This organ pumps blood through the blood vessels of the circulatory system. [24] The left atrium is connected to the left ventricle by the mitral valve. [40], The normal rhythmical heart beat, called sinus rhythm, is established by the heart's own pacemaker, the sinoatrial node (also known as the sinus node or the SA node). The semilunar aortic valve is at the base of the aorta and also is not attached to papillary muscles. [145] There is a heart with three chambers: two atria and one ventricle. [21] The mitral valve lies between the left atrium and left ventricle. WebThe heart is a muscular organ about the size of a fist, located just behind and slightly left of the breastbone. Any elevation of the jugular venous pulse is noted. [87], If the narrowings in coronary arteries are unsuitable for treatment with a percutaneous coronary intervention, open surgery may be required. [92] Otto Frank (18651944) was a German physiologist; among his many published works are detailed studies of this important heart relationship. Heart murmurs may be readily heard by a physician as soft swishing or hissing sounds that follow the normal sounds of heart action. The cardiovascular centres in the brainstem control the sympathetic and parasympathetic influences to the heart through the vagus nerve and sympathetic trunk. Depolarisation of the ventricles occurs concurrently, but is not significant enough to be detected on an ECG. These include drugs to prevent fluid from accumulating in the lungs by increasing the amount of urine a patient produces (diuretics), and drugs that attempt to preserve the pumping function of the heart (beta blockers, ACE inhibitors and mineralocorticoid receptor antagonists). The Aztec believed that the heart (tona) was both the seat of the individual and a fragment of the Sun's heat (istli). The halves are, in turn, divided into four chambers. The right atrium receives venous blood from the head, chest, and arms via the large vein called the superior vena cava and receives blood from the abdomen, pelvic region, and legs via the inferior vena cava. [7] As the heart cells contract, they create a current that travels through the heart. [35] Between the third and fourth week, the heart tube lengthens, and begins to fold to form an S-shape within the pericardium. [7] Once the cell has a sufficiently high charge, the sodium channels close and calcium ions then begin to enter the cell, shortly after which potassium begins to leave it. This states that the force of contraction is directly proportional to the initial length of muscle fiber, meaning a ventricle will contract more forcefully, the more it is stretched. The heart is a muscular organ that pumps blood throughout the body. The conus arteriosus is not present in any amniotes, presumably having been absorbed into the ventricles over the course of evolution. [53] The majority of cardiovascular disease is noncommunicable and related to lifestyle and other factors, becoming more prevalent with ageing. Lung damage caused by the virus prevents oxygen from reaching the heart muscle, which in turn damages the heart tissue and prevents it from getting oxygen to other tissues. These contractile cells are connected by intercalated discs which allow a rapid response to impulses of action potential from the pacemaker cells. Therefore, snakes that are larger in size tend to have a higher blood pressure due to gravitational change. This has three cusps which are not attached to any papillary muscles. [9] Exercise temporarily increases the rate, but lowers it in the long term, and is good for heart health. [59], Abnormal heart rhythms (arrhythmias) can be treated using antiarrhythmic drugs. Finally, when the pressure within the ventricles falls below the pressure within the aorta and pulmonary arteries, the aortic and pulmonary valves close. [1] The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to the lungs. Pressure is reduced in the capillaries (vessels of minute diameter) and is reduced further in the veins returning blood to the right atrium. They are also useful for evaluating the aorta, the major blood vessel which leaves the heart.[77]. Within seconds after birth, a flap of tissue known as the septum primum that previously acted as a valve closes the foramen ovale and establishes the typical cardiac circulation pattern. [12] Doctors that specialise in the heart are called cardiologists. WebHeart is an American rock band formed in 1967 in Seattle, Washington, as The Army. The heart is situated at the centre of the chest and points slightly towards the left. Because the heart is between the lungs, the left lung is smaller than the right lung and has a cardiac notch in its border to accommodate the heart. This is found at the bottom of the right atrium in the atrioventricular septum, the boundary between the right atrium and the left ventricle. More minor forms of congenital heart disease may remain undetected for many years and only reveal themselves in adult life (e.g., atrial septal defect).[65][66]. This shortens the repolarization period, thus speeding the rate of depolarization and contraction, which results in an increased heart rate. The first chamber is the sinus venosus, which collects deoxygenated blood from the body through the hepatic and cardinal veins. [11][12] Of these more than three-quarters are a result of coronary artery disease and stroke. With each heartbeat, an electrical signal travels from the top of the heart to the bottom. From here, blood flows into the atrium and then to the powerful muscular ventricle where the main pumping action will take place. What started during the nascent days of cable television as a scrappy, playful music video lineup, rapidly evolved into a reflection of American youth culture. These may work by manipulating the flow of electrolytes across the cell membrane (such as calcium channel blockers, sodium channel blockers, amiodarone, or digoxin), or modify the autonomic nervous system's effect on the heart (beta blockers and atropine). It's the primary organ of your circulatory system. Pericardial effusions often occur secondary to pericarditis, kidney failure, or tumours, and frequently do not cause any symptoms. [58], In some patients with heart failure, a specialised pacemaker known as cardiac resynchronisation therapy can be used to improve the heart's pumping efficiency. As the signal travels, it causes the heart to contract and pump blood. By the end of the fifth week, the septa are complete, and by the ninth week, the heart valves are complete. An Australian recipe for "mock goose" is actually braised stuffed beef heart.[137]. [142][144] The exception to this rule is crocodiles, which have a four-chambered heart. OpenStax CNX. He also discovered the heart valves. A different type of sound, a pericardial friction rub can be heard in cases of pericarditis where the inflamed membranes can rub together. coarctation of the aorta). The average cardiac output, using an average stroke volume of about 70mL, is 5.25 L/min, with a normal range of 4.08.0 L/min. The halves are, in turn, divided into four chambers. [87][88], Diseased heart valves that have become abnormally narrow or abnormally leaky may require surgery. [7], The strength of heart muscle contractions controls the stroke volume. The average male heart weighs around 280 to 340 grams (10 to 12 ounces). Your heart is in the center of your chest, near your lungs. [118], The heart also played a role in the Aztec system of belief. [89][92], The earliest descriptions of the coronary and pulmonary circulation systems can be found in the Commentary on Anatomy in Avicenna's Canon, published in 1242 by Ibn al-Nafis. This is lined by a double inner membrane called the serous membrane that produces pericardial fluid to lubricate the surface of the heart. Learn more. some forms of ventricular tachycardia), others by an irritable focus (e.g. [53] Heart disease is a major cause of death, accounting for an average of 30% of all deaths in 2008, globally. It usually then travels in front of the ascending aorta and then ends in a brachiocephalic node. The wall of the heart is made up of three layers: epicardium, myocardium, and endocardium. More complex syndromes are seen that affect more than one part of the heart (e.g. This is evidenced by Egyptian expressions which incorporate the word ib, such as Awi-ib for "happy" (literally, "long of heart"), Xak-ib for "estranged" (literally, "truncated of heart"). [53][55], Heart failure is defined as a condition in which the heart is unable to pump enough blood to meet the demands of the body. The most common form of human sacrifice practiced by the Aztecs was heart-extraction. On average, the heart beats about 100,000 times a day, i.e., around 3 billion beats in a lifetime. The left main coronary artery splits shortly after leaving the aorta into two vessels, the left anterior descending and the left circumflex artery. [81] Testing for the MB form of creatine kinase provides information about the heart's blood supply, but is used less frequently because it is less specific and sensitive. Cardiac output (CO) is a measurement of the amount of blood pumped by each ventricle (stroke volume) in one minute. A small amount of blood from the coronary circulation also drains into the right atrium via the coronary sinus, which is immediately above and to the middle of the opening of the inferior vena cava. This early start is crucial for subsequent embryonic and prenatal development. The period of relaxation is called diastole. [120] The message was made into a film, which highlighted that humanity must open their hearts to restore balance to the world. It starts to beat at a rate near to the mother's which is about 7580 beats per minute (bpm). As the pressure rises within the cavities of the ventricles, the mitral and tricuspid valves are forced shut. [142], Archosaurs (crocodilians and birds) and mammals show complete separation of the heart into two pumps for a total of four heart chambers; it is thought that the four-chambered heart of archosaurs evolved independently from that of mammals. Inotropes that increase the force of contraction are "positive" inotropes, and include sympathetic agents such as adrenaline, noradrenaline and dopamine. [9] The period of time during which the ventricles contract, forcing blood out into the aorta and main pulmonary artery, is known as systole, while the period during which the ventricles relax and refill with blood is known as diastole. [86], In addition to using medications, narrowed heart arteries can be treated by expanding the narrowings or redirecting the flow of blood to bypass an obstruction. patent foramen ovale, arguably a variant of normal) to serious life-threatening abnormalities (e.g. It is located in the middle cavity of the chest, between the lungs. [7], The right atrium receives blood almost continuously from the body's two major veins, the superior and inferior venae cavae. Updates? The embryonic heart rate then accelerates and reaches a peak rate of 165185 bpm early in the early 7th week (early 9th week after the LMP). The levels of electrolytes including calcium, potassium, and sodium can also influence the speed and regularity of the heart rate; low blood oxygen, low blood pressure and dehydration may increase it. It rests on the diaphragm, the muscular partition between the chest and the abdominal cavity. [7], The largest part of the heart is usually slightly offset to the left side of the chest (though occasionally it may be offset to the right) and is felt to be on the left because the left heart is stronger and larger, since it pumps to all body parts. These contractions are stimulated by electrical impulses from a natural pacemaker, the sinoatrial, or S-A, node located in the muscle of the right atrium. Hrd may be a cognate of the word for heart in Greek, Latin, and English. WebHeart. These conditions are often genetic and can be inherited, but some such as dilated cardiomyopathy may be caused by damage from toxins such as alcohol. A cardioversion, whereby an electric shock is used to stun the heart out of an abnormal rhythm, may also be used. The chambers are separated by heart valves, which make sure that the blood keeps flowing in the right direction. The ventricles start to relax, the mitral and tricuspid valves open, and the cycle begins again.[9]. [117] The identification of the heart as the seat of emotions in particular is due to the Roman physician Galen, who also located the seat of the passions in the liver, and the seat of reason in the brain. Blood in the pulmonary circulation exchanges carbon dioxide for oxygen in the lungs through the process of respiration. It does this by branching into smaller arteriesdiagonal and septal branches. Webheart meaning: 1. the organ in your chest that sends the blood around your body: 2. used to refer to a person's. These networks collect into a main left and a main right trunk, which travel up the groove between the ventricles that exists on the heart's surface, receiving smaller vessels as they travel up. A person's chest is felt for any transmitted vibrations from the heart, and then listened to with a stethoscope. In the lungs venous blood comes in contact with inhaled air, picks up oxygen, and loses carbon dioxide. Normally, two distinct sounds are heard through the stethoscope: a low, slightly prolonged lub (first sound) occurring at the beginning of ventricular contraction, or systole, and produced by closure of the mitral and tricuspid valves, and a sharper, higher-pitched dup (second sound), caused by closure of aortic and pulmonary valves at the end of systole. The heart in arthropods is typically a muscular tube that runs the length of the body, under the back and from the base of the head. Some cause abnormal thickening of the heart muscle (hypertrophic cardiomyopathy), some cause the heart to abnormally expand and weaken (dilated cardiomyopathy), some cause the heart muscle to become stiff and unable to fully relax between contractions (restrictive cardiomyopathy) and some make the heart prone to abnormal heart rhythms (arrhythmogenic cardiomyopathy). Lung damage caused by the virus prevents oxygen from reaching the heart muscle, which in turn damages the heart tissue and prevents it from getting oxygen to other tissues. The cardiac action potential is created by the movement of specific electrolytes into and out of the pacemaker cells. [7], Preload refers to the filling pressure of the atria at the end of diastole, when the ventricles are at their fullest. SARS-CoV-2, the virus that causes COVID-19, most commonly affects the lungs but It can also lead to serious heart problems. [7] Cardiac muscle tissue has autorhythmicity, the unique ability to initiate a cardiac action potential at a fixed ratespreading the impulse rapidly from cell to cell to trigger the contraction of the entire heart. Similarly, the left atrium and the left ventricle together are sometimes referred to as the left heart. All the ions travel through ion channels in the membrane of the sinoatrial cells. The right coronary artery also supplies blood to the atrioventricular node (in about 90% of people) and the sinoatrial node (in about 60% of people). [85] Echocardiograms can also be conducted under circumstances when the body is more stressed, in order to examine for signs of lack of blood supply. This tracing of the electrical signal is the electrocardiogram (ECG) or (EKG). Explore the human heart and how the cardiovascular system help circulate blood throughout the body, Listen to an exposed human heartbeat during open-heart surgery. The right atrium receives venous blood from the head, chest, and arms via the large vein called the superior vena cava and receives blood from the abdomen, pelvic region, and legs via the inferior vena cava. OpenStax College, Anatomy & Physiology. This article incorporates text from the CC-BY book: OpenStax College, Anatomy & Physiology. Your heart is at the center of your circulatory system. [92] The heart did not pump blood around, the heart's motion sucked blood in during diastole and the blood moved by the pulsation of the arteries themselves. In general, the rate of heartbeat varies inversely with the size of the animal. WebThe heart is a muscular organ about the size of a fist, located just behind and slightly left of the breastbone. The heart consists of several layers of a tough muscular wall, the myocardium. [2] [79] There are normally two heart sounds, and abnormal heart sounds can either be extra sounds, or "murmurs" related to the flow of blood between the sounds. The heart then pumps the blood into the hemocoel, a cavity between the organs. [7], Cardiovascular diseases, which include diseases of the heart, are the leading cause of death worldwide. Heart surgeon Bartley P Griffith talks about the unique transplant of pig heart to human. atrial flutter), some from the atrioventricular node (e.g. Oxygenated blood then returns to the left atrium, passes through the left ventricle and is pumped out through the aorta into systemic circulation, traveling through arteries, arterioles, and capillarieswhere nutrients and other substances are exchanged between blood vessels and cells, losing oxygen and gaining carbon dioxidebefore being returned to the heart through venules and veins. [82], Other blood tests are often taken to help understand a person's general health and risk factors that may contribute to heart disease. WebThe heart is a fist-sized organ that pumps blood throughout your body. Because the beating of the heart depends on the proper movement of ions across the surface membrane, cardiac ion channelopathies form a major group of heart diseases. Blood is ejected from the heart, causing the pressure within the ventricles to fall. In most reptilian species, there appears to be little, if any, mixing between the bloodstreams, so the aorta receives, essentially, only oxygenated blood. [93] In his manuscript, al-Nafis wrote that blood passes through the pulmonary circulation instead of moving from the right to the left ventricle as previously believed by Galen. Please refer to the appropriate style manual or other sources if you have any questions. It has four hollow chambers surrounded by muscle and other heart tissue. [55] If a narrowing (or stenosis) is relatively minor then the patient may not experience any symptoms. The foramen ovale allowed blood in the fetal heart to pass directly from the right atrium to the left atrium, allowing some blood to bypass the lungs. [115][116], Many classical philosophers and scientists, including Aristotle, considered the heart the seat of thought, reason, or emotion, often disregarding the brain as contributing to those functions. The ib or metaphysical heart was believed to be formed from one drop of blood from the child's mother's heart, taken at conception. WebThe heart pumps around 6,000-7,500 litres of blood in a day throughout the body. In addition, the body responds to the virus Diseased heart valves may have a narrow opening and therefore restrict the flow of blood in the forward direction (referred to as a stenotic valve), or may allow blood to leak in the reverse direction (referred to as valvular regurgitation). Webheart 1 of 2 noun hrt plural hearts 1 a : a hollow muscular organ of vertebrate animals that by its rhythmic contraction acts as a force pump maintaining the circulation of the blood could feel her heart pounding b : a structure in an invertebrate animal functionally analogous to the vertebrate heart c : breast, bosom placed his hand on his heart It is also known as the bicuspid valve due to its having two cusps, an anterior and a posterior cusp. [48], The adult resting heart rate ranges from 60 to 100 bpm. In crocodilians, there is a small opening, the foramen of Panizza, at the base of the arterial trunks and there is some degree of mixing between the blood in each side of the heart, during a dive underwater;[147][148] thus, only in birds and mammals are the two streams of bloodthose to the pulmonary and systemic circulationspermanently kept entirely separate by a physical barrier. Baroreceptors fire at a rate determined by how much they are stretched,[51] which is influenced by blood pressure, level of physical activity, and the relative distribution of blood. Your brain and nervous system direct your hearts function. They are generally much smaller than the contractile cells and have few myofibrils which gives them limited contractibility. It is caused by pressure exerted on the chest wall at the outset of systole by the rounded and hardened ventricular wall. In fishes the heart is a folded tube, with three or four enlarged areas that correspond to the chambers in the mammalian heart. [146], In the heart of lungfish, the septum extends partway into the ventricle. If the scales balanced, it meant the heart's possessor had lived a just life and could enter the afterlife; if the heart was heavier, it would be devoured by the monster Ammit. This can be influenced positively or negatively by agents termed inotropes. [7][32], The vagus nerve is a long, wandering nerve that emerges from the brainstem and provides parasympathetic stimulation to a large number of organs in the thorax and abdomen, including the heart. [144], In reptiles, other than snakes, the heart is usually situated around the middle of the thorax. WebHeart. On average, the heart beats about 100,000 times a day, i.e., around 3 billion beats in a lifetime. Ejection fraction can then be obtained by dividing the volume ejected by the heart (stroke volume) by the volume of the filled heart (end-diastolic volume). The heart is an organ about the size of your fist that pumps blood through your body. Testing when exercising can be used to provoke an abnormality, or an ECG can be worn for a longer period such as a 24-hour Holter monitor if a suspected rhythm abnormality is not present at the time of assessment. Blood flow through the fish heart: sinus venosus, atrium, ventricle, and outflow tract, Arteries that contain deoxygenated blood, from the heart to the lungs, Veins containing oxygenated blood from the lungs to the heart, Veins that drain blood from the cardiac tissue itself. WebHeart is an international peer reviewed journal that keeps cardiologists up to date with important research advances in cardiovascular disease. [136] In the Peruvian anticuchos de corazn, barbecued beef hearts are grilled after being tenderized through long marination in a spice and vinegar mixture. Oxygenated blood is returned to the left atrium through the pulmonary veins. The heart cavity is divided down the middle into a right and a left heart, which in turn are subdivided into two chambers. [7] Chemoreceptors present in the carotid body or adjacent to the aorta in an aortic body respond to the blood's oxygen, carbon dioxide levels. In the developed world, valvular heart disease is most commonly caused by degeneration secondary to old age, but may also be caused by infection of the heart valves (endocarditis). [79] Murmurs may be caused by damaged heart valves or congenital heart disease such as ventricular septal defects, or may be heard in normal hearts. [131] Many recipes combined them with other giblets, such as the Mexican pollo en menudencias[132] and the Russian ragu iz kurinyikh potrokhov. [7][39], Afterload, or how much pressure the heart must generate to eject blood at systole, is influenced by vascular resistance. The resting heart rate of a newborn can be 129 beats per minute (bpm) and this gradually decreases until maturity. A part of this is called the absolute refractory period. It is divided by a partition (or septum) into two halves. [49] An athlete's heart rate can be lower than 60 bpm. Oxygen travels by diffusion and there are five small muscular vessels that connect these vessels that contract at the front of the animals that can be thought of as "hearts". Your brain and nervous system direct your hearts function. [154], In some other invertebrates such as earthworms, the circulatory system is not used to transport oxygen and so is much reduced, having no veins or arteries and consisting of two connected tubes. The expression of a broken heart is a cross-cultural reference to grief for a lost one or to unfulfilled romantic love. [7] An adult heart has a mass of 250350 grams (912oz). Ernest Starling (18661927) was an important English physiologist who also studied the heart. This is achieved by the coronary circulation, which includes arteries, veins, and lymphatic vessels. Two small openings above the aortic valve carry blood to the heart muscle; the left coronary artery is above the left cusp of the valve, and the right coronary artery is above the right cusp.[7]. New scientific developments are highlighted in editorials and put in context with concise review articles. Diagnosis of heart disease is often done by the taking of a medical history, listening to the heart-sounds with a stethoscope, ECG, echocardiogram, and ultrasound. Dissection review of the anatomy of the Human Heart including vessels, internal and external features, https://en.wikipedia.org/w/index.php?title=Heart&oldid=1130666162, Wikipedia indefinitely semi-protected biographies of living people, Pages using Sister project links with default search, Wikipedia articles incorporating a citation from the 1911 Encyclopaedia Britannica with Wikisource reference, Wikipedia medicine articles ready to translate, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 31 December 2022, at 09:47. In teleosts, the conus arteriosus is very small and can more accurately be described as part of the aorta rather than of the heart proper. Corrections? congenital aortic stenosis), or the main blood vessels that lead from the heart (e.g. [7], Small lymphatic networks called plexuses exist beneath each of the three layers of the heart. Coronary heart disease, in which an inadequate supply of oxygen-rich blood is delivered to the myocardium owing to the narrowing or blockage of a coronary artery by fatty plaques, is a leading cause of death worldwide. [7] [g][21], Two additional semilunar valves sit at the exit of each of the ventricles. Blood returning from both the systemic circulation and the lungs is returned, and blood is pumped simultaneously into the systemic circulation and the lungs. The pulmonary trunk divides into pulmonary arteries and progressively smaller arteries throughout the lungs, until it reaches capillaries. These muscles prevent the valves from falling too far back when they close. Recording of heart sounds from a 16-year-old girl with a cardiac arrhythmia. Passage of blood through the left atrium, bicuspid valve, left ventricle, aorta, tissues of the body, and back to the right atrium constitutes the systemic circulation. The heart is one of the body's most essential organs. [7], The left atrium receives oxygenated blood back from the lungs via one of the four pulmonary veins. The low-pressure circuit from the heart (right atrium and right ventricle), through the lungs, and back to the heart (left atrium) constitutes the pulmonary circulation. [7] Preload can also be affected by a person's blood volume. [7] Norepinephrine binds to the beta1 receptor.[7]. Whilst the majority of arrhythmias can be treated using minimally invasive catheter techniques, some arrhythmias (particularly atrial fibrillation) can also be treated using open or thoracoscopic surgery, either at the time of other cardiac surgery or as a standalone procedure. After the ventricles have completed most of their filling, the atria contract, forcing further blood into the ventricles and priming the pump. It travels to the left atrium via Bachmann's bundle, such that the muscles of the left and right atria contract together. The left atrium has an outpouching called the left atrial appendage. An echocardiogram is an ultrasound of the heart used to measure the heart's function, assess for valve disease, and look for any abnormalities. It may be a straight tube, as in spiders and annelid worms, or a somewhat more elaborate structure with one or more receiving chambers (atria) and a main pumping chamber (ventricle), as in mollusks. Pacemakers, comprising a small battery powered generator implanted under the skin and one or more leads that extend to the heart, are most commonly used to treat abnormally slow heart rhythms. However, as the atrial baroreceptors increase their rate of firing and as they stretch due to the increased blood pressure, the cardiac center responds by increasing sympathetic stimulation and inhibiting parasympathetic stimulation to increase heart rate. It is then pumped into the left ventricle through the mitral valve and into the aorta through the aortic valve for systemic circulation. These structures form the anatomical basis of the electrocardiogram, whose inventor, Willem Einthoven, was awarded the Nobel Prize in Medicine or Physiology in 1924. A heart valve may become narrowed (stenosis), leaky (regurgitation or insufficiency) or close improperly (prolapse). In very severe cases of heart failure, a small pump called a ventricular assist device may be implanted which supplements the heart's own pumping ability. [6] Fish, in contrast, have two chambers, an atrium and a ventricle, while most reptiles have three chambers. The human heart viewed from the front and from behind, Heart illustration with circulatory system, Animated Heart 3d Model Rendered in Computer. They open and close to move blood through the heart. WebHeart is an international peer reviewed journal that keeps cardiologists up to date with important research advances in cardiovascular disease. Tetralogy of Fallot). : The Discovery of the Electrical System of the Heart", "A Brief History of Cross-Species Organ Transplantation", "The operation that took medicine into the media age", "2022 News - IN MEMORIAM: David Bennett, Sr. | University of Maryland School of Medicine", "The Failing Heart An Engine Out of Fuel", "Out of the Head, Into the Heart: The Way of the Human Being", "The Indigenous Art of Following Wisdom from the Heart", "Bible Gateway passage: Matthew 5:8 - New International Version", "Bible Gateway passage: Proverbs 4:23 - New International Version", "Bible Gateway passage: Matthew 6:21 - New International Version", "Bible Gateway passage: Proverbs 23:7 - New King James Version", "Scaling of Cardiovascular Physiology in Snakes", "Cardiovascular Dynamics in Crocodylus Porosus Breathing Air And During Voluntary Aerobic Dives", "Dynamic Anatomical Study of Cardiac Shunting in Crocodiles Using High-Resolution Angioscopy", "World's oldest heart found in prehistoric fish". 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