|
Tricuspid Valves
The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, at the superior portion of the right ventricle. The function of the valve is to allow blood to flow from the right atrium to the right ventricle during diastole, and to close to prevent backflow ( regurgitation) from the right ventricle into the right atrium during right ventricular contraction (systole). Structure The tricuspid valve usually has three cusps or leaflets, named the anterior, posterior, and septal cusps. Each leaflet is connected via chordae tendineae to the anterior, posterior, and septal papillary muscles of the right ventricle, respectively. Tricuspid valves may also occur with two or four leaflets; the number may change over a lifetime. Function The tricuspid valve functions as a one-way valve that closes during ventricular systole to prevent regurgitation of blood from the right ventricle back into the right atrium. It opens during ventricular diastole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, 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. In humans, other mammals, and birds, 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. Fish, in contrast, have two chambers, an atrium and a ventricle, while most reptiles have three chambers. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Right Ventricular Volume Overload
Volume overload refers to the state of one of the chambers of the heart in which too large a volume of blood exists within it for it to function efficiently. Ventricular volume overload is approximately equivalent to an excessively high preload. It is a cause of cardiac failure. Pathophysiology In accordance with the Frank–Starling law of the heart, the myocardium contracts more powerfully as the end-diastolic volume increases. Stretching of the myofibrils in cardiac muscle causes them to contract more powerfully due to a greater number of cross-bridges being formed between the myofibrils within cardiac myocytes.Klabunde, Richard E. "Cardiovascular Physiology Concepts". Lippincott Williams & Wilkins, 2011, p. 74. This is true up to a point, however beyond this there is a loss of contractile ability due to loss of connection between myofibrils; see figure. Various pathologies, listed below, can lead to volume overload. Different mechanisms are involved depending on the cau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiac Muscle
Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of the heart. The cardiac muscle (myocardium) forms a thick middle layer between the outer layer of the heart wall (the pericardium) and the inner layer (the endocardium), with blood supplied via the coronary circulation. It is composed of individual cardiac muscle cells joined by intercalated discs, and encased by collagen fibers and other substances that form the extracellular matrix. Cardiac muscle contracts in a similar manner to skeletal muscle, although with some important differences. Electrical stimulation in the form of a cardiac action potential triggers the release of calcium from the cell's internal calcium store, the sarcoplasmic reticulum. The rise in calcium causes the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Variation
An anatomical variation, anatomical variant, or anatomical variability is a presentation of body structure with morphological features different from those that are typically described in the majority of individuals. Anatomical variations are categorized into three types including morphometric (size or shape), consistency (present or absent), and spatial (proximal/distal or right/left). Variations are seen as normal in the sense that they are found consistently among different individuals, are mostly without symptoms, and are termed anatomical variations rather than abnormalities. Anatomical variations are mainly caused by genetics and may vary considerably between different populations. The rate of variation considerably differs between single organs, particularly in muscles. Knowledge of anatomical variations is important in order to distinguish them from pathological conditions. A very early paper published in 1898, presented anatomic variations to have a wide range and signi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Framingham Heart Study
The Framingham Heart Study is a long-term, ongoing cardiovascular cohort study of residents of the city of Framingham, Massachusetts. The study began in 1948 with 5,209 adult subjects from Framingham, and is now on its third generation of participants. Prior to the study almost nothing was known about the epidemiology of hypertensive or arteriosclerotic cardiovascular disease. Much of the now-common knowledge concerning heart disease, such as the effects of diet, exercise, and common medications such as aspirin, is based on this longitudinal study. It is a project of the National Heart, Lung, and Blood Institute, in collaboration with (since 1971) Boston University. Various health professionals from the hospitals and universities of Greater Boston staff the project. History In 1948, the study was commissioned by Congress, with a choice made between Framingham, Massachusetts and Paintsville, Kentucky. Framingham was chosen when residents showed more general interest in heart rese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tricuspid Regurgitation
Tricuspid regurgitation (TR), also called tricuspid insufficiency, is a type of valvular heart disease in which the tricuspid valve of the heart, located between the right atrium and right ventricle, does not close completely when the right ventricle contracts (systole). TR allows the blood to flow backwards from the right ventricle to the right atrium, which increases the volume and pressure of the blood both in the right atrium and the right ventricle, which may increase central venous volume and pressure if the backward flow is sufficiently severe. The causes of TR are divided into ''hereditary'' and ''acquired''; and also ''primary'' and ''secondary''. Primary TR refers to a defect solely in the tricuspid valve, such as infective endocarditis; secondary TR refers to a defect in the valve as a consequence of some other pathology, such as left ventricular failure or pulmonary hypertension. The mechanism of TR is either a dilatation of the base (annulus) of the valve due to righ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cleveland Clinic
Cleveland Clinic is a nonprofit American academic medical center based in Cleveland, Ohio. Owned and operated by the Cleveland Clinic Foundation, an Ohio nonprofit corporation established in 1921, it runs a 170-acre (69 ha) campus in Cleveland, as well as 11 affiliated hospitals, 19 family health centers in Northeast Ohio, and hospitals in Florida and Nevada. International operations include the Cleveland Clinic Abu Dhabi hospital in the United Arab Emirates and Cleveland Clinic Canada, which has two executive health and sports medicine clinics in Toronto."Facts & Figures" Cleveland Clinic. Another hospital campus in the United Kingdom, Cleveland Clinic London, opened to outpatients in 2021 and is scheduled to fully open in 2022. Tomislav Mihaljevic is the president and CEO. Cleveland Cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serotonin
Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and vasoconstriction. Approximately 90% of the serotonin that the body produces is in the intestinal tract. Biochemically, the indoleamine molecule derives from the amino acid tryptophan, via the (rate-limiting) hydroxylation of the 5 position on the ring (forming the intermediate 5-hydroxytryptophan), and then decarboxylation to produce serotonin. Serotonin is primarily found in the enteric nervous system located in the gastrointestinal tract (GI tract). However, it is also produced in the central nervous system (CNS), specifically in the raphe nuclei located in the brainstem, Merkel cells located in the skin, pulmonary neuroendocrine cells and taste receptor cells in the tongue. Additionally, serotonin is stored in blood platelets and is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ebstein's Anomaly
Ebstein's anomaly is a congenital heart defect in which the septal and posterior leaflets of the tricuspid valve are displaced towards the apex of the right ventricle of the heart. It is classified as a critical congenital heart defect accounting for less than 1% of all congenital heart defects presenting in around per 200,000 live births. Ebstein anomaly is the congenital heart lesion most commonly associated with supraventricular tachycardia. Signs and symptoms The annulus of the valve is still in the normal position. The valve leaflets, however, are to a varying degree, attached to the walls and septum of the right ventricle. A subsequent "atrialization" of a portion of the morphologic right ventricle (which is then contiguous with the right atrium) is seen. This causes the right atrium to be large and the anatomic right ventricle to be small in size. * S3 heart sound * S4 heart sound * Triple or quadruple gallop due to widely split S1 and S2 sounds plus a loud S3 and/or S4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congenital
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth defects are divided into two main types: structural disorders in which problems are seen with the shape of a body part and functional disorders in which problems exist with how a body part works. Functional disorders include metabolic and degenerative disorders. Some birth defects include both structural and functional disorders. Birth defects may result from genetic or chromosomal disorders, exposure to certain medications or chemicals, or certain infections during pregnancy. Risk factors include folate deficiency, drinking alcohol or smoking during pregnancy, poorly controlled diabetes, and a mother over the age of 35 years old. Many are believed to involve multiple factors. Birth defects may be vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Sinai Hospital, New York
Mount Sinai Hospital, founded in 1852, is one of the oldest and largest teaching hospitals in the United States. It is located in East Harlem in the New York City borough of Manhattan, on the eastern border of Central Park stretching along Madison and Fifth Avenues, between East 98th Street and East 103rd Street. The entire Mount Sinai health system has over 7,400 physicians, as well as 3,815 beds, and delivers over 16,000 babies a year. In 2019–20, the hospital was ranked 14th among the nearly 5,000 hospitals in the US by the ''U.S. News & World Report''. Adjacent to the hospital is the Mount Sinai Kravis Children's Hospital which provides comprehensive pediatric specialties and subspecialties to infants, children, teens, and young adults aged 0–21 throughout the region. History At the time of the founding of the hospital in 1852, other hospitals in New York City discriminated against Jewish people both by not hiring them to treat patients, and by prohibiting them from bei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
