Larynx

Hydrogen chloride in air is an irritant, severely affecting the eye and the respiratory tract. The inflammation of the upper respiratory tract can cause edema and spasm of the larynx. The vapor in the air, normally absorbed by the upper respiratory mucous membranes, is lethal at concentrations of over 0.1% in air, when exposed for a few minutes. HCl is detectable by odor at 1—5 ppm level and becomes objectionable at 5—10 ppm. The maximum concentration that can be tolerated for an hour is about 0.01% which, even at these levels, causes severe throat irritation. The maximum allowable concentration under normal working conditions has been set at 5 ppm. 

Thorotrast (colloidal Th02) was once used as a radiopaque agent in medicine (see Radiopaques). Its injection in a dose of 2.0—15.0 g caused rises in body temperature, nausea, and injury to tissues at the injection site, followed by anemia, leukopenia, and impairment of the reticuloendothehal system. After intravenous adrninistration, thorotrast particles are taken up by reticuloendothehal cells of the fiver and spleen. Thorotrast is virtually not eliminated from the body (91). Between 1947 and 1961, 33 cases of cancer of the fiver, larynx, and bronchi and sarcoma of the kidneys, developing from 6 to 24 years after thorotrast administering, have been described in the literature (92). 

Cattle feeding on herbage containing 25-50 mg/kg (ppm wt) lead develop excitable jerking of muscles, frothing at the mouth, grinding of teeth, and paralysis of the larynx muscles a "roaring" noise is caused by the paralysis of the muscles in the throat and neck. 

For example, sulphur dioxide is highly water soluble and tends to be absorbed in the airways above the larynx. Responses at various concentrations are summarized in Table 5.3. However, in the presence of particulate catalysts and sunlight, conversion to sulphur trioxide occurs and the in itant response is much more severe. 

FIGURE 5.14 (a) Anatomical overview of che human respiratory tract. The larynx generally... 

FIGURE 5.22 Schematic depiction of airflow pattern through the larynx. Note how eddies form downstream as air passes through the tracheal jet created by the vocal cords. This effect varies according to vocal chord position. 

Epiglottis Leaf-shaped cartilage which closes larynx during swallowing. 

Breathing zone The space around an operator in which breathing occurs, normally taken as being a hemisphere of radius 0.3 m circumscribing the ears, the top of the head and the larynx. 

Kehle,/. throat, larynx channel, flute, groove, kehlen, v.t. groove, channel, flute. Kehl-entziindung, /. laryngitis. -kopfi m. larynx. 

Hemoptysis The expectoration of blood or blood-tinged sputum from the larynx, trachea, bronchi, or lungs. 

The ICRP deposition model estimates the fraction of inhaled material initially retained in each compartment (see Figure 3-2). The model was developed with five compartments (1) the anterior nasal passages (ET,) (2) all other extrathoracic airways (ET2) (posterior nasal passages, the naso- and oropharynx, and the larynx) (3) the bronchi (BB) (4) the bronchioles (bb) and (5) the alveolar interstitium (AI). Particles deposited in each of the regions may be removed and redistributed either upward into the respiratory tree or to the lymphatic system and blood by different particle removal mechanisms. 

Elder is also used therapeutically as a homeopathic medicine. It was introduced by Dr. Samuel Hahnemann in 1819. The Sambucus ebulus or S. nigra species is most often used. However, it is not one of the more widely used homeopathic medicines. As a homeopathic remedy, elder is known as sambucus. Some of the indications for sambucus include albuminuria (the presence of protein in the urine), angina pectoris, asthma, dizziness and headache upon arising, dry larynx and lumbago. 

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