Mucus glands

MaePherson, L. M. D., and Dawes, C. (1991). Urea concentration in minor mucus gland secretions and the effect of salivary film velocity on urea metabolism by streptococcus vestibularis in an artificial plaque./Periodont. Res. 26, 395- 01. 

An inflammatory exudate is often present in the airways that leads to an increased number and size of goblet cells and mucus glands. Mucus... 

Davis, B., Marin, M.G., Fischer, S., Graf, P., Widdicombe, XG. and Nadel, XA. (1976). New method for study of canine mucus gland secretion in vivo Cholinergic regulation. Am. Rev. Respir. Dis. 113 257 (abstract). 

Amphibians have mucus glands over their whole body to provide the mucus needed to keep their skin moist, and fields of granular glands that secrete alkaloid toxins. In addition to these general glands, salamanders possess glands... 

The airway effects of released acetylcholine are mediated via activation of three distinct muscarinic receptor subtypes Mj, in parasympathetic ganglia, mucous glands and alveolar walls autoinhibitory M2, in parasympathetic nerve terminals and M3, in airway smooth muscle, mucus glands, and airway epithelium. 

The antibacterial enzyme lysozyme is also found in nasal secretions. Lysozyme is produced by the epithelium and mucus glands where it can attack the cell walls of susceptible microorganisms, its action being optimal at the slightly acidic microclimate pH. The pH of nasal mucus varies with age, sleep, rest, emotion, infection, and diet. When it is cold, or during rhinitis or sinusitis, the pH tends to be alkaline, which deactivates the lysozyme in mucus and therefore increases the risk of microbial infection. Under normal conditions, the nasal secretions, as indicated earlier, have a pH of 5.5 to 6.5, which is the optimum pH for the activity of lysozyme. 

The release of mediators (histamine, serotonin, bradykinin etc.) from mast cells is activated by IgE-antigen interactions and their action on smooth muscle, mucus glands and blood vessels probably plays an important role in the responses to intestinal infections. For example, mucus gland secretion can be stimulated by histamine and increased mucous secretion is a characteristic of several intestinal helminth infections (80). 

Chronic bronchitis is characterized by increased mucus production and hypertrophy of the mucus glands in the airway mucosa. It is defined as the presence of a chronic or recurrent cough with sputum production on most days, for at least three months of the year, during at least two consecutive years. Patients have hypoxia and retain excess CCh-they are sometimes referred to as blue bloaters. 

The histologic findings in asthma consist of massive epithelial shedding, hyperplasia of smooth muscle fibers, mucus glands and goblet cells, basement membrane thickening (Brewster etal., 1990), and eosinophil infiltra-... 

Acute inflammation is a beneflcial, nonspeciflc response of tissues to injury and generally leads to repair and restoration of the normal structure and function. In contrast, asthma represents a chronic inflammatory process of the airways followed by healing. The end result may be an altered structure referred to as a remodeling of the airways Repair involves replacement of injured tissue by parenchymal cells of the same type and replacement by connective tissue and its maturation into scar tissue. In asthma, the repair process can be followed by complete or altered restitution of airways structure and function, presenting as fibrosis and an increase in smooth muscle and mucus gland mass. ... 

Histamine is a low-molecular-weight amine compound formed by decarboxylation of histidine and is stored in basophil and mast cell granules. The release of histamine from these cells is triggered by antigen cross-linking IgE bound to specific receptors on the surface membranes of mast cells and basophils. The tissue effects of histamine are evident within 1 to 2 minutes, but it is rapidly metabolized within 10 to 15 minutes. The major effects of histamine on target tissues include increased capillary permeability, contraction of bronchial and vascular smooth muscle, and hypersecretion of mucus glands. 

The trachea passes from the larynx to the level of the fourth thoracic vertebra, where it divides into the two main bronchi that enter the right and left lungs. The anterior and lateral walls of the trachea and main bronchi are composed of about 20 C-shaped plates of cartilage, which are joined together by a posterior wall composed of bundles of interlacing smooth-muscle fibers, epithelial cells, mucus glands, and elastic fibers. A schematic diagram of the trachea and main bronchi is presented in Fig. 2. Just after the tracheal... 

The role of the tracheobronchial circulation in aerosol clearance has been discussed by Wagner (1995). Its supportive role for ciliated cells and mucus glands has not been studied. For this reason it is unclear whether this circulation plays a significant part in maintaining mucociliary clearance. Consequently, the capacity of the airway circulation to influence the clearance of soluble and insoluble particles remains ill-defined and requires investigation at a fundamental level. 

A number of studies indicate that irreversible airflow obstruction may occur in asthma, associated with structural changes consistent with an airway remodeling process (153). Morphometric studies have shown prominent smooth muscle hyperplasia and hypertrophy in both large and small airways (154), increased angiogenesis (155), prominent mucus gland hyperplasia (156), and airway wall thickening particularly in cases of fatal asthma (157). 

Takizawa T, Thurlsbeck W. Muscle and mucus gland size in the major bronchi of patients with chronic bronchitis, asthma, and asthmatic bronchitis. Am Rev Respir Dis 1971 104 331-336. 

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