Bronchiole

It is a powerful antagonist of histamine, antagonizing its effect on smooth muscle of the bronchioles, bladder and partially the intestines and preventing the dilation of capillaries. Promethazine is used in the treatment of allergic reactions. 

P-Adrenoceptors have been subdivided into P - and P2-adrenoceptors. A third subset called nontypical P-adrenoceptors or P -adrenoceptors have been described but are stiU the subject of debate. In terms of the interactions with various subsets of P-adrenoceptors, some antagonists are nonselective in that they antagonize the effects of activation of both P - and P2-adrenoceptors, whereas others are selective for either P - or P2-adrenoceptors. P - and P2-adrenoceptors coexist in almost all organs but generally, one type predominates. The focus herein is on the clinically relevant P -adrenoceptor-mediated effects on heart and on P2-adrenoceptor-mediated effects on smooth muscles of blood vessels and bronchioles, the insulin-secreting tissue of the pancreas, and skeletal muscle glycogenolysis for side effects profile (36). 

Beta receptors of the beta-1 subtype mediate an increase in heart rate and increased force of contraction they are also found in the central nervous system. E and NE are equaHy potent agonists and selective antagonists are atenolol [29122-68-7] and betaxolol [63659-18-7]. Beta-2 receptors are weH known for their involvement in relaxing bronchioles. E is a more potent agonist than NE procaterol [72332-33-3] is a selective agonist ICl 118551 and a-methylpropranolol are selective antagonists. A particular amine may act on both alpha and beta receptors or predominandy on one type. NE acts mainly on alpha-1, E on both alpha and beta, and isoprotemol [7683-59-2] almost exclusively on beta receptors. Numerous antagonists also differentiate between... 

Death after 2 or 3 weeks by bronchiolitis fibrosa obliterans... 

Severe pulmonary edema possible acute bronchiolitis decreased blood pressure rapid weak pulse... 

Mean airstream velocity diminishes as inspiratory flow moves toward the lung parenchyma because of the rapid increase in total cross-sectional area. The largest increases in area occur in the distal bronchioles and pulmonary airways, causing u to approach zero because... 

Alveolar duct Airway distal to respiratory bronchiole leading to individual alveoli and alveolar sacs. 

Bronchioles Noncartilaginous, smaller, more distal subdivision of tracheo-... 

Allergic alveolitis An allergic response to inhalation of organic particles that involves inflammation of the small terminal branches of the bronchioles. Symptoms include coughing, increased production of mucus, fever, fatigue, and muscle aches. 

Bronchioles The very small airways of the lungs that terminate in the alveoli. 

A condition of the lung characterized by abnormal permanent enlargement of the air spaces distal to the terminal bronchioles accompanied by destruction of their walls and without obvious fibrosis. 

RSV infection is highly contagious and infects mostly children, causing bronchiolitis and pneumonia. Infants younger than 6 months are the most severely affected. In adults, RSV causes colds and bronchitis, with fever, cough, and nasal congestion. When RSV affects immunocompromised patients, the consequences can be severe and sometimes fatal. 

Asthma is a reversible obstructive disease of the lower airway. With asthma there is increasing airway obstruction caused by bronchospasm and bronchoconstriction, inflammation and edema of the lining of the bronchioles, and the production of thick mucus that can plug the airway (see Pig. 37-1). There are three types of asthma ... 

Other disorders of the lower respiratory tract include emphysema (lung disorder in which the terminal bronchioles or alveoli become enlarged and plugged with mucus) and chronic bronchitis (chronic inflammation and possibly infection of die bronchi). Chronic obstructive pulmonary disease (COPD) is die name given collectively to emphysema and chronic bronchitis because die obstruction to die airflow is present most of the time. Asdima diat is persistent and present for most of die time may also be referred to as COPD. 

COPD includes chronic bronchitis and emphysema. Chronic bronchitis is defined clinically as a chronic productive cough for at least 3 months in each of two consecutive years in a patient in whom other causes have been excluded.1 Emphysema is defined pathologically as the presence of permanent enlargement of the airspaces distal to the terminal bronchioles, accompanied by destruction of their walls without obvious fibrosis.1 The major risk factor for both conditions is cigarette smoking, and many patients share characteristics of each condition. Therefore, new consensus guidelines have moved away from using these subsets and instead focus on chronic airflow limitation. 

In the central airways (the trachea, bronchi, and bronchioles greater than 2 to 4 mm in internal diameter), inflammatory cells and mediators stimulate mucus-secreting gland hyperplasia... 

In advanced COPD, airflow obstruction, damaged bronchioles and alveoli, and pulmonary vascular abnormalities lead to impaired gas exchange. This results in hypoxemia and eventually hypercapnia. Hypoxemia is initially present only during exercise but occurs at rest as the disease progresses. Inequality in the ventilation/perfusion ratio (VAQ) is the major mechanism behind hypoxemia in COPD. 

Lung Bronchiolitis obliterans diagnosed with lung biopsy Bronchiolitis obliterans diagnosed with pulmonary function tests and radiology0 Bronchiolitis obliterans organizing pneumonia... 

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