| fibrous ring of heart | One of four fibrous rings that surround atrioventricular and arterial orifices of the heart, providing attachment for the valve leaflets and maintaining patency of the orifice. As part of the fibrous skeleton of the heart, the fibrous rings also provide origin and insertion for the myocardium. Synonym: annulus fibrosus cordis, annulus fibrosus, coronary tendon, fibrous ring, Lower's ring. (05 Mar 2000) |
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| fibrous skeleton of heart | A complex framework of dense collagen forming four fibrous rings (annuli fibrosi), which surround the ostia of the valves, a right and left fibrous trigone, formed by connecting the rings, and the membranous portions of the interatrial and interventricular septa; it is found in association with the base of the ventricles, i.e., at the level of the coronary sulcus; its functions include: 1) contributing reinforcement of the valvular ostia while providing attachment for the leaflets and cusps of the valves; 2) providing origin and insertion for the myocardium; and 3) serving as a sort of electrical "insulator," separating the electrically conducted impulses of the atria and ventricles and providing passage for the common atrioventricular bundle of conductive tissue through the right fibrous trigone and membranous interventricular septum. Synonym: cardiac fibrous skeleton, cardiac skeleton, skeleton of heart. (05 Mar 2000) |
| fibrous trigones of heart | See: right fibrous trigone, left fibrous trigone. (05 Mar 2000) |
| first heart sound | Occurs with ventricular systole and is mainly produced by closure of the atrioventricular valves. (05 Mar 2000) |
| foetal heart | The heart of the foetus of any viviparous animal. It refers to the heart in the postembryonic period and is differentiated from the embryonic heart (heart/embryology) only on the basis of time. (12 Dec 1998) |
| foetal heart rate | In the foetus, the number of heart beats per minute, normally 120 to 160. (05 Mar 2000) |
| foramina of the smallest veins of heart | <anatomy> A number of fossae in the wall of the right atrium, containing the openings of minute intramural veins. Synonym: foramina venarum minimarum cordis, foramina of the smallest veins of heart, Lannelongue's foramina, thebesian foramina, Vieussens' foramina. (05 Mar 2000) |
| forward heart failure | A concept (formerly considered mutually exclusive of backward heart failure) that maintains that the phenomena of congestive heart failure result from the inadequate cardiac output, and especially from the consequent inadequacy of renal blood flow with resulting retention of sodium and water. Compare: backward heart failure. (05 Mar 2000) |
| fourth heart sound | The sound produced in late diastole in association with ventricular filling due to atrial systole and related to reduced ventricular compliance. It is a low frequency oscillation that may be normal at older ages owing to a physiologic decline in ventricular compliance but is nearly always abnormal at younger ages if it is of high intensity or palpable. It is common in ventricular hypertrophy, particularly with hypertension, and is almost invariable during acute myocardial infarction. Fourth heart sounds may arise from the right or left ventricle or both. Synonym: atrial sound. (05 Mar 2000) |
| Framingham Heart study | <epidemiology> Ongoing epidemiologic study of a cohort of over 5,000 of the population of Framingham, MA conducted since 1949 under the auspices of the National Institutes of Health and Boston University. (05 Mar 2000) |
| law of the heart | The energy liberated by the heart when it contracts is a function of the length of its muscle fibres at the end of diastole. Synonym: Starling's law. (05 Mar 2000) |
| left heart | The left atrium and left ventricle. (05 Mar 2000) |
| left heart bypass | Any procedure that shunts blood returning from the pulmonary circulation to the systemic circulation without passing through the left heart. This is utilised during some cardiac surgery and experimentally during severe left heart failure or cardiogenic shock. (05 Mar 2000) |
| left-sided heart failure | Inability of the left heart to maintain its circulatory load with corresponding rise in pressure in the pulmonary circulation usually with pulmonary congestion and ultimately pulmonary oedema. (05 Mar 2000) |
| frosted heart | Hyaloserositis involving the pericardium. Synonym: icing heart. (05 Mar 2000) |