Words for the Heart: A Treasury of Emotions from Classical India

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The heart also played a role in the Aztec system of belief. The most common form of human sacrifice practiced by the Aztecs was heart-extraction. The Aztec believed that the heart ( tona) was both the seat of the individual and a fragment of the Sun's heat ( istli). To this day, the Nahua consider the Sun to be a heart-soul ( tona-tiuh): "round, hot, pulsating". [121] The left heart has two chambers: the left atrium and the left ventricle, separated by the mitral valve. [7] The average cardiac output, using an average stroke volume of about 70mL, is 5.25 L/min, with a normal range of 4.0–8.0 L/min. [7] The stroke volume is normally measured using an echocardiogram and can be influenced by the size of the heart, physical and mental condition of the individual, sex, contractility, duration of contraction, preload and afterload. [7] Kurian G (2001). "Sacred Heart of Jesus". Nelson's Dictionary of Christianity: The Authoritative Resource on the Christian World. Thomas Nelson Inc. ISBN 978-1-4185-3981-8. arrhythmia (say: uh -RITH-mee-uh) : An arrhythmia is an abnormal heartbeat usually caused by an electrical "short circuit" in the heart. It can cause the heart to pump too fast, too slow, or irregularly, which may lead to shortness of breath, dizziness, and chest pain.

When the sinoatrial cells are resting, they have a negative charge on their membranes. A rapid influx of sodium ions causes the membrane's charge to become positive; this is called depolarisation and occurs spontaneously. [7] Once the cell has a sufficiently high charge, the sodium channels close and calcium ions then begin to enter the cell, shortly after which potassium begins to leave it. All the ions travel through ion channels in the membrane of the sinoatrial cells. The potassium and calcium start to move out of and into the cell only once it has a sufficiently high charge, and so are called voltage-gated. Shortly after this, the calcium channels close and potassium channels open, allowing potassium to leave the cell. This causes the cell to have a negative resting charge and is called repolarisation. When the membrane potential reaches approximately −60 mV, the potassium channels close and the process may begin again. [7]angina (say: an-JY-nuh) : People with angina feel a pain in the chest that means the heart isn't getting enough oxygen. mitral (say: MY-truhl) valve: The mitral valve lets blood flow from the left atrium to the left ventricles. Main articles: Heart development and Human embryogenesis Development of the human heart during the first eight weeks (top) and the formation of the heart chambers (bottom). In this figure, the blue and red colors represent blood inflow and outflow (not venous and arterial blood). Initially, all venous blood flows from the tail/atria to the ventricles/head, a very different pattern from that of an adult. [7] The heart derives from splanchnopleuric mesenchyme in the neural plate which forms the cardiogenic region. Two endocardial tubes form here that fuse to form a primitive heart tube known as the tubular heart. [37] Between the third and fourth week, the heart tube lengthens, and begins to fold to form an S-shape within the pericardium. This places the chambers and major vessels into the correct alignment for the developed heart. Further development will include the formation of the septa and the valves and the remodeling of the heart chambers. By the end of the fifth week, the septa are complete, and by the ninth week, the heart valves are complete. [7] The normal sinus rhythm of the heart, giving the resting heart rate, is influenced by a number of factors. The cardiovascular centres in the brainstem control the sympathetic and parasympathetic influences to the heart through the vagus nerve and sympathetic trunk. [52] These cardiovascular centres receive input from a series of receptors including baroreceptors, sensing the stretching of blood vessels and chemoreceptors, sensing the amount of oxygen and carbon dioxide in the blood and its pH. Through a series of reflexes these help regulate and sustain blood flow. [7]

atrioventricular (say: AY-tree-oh-ven-TRIK-yoo-lar) canal defect:This defect — also known as endocardial cushion defect or atrioventricular septal defect — is caused by a poorly formed central area of the heart. Typically there is a large hole between the upper chambers of the heart (the atria) and, often, an additional hole between the lower chambers of the heart (the ventricles). Instead of two separate valves allowing flow into the heart, there is one large common valve that might be quite malformed. Rosner, Fred (1995). Medicine in the Bible and the Talmud: selections from classical Jewish sources (Augm.ed.). Hoboken, NJ: KTAV Pub. House. pp.87–96. ISBN 978-0-88125-506-5. Bible Gateway passage: Matthew 6:21 - New International Version". Bible Gateway . Retrieved 22 December 2022. Bible Gateway passage: Proverbs 4:23 - New International Version". Bible Gateway . Retrieved 19 December 2022. a b c d e Ponikowski, Piotr; Voors, Adriaan A.; Anker, Stefan D.; Bueno, Héctor; Cleland, John G. F.; Coats, Andrew J. S.; Falk, Volkmar; González-Juanatey, José Ramón; Harjola, Veli-Pekka (August 2016). "2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: The Task Force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC). Developed with the special contribution of the Heart Failure Association (HFA) of the ESC" (PDF). European Journal of Heart Failure. 18 (8): 891–975. doi: 10.1002/ejhf.592. hdl: 2434/427148. ISSN 1879-0844. PMID 27207191. S2CID 221675744. Archived (PDF) from the original on 14 June 2020 . Retrieved 24 September 2019.Definition of SA node". MedicineNet.com. 27 April 2011. Archived from the original on 1 August 2012 . Retrieved 7 June 2012. Purkinje Fibers". About.com. 9 April 2012. Archived from the original on 14 April 2012 . Retrieved 7 June 2012.