the heart.
- A.
Chordae tendineae
- B.
Intervenous tubercle
- C.
Purjinke fibers
- D.
Sternopericardiac ligaments
Correct Answer
A. Chordae tendineaeExplanation
Chordae tendineae are cord-like tendons that connect the papillary muscles to the tricuspid valve and mitral valve in the heart. These tendons help to anchor the valves and prevent them from prolapsing or inverting into the atria during ventricular contraction. They also help to maintain the proper closure of the valves, ensuring efficient blood flow through the heart.Rate this question:
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- 33.
____________ refers to blood flow that reaches the upper and lower extremities of the body and the surface of the skin.
- A.
Systemic circulation
- B.
Positive circulation
- C.
Peripheral circulation
- D.
Complete circulation
Correct Answer
C. PeripHeral circulationExplanation
Peripheral circulation refers to blood flow that reaches the upper and lower extremities of the body and the surface of the skin. It is responsible for delivering oxygen and nutrients to these areas, as well as removing waste products. This circulation is essential for maintaining the health and function of the extremities and skin.Rate this question:
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- 34.
The __________ valves are the pulmonic and aortic valve. Their cusps resemble three half-moons.
Correct Answer
semilunarExplanation
The explanation for the given correct answer is that the term "semilunar" refers to the shape of the cusps of the pulmonic and aortic valves, which resemble three half-moons. These valves are located between the ventricles and the arteries, and they allow blood to flow in one direction while preventing backflow. The term "semilunar" accurately describes the shape and function of these valves.Rate this question:
- 35.
When the left ventricle contracts it pumps blood through the _______ valve.
Correct Answer
aorticExplanation
When the left ventricle contracts, it pumps oxygenated blood out of the heart and into the aorta, which is the largest artery in the body. The aortic valve is located between the left ventricle and the aorta, and it ensures that blood flows in one direction, preventing backflow into the heart. Therefore, when the left ventricle contracts, it pumps blood through the aortic valve into the aorta.Rate this question:
- 36.
_______________ is/ are the bundle of cardiac muscle fibers that pass from the atrioventricular node to the interventricular septum and then the ventricles. It conducts the electrical impulses that regulate the heartbeat from the right atrium to the left and right ventricles.
- A.
Bundle of His
- B.
Purkinje fibers
- C.
Bachmann's bundle
- D.
None of the above
Correct Answer
A. Bundle of HisExplanation
The correct answer is Bundle of His. The Bundle of His is a group of specialized cardiac muscle fibers that transmit electrical impulses from the atrioventricular node to the interventricular septum and then to the ventricles. These fibers play a crucial role in coordinating and regulating the heartbeat by ensuring the synchronized contraction of the left and right ventricles.Rate this question:
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- 37.
The left coronary branches off into the left anterior descending and the left circumflex arteries.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because the left coronary artery does indeed branch off into two main arteries: the left anterior descending artery and the left circumflex artery. These arteries supply blood to different regions of the heart muscle.Rate this question:
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- 38.
___________ specialized myocardial fibers, located just beneath the endocardium, that conduct an electrical stimulus or impulse that enables the heart to contract in a coordinated fashion.
- A.
Sinoatrial node
- B.
Anastomoses
- C.
Purkinje fibers
- D.
None of the above
Correct Answer
C. Purkinje fibersExplanation
Purkinje fibers are specialized myocardial fibers that are located just beneath the endocardium. These fibers are responsible for conducting electrical impulses or stimuli that enable the heart to contract in a coordinated fashion. They play a crucial role in ensuring the synchronized and efficient pumping of blood by the heart.Rate this question:
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- 39.
During one heartbeat. ventricular diastole and ventricular systole occur.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
During one heartbeat, both ventricular diastole and ventricular systole occur. Ventricular diastole is the relaxation phase of the ventricles, during which the ventricles fill with blood. Ventricular systole is the contraction phase of the ventricles, during which the blood is pumped out of the heart. These two phases are essential for the proper functioning of the heart and the circulation of blood throughout the body. Therefore, the statement is true.Rate this question:
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- 40.
During diastole, the ventricles contract and the atria relaxes.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
During diastole, the ventricles actually relax and fill with blood, while the atria contract and push blood into the ventricles. This is an important phase of the cardiac cycle that allows for the efficient pumping of blood throughout the body.Rate this question:
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- 41.
This phase of the cardiac cycle is in response to ventricular depolarization which causes the tension in the ventricles to increase.
- A.
Isovolumetric relaxation
- B.
Atrial kick
- C.
Ventricular ejection
- D.
Isovolumetric ventricular contraction
Correct Answer
D. Isovolumetric ventricular contractionExplanation
During isovolumetric ventricular contraction, the ventricles contract without any change in volume. This phase occurs in response to ventricular depolarization, which is the electrical activation of the ventricles. As the ventricles contract, the tension in the ventricular walls increases, leading to an increase in pressure. However, since the semilunar valves are still closed, no blood is ejected from the ventricles and the volume remains constant. Once the pressure in the ventricles exceeds the pressure in the arteries, the semilunar valves open and ventricular ejection begins.Rate this question:
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- 42.
Isovolumetric relaxation occurs when ventricular pressure falls below pressure in the aorta and pulmonary artery causing the aortic and pulmonary valves to close.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Isovolumetric relaxation refers to the phase of the cardiac cycle in which the ventricles are relaxed and the pressure in the ventricles falls below the pressure in the aorta and pulmonary artery. This pressure difference causes the aortic and pulmonary valves to close, preventing blood from flowing back into the ventricles. Therefore, the given statement is true.Rate this question:
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- 43.
During ventricular ejection the ventricles eject 70% of the blood.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
During ventricular ejection, the ventricles contract and pump blood out of the heart into the arteries. This is the phase of the cardiac cycle where blood is being forcefully ejected from the ventricles into the systemic circulation. The amount of blood ejected during ventricular ejection is known as the stroke volume. On average, the stroke volume is about 70% of the total volume of blood in the ventricles, meaning that approximately 70% of the blood is ejected during this phase. Therefore, the statement that the ventricles eject 70% of the blood during ventricular ejection is true.Rate this question:
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- 44.
Cardiac output refers to the amount of blood pumped by the ventricles in
- A.
60 beats
- B.
1 minute
- C.
24 hour cycle
Correct Answer
B. 1 minuteExplanation
Cardiac output is a measure of the volume of blood pumped by the ventricles of the heart in a given time. It is usually expressed as the amount of blood pumped per minute. Therefore, the correct answer is "1 minute" because cardiac output is measured over a period of one minute. This measurement is important in assessing the heart's ability to meet the body's demands for oxygen and nutrients.Rate this question:
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- 45.
________ affects cardiac output by shortening diastole and allowing less time for the ventricles to fill.
Correct Answer
TachycardiaExplanation
Tachycardia is a condition characterized by a rapid heart rate. In this context, tachycardia affects cardiac output by shortening diastole, which is the resting phase of the cardiac cycle when the heart chambers fill with blood. With tachycardia, the heart beats faster, reducing the duration of diastole and allowing less time for the ventricles to fill with blood. As a result, the amount of blood pumped out of the heart with each contraction, known as the stroke volume, decreases, leading to a decrease in cardiac output.Rate this question:
- 46.
Stroke volume is the amount of blood ejected with each ventricular contraction.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Stroke volume refers to the amount of blood that is pumped out of the ventricles of the heart with each contraction. It is a measure of the efficiency of the heart in pumping blood. Therefore, the statement that stroke volume is the amount of blood ejected with each ventricular contraction is correct.Rate this question:
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- 47.
Normal cardiac output is
- A.
2 to 6L/minute
- B.
4 to 8L/minute
- C.
6 to 10L/minute
Correct Answer
B. 4 to 8L/minuteExplanation
Normal cardiac output refers to the amount of blood pumped by the heart per minute. The average range for normal cardiac output is between 4 to 8 liters per minute. This range ensures that the body's organs and tissues receive an adequate supply of oxygenated blood. Cardiac output can vary depending on factors such as physical activity, stress, and overall health.Rate this question:
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- 48.
Cardiac output is measured by multiplying _____________ by stroke volume.
Correct Answer
heart rate
HR
heartrateExplanation
Cardiac output is a measure of the amount of blood pumped by the heart per minute. It is calculated by multiplying the heart rate, which is the number of times the heart beats per minute, by the stroke volume, which is the amount of blood pumped by the heart with each beat. Therefore, to measure cardiac output, one needs to multiply the heart rate by the stroke volume.Rate this question:
- 49.
The three factors that affect stroke volume are preload, afterload and myocardial contractility.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because preload, afterload, and myocardial contractility are indeed three factors that affect stroke volume. Preload refers to the amount of blood that fills the ventricles before contraction, afterload is the resistance the heart must overcome to eject blood from the ventricles, and myocardial contractility is the strength of the heart's contraction. These factors play a crucial role in determining the amount of blood pumped out of the heart with each beat, which is known as stroke volume.Rate this question:
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- 50.
This ability depends on how much the muscle fibers are stretched at the end of diastole.
- A.
Preload
- B.
Afterload
- C.
Contractility
Correct Answer
C. ContractilityExplanation
Contractility refers to the inherent strength and ability of the muscle fibers to contract forcefully. It is independent of the initial length of the muscle fibers and is determined by factors such as the number of actin and myosin filaments, the availability of ATP, and the sensitivity of the muscle fibers to calcium ions. Therefore, contractility is not affected by how much the muscle fibers are stretched at the end of diastole, unlike preload, which is determined by the degree of stretching of the ventricular muscle fibers at the end of diastole. Afterload, on the other hand, refers to the resistance that the ventricle must overcome to eject blood during systole and is not related to the stretching of muscle fibers at the end of diastole.Rate this question:
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