How does epinephrine relax bronchiolar smooth muscle (dilating airways) while constricting arteriolar smooth muscle (constricting vessels)?
Epinephrine acts on different type of receptors located at different tissues of body.The type of action a hormone/neurotransmitter will produce depends not only upon its nature but also on which type of receptors it is acting.Epinephrine is a neurotransmitter of sympathetic system and the receptors on which it acts are:Alpha1:present on the blood vessels which vasoconstricts leading to increase in peripheral resistanceAlpha 2:present at heart muscle,pancreatic beta cells and certain blood vessel.Increased heart beat, force of contraction,decreased insulin release are its effectsBeta 1:kidney and secretes reninBeta 2: bronchial smooth muscles uterus,urinary bladder.There is no sympathetic nerve supply to bronchial smooth muscle..... only exogenous drugs can affect them.It causes bronchial relaxation,uterine and bladder relaxation. 5. Beta 3:adipose tissue..causes lipolysis. Thus epinephrine can cause different effects in different type of tissues depending upon the receptors..Hope this answer helps.
What is the importance of smooth muscle in the bronchial tree?
smooth muscles constrict the bronchi when they contract and dilate the bronchi when they relax. this is mostly a protective feature since it can allow regulation of the amount of air that can enter the lungs. eg, if you enter a smoky room, chances are your bronchi will constrict reflexively to limit the amount of irritating smoke that enters your lungs
What does constriction of smooth muscle in the bronchioles do?
Constriction of smooth muscles in the bronchioles is controlled by the parasympathetic nervous system. Antigens, asthma, and inflammatory responses will cause the smooth muscles to contract, narrowing the bronchioles, and reducing air flow, thus reducing oxygen exchange. Such constriction is a protective mechanism for the respiratory system. When exercising, the sympathetic nervous system predominates, causing relaxation of bronchiolar smooth muscle, which expands the diameter of bronchioles, increasing the amount of air that can enter the bronchioles, increasingly alveolar gas exchange.
Does Ventolin works on the bronchial smooth muscle itself or on the blood vessels located inside the bronchial?
Salbutamol helps to dilate the smooth muscles present in the bronchi .It Beta 2 adrenergic receptor agonist . It also causes relaxation of gravid (pregnant) uterus. Side effects includes palpitations/ tachycardia, fine tremors of the limbs and anxiety.
Are bronchus, bronchioles, and bronchi different? If so, how?
they do differ in size, from larger brochus, to bronchi, and then bronchioles. anatomically they are similar, with more smooth muscle in larger airways than the smaller one, and therefore more rigid . bronchioles are then followed by the clusters of alveoli, where gas exchange takes place.
What are the differences of bronchi and bronchioles and what are their separate functions?
The difference between bronchi and bronchioles is cartilage.Bronchi have cartilaginous support in the connective tissue that helps keep them open even if the smooth muscle contracts in response to an irritant.Bronchioles, by contrast, are smaller, have no cartilaginous support, and are at the end of the respiratory conducting system, the tubes that lead directly into alveoli, the gas-exchange epithelium. If the smooth muscle contracts, these tubules can close almost completely, making it very difficult for air to reach the alveoli.This is what commonly happens in asthma, and it can be a life-threatening condition. Beta-adrenergic agonists of the sort found in “rescue inhalers” can help relax bronciolar smooth muscle and relieve the respiratory symptoms.
Respiratory System: What is bronchoconstriction?
broncho: of or relating to the bronchi.CONSTRICT: to make narrow or draw together; compress, squeezeBronchoconstriction is the constriction of the airways in the lungs due to the tightening of surrounding smooth muscle, with consequent coughing, wheezing, and shortness of breathBut if I'd looked I would have seen that you already have an answer from someone who does now, or will, know more than the dictionary!
What is a bronchospasm?
Bronchospasm or a bronchial spasm is a sudden constriction of the muscles in the walls of the bronchioles. It is caused by the release (degranulation) of substances from mast cells or basophils under the influence of anaphylatoxins. It causes difficulty in breathing which can be very mild to severe. Bronchospasms appear as the feature of asthma, chronic bronchitis, anaphylaxis, as a possible side-effect of the drug pilocarpine (which is used to treat illness resulting from the ingestion of deadly nightshade as well as other things) and also as a side effect for beta blockers (used to treat hypertension) and other drugs. Bronchospasms are one of several conditions associated with cold housing.[1] Some of the things that can cause bronchospasms are consuming foods, taking medicines or getting insect bites or stings when one is allergic to them. A few of the more common allergens are foods such as eggs, milk, peanuts, tree and other nuts, fish, especially shellfish, soy and wheat; insect bites and stings, especially bee stings; and other medicines, especially penicillin and its derivatives. The overactivity of the bronchioles' muscle is a result of exposure to a stimulus which under normal circumstances would cause little or no response. The resulting constriction and inflammation causes a narrowing of the airways and an increase in mucus production; this reduces the amount of oxygen that is available to the individual causing breathlessness, coughing and hypoxia. Bronchospasms are a serious potential complication of placing a breathing tube during general anesthesia. When the airways spasm or constrict in response to the irritating stimulus of the breathing tube, it is difficult to maintain the airway and the patient can become apnic
What are symptoms of bronchitis?
Bronchitis is inflammation of airway below vocal cord.Bronchitis can occur because of several reasons. Few of them areViral InfectionDust exposure/ AllergiesChemical/soot / smog exposureBronchus or the pipe which carries air to oxygen to absorbing tissues of lung can be a wide or narrow. It divides like branches of a tree into the lungs, farther branches being narrower.Bronchitis is can be an acute problem in most who are afflicted with it, like in young children OR chronic ailment in some as in elders having asthma or Chronic Obstructive Pulmonary Disease [COPD].Smaller Bronchi or bronchioles may get choked due to mucous plug, injured mucosa [which forms the inner lining of the tube] or constriction of smooth muscles which surround the air passage. This leads to reduced oxygenation of lungs and distress.When one gets bronchitis, it is advised to remove the mucous from air way by gentle coughing. Avoid cough suppressing medications in this situation. Take antiallergic and antiinflammary [crocin,calpol] medications for short period and antibiotics if problem severe and associated with high fever.If the narrowing is due to constriction of muscles, the patient produces a whistling sound while breathing. One has to consume smooth muscle relaxants like bronchodilator drugs deriphylline, salbutamol etc. in this situation along with antiallergic [antihistaminics and sometimes steroids] and mild antiinflammatory medicines.