EKG Tech Cardiac Anatomy and Physiology

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.

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.

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.

This statement is false. Bradycardia actually means a slow heart rate, while tachycardia indicates a rapid heart rate.

During the depolarization cycle, ions move across the cell membrane following a stimulus, resulting in the generation of an action potential. This process is essential for cell depolarization, where the membrane potential becomes less negative. Therefore, the statement "True" accurately describes the relationship between the depolarization cycle, ions crossing the cell membrane, and the occurrence of an action potential.

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.

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.

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.

The SA (sinoatrial) node is considered the heart's main pacemaker. It is responsible for initiating the electrical impulses that regulate the heart's rhythm. Located in the right atrium, the SA node generates electrical signals that cause the atria to contract and pump blood into the ventricles. This node sets the pace for the entire heart, determining the heart rate and coordinating the timing of contractions. The AV node, bundle branches, and internodal tracts also play important roles in the heart's electrical conduction system, but they are not considered the main pacemaker.

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.

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.

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.

Norepinephrine and epinephrine are hormones that are released by the sympathetic nervous system in response to stress or danger. These hormones bind to receptors on the heart, causing an increase in heart rate, automaticity (the ability of the heart to generate its own electrical impulses), AV conduction (the speed at which electrical signals travel through the heart), and contractility (the force of the heart's contractions). Therefore, it is true that norepinephrine and epinephrine increase heart rate, automaticity, AV conduction, and contractility.

*The correct term is pulmonic however, for the purpose of this quiz, pulmonary will be accepted.*

Atrial fibrillation is a condition characterized by irregular and rapid heartbeats, which disrupts the normal pumping action of the atria. The atrial kick refers to the contraction of the atria that helps to fill the ventricles with blood. In atrial fibrillation, this atrial kick is lost, leading to a decrease in cardiac output. This is because the irregular and rapid heartbeats prevent the atria from effectively pumping blood into the ventricles, resulting in reduced blood flow to the rest of the body. Therefore, it is true that atrial fibrillation can cause a loss of atrial kick and cardiac output.

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.

Tachycardia is a condition characterized by an abnormally fast heart rate. The correct answer, "an increase," explains that tachycardia is commonly caused by an increase in the automaticity of pacemaker cells located below the sinoatrial (SA) node. This means that these cells are firing at a faster rate than normal, leading to a rapid heart rate.

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.

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.

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.

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.

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.

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.

The SA Node, also known as the sinoatrial node, is responsible for initiating the electrical impulses that regulate the heartbeat. It is often referred to as the "natural pacemaker" of the heart. The SA Node is located in the upper right corner of the right atrium. This position allows it to send electrical signals to the atria, causing them to contract and pump blood into the ventricles. From there, the electrical impulses travel to the AV Node and then to the rest of the heart, coordinating the heartbeat.

The AV node, or atrioventricular node, is an important part of the electrical conduction system of the heart. It acts as a gatekeeper, delaying the electrical impulses that originate from the SA node, or sinoatrial node. This delay allows the atria to contract and pump blood into the ventricles before they contract. By delaying the impulses, the AV node ensures that the atria and ventricles are coordinated in their contractions, allowing for efficient blood flow throughout the heart. Therefore, the statement that the AV node is responsible for delaying impulses from the SA node is true.

The vagus nerve is responsible for carrying impulses that slow down the heart rate and regulate the conduction of impulses through the AV node and ventricles. This nerve plays a crucial role in maintaining heart rate and rhythm, as well as controlling the electrical signals that allow the heart to pump blood effectively.

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.

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.

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.

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.

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.

When a cell is fully depolarized, it means that the electrical charges inside and outside the cell have become equal. In order to return to its resting state, the cell undergoes repolarization. During repolarization, the electrical charges in the cell reverse their polarity and return to their normal state. This process is crucial for the proper functioning of cells and maintaining the balance of electrical signals in the body.

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.

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.

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.

The sympathetic and the adrenergic are the same. The second branch is the parasympathetic, also known as the cholinergic.

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.

The Purkinje fibers are specialized cardiac muscle fibers that conduct electrical impulses throughout the heart. They extend from the bundle branches, which are part of the electrical conduction system of the heart, into the endocardium. The endocardium is the innermost layer of the heart, consisting of a thin layer of endothelial cells. Therefore, the Purkinje fibers extend deep into the myocardial tissue, which is the middle layer of the heart and consists of cardiac muscle cells responsible for the contraction of the heart.

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.

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.

The statement is true because the His-Purkinje system is indeed the network of specialized nervous tissue that extends through the ventricles. This system is responsible for transmitting electrical signals that regulate the contraction of the heart muscles, helping to coordinate the pumping action of the heart.

Automaticity is a special characteristic of pacemaker cells that allows them to generate electrical impulses spontaneously, without any external stimulation. These cells have an intrinsic ability to initiate and regulate the heartbeat, making them essential for maintaining the regular rhythm of the heart. This automaticity is crucial for the heart to function properly and ensure a consistent and coordinated contraction of its chambers.

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.

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.

Purkinje fibers are specialized cardiac muscle fibers that conduct electrical impulses rapidly through the muscle. These fibers are responsible for assisting in the depolarization and contraction of the heart muscle. They play a crucial role in coordinating the contraction of the ventricles and ensuring efficient pumping of blood.

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.

Purkinje fibers discharge at a rate of 20-40 times per minute.