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Jump to: navigation, search A heart valve normally allows blood to flow in only one direction through the heart. The four valves commonly represented in a mammalian heart determine the pathway of blood flow through the heart. A heart valve opens or closes incumbent on differential blood pressure on each side.[1][2][3]
Organ system – A biological system is a complex network of biologically relevant entities. On the micro to the scale, examples of biological systems are cells, organelles, macromolecular complexes. A biological system is not to be confused with a living system, for further information see e. g. definition of life or synthetic biology. These specific systems are s
Heart valves
The four main valves in the heart are: The two atrioventricular (AV) valves, the mitral valve (bicuspid valve), and the tricuspid valve, which are between the upper chambers (atria) and the lower chambers (ventricles). The two semilunar (SL) valves, the aortic valve and the pulmonary valve, which are in the arteries leaving the heart.
Valves of the heart in motion, the front wall of the heart is removed in this image. Details System
Anatomical terminology – Anatomical terminology is a form of scientific terminology used by anatomists, zoologists, and health professionals such as doctors. Anatomical terminology uses many terms, suffixes, and prefixes deriving from Ancient Greek. These terms can be confusing to those unfamiliar with them, but can be more precise reducing ambiguity, also, since these ana
Cardiovascular Identifiers
FMA
The mitral valve and the aortic valve are in the left heart; the tricuspid valve and the pulmonary valve are in the right heart.
1. An example of a system: The brain, the cerebellum, the spinal cord, and the nerves are the four basic components of the nervous system.
7110 Anatomical terminology [edit on Wikidata]
There are also the coronary sinus and the inferior vena cava valves. 1. The anatomical position, with terms of relative location noted. 2. The human body is shown in anatomical position in an anterior view and a posterior view. The regions of the body are labeled in boldface. 3. Abdominal regions are used for example to localize pain.
Contents 1 Structure 1.1 Atrioventricular valves 1.2 Semilunar valves 1.3 Development 2 Physiology 3 Clinical significance 3.1 Congenital heart disease 4 History 5 See also 6 References 7 External links
Blood – Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells. In vertebrates, it is composed of blood cells suspended in blood plasma, plasma, which constitutes 55% of blood fluid, is mostly water, and contains dissip
Structure 1. Human blood smear: a – erythrocytes; b – neutrophil; c – eosinophil; d – lymphocyte. 2. A scanning electron microscope (SEM) image of a normal red blood cell, a platelet, and a white blood cell. 3. Two tubes of EDTA -anticoagulated blood. Left tube: after standing, the RBCs have settled at the bottom of the tube. Right tube: contains freshly drawn blood. 4. Vertebrate red blood cell types, measurements in micrometers Blood flow – Hemodynamics or hæmodynamics is the dynamics of blood flow. The circulatory system is controlled by mechanisms, much as hydraulic circuits are controlled by control systems. Hemodynamic response continuously monitors and adjusts to conditions in the body, thus hemodynamics explains the physical laws that govern the flow of blood in the blood vessel
Structure of the heart valves
1. Laminar shear of fluid between two plates.. Friction between the fluid and the moving boundaries causes the fluid to shear (flow). The force required for this action per unit area is the stress. The relation between the stress (force) and the shear rate (flow velocity) determines the viscosity.
Blood flow through the valves The heart valves and the chambers are lined with endocardium. Heart valves separate the atria from the ventricles, or the ventricles from a blood vessel. Heart valves are situated around the fibrous rings of the cardiac skeleton. The valves incorporate leaflets or cusps, which are pushed open to allow blood flow and which then close together to seal and prevent backflow. The mitral valve has two cusps, whereas the others have three. There are nodules at the tips of the cusps that make the seal tighter. The pulmonary valve has left, right, and anterior cusps.[4] The aortic valve has left, right, and posterior cusps.[5] The tricuspid valve has anterior, posterior, and septal cusps; and the mitral valve has just anterior and posterior cusps.
Atrioventricular valves Main articles: Mitral valve and Tricuspid valve
Aortic valve – The aortic valve is a valve in the human heart between the left ventricle and the aorta. It is one of the two valves of the heart, the other being the pulmonary valve. The heart has four valves and the two are the mitral and the tricuspid valves. The aortic valve normally has three cusps or leaflets, although in 1–2% of the population it is found t
1. Micrograph demonstrating thickening of the spongiosa layer (blue) in myxomatous degeneration of the aortic valve. 3. A replaceable model of Cardiac Biological Valve Prosthesis. 4. Micrograph of a papillary fibroelastoma, a benign tumour seen on heart valves. Valve of the coronary sinus – The valve of the coronary sinus is a semicircular fold of the lining membrane of the right atrium, at the orifice of the coronary sinus. It is situated at the base of the vena cava. The valve may vary in size, or be completely absent and it may prevent the regurgitation of blood into the sinus during the contraction of the atrium. This valve may be
1. Interior of right side of heart. (Valve of the coronary sinus labeled at bottom left.)
3D - loop of a heart viewed from the apex, with the apical part of the ventricles removed and the mitral valve clearly visible. Due to missing data, the leaflets of the tricuspid and aortic valves are not clearly visible, but the openings are; the pulmonary valve is not visible. On the left are two standard 2D views (taken from the 3D dataset) showing tricuspid and mitral valves (above) and aortal valve (below). These are the mitral and tricuspid valves, which are situated between the atria and the ventricles and prevent backflow from the ventricles into the atria during systole. They are anchored to the walls of the ventricles by chordae tendineae, which prevent the valves from inverting. The chordae tendineae are attached to papillary muscles that cause tension to better hold the valve. Together, the papillary muscles and the chordae tendineae are known as the subvalvular apparatus. The function of the subvalvular apparatus is to keep the valves from prolapsing into the atria when they close. The subvalvular apparatus has no effect on the opening and closure of the valves, however, which is caused entirely by the pressure gradient across the valve. The peculiar insertion of chords on the leaflet free margin, however, provides systolic stress sharing between chords according to their different thickness.[6] The closure of the AV valves is heard as lub, the first heart sound (S1). The closure of the SL valves is heard as dub, the second heart sound (S2). The mitral valve is also called the bicuspid valve because it contains two leaflets or cusps. The mitral valve gets its name from the resemblance to a bishop's mitre (a type of hat). It is on the left side of the heart and allows the blood to flow from the left atrium into the left ventricle.
Valve of the inferior vena cava – The valve of the inferior vena cava is a venous valve that lies at the junction of the inferior vena cava and right atrium. In fetal life, the eustachian valve helps direct the flow of blood through the right atrium into the left atrium. Before birth, the fetal circulation directs oxygen-rich blood returning from the placenta to mix with blood from
1. Interior of right side of heart. (Valve of inf. vena cava labeled at lower left.) Endocardium – The endocardium is the innermost layer of tissue that lines the chambers of the heart. Its cells are embryologically and biologically similar to the cells that line blood vessels. The endocardium also provides protection to the valves and heart chambers, the endocardium underlies the much more voluminous myocardium, the muscular tissue responsible
1. Interior of right side of heart. Atrium (heart) – The atrium is a blood collection chamber of the heart. It was previously called the auricle, and that term is used to describe this chamber in, for example, the Mollusca. The atrium is a chamber in which blood enters the heart, as opposed to the lower ventricle. It has a structure that allows blood to return to the heart. All animals with a closed
During diastole, a normally-functioning mitral valve opens as a result of increased pressure from the left atrium as it fills with blood (preloading). As atrial pressure increases above that of the left ventricle, the mitral valve opens. Opening facilitates the passive flow of blood into the left ventricle. Diastole ends with atrial contraction, which ejects the final 30% of blood that is transferred from the left atrium to the left ventricle. This amount of blood is known as the end diastolic volume (EDV), and the mitral valve closes at the end of atrial contraction to prevent a reversal of blood flow.
The tricuspid valve has three leaflets or cusps and is on the right side of the heart. It is between the right atrium and the right ventricle, and stops the backflow of blood between the two.
1. Right heart anatomy 2. Front view of heart showing the atria 3. left atrial appendage shown at upper right
Semilunar valves
Ventricle (heart) – In the heart, a ventricle is one of two large chambers that collect and expel blood received from an atrium towards the peripheral beds within the body and lungs. Interventricular means between the ventricles, while intraventricular means within one ventricle, ventricles have thicker walls than atria and generate higher blood pressures. The physiol
Main articles: Aortic valve and Pulmonary valve The aortic and pulmonary valves are located at the base of the aorta and the pulmonary trunk respectively. These are also called the "semilunar valves". These two arteries receive blood from the ventricles and their semilunar valves permit blood to be forced into the arteries, and prevent backflow from the arteries into the ventricles. These valves do not have chordae tendineae, and are more similar to the valves in veins than they are to the atrioventricular valves. The closure of the semilunar valves causes the second heart sound. The aortic valve, which has three cusps, lies between the left ventricle and the aorta. During ventricular systole, pressure rises in the left ventricle and when it is greater than the pressure in the aorta, the aortic valve opens, allowing blood to exit the left ventricle into the aorta. When ventricular systole ends, pressure in the left ventricle rapidly drops and the pressure in the aorta forces aortic valve to close. The closure of the aortic valve contributes the A2 component of the second heart sound. The pulmonary valve (sometimes referred to as the pulmonic valve) lies between the right ventricle and the pulmonary artery, and has three cusps. Similar to the aortic valve, the pulmonary valve opens in ventricular systole, when the pressure in the right ventricle rises above the pressure in the pulmonary artery. At the end of ventricular systole, when the pressure in the right ventricle falls rapidly, the pressure in the pulmonary artery will close the pulmonary valve. The closure of the pulmonary valve contributes the P2 component of the second heart sound. The right heart is a low-pressure system, so the P2 component of the second heart sound is usually softer than the A2 component of the second heart sound. However, it is physiologically normal in some young people to hear both components separated during inhalation.
Development See also: Heart development In the developing heart, the valves between the atria and ventricles, the bicuspid and the tricuspid valves, develop on either side of the atrioventricular canals.[7] The upward extension of the bases of the ventricles causes the canal to become invaginated into the ventricle cavities. The invaginated margins form the rudiments of the lateral cusps of the AV valves. The middle and septal cusps develop from the downward extension of the septum intermedium. The semilunar valves (the pulmonary and aortic valves) are formed from four thickenings at the cardiac end of the truncus arteriosus.[7] These thickenings are called endocardial cushions.[citation needed] The truncus arteriosus is originally a single outflow tract from the embryonic heart that will later split to become the ascending aorta and pulmonary trunk. Before it has split, four thickenings occur. There are anterior, posterior, and two lateral thickenings. A septum begins to form between what will later become the ascending aorta and pulmonary tract. As the septum forms, the two lateral thickenings are split, so that the ascending aorta and pulmonary trunk have three thickenings each (an anterior or posterior, and half of each of the lateral thickenings). The thickenings are the origins of the three cusps of the semilunar valves. The valves are visible as unique structures by the ninth week. As they mature, they rotate slightly as the outward vessels spiral, and move slightly closer to the heart.[7]
1. Structure diagram of the human heart from an anterior view. The larger cavities are the ventricles. Blood vessel – The blood vessels are the part of the circulatory system that transports blood throughout the human body. The word vascular, meaning relating to the vessels, is derived from the Latin vas. A few structures do not contain blood vessels and are labeled, tunica media, circularly arranged elastic fiber, connective tissue, polysaccharide substances, the
1. Blood vessel with an erythrocyte (red blood cell, E) within its lumen, endothelial cells forming its tunica intima (inner layer), and pericytes forming its tunica adventitia (outer layer) 2. Simple diagram of the human circulatory system Cardiac skeleton – The cardiac skeleton separates and partitions the atria from the ventricles. This is important because it forms the channel that electrical energy follows from the top to the bottom of the heart. The cardiac skeleton consists of four bands of connective tissue, as collagen, that encircle the bases of the pulmonary trunk, aorta. While not a skeleton
1. Transverse section of the heart showing the fibrous rings surrounding the valves Atrium (anatomy) – The atrium is a blood collection chamber of the heart. It was previously called the auricle, and that term is used to describe this chamber in, for example, the Mollusca. The atrium is a chamber in which blood enters the heart, as opposed to the lower ventricle. It has a structure that allows blood to return to the heart. All animals with a closed
Physiology In general, the motion of the heart valves is determined using the Navier–Stokes equation, using boundary conditions of the blood pressures, pericardial fluid, and external loading as the constraints. The motion of the heart valves is used as a boundary condition in the Navier–Stokes equation in determining the fluid dynamics of blood ejection from the left and right ventricles into the aorta and the lung.
1. Right heart anatomy 2. Front view of heart showing the atria 3. left atrial appendage shown at upper right Systole (medicine) – Systole /sstli/ is the part of the cardiac cycle when the ventricles contract. The term systole originates from New Latin, from Ancient Greek , from , the mammalian heart has 4 chambers, the left atrium, the left ventricle, the right atrium and the right ventricle. When the smaller, upper atria chambers contract in late diastol
1. Ventricular systole
Wiggers diagram, showing various events during a cardiac cycle, with closures and openings of the aortic and mitral marked in the pressure curves.
Papillary muscle – The papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the valves via the chordae tendineae. There are five total papillary muscles in the heart, three in the ventricle and two in the left. The anterior, posterior, and septal papillary muscles of the right ventricle each attach via chordae tendineae to
This is further explanation of the echocardiogram above. MV: Mitral valve, TV: Tricuspid valve, AV: Aortic valve, Septum: Interventricular septum. Continuous lines demarcate septum and free wall seen in echocardiogram, dotted line is a suggestion of where the free wall of the right ventricle should be. The red line represents where the upper left loop in the echocardiogram transects the 3D-loop, the blue line represents the lower loop.
1. Opened chambers of the heart displaying papillary muscles and chordae tendinae 2. Interior of right side of heart. Papillary muscles labeled in purple. 3. Papillary muscles and chordae tendinae Heart sound – Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. Specifically, the sounds reflect the turbulence created when the heart valves snap shut, in cardiac auscultation, an examiner may use a stethoscope to listen for these unique and distinct sounds that provide important auditory data regarding the c
Relationship between pressure and flow in open valves The pressure drop, the valve:
, across an open heart valve relates to the flow rate, Q, through
1. Front of thorax, showing surface relations of bones, lungs (purple), pleura (blue), and heart (red outline). The location of best auscultation for each heart valve are labeled with "M", "T", "A", and "P". First heart sound: caused by atrioventricular valves - Mitral (M) and Tricuspid (T). Second heart sound caused by semilunar valves -- Aortic (A) and Pulmonary/Pulmonic (P). Bishop – A bishop is an ordained, consecrated, or appointed member of the Christian clergy who is generally entrusted with a position of authority and oversight. Within these churches, bishops are seen as those who possess the full priesthood, Some Protestant churches including the Lutheran and Methodist churches have bishops serving similar functions as we
If: Inflow energy conserved Stagnant region behind leaflets Outflow momentum conserved Flat velocity profile Valves with a single degree of freedom Usually, the aortic and mitral valves are incorporated in valve studies within a single degree of freedom. These relationships are based on the idea of the valve being a structure with a single degree of freedom. These relationships are based on the Euler equations.
Equations for the aortic valve in this case: 1. A 6th-century image of Saint Augustine, bishop of Hippo Regius. 2. Ignatius, bishop of Antioch, student of John the Apostle 3. A bishop with other officials on an 11th-century grave in Sweden. 4. Johann Otto von Gemmingen, Prince-Bishop of Augsburg Mitre – The Mitre Corporation is an American not-for-profit organization based in Bedford, Massachusetts, and McLean, Virginia. It manages Federally Funded Research and Development Centers supporting several U. S. government agencies, Mitre is organized as follows, Additionally, internal research and development explores new technologies and ways to apply
where: u = axial velocity p = pressure A = cross sectional area of valve L = axial length of valve ( t) = single degree of freedom; when
1. The MITRE Center at MITRE's campus in Bedford Left atrium – The atrium is a blood collection chamber of the heart. It was previously called the auricle, and that term is used to describe this chamber in, for example, the Mollusca. The atrium is a chamber in which blood enters the heart, as opposed to the lower ventricle. It has a structure that allows blood to return to the heart. All animals with a closed
Atrioventricular valve
Clinical significance Main article: Valvular heart disease Valvular heart disease is a general term referring to dysfunction of the valves, and is primarily in two forms, either regurgitation, where a dysfunctional valve lets blood flow in the wrong direction, or stenosis, when a valve is narrow.[8] Regurgitation occurs when a valve becomes insufficient and malfunctions, allowing some blood to flow in the wrong direction. This insufficiency can affect any of the valves as in aortic insufficiency, mitral insufficiency, pulmonary insufficiency and tricuspid insufficiency. The other form of valvular heart disease is stenosis, a narrowing of the valve. This is a result of the valve becoming thickened and any of the heart valves can be affected, as in mitral valve stenosis, tricuspid valve stenosis, pulmonary valve stenosis and aortic valve stenosis. Stenosis of the mitral valve is a common complication of rheumatic fever. Inflammation of the valves can be caused by infective endocarditis, usually a bacterial infection but can sometimes be caused by other organisms. Bacteria can more readily attach to damaged valves.[9] Another type of endocarditis which doesn't provoke an inflammatory response, is nonbacterial thrombotic endocarditis. This is commonly found on previously undamaged valves.[9] A major valvular heart disease is mitral valve prolapse, which is a weakening of connective tissue called myxomatous degeneration of the valve. This sees the displacement of a thickened mitral valve cusp into the left atrium during systole.[8] Disease of the heart valves can be congenital, such as aortic regurgitation or acquired, for example infective endocarditis. Different forms are associated with cardiovascular disease, connective tissue disorders and hypertension. The symptoms of the disease will depend on the affected valve, the type of disease, and the severity of the disease. For example, valvular disease of the aortic valve, such as aortic stenosis or aortic regurgitation, may cause breathlessness, whereas valvular diseaes of the tricuspid valve may lead to dysfunction of the liver and jaundice. When valvular heart disease results from infectious causes, such as infective endocarditis, an affected person may have a fever and unique signs such as splinter haemorrhages of the nails, Janeway lesions, Osler nodes and Roth spots. A particularly feared complication of valvular disease is the creation of emboli because of turbulent blood flow, and the development of heart failure.[8]
1. Right heart anatomy 2. Front view of heart showing the atria 3. left atrial appendage shown at upper right Left ventricle – In the heart, a ventricle is one of two large chambers that collect and expel blood received from an atrium towards the peripheral beds within the body and lungs. Interventricular means between the ventricles, while intraventricular means within one ventricle, ventricles have thicker walls than atria and generate higher blood pressures. The physiol
1. Structure diagram of the human heart from an anterior view. The larger cavities are the ventricles. Right atrium – The atrium is a blood collection chamber of the heart. It was previously called the auricle, and that term is used to describe this chamber in, for example, the Mollusca. The atrium is a chamber in which blood enters the heart, as opposed to the lower ventricle. It has a structure that allows blood to return to the heart. All animals with a closed
Valvular heart disease is diagnosed by echocardiography, which is a form of ultrasound. Damaged and defective heart valves can be repaired, or replaced with artificial heart valves. Infectious causes may also require treatment with antibiotics.[8]
Congenital heart disease Main article: Congenital heart defect The most common form of valvular anomaly is a congenital heart defect (CHD), called a bicuspid aortic valve. This results from the fusing of two of the cusps during embryonic development forming a bicuspid valve instead of a tricuspid valve. This condition is often undiagnosed until calcific aortic stenosis has developed, and this usually happens around ten years earlier than would otherwise develop.[10][11] Less common CHD's are tricuspid and pulmonary atresia, and Ebstein's anomaly. Tricuspid atresia is the complete absence of the tricuspid valve which can lead to an underdeveloped or absent right ventricle. Pulmonary atresia is the complete closure of the pulmonary valve. Ebstein's anomaly is the displacement of the septal leaflet of the tricuspid valve causing a larger atrium and a smaller ventricle than normal.
1. Right heart anatomy 2. Front view of heart showing the atria 3. left atrial appendage shown at upper right Right ventricle – In the heart, a ventricle is one of two large chambers that collect and expel blood received from an atrium towards the peripheral beds within the body and lungs. Interventricular means between the ventricles, while intraventricular means within one ventricle, ventricles have thicker walls than atria and generate higher blood pressures. The physiol
History 1. Structure diagram of the human heart from an anterior view. The larger cavities are the ventricles. Second heart sound – Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. Specifically, the sounds reflect the turbulence created when the heart valves snap shut, in cardiac auscultation, an examiner may use a stethoscope to listen for these unique and distinct sounds that provide important auditory data regarding the c
Illustration of the valves of the heart when the ventricles are contracting.
See also 1. Front of thorax, showing surface relations of bones, lungs (purple), pleura (blue), and heart (red outline). The location of best auscultation for each heart valve are labeled with "M", "T", "A", and "P". First heart sound: caused by atrioventricular valves - Mitral (M) and Tricuspid (T). Second heart sound caused by semilunar valves -- Aortic (A) and Pulmonary/Pulmonic (P).
Pericardial heart valves Bjork–Shiley valve
References This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918) 1. ^ "Heart Valves". American Heart Association, Inc -- 10000056 Heart and Stroke Encyclopedia. American Heart Association, Inc. Retrieved 2010-08-05. 2. ^ Klabunde, RE (2009-07-02). "Pressure Gradients". Cardiovascular Physiology Concepts. Richard E. Klabunde. Retrieved 2010-08-06. 3. ^ Klabunde, RE (2007-04-05). "Cardiac Valve Disease". Cardiovascular Physiology Concepts. Richard E. Klabunde. Retrieved 2010-08-06. 4. ^ Anatomy photo:20:21-0102 at the SUNY Downstate Medical Center – "Heart: The Pulmonic Valve" 5. ^ Anatomy photo:20:29-0104 at the SUNY Downstate Medical Center – "Heart: The Aortic Valve and Aortic Sinuses" 6. ^ S Nazari et al.: Patterns Of Systolic Stress Distribution On Mitral Valve Anterior Leaflet Chordal Apparatus. A Structural Mechanical Theoretical Analysis. J Cardiovasc Surg (Turin) 2000 Apr;41(2):193–202 (video) 7. ^ a b c Schoenwolf, Gary C.; et al. (2009). "Development of the Urogenital system". Larsen's human embryology (4th ed.). Philadelphia: Churchill Livingstone/Elsevier. pp. 177– 179. ISBN 978-0-443-06811-9. 8. ^ a b c d Britton, the editors Nicki R. Colledge, Brian R. Walker, Stuart H. Ralston ; illustrated by Robert (2010). Davidson's principles and practice of medicine (21st ed.). Edinburgh: Churchill Livingstone/Elsevier. pp. 612–628. ISBN 978-0-7020-3085-7. 9. ^ a b Mitchell RS, Kumar V, Robbins SL, Abbas AK, Fausto N (2007). Robbins Basic Pathology (8th ed.). Saunders/Elsevier. pp. 406–8. ISBN 1-4160-2973-7. 10. ^ Bertazzo, S. et al. Nano-analytical electron microscopy reveals fundamental insights into human cardiovascular tissue calcification. Nature Materials 12, 576–583 (2013). 11. ^ Miller, J. D. Cardiovascular calcification: Orbicular origins. Nature Materials 12, 476–478 (2013).
Aorta – The aorta is the main artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries. The aorta distributes oxygenated blood to all parts of the body through the systemic circulation, in anatomical sources, the aorta is usually divided into sections. One way of
1. A pig's aorta cut open showing also some leaving arteries. 2. Course of the aorta in the thorax (anterior view), starting posterior to the main pulmonary artery, then anterior to the right pulmonary arteries, the trachea and the esophagus, then turning posteriorly to course dorsally to these structures. 3. Major Aorta anatomy displaying Ascending Aorta, Brachiocephalic trunk, Left Common Carotid Artery, Left Subclavian Artery, Aortic Isthmus, Aortic Arch and Descending Thoracic Aorta Heart development – Heart development refers to the prenatal development of the human heart. The heart is the first functional organ in vertebrate embryos, and in the human, the tubular heart quickly differentiates into the truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and the sinus venosus. The truncus arteriosus splits into the aorta and
External links Wikimedia Commons has media related to Heart valves. Mitral Valve Repair at The Mount Sinai Hospital – "Mitral Valve Anatomy" 3D, animated, rotatable heart valves (Rich media including Javascript and Flash player required) Anatomy of the heart Surface General Internal
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base · apex · sulci (coronary · interatrial · anterior interventricular · posterior interventricular) · borders (right · left) atria (interatrial septum · pectinate muscles · terminal sulcus) · ventricles (interventricular septum · trabeculae carneae · chordae tendineae · papillary muscle) · valves · cusps · atrioventricular septum
Right heart Chambers
Left heart
(pulmonary veins) Õ left atrium (atrial appendage) Õ mitral valve Õ left ventricle Õ aortic valve (aortic sinus) Õ (aorta and systemic circulation)
Endocardium Myocardium Layers
Pericardial cavity Pericardium
Atrioventricular canal – When this process does not happen correctly, a child will develop atrioventricular canal defect which occurs in 2 out of every 10,000 births. It also has a correlation with Down Syndrome because 20% of children with Down Syndrome suffer from atrioventricular canal disease as well and this is a very serious condition and surgery is necessary within
1. This is an echocardiography of "Complete" Atriventricular Canal Disorder. There is a clear absence of lower septum that would separate all four chambers of the heart 2. A photo of the basic anatomical structures of the heart. During normal heart development all four chambers are separated and the mitral and tricupsid valves are properly developed. Septum intermedium
heart valves Conduction system (cardiac pacemaker · SA node · Bachmann's bundle · AV node · bundle of His · bundle branches · Purkinje fibers) pericardial sinus fibrous pericardium (sternopericardial ligaments) · serous pericardium (epicardium/visceral layer) · fold of left vena cava
Blood supply
1. Outline of the formation of the heart 2. Septa formation in 30 day embryo 3. M-mode ultrasound measuring embryonic heart rate. 4. Human embryo, 38 mm, 8–9 weeks–anterior view, heart is visible.
cardiac skeleton · intervenous tubercle (venae cavae, coronary sinus) Õ right atrium (atrial appendage, fossa ovalis, limbus of fossa ovalis, crista terminalis, valve of inferior vena cava, valve of coronary sinus) Õ tricuspid valve Õ right ventricle (infundibulum, moderator band/septomarginal trabecula) Õ pulmonary valve Õ (pulmonary artery and pulmonary circulation)
Circulatory system · Coronary circulation · Coronary arteries
Retrieved from "https://en.wikipedia.org/w/index.php?title=Heart_valve&oldid=813602204" Categories: Wikipedia articles incorporating text from the 20th edition of Gray's Anatomy (1918) Cardiac anatomy Heart valves Hidden categories: All articles with unsourced statements Articles with unsourced statements from October 2014 Articles to be expanded from October 2014 All articles to be expanded Articles using small message boxes
1. Interior of dorsal half of heart of human embryo of about thirty-five days. Endocardial cushion – Endocardial cushions, or atrioventricular cushions, refer to a subset of cells in the development of the heart that play a vital role in the proper formation of the heart septa. They develop on the canal and conotruncal region of the bulbus cordis. During heart development, the heart out as a tube. As heart development continues this tube undergoes
1. Interior of dorsal half of heart from a human embryo of about thirty days. Ascending aorta – The total length is about 5 centimetres. The aortic root is the portion of the beginning at the aortic annulus. It is sometimes regarded as an entity from the rest of the ascending aorta. Between each commissure of the valve and opposite the cusps of the aortic valve. The sinotubular junction is the point in the ascending aorta where the aortic sin
RELATED TOPICS 1. Organ system – A biological system is a complex network of biologically relevant entities. On the micro to the scale, examples of biological systems are cells, organelles, macromolecular complexes. A biological system is not to be confused with a living system, for further information see e. g. definition of life or synthetic biology. These specific systems are studied in Human anatomy. Human systems are present in many other animals. Circulatory system, pumping and channeling blood to and from the body and lungs with heart, integumentary system, skin, hair, fat, and nails. Skeletal system, structural support and protection with bones, cartilage, ligaments, urinary system, kidneys, ureters, bladder and urethra involved in fluid balance, electrolyte balance and excretion of urine. Respiratory system, the used for breathing, the pharynx, larynx, bronchi, lungs. The lymphatic system includes functions including immune responses and development of antibodies, muscular system, allows for manipulation of the environment, provides locomotion, maintains posture, and produces heat. Includes skeletal muscles, smooth muscles and cardiac muscle, nervous system, collecting, transferring and processing information with brain, spinal cord and peripheral nervous system. The notion of system relies upon the concept of vital or organic function and this idea was already present in Antiquity, but the application of the term system is more reccent. Inspired in the work of Adam Smith, Milne-Edwards wrote that the body of all living beings, whether animal or plant, where the organs, comparable to workers, work incessantly to produce the phenomena that constitute the life of the individual. In more differentiated organisms, the labor could be apportioned between different instruments or systems. Synthesis and Analysis of a Biological System, by Hiroyuki Kurata,1999 2. Anatomical terminology – Anatomical terminology is a form of scientific terminology used by anatomists, zoologists, and health professionals such as doctors. Anatomical terminology uses many terms, suffixes, and prefixes deriving from Ancient Greek. These terms can be confusing to those unfamiliar with them, but can be more precise reducing ambiguity, also, since these anatomical terms are not used in everyday conversation, their meanings are less likely to change, and less likely to be misinterpreted. By using precise anatomical terminology such ambiguity is eliminated, an international standard for anatomical terminology, Terminologia Anatomica has been created. Anatomical terminology has quite regular morphology, the prefixes and suffixes are used to add meanings to different roots. The root of a term refers to an organ, tissue. For example, in the disorder hypertension, the prefix hyper- means high or over, the roots, prefixes and suffixes are often derived from Greek or Latin, and often quite dissimilar from their English-language variants. Latin names of such as musculus biceps brachii can be split up and refer to, musculus for muscle, biceps for two-headed. The first word tells us what we are speaking about, the second describes it, when describing the position of anatomical structures, structures may be described according to the anatomical landmark they are near. These landmarks may include structures, such as the umbilicus or sternum, or anatomical lines, the cephalon or cephalic region refers to the head. This area is differentiated into the cranium, facies, frons, oculus, auris, bucca, nausus, oris. The neck area is called the cervicis or cervical region, examples of structures named according to this include the frontalis muscle, submental lymph nodes, buccal membrane and orbicularis oculi muscle. Sometimes, unique terminology is used to reduce confusion in different parts of the body, for example, different terms are used when it comes to the skull in compliance with its embryonic origin and its tilted position compared to in other animals. Here, Rostral refers to proximity to the front of the nose, similarly, in the arms, different terminology is often used in the arms, in part to reduce ambiguity as what is the front, back, inner and outer surfaces. For this reason, the terms below are used, Radial referring to the radius bone, ulnar referring to the ulna bone, medially positioned when in the standard anatomical position. Other terms are used to describe the movement and actions of the hands and feet. International morphological terminology is used by the colleges of medicine and dentistry and it facilitates communication and exchanges between scientists from different countries of the world and it is used daily in the fields of research, teaching and medical care. The international morphological terminology refers to morphological sciences as a biological sciences branch, in this field, the form and structure are examined as well as the changes or developments in the organism 3. Blood – Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells. In vertebrates, it is composed of blood cells suspended in blood plasma, plasma, which constitutes 55% of blood fluid, is mostly water, and contains dissipated proteins, glucose, mineral ions, hormones, carbon dioxide, and blood cells themselves. Albumin is the protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood. The blood cells are red blood cells, white blood cells. The most abundant cells in blood are red blood cells. These contain hemoglobin, a protein, which facilitates oxygen transport by reversibly binding to this respiratory gas. In contrast, carbon dioxide is mostly transported extracellularly as bicarbonate ion transported in plasma, vertebrate blood is bright red when its hemoglobin is oxygenated and dark red when it is deoxygenated. Some animals, such as crustaceans and mollusks, use hemocyanin to carry oxygen, insects and some mollusks use a fluid called hemolymph instead of blood, the difference being that hemolymph is not contained in a closed circulatory system. In most insects, this blood does not contain oxygen-carrying molecules such as hemoglobin because their bodies are small enough for their system to suffice for supplying oxygen. Jawed vertebrates have an immune system, based largely on white blood cells. White blood cells help to resist infections and parasites, platelets are important in the clotting of blood. Arthropods, using hemolymph, have hemocytes as part of their immune system, Blood is circulated around the body through blood vessels by the pumping action of the heart. Medical terms related to blood often begin with hemo- or hemato- from the Greek word µ for blood. In terms of anatomy and histology, blood is considered a form of connective tissue, given its origin in the bones. The average adult has a volume of roughly 5 litres. These blood cells consist of erythrocytes, leukocytes, and thrombocytes, by volume, the red blood cells constitute about 45% of whole blood, the plasma about 54. 3%, and white cells about 0. 7%. Whole blood exhibits non-Newtonian fluid dynamics, if all human hemoglobin were free in the plasma rather than being contained in RBCs, the circulatory fluid would be too viscous for the cardiovascular system to function effectively. One microliter of blood contains,4.7 to 6.1 million,4.2 to 5.4 million erythrocytes, Red blood cells contain the bloods hemoglobin, mature red blood cells lack a nucleus and organelles in mammals 4. Blood flow – Hemodynamics or hæmodynamics is the dynamics of blood flow. The circulatory system is controlled by mechanisms, much as hydraulic circuits are controlled by control systems. Hemodynamic response continuously monitors and adjusts to conditions in the body, thus hemodynamics explains the physical laws that govern the flow of blood in the blood vessels. Blood is a fluid, best studied using rheology rather than hydrodynamics. Blood vessels are not rigid tubes, so classic hydrodynamics and fluids mechanics based on the use of classical viscometers are not capable of explaining hemodynamics, Blood is composed of plasma and formed elements. The plasma contains 91. 5% water, 7% proteins and 1. 5% other solutes, normal blood plasma behaves like a Newtonian fluid at physiological rates of shear. Typical values for the viscosity of human plasma at 37 °C is 1.4 mN·s/m2. The osmotic pressure of solution is determined by the number of particles present, for example, a 1 molar solution of a substance contains 7023602200000000000«6. 022×1023 molecules per liter of that substance and at 0 °C it has an osmotic pressure of 2.27 MPa. The osmotic pressure of the plasma affects the mechanics of the circulation in several ways, an alteration of the osmotic pressure difference across the membrane of a blood cell causes a shift of water and a change of cell volume. The changes in shape and flexibility affect the properties of whole blood. This in turn affects the mechanics of the whole blood, the red blood cell is highly flexible and biconcave in shape. Its membrane has a Youngs modulus in the region of 106 Pa, deformation in red blood cells is induced by shear stress. When a suspension is sheared, the red blood cells deform and spin because of the velocity gradient, with the rate of deformation and spin depending on the shear-rate and this can influence the mechanics of the circulation and may complicate the measurement of blood viscosity. From the above equation we can see that the velocity of the particle depends on the square of the radius. If the particle is released from rest in the fluid, its sedimentation velocity Us increases until it attains the value called the terminal velocity. We have looked at blood flow and blood composition, before we look at the main issue, hemodilution, let us take a brief history into the use of blood. Its therapeutic use is not a modern phenomenon, egyptian writings dates back at least 2000 years suggest oral ingestion of blood as a ‘sovereign remedy’ for leprosy. However, the use of blood comes with significant risks 5. Aortic valve – The aortic valve is a valve in the human heart between the left ventricle and the aorta. It is one of the two valves of the heart, the other being the pulmonary valve. The heart has four valves and the two are the mitral and the tricuspid valves. The aortic valve normally has three cusps or leaflets, although in 1–2% of the population it is found to congenitally have two leaflets, the aortic valve normally has three cusps – a left, right and posterior cusp. When the left ventricle contracts, pressure rises in the left ventricle, when the pressure in the left ventricle rises above the pressure in the aorta, the aortic valve opens, allowing blood to exit the left ventricle into the aorta. When ventricular systole ends, pressure in the left ventricle rapidly drops, when the pressure in the left ventricle decreases, the aortic pressure forces the aortic valve to close. The closure of the aortic valve contributes the A2 component of the heart sound. Narrowing of the valve is called aortic stenosis, limiting the blood that can leave the valve. Aortic insufficiency, also called aortic regurgitation, is when the valve is unable to close properly, blood consequently flows passively back to the heart in the wrong direction. Common causes of aortic regurgitation include vasodilation of the aorta, previous rheumatic fever, infection such as endocarditis, degeneration of the aortic valve. Aortic stenosis can also be caused by fever and degenerative calcification. The most common abnormality of the heart is the bicuspid aortic valve. In this condition, instead of three cusps, the valve has two cusps. This condition is often undiagnosed until later in life when the person develops symptomatic aortic stenosis, aortic stenosis occurs in this condition usually in patients in their 40s or 50s, an average of 10 years earlier than can occur in people with normal aortic valves. Turner syndrome, a condition that affects females, can often have a bicuspid aortic valve as one of its symptoms. Aortic valve repair or aortic valve reconstruction describes the reconstruction of both form and function of the native and dysfunctioning aortic valve, most frequently it is applied for the treatment of aortic regurgitation. It can also become necessary for the treatment of aortic aneurysm, aortic valve replacement is a surgical procedure in which a patients aortic valve is replaced by a different valve. The aortic valve can be affected by a range of diseases, the valve can become either leaky or stuck partially shut 6. Valve of the coronary sinus – The valve of the coronary sinus is a semicircular fold of the lining membrane of the right atrium, at the orifice of the coronary sinus. It is situated at the base of the vena cava. The valve may vary in size, or be completely absent and it may prevent the regurgitation of blood into the sinus during the contraction of the atrium. This valve may be double or it may be cribriform and it is named for German anatomist Adam Christian Thebesius. This article incorporates text in the domain from the 20th edition of Grays Anatomy -194314183 at GPnotebook 7. Valve of the inferior vena cava – The valve of the inferior vena cava is a venous valve that lies at the junction of the inferior vena cava and right atrium. In fetal life, the eustachian valve helps direct the flow of blood through the right atrium into the left atrium. Before birth, the fetal circulation directs oxygen-rich blood returning from the placenta to mix with blood from the veins in the inferior vena cava. Streaming this blood across the atrial septum via the foramen ovale increases the content of blood in the left atrium. This in turn increases the concentration of blood in the left ventricle, the aorta, the coronary circulation. Following birth and separation from the placenta, the content in the inferior vena cava falls. With the onset of breathing, the left atrium receives blood from the lungs via the pulmonary veins. As blood flow to the lungs increases, the amount of blood entering the left atrium increases. When the pressure in the left atrium exceeds the pressure in the right atrium, while the eustachian valve persists in adult life, it essentially does not have a specific function after the gestational period. There is a variability in size, shape, thickness, and texture of the persistent eustachian valve. At one end of the spectrum, the eustachian valve disappears completely or is represented only by a thin ridge. Most commonly, it is a fold of endocardium arising from the anterior rim of the IVC orifice. At the other extreme, it persists as a mobile, elongated structure projecting several centimeters into the right atrial cavity. In this case, it may demonstrate an undulating motion in real time echocardiography, however, higher insertion of a giant eustachian valve, which mimics the echocardiographic appearance of divided right atrium, is very rare. This type of abnormality may be confused with cor triatriatum dexter, very rarely, such a configuration of a large eustachian valve may mimic a right atrial cystic tumor. The superior vena cava does not have any homologous valve or valvule, no such valve is needed, because the SVCs venous return is flowing in the direction of gravity. The eustachian valve is seen with transthoracic echocardiography from the parasternal long axis, the apical four-chamber. The eustachian valve better seen with transesophageal echocardiography in the bi-caval view, association between the eustachian valve and patent foramen ovale has been studied in patients with cryptogenic stroke 8. Endocardium – The endocardium is the innermost layer of tissue that lines the chambers of the heart. Its cells are embryologically and biologically similar to the cells that line blood vessels. The endocardium also provides protection to the valves and heart chambers, the endocardium underlies the much more voluminous myocardium, the muscular tissue responsible for the contraction of the heart. The outer layer of the heart is termed epicardium and the heart is surrounded by an amount of fluid enclosed by a fibrous sac called the pericardium. The endocardium, which is made up of endothelial cells, controls myocardial function. This modulating role is separate from the homeometric and heterometric regulatory mechanisms that control myocardial contractility, moreover, the endothelium of the myocardial capillaries, which is also closely appositioned to the cardiomyocytes, is involved in this modulatory role. Thus, the cardiac endothelium controls the development of the heart in the embryo as well as in the adult, additionally, the contractility and electrophysiological environment of the cardiomyocyte are regulated by the cardiac endothelium. The endocardial endothelium may also act as a kind of blood–heart barrier, in myocardial infarction, ischemia of the myocardium can extend to the endocardium, disrupting the inner lining of the heart. Less extensive infarctions are often subendocardial and do not affect the epicardium, in the acute setting, subendocardial infarctions are more dangerous than transmural infarctions because they create an area of dead tissue surrounded by a boundary region of damaged myocytes. This damaged region will conduct impulses more slowly, resulting in irregular rhythms, the damaged region may enlarge or extend and become more lifethreatening. During depolarization the impulse is carried from endocardium to epicardium, in infective endocarditis, the endocardium is affected by bacteria 9. Atrium (heart) – The atrium is a blood collection chamber of the heart. It was previously called the auricle, and that term is used to describe this chamber in, for example, the Mollusca. The atrium is a chamber in which blood enters the heart, as opposed to the lower ventricle. It has a structure that allows blood to return to the heart. All animals with a closed circulatory system include at least one atrium/ auricle, the atrium receives blood as it returns to the heart to complete a circulating cycle, whereas the ventricle pumps blood out of the heart to start a new cycle. Humans have a fourchambered heart consisting of the atrium, left atrium, right ventricle. The atria are the two upper chambers, the left atrium receives the oxygenated blood from the left and right pulmonary veins, which it pumps to the left ventricle for pumping out through the aorta for systemic circulation. The right atrium and right ventricle are referred to as the right heart and similarly the left atrium. The atria do not have valves at their inlets and as a result, the sinus venarum is the adult remnant of the sinus venous and it surrounds the openings of the venae cavae and the coronary sinus. Attached to the atrium is the right atrial appendage – a pouch-like extension of the pectinate muscles. The interatrial septum separates the right atrium from the left atrium, the atria are depolarised by calcium. High in the part of the left atrium is a muscular ear-shaped pouch – the left atrial appendage. This appears to function as a decompression chamber during left ventricular systole, the sinoatrial node is located in posterior aspect of the right atrium, next to the superior vena cava. This is a group of cells which spontaneously depolarize to create an action potential. The cardiac action potential then spreads across both atria causing them to contract, forcing the blood they hold into their corresponding ventricles, the atrioventricular node is another node in the cardiac electrical conduction system. This is located between the atria and the ventricles, during embryogenesis at about two weeks, a primitive atrium begins to be formed. It begins as one chamber which over the two weeks becomes divided by the septum primum into the left atrium and the right atrium. The interatrial septum has an opening in the atrium, the foramen ovale which provides access to the left atrium 10. Ventricle (heart) – In the heart, a ventricle is one of two large chambers that collect and expel blood received from an atrium towards the peripheral beds within the body and lungs. Interventricular means between the ventricles, while intraventricular means within one ventricle, ventricles have thicker walls than atria and generate higher blood pressures. The physiological load on the ventricles requiring pumping of blood throughout the body, further, the left ventricle has thicker walls than the right because it needs to pump blood to most of the body while the right ventricle fills only the lungs. There are three types of these muscles, the third type, the papillary muscles give origin at their apices to the chordae tendinae which attach to the cusps of the tricuspid valve and to the mitral valve. The mass of the ventricle, as estimated by magnetic resonance imaging, averages 143 g ±38.4 g. The right ventricle is equal in size to that of the left ventricle and its upper front surface is circled and convex, and forms much of the sternocostal surface of the heart. Its under surface is flattened, forming part of the surface of the heart that rests upon the diaphragm. Its posterior wall is formed by the septum, which bulges into the right ventricle. Its upper and left angle forms a pouch, the conus arteriosus. A tendinous band, called the tendon of the conus arteriosus, extends upward from the right atrioventricular fibrous ring, the left ventricle is longer and more conical in shape than the right, and on transverse section its concavity presents an oval or nearly circular outline. It forms a part of the sternocostal surface and a considerable part of the diaphragmatic surface of the heart. The left ventricle is thicker and more muscular than the right ventricle because it pumps blood at a higher pressure, the right ventricle is triangular in shape and extends from the tricuspid valve in the right atrium to near the apex of the heart. Its wall is thickest at its base and thins towards the atrium, by early maturity, the walls of the left ventricle have thickened from three to six times greater than that of the right ventricle. During systole, the contract, pumping blood through the body. During diastole, the ventricles relax and fill with blood again, the left ventricle receives oxygenated blood from the left atrium via the mitral valve and pumps it through the aorta via the aortic valve, into the systemic circulation. The left ventricular muscle must relax and contract quickly, and be able to increase or lower its pumping capacity under the control of the nervous system. In the diastolic phase, it has to relax very quickly after each contraction so as to fill with the oxygenated blood flowing from the pulmonary veins. Likewise in the phase, the left ventricle must contract rapidly and forcibly to pump this blood into the aorta 11. Blood vessel – The blood vessels are the part of the circulatory system that transports blood throughout the human body. The word vascular, meaning relating to the vessels, is derived from the Latin vas. A few structures do not contain blood vessels and are labeled, tunica media, circularly arranged elastic fiber, connective tissue, polysaccharide substances, the second and third layer are separated by another thick elastic band called external elastic lamina. The tunica media may be rich in smooth muscle, which controls the caliber of the vessel. Veins dont have the external elastic lamina, but only an internal one, tunica adventitia, entirely made of connective tissue. It also contains nerves that supply the vessel as well as nutrient capillaries in the blood vessels. Capillaries consist of more than a layer of endothelium and occasional connective tissue. When blood vessels connect to form a region of diffuse vascular supply it is called an anastomosis, anastomoses provide critical alternative routes for blood to flow in case of blockages. There is a layer of muscle surrounding the arteries and the veins which help contract and this creates enough pressure for blood to be pumped around the body. Blood vessels are part of the system, together with the heart. They are roughly grouped as arterial and venous, determined by whether the blood in it is flowing away from or toward the heart. The term arterial blood is used to indicate blood high in oxygen. This is because they are carrying the blood to and from the lungs, respectively, blood vessels do not actively engage in the transport of blood, but arteries —and veins to a degree—can regulate their inner diameter by contraction of the muscular layer. This changes the flow to downstream organs, and is determined by the autonomic nervous system. Vasodilation and vasoconstriction are also used antagonistically as methods of thermoregulation, oxygen is the most critical nutrient carried by the blood. In all arteries apart from the artery, hemoglobin is highly saturated with oxygen. In all veins apart from the vein, the hemoglobin is desaturated at about 75%. The blood pressure in blood vessels is traditionally expressed in millimetres of mercury, in the arterial system, this is usually around 120 mmHg systolic and 80 mmHg diastolic 12. Cardiac skeleton – The cardiac skeleton separates and partitions the atria from the ventricles. This is important because it forms the channel that electrical energy follows from the top to the bottom of the heart. The cardiac skeleton consists of four bands of connective tissue, as collagen, that encircle the bases of the pulmonary trunk, aorta. While not a skeleton, it does provide structure and support for the heart. In youth, this structure is free of calcium adhesions and is quite flexible. With aging some calcium can accumulate on this skeleton and this accumulation contributes to the delay of the depolarisation wave in geriatric patients that can take place from the AV node and the bundle of His. The right and left fibrous rings of heart surround the atrioventricular, the right fibrous ring is known as the anulus fibrosus dexter cordis, and the left is known as the anulus fibrosus sinister cordis. The right fibrous trigone is continuous with the central fibrous body and this is the strongest part of the fibrous cardiac skeleton. The upper chambers and lower are electrically divided by the properties of proteins within the rings. The valve rings, central body and skeleton of the heart consisting of collagen are impermeable to electrical propagation, the only channel allowed through this collagen barrier is represented by a sinus that opens up to the atrioventricular node and exits to the bundle of His. The muscle origins/insertions of many of the cardiomyocytes are anchored to opposite sides of the valve rings, the atrioventricular rings serve for the attachment of the muscular fibers of the atria and ventricles, and for the attachment of the bicuspid and tricuspid valves. Lastly, there is the band, already referred to. The fibrous rings surrounding the arterial orifices serve for the attachment of the vessels and semilunar valves. The attachment of the artery to its fibrous ring is strengthened by the coat and serous membrane externally. From the margins of the notches the fibrous structure of the ring is continued into the segments of the valves. The middle coat of the artery in this situation is thin, electrical signals from the sinoatrial node and the autonomic nervous system must find their way from the upper chambers to the lower
2. The ascending aorta and arch of aorta with their branches 3. Ascending aorta Septum – See Ceuta#History for the city in Roman Mauretania. In biology, a septum is a wall, dividing a cavity or structure into smaller ones, because the dense collagen fibres of a septum usually extend out into the softer adjacent tissues, microscopic fibrous septa are less clearly defined than the macroscopic types of septa listed above. In rare instance
1. Alveolar septa (AS) Wiggers diagram – A Wiggers diagram is a standard diagram used in cardiac physiology named after Dr. Carl J. Wiggers. Note that during isovolumetric/isovolumic contraction and relaxation, all the valves are closed. At no time are all the valves open. S3 and S4 heart sounds are associated with pathologies and are not routinely heard, pressure volume diagram Flash ani
1. Wiggers Diagram, showing various events of a cardiac cycle. Cardiac cycle – The cardiac cycle refers to the sequence of mechanical and electrical events that repeats with every heartbeat. It includes the phase of relaxation diastole and the phase of contraction systole, because the human heart is a four chambered organ, there are atrial systole, atrial diastole, ventricular systole and ventricular diastole. The frequency o
1. Cardiac events occurring in the cardiac cycle. Two complete cycles are illustrated. Euler equations (fluid dynamics) – In fluid dynamics, the Euler equations are a set of quasilinear hyperbolic equations governing adiabatic and inviscid flow. They are named after Leonhard Euler, in fact, Euler equations can be obtained by linearization of some more precise continuity equations like Navier–Stokes equations in a local equilibrium state given by a Maxwellian. The Eule
1. The "Streamline curvature theorem" states that the pressure at the upper surface of an airfoil is lower than the pressure far away and that the pressure at the lower surface is higher than the pressure far away; hence the pressure difference between the upper and lower surfaces of an airfoil generates a lift force. Myxomatous degeneration
1. Micrograph demonstrating thickening of the spongiosa layer (blue) in myxomatous degeneration of the aortic valve. Movat's stain. Splinter haemorrhage
1. Splinter hemorrhage on a fingernail of the little finger. Osler nodes
1. Osler's lesions found on the hand and fingers of a 43-year-old male with subacute bacterial endocarditis. Ultrasound
1. Ultrasound image of a fetus in the womb, viewed at 12 weeks of pregnancy (bidimensionalscan) 2. An ultrasonic examination 3. Bats use ultrasounds to navigate in the darkness. 4. Sonogram of a fetus at 14 weeks (profile) Artificial heart valve
1. Different types of artificial heart valves 2. 1. Starr-Edwards Valve 2. Starr-Edwards Valve 3. Smeloff-Cutter Valve 3. Caged ball valve 4. tilting-disc valve Antibiotic
1. Testing the susceptibility of Staphylococcus aureus to antibiotics by the Kirby-Bauer disk diffusion method – antibiotics diffuse from antibiotic-containing disks and inhibit growth of S. aureus, resulting in a zone of inhibition. 2. Scanning electron micrograph of a human neutrophil ingesting methicillin-resistant Staphylococcus aureus (MRSA) 3. Alexander Fleming Embryogenesis
1. Dissection of human embryo 2. Cell divisions (cleavage). 3. Human embryo, 8-9 weeks, 38 mm Public domain
1. Newton's own copy of his Principia, with hand-written corrections for the second edition 2. L.H.O.O.Q. (1919). Derivative work by the Dadaist Marcel Duchamp based on the Mona Lisa. Gray's Anatomy
1. Henry Gray 2. Title page of American 20th edition (1918) International Standard Book Number
1. A 13-digit ISBN, 978-3-16-148410-0, as represented by an EAN-13 bar code Apex of the heart
1. Algorithm for classification of the apex beat characters Sulcus (morphology)
1. Gingival sulcus at neck of mammalian tooth Coronary sulcus
1. Sternocostal surface of heart. (Right coronary artery, which runs down coronary sulcus, is visible at left.) Anterior interventricular sulcus
1. Heart of a dog. 1. left ventricle 2. anterior interventricular sulcus 3. right ventricle 4. conus arteriosus 5. pulmonary artery 6. Ligamentum arteriosum 7. aortic arch 8. brachiocephalic artery 9. left subclavian artery 10. right auricle 11. left auricle 12. fat 13. pulmonary vein 2. Sternocostal surface of heart (sulcus visible at bottom right, but not labeled) Posterior interventricular sulcus
1. Base and diaphragmatic surface of heart. (Posterior interventricular sulcus visible at lower left, where the middle cardiac vein is labeled.) Right border of heart
1. Sternocostal surface of heart. (Right margin visible but not labeled.) Left margin of heart
1. Sternocostal surface of heart. Pectinate muscles
1. Section of the heart showing the ventricular septum. (Pectinate muscles labeled at center left.) Cusps of heart valves
1. Valve positions in heart Atrioventricular septum
1. Coronal cross section of heart. Note how the septum between the RA and LV becomes membranous. 2. Interior of heart. (AV septum not labeled, but region is visible.) Coronary sinus
1. Back (posterior) side of the heart, with coronary sinus (blue) labeled