Atrial
The atrium (; : atria) is one of the two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular mitral and tricuspid heart valves. There are two atria in the human heart – the left atrium receives blood from the pulmonary circulation, and the right atrium receives blood from the venae cavae of the systemic circulation. During the cardiac cycle, the atria receive blood while relaxed in diastole, then contract in systole to move blood to the ventricles. Each atrium is roughly cube-shaped except for an ear-shaped projection called an atrial appendage, previously known as an auricle. All animals with a closed circulatory system have at least one atrium. The atrium was formerly called the 'auricle'. That term is still used to describe this chamber in some other animals, such as the ''Mollusca''. Auricles in this modern terminology are distinguished by having thicker ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Systole
Systole ( ) is the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood. Its contrasting phase is diastole, the relaxed phase of the cardiac cycle when the chambers of the heart are refilling with blood. Etymology The term originates, via Neo-Latin, from Ancient Greek (''sustolē''), from (''sustéllein'' 'to contract'; from ''sun'' 'together' + ''stéllein'' 'to send'), and is similar to the use of the English term ''to squeeze''. Terminology, general explanation The mammalian heart has four chambers: the left atrium above the left ventricle (lighter pink, see graphic), which two are connected through the mitral (or bicuspid) valve; and the right atrium above the right ventricle (lighter blue), connected through the tricuspid valve. The atria are the receiving blood chambers for the circulation of blood and the ventricles are the discharging chambers. In late ventricular diastole, the atrial chambers contract and ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Cardiac Cycle
The cardiac cycle is the performance of the heart, human heart from the beginning of one heartbeat to the beginning of the next. It consists of two periods: one during which the heart muscle relaxes and refills with blood, called diastole, following a period of robust contraction and pumping of blood, called systole. After emptying, the heart relaxes and expands to receive another influx of blood returning from the lungs and other systems of the body, before again contracting. Assuming a healthy heart and a typical rate of 70 to 75 beats per minute, each cardiac cycle, or heartbeat, takes about 0.8 second to complete the cycle. Duration of the cardiac cycle is inversely proportional to the heart rate. Description There are two atrium (heart), atrial and two ventricle (heart), ventricle chambers of the heart; they are paired as the heart#Left heart, left heart and the heart#Right heart, right heart—that is, the left atrium with the left ventricle, the right atrium with the r ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Sinus Venosus
The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart. In mammals, the sinus venosus exists distinctly only in the embryonic heart where it is found between the two venae cavae; in the adult, the sinus venosus becomes incorporated into the wall of the right atrium to form a smooth part called the sinus venarum which is separated from the rest of the atrium by a ridge called the crista terminalis. In most mammals, the sinus venosus also forms the sinoatrial node and the coronary sinus. Development In the embryo, the thin walls of the sinus venosus are connected below with the right ventricle, and medially with the left atrium, but are free in the rest of their extent. It receives blood from the vitelline vein, umbilical vein and common cardinal vein The common cardinal veins, also known as the ducts of Cuvier, [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Diastole
Diastole ( ) is the relaxed phase of the cardiac cycle when the chambers of the heart are refilling with blood. The contrasting phase is systole when the heart chambers are contracting. Atrial diastole is the relaxing of the atria, and ventricular diastole the relaxing of the ventricles. The term originates from the Greek word (''diastolē''), meaning "dilation", from (''diá'', "apart") + (''stéllein'', "to send"). Role in cardiac cycle A typical heart rate is 75 beats per minute (bpm), which means that the cardiac cycle that produces one heartbeat, lasts for less than one second. The cycle requires 0.3 sec in ventricular systole (contraction)—pumping blood to all body systems from the two ventricles; and 0.5 sec in diastole (dilation), re-filling the four chambers of the heart, for a total of 0.8 sec to complete the cycle. Early ventricular diastole During early ventricular diastole, pressure in the two ventricles begins to drop from the peak reached during systole ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Jugular Venous Pressure
The jugular venous pressure (JVP, sometimes referred to as ''jugular venous pulse'') is the indirectly observed pressure over the venous system via visualization of the internal jugular vein. It can be useful in the differentiation of different forms of heart and lung disease. Classically three upward deflections and two downward deflections have been described. * The upward deflections are the "a" (atrial contraction), "c" (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and "v" (venous filling). * The downward deflections of the wave are the "x" descent (the atrium relaxes and the tricuspid valve moves downward) and the "y" descent (filling of ventricle after tricuspid opening). Method Visualization The patient is positioned at a 45° incline. The head is gently turned to the left, and the right external jugular vein should be identified which may be pulsatile and the filling level noted. If the external jugular ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Heart
The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrients to the tissue, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the thorax, chest, called the mediastinum. In humans, the heart is divided into four chambers: upper left and right Atrium (heart), atria and lower left and right Ventricle (heart), ventricles. Commonly, the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart. In a healthy heart, blood flows one way through the heart due to heart valves, which prevent cardiac regurgitation, backflow. The heart is enclosed in a protective sac, the pericardium, which also contains a sma ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Pectinate Muscles
The pectinate muscles (musculi pectinati) are parallel muscular ridges in the walls of the atria of the heart. Structure Behind the crest (crista terminalis) of the right atrium the internal surface is smooth. Pectinate muscles make up the part of the wall in front of this, the right atrial appendage. In the left atrium, the pectinate muscles are confined to the inner surface of its atrial appendage. They tend to be fewer and smaller than in the right atrium The atrium (; : atria) is one of the two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular mitral and tricuspid heart valves. .... This is due to the embryological origin of the auricles, which are the true atria. Some sources cite that the pectinate muscles are useful in increasing the power of contraction without increasing heart mass substantially. Pectinate muscles of the atria are different f ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Jugular Vein
The jugular veins () are veins that take blood from the head back to the heart via the superior vena cava. The internal jugular vein descends next to the internal carotid artery and continues posteriorly to the sternocleidomastoid muscle. Structure and function There are two sets of jugular veins: external and internal. The left and right external jugular veins drain into the subclavian veins. The internal jugular veins join with the subclavian veins more medially to form the brachiocephalic veins. Finally, the left and right brachiocephalic veins join to form the superior vena cava, which delivers deoxygenated blood to the right atrium of the heart. The jugular vein has tributaries consisting of petrosal sinus, facial, lingual, pharylingual, the thyroid, and sometimes the occipital vein. Internal The internal jugular vein is formed by the anastomosis of blood from the sigmoid sinus of the dura mater and the ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Wilhelm His Jr
Wilhelm His Jr. (29 December 1863 – 10 November 1934) was a Swiss cardiologist and anatomist, son of Wilhelm His Sr. In 1893, His discovered the bundle of His, the collection of specialized cardiac muscle cells in the heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ... that transmits electrical impulses and helps synchronize contraction of the cardiac muscles. Later in life, as a professor of medicine at the University of Berlin, he was one of the first to recognize that "the heartbeat has its origin in the individual cells of heart muscle." Werner–His disease (or trench fever) was also named after him. Angle of His (or incisura cardiaca) was posthumously named after him by Daniel John Cunningham in 1906. Works * ''Die Front der Ärzte'' . Velhagen & Klasi ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Crista Terminalis
The crista terminalis (also known as the terminal crest, or crista terminalis of His) is a vertical ridge on the posterolateral inner surface of the adult right atrium extending between the superior vena cava, and the inferior vena cava. The crista terminalis denotes where the junction of the embryologic sinus venosus and the right atrium occurred during embryonic development. It forms a boundary between the rough trabecular portion and the smooth, sinus venosus-derived portion (sinus venarum) of the internal surface of the right atrium. The sinoatrial node is located within the crista terminalis. Anatomy The crista terminalis generally takes the form of a smooth-surfaced, crescent-shaped thickened portion of heart muscle at the opening into the right atrial appendage. It consists of fibromuscular tissue. Features On the external aspect of the right atrium, corresponding to the crista terminalis, is a groove - the terminal sulcus. The crista terminalis provides the origin ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Right Heart
The heart is a muscular organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrients to the tissue, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest, called the mediastinum. In humans, the heart is divided into four chambers: upper left and right atria and lower left and right ventricles. Commonly, the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart. In a healthy heart, blood flows one way through the heart due to heart valves, which prevent backflow. The heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fluid. The wall of the heart is made up of three layers: ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Superior Vena Cava
The superior vena cava (SVC) is the superior of the two venae cavae, the great venous trunks that return deoxygenated blood from the systemic circulation to the right atrium of the heart. It is a large-diameter (24 mm) short length vein that receives venous return from the upper half of the body, above the diaphragm. Venous return from the lower half, below the diaphragm, flows through the inferior vena cava. The SVC is located in the anterior right superior mediastinum. It is the typical site of central venous access via a central venous catheter or a peripherally inserted central catheter. Mentions of "the cava" without further specification usually refer to the SVC. Structure The superior vena cava is formed by the left and right brachiocephalic veins, which receive blood from the upper limbs, head and neck, behind the lower border of the first right costal cartilage. It passes vertically downwards behind the first intercostal space and receives the azygos vei ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |