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Respiratory sounds, also known as lung sounds or breath sounds, are the specific sounds generated by the movement of air through the respiratory system. [1] These may be easily audible or identified through auscultation of the respiratory system through the lung fields with a stethoscope as well as from the spectral characteristics of lung sounds. [2]
The temperature and heat levels of the body are directly correlated with the temporary threshold shifts of the ear. [8] When the levels of blood temperature increase, these threshold shifts increase as well. The transduction of sounds requires an oxygen supply that will be readily depleted due to the prolonged threshold shifts.
The normal relaxed state of the lung and chest is partially empty. Further exhalation requires muscular work. Inhalation is an active process requiring work. [4] Some of this work is to overcome frictional resistance to flow, and part is used to deform elastic tissues, and is stored as potential energy, which is recovered during the passive process of exhalation, Tidal breathing is breathing ...
Although total liquid ventilation (TLV) with completely liquid-filled lungs can be beneficial, [9] the complex liquid-filled tube system required is a disadvantage compared to gas ventilation—the system must incorporate a membrane oxygenator, heater, and pumps to deliver to, and remove from the lungs tidal volume aliquots of conditioned perfluorocarbon (PFC).
Percussion and resonance (the quality and feeling of sound) are used to examine lung movement and possible lung conditions. Specifically, percussion is performed by first placing the middle finger of one hand over the area of interest. The middle finger of the other hand is used to strike the last joint of the placed finger.
Noise-induced hearing loss is a permanent shift in pure-tone thresholds, resulting in sensorineural hearing loss. The severity of a threshold shift is dependent on duration and severity of noise exposure. Noise-induced threshold shifts are seen as a notch on an audiogram from 3000 to 6000 Hz, but most often at 4000 Hz. [16]
In healthy lungs where the alveolar dead space is small, Fowler's method accurately measures the anatomic dead space using a single breath nitrogen washout technique. [ 4 ] [ 5 ] The normal value for dead space volume (in mL) is approximately the lean mass of the body (in pounds), and averages about a third of the resting tidal volume (450-500 mL).
Although the ear is the primary organ for sensing low sound, at higher intensities it is possible to feel infrasound vibrations in various parts of the body. The study of such sound waves is sometimes referred to as infrasonics , covering sounds beneath 20 Hz down to 0.1 Hz (and rarely to 0.001 Hz).