Respiratory Organ
The respiratory system is the network of organs and tissues that help you breathe. It includes your airways, lungs and blood vessels. The muscles that power your lungs are also part of the respiratory system. These parts work together to move oxygen throughout the body and clean out waste gases like carbon dioxide.
respiratory organ
Many conditions can affect the organs and tissues that make up the respiratory system. Some develop due to irritants you breathe in from the air, including viruses or bacteria that cause infection. Others occur as a result of disease or getting older.
Contact your provider if you have breathing trouble or pain. Your provider will listen to your chest, lungs, and heartbeat and look for signs of a respiratory issue such as infection. To see if your respiratory system is working as it should, your healthcare provider may use imaging tests such as a CT scan or MRI. These tests allow your provider to see swelling or blockages in your lungs and other parts of your respiratory system. Your provider may also recommend pulmonary function tests, which will include spirometry. A spirometer is a device that can tell how much air you inhale and exhale. See your doctor for regular checkups to help prevent serious respiratory conditions and lung disease. Early diagnosis of these issues can help prevent them from becoming severe.
Breathing is the process that brings oxygen in the air into your lungs and moves oxygen and through your body. Our lungs remove the oxygen and pass it through our bloodstream, where it's carried off to the tissues and organs that allow us to walk, talk, and move.Our lungs also take carbon dioxide from our blood and release it into the air when we breathe out.
Air enters the respiratory system through the nose or the mouth. If it goes in the nostrils (also called nares), the air is warmed and humidified. Tiny hairs called cilia (pronounced: SIL-ee-uh) protect the nasal passageways and other parts of the respiratory tract, filtering out dust and other particles that enter the nose through the breathed air.
The two openings of the airway (the nasal cavity and the mouth) meet at the pharynx (pronounced: FAR-inks), or throat, at the back of the nose and mouth. The pharynx is part of the digestive system as well as the respiratory system because it carries both food and air.
Once in the lungs, oxygen is moved into the bloodstream and carried through your body. At each cell in your body, oxygen is exchanged for a waste gas called carbon dioxide. Your bloodstream then carries this waste gas back to the lungs where it is removed from the bloodstream and then exhaled. Your lungs and respiratory system automatically perform this vital process, called gas exchange.
When the respiratory system is mentioned, people generally think of breathing, but breathing is only one of the activities of the respiratory system. The body cells need a continuous supply of oxygen for the metabolic processes that are necessary to maintain life. The respiratory system works with the circulatory system to provide this oxygen and to remove the waste products of metabolism. It also helps to regulate pH of the blood.
Etiology: Most upper respiratory infections are of viral etiology.Epiglottitis and laryngotracheitis are exceptions with severe cases likelycaused by Haemophilus influenzae type b. Bacterial pharyngitisis often caused by Streptococcus pyogenes Table 93-1
Pathogenesis: Organisms gain entry to the respiratory tract byinhalation of droplets and invade the mucosa. Epithelial destruction may ensue,along with redness, edema, hemorrhage and sometimes an exudate.
Clinical Manifestations: Initial symptoms of a cold are runny,stuffy nose and sneezing, usually without fever. Other upper respiratoryinfections may have fever. Children with epiglottitis may have difficulty inbreathing, muffled speech, drooling and stridor. Children with seriouslaryngotracheitis (croup) may also have tachypnea, stridor and cyanosis.
Etiology: Causative agents of lower respiratory infections are viralor bacterial. Viruses cause most cases of bronchitis and bronchiolitis. Incommunity-acquired pneumonias, the most common bacterial agent isStreptococcus pneumoniae. Atypical pneumonias are cause bysuch agents as Mycoplasma pneumoniae, Chlamydia spp, Legionella,Coxiella burnetti and viruses. Nosocomial pneumonias and pneumoniasin immunosuppressed patients have protean etiology with gram-negative organismsand staphylococci as predominant organisms.
Clinical Manifestations: Symptoms include cough, fever, chest pain,tachypnea and sputum production. Patients with pneumonia may also exhibitnon-respiratory symptoms such as confusion, headache, myalgia, abdominal pain,nausea, vomiting and diarrhea.
Infections of the respiratory tract are grouped according to their symptomatology andanatomic involvement. Acute upper respiratory infections (URI) include the commoncold, pharyngitis, epiglottitis, and laryngotracheitis (Fig. 93-1). These infections are usually benign, transitoryand self-limited, altho ugh epiglottitis and laryngotracheitis can be seriousdiseases in children and young infants. Etiologic agents associated with URI includeviruses, bacteria, mycoplasma and fungi (Table93-1). Respiratory infections are more common in the fall and winter whenschool starts and indoor crowding facilitates transmission.
Common colds are the most prevalent entity of all respiratory infections and arethe leading cause of patient visits to the physician, as well as work and schoolabsenteeism. Most colds are caused by viruses. Rhinoviruses with more than 100serotypes are the most common pathogens, causing at least 25% of colds inadults. Coronaviruses may be responsible for more than 10% of cases.Parainfluenza viruses, respiratory syncytial virus, adenoviruses and influenzaviruses have all been linked to the common cold syndrome. All of these organismsshow seasonal variations in incidence. The cause of 30% to 40% of cold syndromeshas not been determined.
The viruses appear to act through direct invasion of epithelial cells of therespiratory mucosa (Fig. 93-2), butwhether there is actual destruction and sloughing of these cells or loss ofciliary activity depends on the specific organism involved. There is an increasein both leukocyte infiltration and nasal secretions, including large amounts ofprotein and immunoglobulin, suggesting that cytokines and immune mechanisms maybe responsible for some of the manifestations of the common cold (Fig. 93-3).
Sinusitis is an acute inflammatory condition of one or more of the paranasalsinuses. Infection plays an important role in this affliction. Sinusitis oftenresults from infections of other sites of the respiratory tract since theparanasal sinuses are contiguous to, and communicate with, the upper respiratorytract.
Acute sinusitis most often follows a common cold which is usually of viraletiology. Vasomotor and allergic rhinitis may also be antecedent to thedevelopment of sinusitis. Obstruction of the sinusal ostia due to deviation ofthe nasal septum, presence of foreign bodies, polyps or tumors can predispose tosinusitis. Infection of the maxillary sinuses may follow dental extractions oran extension of infection from the roots of the upper teeth. The most commonbacterial agents responsible for acute sinusitis are Streptococcuspneumoniae, Haemophilus influenzae, and Moraxellacatarrhalis. Other organisms including Staphylococcusaureus, Streptococcus pyogenes, gram-negative organisms andanaerobes have also been recovered. Chronic sinusitis is commonly a mixedinfection of aerobic and anaerobic organisms.
For acute sinusitis, the diagnosis is made from clinical findings. A bacterialculture of the nasal discharge can be taken but is not very helpful as therecovered organisms are generally contaminated by the resident flora from thenasal passage. In chronic sinusitis, a careful dental examination, with sinusx-rays may be required. An antral puncture to obtain sinusal specimens forbacterial culture is needed to establish a specific microbiologic diagnosis.
Symptomatic treatment with analgesics and moist heat over the affected sinus painand a decongestant to promote sinus drainage may suffice. For antimicrobialtherapy, a beta-lactamase resistant antibiotic such as amoxicillin-clavulanateor a cephalosporin may be used. For chronic sinusitis, when conservativetreatment does not lead to a cure, irrigation of the affected sinus may benecessary. Culture from an antral puncture of the maxillary sinus can beperformed to identify the causative organism for selecting antimicrobialtherapy. Specific preventive procedures are not available. Proper care ofinfectious and/or allergic rhinitis, surgical correction to relieve or avoidobstruction of the sinusal ostia are important. Root abscesses of the upperteeth should receive proper dental care to avoid secondary infection of themaxillary sinuses.
For otitis externa, the skin flora such as Staphylococcus epidermidis,Staphylococcus aureus, diphtheroids and occasionally an anaerobicorganism, Propionibacterium acnes are major etiologic agents.In a moist and warm environment, a diffuse acute otitis externa (Swimmer's ear)may be caused by Pseudomonas aeruginosa, along with other skinflora. Malignant otitis externa is a severe necrotizing infection usually causedby Pseudomonas aeruginosa.
Acute otitis media commonly follows an upper respiratory infection extending fromthe nasopharynx via the eustachian tube to the middle ear. Vigorous nose blowingduring a common cold, sudden changes of air pressure, and perforation of thetympanic membrane also favor the development of otitis media. The presence ofpurulent exudate in the middle ear may lead to a spread of infection to theinner ear and mastoids or even meninges
As with common cold, viral pathogens in pharyngitis appear to invade the mucosalcells of the nasopharynx and oral cavity, resulting in edema and hyperemia ofthe mucous membranes and tonsils (Fig93-2). Bacteria attach to and, in the case of group A beta-hemolyticstreptococci, invade the mucosa of the upper respiratory tract. Many clinicalmanifestations of infection appear to be due to the immune reaction to productsof the bacterial cell. In diphtheria, a potent bacterial exotoxin causes localinflammation and cell necrosis. 041b061a72