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Aorticopulmonary Septum
The aorticopulmonary septum is developmentally formed from neural crest, specifically the cardiac neural crest, and actively separates the aorta and pulmonary arteries and fuses with the interventricular septum within the heart during heart development. Structure In the developing heart, the truncus arteriosus and bulbus cordis are divided by the aortic septum. This makes its appearance in three portions. # Two distal ridge-like thickenings project into the lumen of the tube; these increase in size, and ultimately meet and fuse to form a septum, which takes a spiral course toward the proximal end of the truncus arteriosus. It divides the distal part of the truncus into two vessels, the aorta and pulmonary artery, which lie side by side above, but near the heart the pulmonary artery is in front of the aorta. # Four endocardial cushions appear in the proximal part of the truncus arteriosus in the region of the future semilunar valves; the manner in which these are related to the aorti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aortic Bulb
The aortic sac or aortic bulb is a dilated structure in mammalian embryos, lined by endothelial cells and is the most distal part of the truncus arteriosus. It is the primordial vascular channel from which the aortic arches arise (and eventually the dorsal aortae) and is homologous to the ventral aorta of gill-bearing vertebrates. The aortic sac eventually forms right and left horns, which subsequently give rise to the brachiocephalic trunk and the proximal segment of the arch of aorta, respectively. Genes ''HAND2'' (''dHAND'') and ''HAND1'' (''eHAND'') are expressed during the development of the aortic bulb and the arteries which arise from it.Richard P. Harvey, Nadia Rosenthal (ed)Heart Development Gulf Professional Publishing, 1999; page 150-151. The protein encoded by these genes belong to the basic helix-loop-helix family of transcription factor In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aortic Arches
The aortic arches or pharyngeal arch arteries (previously referred to as branchial arches in human embryos) are a series of six paired embryological vascular structures which give rise to the great arteries of the neck and head. They are ventral to the dorsal aorta and arise from the aortic sac. The aortic arches are formed sequentially within the pharyngeal arches and initially appear symmetrical on both sides of the embryo, but then undergo a significant remodelling to form the final asymmetrical structure of the great arteries. Structure Arches 1 and 2 The ''first'' and ''second arches'' disappear early. A remnant of the 1st arch forms part of the maxillary artery, a branch of the external carotid artery. The ventral end of the second develops into the ascending pharyngeal artery, and its dorsal end gives origin to the stapedial artery, a vessel which typically atrophies in humans but persists in some mammals. The stapedial artery passes through the ring of the stapes and di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aortopulmonary Septal Defect
Aortopulmonary septal defect is a rare congenital heart disorder accounting for only 0.1-0.3% of congenital heart defects worldwide. It is characterized by a communication between the aortic and pulmonary arteries, with preservation of two normal semilunar valves. It is the result of an incomplete separation of the aorticopulmonary trunk that normally occurs in early fetal development with formation of the spiral septum.Burakovsky, V. I., Falkovsky, G. E., & Ivanitsky, A. V. (1984). Surgical repair of truncus arteriosus. ''Pediatric cardiology'', ''5''(2), 111-114. Aortopulmonary septal defects occur in isolation in about half of cases, the remainder are associated with more complex heart abnormalities. Causes Diagnosis Subtypes There are numerous types, differentiated by the extent of the defect. These types are: * Type I: simple defects leading to communication between the ascending aorta and pulmonic trunk * Type II: defects that extend to the origin of the right pulmona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anomalous Pulmonary Venous Connection
Anomalous pulmonary venous connection (or anomalous pulmonary venous drainage or anomalous pulmonary venous return) is a congenital defect of the pulmonary veins. Total anomalous pulmonary venous connection ''Total anomalous pulmonary venous connection'', also known as total ''anomalous pulmonary venous return'', is a rare cyanotic congenital heart defect in which all four pulmonary veins are malpositioned and make anomalous connections to the systemic venous circulation. (Normally, pulmonary veins return oxygenated blood from the lungs to the left atrium where it can then be pumped to the rest of the body). A patent foramen ovale, patent ductus arteriosus or an atrial septal defect ''must'' be present, or else the condition is fatal due to a lack of systemic blood flow. In some cases, it can be detected prenatally. There are four variants: Supracardiac (50%): blood drains to one of the innominate veins (brachiocephalic veins) or the superior vena cava; Cardiac (20%), where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tricuspid Atresia
Tricuspid atresia is a form of congenital heart disease whereby there is a complete absence of the tricuspid valve. Therefore, there is an absence of right atrioventricular connection. This leads to a hypoplastic (undersized) or absent right ventricle. This defect is contracted during prenatal development, when the heart does not finish developing. It causes the systemic circulation to be filled with relatively deoxygenated blood. The causes of tricuspid atresia are unknown. In most cases of tricuspid atresia, additional defects exist to allow exchange of blood between the loops of systematic circulation and pulmonary circulation, filling in the role of the missing atrioventricular connection. An atrial septal defect (ASD) must be present to fill the left atrium and the left ventricle with blood. Since there is a lack of a right ventricle, there must also be a way to pump blood into the pulmonary artery. This can be accomplished by a ventricular septal defect (VSD) connecting the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dextro-Transposition Of The Great Arteries
dextro-Transposition of the great arteries (d-Transposition of the great arteries, dextro-TGA, or d-TGA) is a potentially life-threatening birth defect in the large arteries of the heart. The primary arteries (the aorta and the pulmonary artery) are transposed. It is called a cyanotic congenital heart defect (CHD) because the newborn infant turns blue from lack of oxygen. In segmental analysis, this condition is described as ventriculoarterial discordance with atrioventricular concordance, or just ventriculoarterial discordance. d-TGA is often referred to simply as transposition of the great arteries (TGA); however, TGA is a more general term which may also refer to levo-transposition of the great arteries (l-TGA).Another term commonly used to refer to both d-TGA and l-TGA is transposition of the great vessels (TGV), although this term might have an even broader meaning than TGA. Prenatally, a baby with d-TGA experiences no symptoms as the lungs will not be used until after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Persistent Truncus Arteriosus
Persistent truncus arteriosus (PTA), often referred to simply as truncus arteriosus, is a rare form of congenital heart disease that presents at birth. In this condition, the embryological structure known as the truncus arteriosus (embryology), truncus arteriosus fails to properly divide into the pulmonary trunk and aorta. This results in one arterial trunk arising from the heart and providing mixed blood to the coronary arteries, pulmonary arteries, and systemic circulation. For the ICD-11, International Classification of Diseases (ICD-11), the International Paediatric and Congenital Cardiac Code (IPCCC) was developed to standardize the nomenclature of congenital heart disease. Under this system, English is now the official language, and persistent truncus arteriosus should properly be termed common arterial trunk. Causes Most of the time, this defect occurs spontaneously. Genetic disorders and teratogens (viruses, metabolic imbalance, and industrial or pharmacological agents) ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetralogy Of Fallot
Tetralogy of Fallot (TOF), formerly known as Steno-Fallot tetralogy, is a congenital heart defect characterized by four specific cardiac defects. Classically, the four defects are: *pulmonary stenosis, which is narrowing of the exit from the right ventricle; * a ventricular septal defect, which is a hole allowing blood to flow between the two ventricles; * right ventricular hypertrophy, which is thickening of the right ventricular muscle; and * an overriding aorta, which is where the aorta expands to allow blood from both ventricles to enter. At birth, children may be asymptomatic or present with many severe symptoms. Later in infancy, there are typically episodes of bluish colour to the skin due to a lack of sufficient oxygenation, known as cyanosis. When affected babies cry or have a bowel movement, they may undergo a "tet spell" where they turn cyanotic, have difficulty breathing, become limp, and occasionally lose consciousness. Other symptoms may include a heart murmur, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extracellular Matrix
In biology, the extracellular matrix (ECM), also called intercellular matrix, is a three-dimensional network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and biochemical support to surrounding cells. Because multicellularity evolved independently in different multicellular lineages, the composition of ECM varies between multicellular structures; however, cell adhesion, cell-to-cell communication and differentiation are common functions of the ECM. The animal extracellular matrix includes the interstitial matrix and the basement membrane. Interstitial matrix is present between various animal cells (i.e., in the intercellular spaces). Gels of polysaccharides and fibrous proteins fill the Interstitial fluid, interstitial space and act as a compression buffer against the stress placed on the ECM. Basement membranes are sheet-like depositions of ECM on which various epithelial cells rest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemodynamics
Hemodynamics or haemodynamics are the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms of autoregulation, just as hydraulic circuits are controlled by control systems. The hemodynamic response continuously monitors and adjusts to conditions in the body and its environment. Hemodynamics explains the physical laws that govern the flow of blood in the blood vessels. Blood flow ensures the transportation of nutrients, hormones, metabolic waste products, oxygen, and carbon dioxide throughout the body to maintain cell-level metabolism, the regulation of the pH, osmotic pressure and temperature of the whole body, and the protection from microbial and mechanical harm. Blood is a non-Newtonian fluid, and is most efficiently studied using rheology rather than hydrodynamics. Because blood vessels are not rigid tubes, classic hydrodynamics and fluids mechanics based on the use of classical viscometers are not capable of explaining haemodynamics. The st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contractile
Contractility refers to the ability for self-contraction, especially of the muscles or similar active biological tissue *Contractile ring in cytokinesis *Contractile vacuole *Muscle contraction **Myocardial contractility *See contractile cell for an overview of cell types in humans. See also *motility Motility is the ability of an organism to move independently, using metabolic energy. Definitions Motility, the ability of an organism to move independently, using metabolic energy, can be contrasted with sessility, the state of organisms th ... {{SIA Cell movement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semilunar Valves
A heart valve is a one-way valve that allows blood to flow in one direction through the chambers of the heart. Four valves are usually present in a mammalian heart and together they determine the pathway of blood flow through the heart. A heart valve opens or closes according to differential blood pressure on each side. The four valves in the mammalian heart are two atrioventricular valves separating the upper atria from the lower ventricles – the mitral valve in the left heart, and the tricuspid valve in the right heart. The other two valves are at the entrance to the arteries leaving the heart these are the semilunar valves – the aortic valve at the aorta, and the pulmonary valve at the pulmonary artery. The heart also has a coronary sinus valve, and an inferior vena cava valve, not discussed here. Structure 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 va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
