What are beta blockers and how do they work? Beta blockers, also known as beta-adrenergic blocking agents, are a class of drugs that works by blocking the neurotransmitters norepinephrine and epinephrine from binding to receptors. There are three known types of beta receptors, known as beta1 (Î²1), beta2 (Î²2) and beta3 (Î²3).
Although many newer imaging techniques for the evaluation of lung pathology have been developed, auscultation of the chest remains an invaluable clinical tool and is still probably the most common method of evaluating the lung. Evaluation of lung sounds is a routine part of a clinical examination. Breath sounds can be classified into 2 broad categories: normal breath sounds and adventitious (or abnormal) sounds. Adventitious breath sounds include wheezes, coarse crackles, fine crackles, and rhonchi. See the video of breath sound assessment, below.
Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. Specifically, the sounds reflect the turbulence created when the heart valves snap shut. In cardiac auscultation, an examiner may use a stethoscope to listen for these unique and distinct sounds that provide important auditory data regarding the condition of the heart. In healthy adults, there are two normal heart sounds often described as a lub and a dub, that occur in sequence with each heart