The Tell Tale Heart ( ANNOTATED )

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Ventricular systole is where the ventricles chambers contract and forces the blood up and out of the heart and into the arteries The other obvious structures seen within the heart are the chordae tendinae which are attached to papillary muscles. These tendons hold the heart valves in place, sometimes they are called the "heartstrings". The valves were probably cut when the heart was opened, but if you follow the "cords" they should lead you to a thin flap that is the atrioventricular (bicuspid) valve. You can find a similar valve on the right side of the heart (tricuspid). The animal material used has not been produced for the purpose of the investigation – it is a regular by-product of the meat industry, available for consumption from some butchers, or part of the waste stream if not used for dissection. Parasympathetic nervous system (rest and digest response) makes your SA node work slower, which decreases your heart rate.

The line can become somewhat blurred between what constitutes an anatomical variation and congenital heart disease but the key differentiator could be considered the presence or absence of symptoms in the majority of cases:I kept quite still and said nothing. For a whole hour I did not move a muscle, and in the meantime I did not hear him lie down. He was still sitting up in the bed listening; --just as I have done, night after night, hearkening to the death watches in the wall. The sino-atrial node sends impulses over the two atria which are then stimulated to contract. When the electrical impulses reach the atrioventricular node (at the junction between the atria and the ventricles), the impulses will spread rapidly through special fibers from the inter-ventricular septum to the walls of both ventricles, where the muscles are stimulated to contract. preoperative assessment of the coronary arteries before noncoronary cardiac surgery if intermediate risk of CAD Arad Y, Spadaro L, Goodman K, Newstein D, Guerci A. Prediction of Coronary Events with Electron Beam Computed Tomography. J Am Coll Cardiol. 2000;36(4):1253-60. doi:10.1016/s0735-1097(00)00872-x - Pubmed

The heart is subdivided by septa into right and left halves, and a constriction subdivides each half of the organ into two cavities, the upper cavity being called the atrium, the lower the ventricle. The heart, therefore, consists of four chambers: Zreik M, Lessmann N, van Hamersvelt R et al. Deep Learning Analysis of the Myocardium in Coronary CT Angiography for Identification of Patients with Functionally Significant Coronary Artery Stenosis. Med Image Anal. 2018;44:72-85. doi:10.1016/j.media.2017.11.008 - Pubmed This is a short 3-D animation of the heart in action, showing the detailed movement of the valve flaps and the heart muscle. The commentary has an American accent, but is quite clear. Relaxation phase: During the relaxation phase, all 4 chambers of the heart are in diastole as blood pours into the heart from the veins. The ventricles fill to about 75% capacity during this phase and will be completely filled only after the atria enter systole. The cardiac muscle cells of the ventricles repolarize during this phase to prepare for the next round of depolarization and contraction. During this phase, the AV valves open to allow blood to flow freely into the ventricles while the semilunar valves close to prevent the regurgitation of blood from the great arteries into the ventricles. We can distinguish two sounds in the heartbeat: the long and low-pitched ‘lubb’, which is due to closure of the two valves between the atria and the ventricles during ventricular contraction , and the shorter and high-pitched ‘dupp’, which is due to the closure of the aortic and pulmonary valves during ventricular relaxation.The right atrioventricular/tricuspid valve is between the right atrium and right ventricle. It has three cusps/leaflets: anterior/anterosuperior, septal, and posterior/inferior.

The bundle of His is a collection of heart muscles cells specialised for electrical conduction. These cells receive input from the AVN. 1,4,5 To allow for improved image quality and dose reduction, cCTA is usually ECG-triggered to adapt the scan sequence to the patient's heartbeat.In cardiac diastole the entire heart is relaxed. Both the atria and ventricles are relaxed and the blood enters at low pressure through the veins, the pulmonary vein and the vena cava into the atria. As the blood flows in the atria the blood pressure begins to increase causing the AV valves to become opened allowing for the blood to enter the ventricles. Atrial Systole

The heart cycle is regulated completely subconsciously by an autonomic nerve plexus called the cardiac plexus.Right coronary artery (sinuatrial nodal branch, right marginal branch, atrioventricular nodal branch, posterior interventricular branch) The atrioventricular node delays the SA node’s electrical signal. It delays the signal by a consistent amount of time (a fraction of a second) each time. The human heart has four chambers. Left atrium, left ventricle, right atrium, and right ventricle. What type of muscles make up the heart? I am sorry to own I began to worry them. This was already a fresh departure for me. I was not used to get things that way, you know. I always went my own road and on my own legs where I had a mind to go. I wouldn't have believed it of myself; but, then -- you see -- I felt somehow I must get there by hook or by crook . So I worried them. The men said 'My dear fellow,' and did nothing. Then -- would you believe it? -- I tried the women. I, Charlie Marlow, set the women to work -- to get a job. Heavens! Well, you see, the notion drove me. I had an aunt, a dear enthusiastic soul. She wrote: 'It will be delightful. I am ready to do anything, anything for you. It is a glorious idea. I know the wife of a very high personage in the Administration, and also a man who has lots of influence with,' etc. She was determined to make no end of fuss to get me appointed skipper of a river steamboat, if such was my fancy