Concept
The heart functions as a muscular pump that circulates blood throughout the body, delivering oxygen and nutrients to tissues and removing waste products. Its coordinated contractions are regulated by electrical signals, ensuring efficient blood flow and maintaining homeostasis.
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Concept
The cardiac cycle is the sequence of events in the heart from the beginning of one heartbeat to the beginning of the next, involving systole and diastole phases for both atria and ventricles. This process ensures the coordinated pumping of blood throughout the body, maintaining efficient circulation and oxygen delivery.
Concept
Myocardial contractility refers to the intrinsic ability of the heart muscle to contract independently of preload and afterload, directly influencing cardiac output and overall heart performance. It is primarily modulated by the autonomic nervous system and various inotropic agents, reflecting changes in intracellular calcium levels and myofilament sensitivity.
Concept
Electrophysiology is the study of the electrical properties of biological cells and tissues, focusing on the flow of ions and the electrical activity that governs the function of neurons, muscles, and other cells. It is crucial for understanding how electrical signals in the body are generated, propagated, and interpreted, thereby providing insights into normal physiology and pathological conditions such as arrhythmias and epilepsy.
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Coronary circulation refers to the movement of blood through the network of arteries and veins that supply the heart muscle (myocardium) with oxygen and nutrients, essential for maintaining its continuous and efficient function. Any disruption in this circulation, such as through blockages or narrowing of coronary arteries, can lead to serious cardiovascular conditions like angina or myocardial infarction (heart attack).
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Stroke volume is the amount of blood ejected by the left ventricle of the heart in one contraction, crucial for determining cardiac output, which is the volume of blood the heart pumps per minute. It is influenced by factors such as preload, afterload, and myocardial contractility, and plays a vital role in maintaining adequate tissue perfusion and oxygenation throughout the body.
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Cardiac output is the volume of blood the heart pumps per minute and is a critical indicator of cardiovascular health. It is determined by the heart rate and stroke volume, reflecting the heart's efficiency in delivering oxygen and nutrients to tissues.
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Heart rate is the number of times a person's heart beats per minute, reflecting the heart's ability to meet the body's demands for oxygen and nutrients. It is a crucial indicator of cardiovascular health and can be influenced by factors such as activity level, emotional state, and overall fitness.
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The sinoatrial node, often referred to as the heart's natural pacemaker, is a group of specialized cells located in the right atrium that initiates the electrical impulses responsible for setting the rhythm of the heartbeat. It plays a crucial role in maintaining the heart's regular rhythm and rate, adapting to the body's needs by responding to signals from the autonomic nervous system.
Concept
The atrioventricular node is a critical component of the cardiac conduction system, acting as a gateway that regulates the electrical impulses between the atria and ventricles, ensuring coordinated heart contractions. It delays the impulse transmission to allow the ventricles to fill with blood before they contract, playing a vital role in maintaining an efficient and synchronized heartbeat.
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Ventricular systole is the phase of the cardiac cycle during which the ventricles contract, pumping blood into the pulmonary artery and aorta. This contraction is crucial for maintaining blood circulation throughout the body and is regulated by electrical signals originating from the sinoatrial node.
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Diastole is the phase of the cardiac cycle during which the heart muscles relax and the chambers fill with blood, following contraction. It is crucial for maintaining adequate blood circulation and ensuring the heart is ready for the next contraction, or systole.
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Ejection fraction is a crucial measurement used to assess how well the heart is pumping blood, specifically indicating the percentage of blood leaving the heart each time it contracts. It is a key indicator in diagnosing and monitoring heart conditions such as heart failure and cardiomyopathy.
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Atrioventricular valves are crucial components of the heart that regulate blood flow between the atria and ventricles, ensuring unidirectional flow and preventing backflow during cardiac cycles. These valves, consisting of the tricuspid and Mitral Valves, play a vital role in maintaining efficient cardiac function and overall circulatory health.
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Intercalated discs are specialized structures in cardiac muscle cells that facilitate synchronized contraction by allowing electrical and mechanical coupling between cells. They contain gap junctions, desmosomes, and adherens junctions, which are crucial for the heart's coordinated function and structural integrity.
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Diastolic pressure is the measurement of blood pressure in the arteries when the heart is at rest between beats, providing critical insight into cardiovascular health. It is the lower number in a blood pressure reading and is crucial for diagnosing conditions like hypertension and hypotension.
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Circulatory systems are complex networks that transport nutrients, gases, and wastes to and from cells, playing a crucial role in maintaining homeostasis. They can be open or closed systems, with the closed system being more efficient due to its ability to regulate blood flow and pressure precisely.
Systolic and diastolic pressures are the two measurements used to assess blood pressure, with systolic pressure representing the force exerted on artery walls during heartbeats and diastolic pressure indicating the force when the heart is at rest between beats. These measurements are crucial for diagnosing and managing conditions like hypertension, as they reflect cardiovascular health and the risk of heart disease and stroke.
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Blood pressure differential refers to the difference between systolic and diastolic blood pressure, known as pulse pressure, which can indicate cardiovascular health. A wide pulse pressure may suggest arterial stiffness or other cardiovascular issues, while a narrow pulse pressure can be a sign of poor heart function or other health concerns.
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Purkinje fibers are specialized myocardial fibers located in the inner ventricular walls of the heart that conduct electrical impulses, enabling synchronized contraction of the ventricles. They play a crucial role in the cardiac conduction system by rapidly transmitting impulses from the atrioventricular node to the ventricles, ensuring efficient heart function.
Concept
Pericardial fluid is a serous fluid found in the pericardial cavity, which acts as a lubricant to reduce friction between the heart and pericardial sac during cardiac cycles. An imbalance in its volume or composition can lead to medical conditions such as pericardial effusion or pericarditis, impacting heart function.
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Myocardial Perfusion Imaging (MPI) is a non-invasive imaging test that evaluates the blood flow to the heart muscle, often used to diagnose coronary artery disease and assess the severity of ischemia. By using radioactive tracers and imaging techniques like SPECT or PET, MPI provides crucial information on both the function and structure of the heart, aiding in treatment decisions and risk stratification.
William Harvey's discovery of the circulation of blood in the early 17th century revolutionized the understanding of the cardiovascular system by demonstrating that blood moves in a continuous loop driven by the heart. This challenged the previously held Galenic theories and laid the foundation for modern physiology and medicine.
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Oxygen flow is how the air we breathe moves through our body to help us stay alive and healthy. It's like a special delivery service that brings oxygen to all the parts of our body that need it to work properly.
Left ventricular end-diastolic pressure is like the amount of air in a balloon right before you let it go. It tells us how full the heart is before it squeezes to send blood to the rest of the body.
Chordae tendineae reconstruction is like fixing the strings that help a heart valve open and close properly. It's important because it helps the heart work well so that it can pump blood to the rest of the body.
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Vertebral veins are like little rivers in your neck that help take blood from your head back to your heart. They work with other veins to make sure your brain and spine stay healthy by carrying away used blood.
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Early defibrillation is when a special machine called a defibrillator helps a heart start beating correctly again, and doing this quickly can save someone's life. It's like giving the heart a little jump start when it's not working right.
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