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S 2 |
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S2, the second heart sound in the cardiac cycle. It is associated with closure of the aortic and pulmonic valves at the outset of ventricular diastole. The second sound is louder and shorter than the first. The sound of the aortic valve is loudest on the right sternal border, and that of the pulmonic valve is most distinct on the left sternal border over the second intercostal space. heart sounds the sounds heard on the surface of the chest in the heart region; they are amplified by and heard more distinctly through a stethoscope. They are caused by the vibrations generated during the normal cardiac cycle and may be produced by muscular action, valvular actions, motion of the heart, or blood passing through the heart. The first heart sound (S1) is heard as a firm but dull “lubb” sound. It consists of four components: a low-frequency, indistinct vibration caused by ventricular contraction; a louder sound of higher frequency caused by closure of the mitral and tricuspid valves; a vibration caused by opening of the semilunar valves and early ejection of blood from the ventricles; and a low-pitched vibration produced by rapid ejection. The second heart sound (S2) is shorter and higher pitched than the first, is heard as a “dupp” and is produced by closure of the aortic and pulmonary valves. The third heart sound (S3) is very faint and is caused by blood rushing into the ventricles. It can be heard in most normal persons between the ages of 10 and 20 years. The fourth heart sound (S4) is rarely audible in a normal heart but can be demonstrated on graphic records. It is short and of low frequency and intensity, and is caused by atrial contraction. The vibrations arise from atrial muscle and from blood flow into, and distention of, the ventricles. Abnormalities in Heart Sounds. Decreased compliance of a ventricle is characterized by a gallop or triple rhythm. Accentuation of the third heart sound (protodiastolic or ventricular gallop) is caused by the filling of a poorly compliant ventricle with blood under high venous pressure. A presystolic or atrial gallop is an accentuated fourth heart sound and is also caused by blood filling a poorly compliant ventricle. Merging of the third and fourth heart sounds is called a mesodiastolic or summation gallop. A very rare abnormality in which four heart sounds are heard distinctly is called a “locomotive” rhythm. Heart Murmurs are sounds other than the normal heart sounds emanating from the heart region. They are often heard as blowing or hissing sounds as blood leaks back through diseased and malfunctioning valves or as blood is pushed through narrowed or stenotic valve orifices. ![]() Precordial locations for cardiac palpation and auscultation of heart sounds. Closure of the mitral and tricuspid valves produces the S1 heart sound; closure of the pulmonic and aortic (semilunar) valves produces the S2 sound. From Polaski and Tatro, 1996. Patient discussion about S 2. Q. I've a chronic pain website & would love 2 get comments on how 2 make it better http://chronicpain.today.c A. nice site! very useful! i liked the "freebies"...good idea. how about some links to videos about the subject? could be nice... Q. I gave birth 2 weeks ago and I am having real difficulties breast feeding it hurts really bad, and I am constantly worried that my baby isn't eating enough. What can I do? A. My mom always said something about brewers yeast helping to produce more milk for the baby. Q. I am having fibromyalgia syndrome for the past 2 years.why outside food consumption makes my pain to increase? I am having fibromyalgia syndrome for the past 2 years. Because of my medicines I have some relief from my pain. Whenever I eat outside food like fast foods I feel the increase in my pain. Doctor has said to avoid those foods completely. I want to know that why their consumption makes my pain to increase? A. http://AutoimmunityResearch.org/Phase1.pdf Read more or ask a question about S 2http://AutoimmunityResearch.org/Phase2.pdf Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content. |
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