It was open — wide, wide open — and I grew furious as I gazed upon it. I saw it with perfect distinctness — all a dull blue, with a hideous veil over it that chilled the very marrow in my bones; but I could see nothing else of the old man's face or person: for I had directed the ray as if by instinct, precisely upon the damned spot. 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 Poe uses his words economically in the “Tell-Tale Heart”—it is one of his shortest stories—to provide a study of paranoia and mental deterioration. Poe strips the story of excess detail as a way to heighten the murderer’s obsession with specific and unadorned entities: the old man’s eye, the heartbeat, and his own claim to sanity. Poe’s economic style and pointed language thus contribute to the narrative content, and perhaps this association of form and content truly exemplifies paranoia. Even Poe himself, like the beating heart, is complicit in the plot to catch the narrator in his evil game. 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).

It is important to remember the key time when the valves open and when they close; the AV valve closes when the ventricular pressure exceeds the atrial pressure, indicated on Figure 2. The AV valve will only open again when the ventricular pressure is below the atrial pressure. Atrial systole is where the atria within the heart contract and tops up the ventricles that are already filled with blood. Your autonomic nervous system controls how fast or slowly your SA node sends electrical signals. This part of the nervous system directs hormones that control your heart rate based on what you are doing. For example, your heart rate increases during exercise and slows when you are asleep. Sympathetic nervous system (fight or flight response) makes your SA node work faster, which increases your heart rate. This will depend on how many hearts you obtain and on how many of your students opt out of handling (or closely observing) the specimens.preoperative assessment of the coronary arteries before noncoronary cardiac surgery if intermediate risk of CAD Veins are made up of thin layers with a few circular elastic fibres and muscle fibres. This is because blood does not flow in pulses and so the vein walls cannot help pump the blood on. Veins also have thin walls which allows the near by muscles to press against them so that they become flat. This helps the blood to be pushed forwards towards the heart. There is only a thin outer layer of longitudinal collagen and elastic fibres as there is low pressure inside the vein and so little chance of bursting. Finally, a wide lumen is needed to accommodate the slow flowing blood due to the low pressure.

the right ventricle pumps blood through the pulmonary semilunar valve into the pulmonary trunk to be oxygenated in the lungs If you have access to a magnifying video camera you could project a demonstration dissection. If you have a plastic model heart, a number of students could work from that. Prepare a handout with a drawing of the heart and questions for students who are not taking a practical part in the activity. Students who are unwilling to handle hearts, but keen to see what is going on could take digital photographs of the heart in different stages of dissection. In about forty-five seconds I found myself again in the waiting-room with the compassionate secretary, who, full of desolation and sympathy , made me sign some document. I believe I undertook amongst other things not to disclose any trade secrets. Well, I am not going to Right coronary artery (sinuatrial nodal branch, right marginal branch, atrioventricular nodal branch, posterior interventricular branch)

His remark did not seem at all surprising. It was just like Marlow. It was accepted in silence. No one took the trouble to grunt even ; and presently he said, very slow --

TRUE! — nervous — very, very dreadfully nervous I had been and am; but why will you say that I am mad? The disease had sharpened my senses — not destroyed — not dulled them. Above all was the sense of hearing acute. I heard all things in the heaven and in the earth. I heard many things in hell. How, then, am I mad? Harken! and observe how healthily — how calmly I can tell you the whole story.

Clinical notes

blood moves into this chamber through the tricuspid valve (aka right atrioventricular valve) during ventricular diastole; blood moves out of this chamber through the pulmonary valve during ventricular systole the left ventricle pumps blood through the aortic semilunar valve into the ascending aorta to supply the body At this point, you may want to use your colored pencils to mark these vessels so that you don't get them confused when you are searching for the other two openings that top of the heart. Parasympathetic nervous system (rest and digest response) makes your SA node work slower, which decreases your heart rate. The heart is a muscular organ about the size of a closed fist that functions as the body’s circulatory pump. It takes in deoxygenated blood through the veins and delivers it to the lungs for oxygenation before pumping it into the various arteries (which provide oxygen and nutrients to body tissues by transporting the blood throughout the body). The heart is located in the thoracic cavity medial to the lungs and posterior to the sternum.