Tracheae

On a vitamin A-deficient diet, mucus-secreting tissues become keratinized. This condition tends to occur in the trachea, the skin, the saUvary glands, the cornea, and the testes. When this occurs in the cornea, it can be followed by blindness. Vitamin A deficiency is the principal cause of blindness in the very young. This problem is particularly acute in the third world (8). 

Physiological Effects. The sulfur and nitrogen mustards act first as cell irritants and finally as a cell poison on all tissue surfaces contacted. The first symptoms usually appear in 4—6 h (4). The higher the concentration, the shorter the interval of time between the exposure to the agent and the first symptoms. Local action of the mustards results in conjunctivitis (inflammation of the eyes) erythema (redness of the skin), which may be followed by blistering or ulceration and an inflammatory reaction of the nose, throat, trachea, bronchi, and lung tissue. Injuries produced by mustard heal much more slowly and are much more Fable to infection than bums of similar intensity produced by physical means or by other chemicals. 

FIGURE 5.16 Depiedon of eepresentaiive airway cros seaion at various points (trachea, bronchi, and pulmonary airway) along the respiratory tract showing common cell types. Note how mucus gei is generally presumed to form sheets in the more proximal airways. The pulmonary airway depiction includes both a section of respiratory bronchi and an alveolus. 

Finer particles ( < 3 pm), termed respirable particles, pass beyond the ex-trathoracic airways and enter the tracheobronchial tree. Impaction plays a significant role near the tracheal jet, but sedimentation predominates as the effects of rapid conduit expansion dampen in the distal trachea and beyond. Sedimentation occurs when gravitational forces exerted on a particle equal drag forces, i.e., when particle velocity falls to u . As mean inspiratory air-stream velocity gradually declines along the tracheobronchial tree, particle momentum diminishes and 0.5-3 pm MMAD particles settle out of the airflow and onto mucosal surfaces. 

Verdugo, P. (1984). Hydration kinetics of exocyto.sed mucins in cultured secretory cells of the rabbit trachea a new model. Mucus and Mucosa (Ciba Foundation symposium 109), 212-225. 

Dckker, E. (1961). Transition between laminar and turbulent flow in human trachea./. Appl. Physiol. 16, 1060-1064. 

Deffebach, M. E., Salonen, R. O., Webber, S. E., and Widdiconibe, J. G. (1989), Cold and hyperosmolar fluids in canine trachea Vascular and smooth muscle tone and. ilbuniin flux. ]. Appi. Physiol. 66, 1309-1315. 

Tracheobronchial tree Series of bifurcating tubes originating at the trachea... 

Tracheobronchial region The middle region of the respiratory system, comprised of the trachea and the bronchi. 

Luft-reiniger, m. air purifler. -rohr, n. air tube or pipe. -rShre, /. air tube, air pipe windpipe, trachea. 

Kenakin, T. P., and Boselli, C. (1989). Pharmacologic discrimination between receptor heterogeneity and allosteric interaction Resultant analysis of gallamine and pirenzeipine antagonism of muscarinic responses in rat trachea. J. Pharmacol. Exp. Ther. 250 944—952. 

Data for Figure 11.15. Schild analysis for atenolol trachea. in guinea pig... 

Dose-response curves to the agonist carbachol are obtained in the presence and absence of the antagonist scopolamine. The data are given in Table 12.6a. Responses are contractions of rat trachea resulting from muscarinic receptor... 

The act of vomiting is a complex process accompanied by several events apart from activation of the motor nerves and various voluntary muscles involved in the increase of intragastric pressure and evacuation of the stomach contents. Vomiting is preceded by a deep inspiration, closure of the glottis and raising of the soft palate to prevent vomitus entering the trachea and nasopharynx, respectively. There is also increased heart rate, pallor, salivation, sweating and lacrimation. 

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