Lung Trachea & Bronchial Tree Diagram & Function | Body Maps
Bronchioles end in tiny air sacs called alveoli, where the exchange of oxygen and carbon dioxide The most common problems of the respiratory system are. Respiratory disease: Any of the diseases and disorders of the airways and Emphysema destroys the walls of the alveoli of the lungs, resulting in a loss of. They are the passages through which air is directed from the nose and mouth to the alveoli (air sacs) at the end of the respiratory tree, literally.
In a process called diffusion, oxygen moves from the alveoli to the blood through the capillaries tiny blood vessels lining the alveolar walls. Once in the bloodstream, oxygen gets picked up by the hemoglobin in red blood cells.
This oxygen-rich blood then flows back to the heart, which pumps it through the arteries to oxygen-hungry tissues throughout the body. In the tiny capillaries of the body tissues, oxygen is freed from the hemoglobin and moves into the cells.
Carbon dioxide, which is made by the cells as they do their work, moves out of these cells into the capillaries, where most of it becomes dissolved in the plasma of the blood. Blood rich in carbon dioxide then returns to the heart via the veins.
From the heart, this blood is pumped to the lungs, where carbon dioxide passes into the alveoli to be exhaled. The most common problems of the respiratory system are: More than 20 million people in the United States have asthma, and it's the 1 reason that kids frequently miss school.
Asthma is a chronic inflammatory lung disease that causes airways to tighten and narrow. Often triggered by irritants such as cigarette smoke or exposure to cold air, viral or bacterial infections of the respiratory tract, and exposure to animal dander or pollens in kids who are allergic to them. Asthma flares involve contraction of the muscles and swelling of the lining of the tiny airways.
Lungs and Respiratory System (for Parents)
The resulting narrowing of the airways prevents air from flowing properly, causing wheezing and difficulty breathing, sometimes to the point of being life-threatening. Controlling asthma starts with an asthma action planwhich usually involves avoiding asthma triggers and, sometimes, taking medicines.
Not to be confused with bronchitis, bronchiolitis is an inflammation of the bronchioles, the smallest branches of the bronchial tree. Bronchiolitis affects mostly infants and young children, and can cause wheezing and serious difficulty breathing. It's usually caused by specific viruses in the wintertime, including respiratory syncytial virus RSV.
Chronic obstructive pulmonary disease COPD. COPD is a term that describes two lung diseases — emphysema and chronic bronchitis: Long-term smoking often causes emphysema, and although it seldom affects kids and teens, it can have its roots in the teen and childhood years. Talking to your kids about smoking is a key part of preventing smoking-related diseases.
In emphysema, the lungs produce an excessive amount of mucus and the alveoli become damaged. It becomes difficult to breathe and get enough oxygen into the blood. In chronic bronchitis, a common disease of adults and teens, the membranes lining the larger bronchial tubes become inflamed and an excessive amount of mucus is produced. The person develops a bad cough to get rid of the mucus.
Cigarette smoking is a major cause of chronic bronchitis in teens.
- If You Have Non-small Cell Lung Cancer
- Respiratory disease
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Other Conditions Common cold. Caused by more than different viruses that cause inflammation in the upper respiratory tract, the common cold is the most common respiratory infection. Symptoms may include a mild fever, cough, headache, runny nose, sneezing, and sore throat.
A cough is a symptom of an illness, not an illness itself. There are many different types of cough and many different causes, ranging from not-so-serious to life-threatening. Some of the more common causes affecting kids are the common cold, asthma, sinusitis, seasonal allergies, croup, and pneumonia. Among the most serious causes of cough are tuberculosis TB and whooping cough pertussis. Affecting more than 30, kids and young adults in the United States, cystic fibrosis is the most common inherited disease affecting the lungs.
As branching continues through the bronchial tree, the amount of hyaline cartilage in the walls decreases until it is absent in the bronchioles. As the cartilage decreases, the amount of smooth muscle increases.
The mucous membrane also undergoes a transition from ciliated pseudostratified columnar epithelium to simple cuboidal epithelium to simple squamous epithelium.
This is known as a tracheal bronchus, and seen as an anatomical variation. It can have multiple variations and, although usually asymptomatic, it can be the root cause of pulmonary disease such as a recurrent infection. Respiratory tree The alveolar ducts and alveoli consist primarily of simple squamous epitheliumwhich permits rapid diffusion of oxygen and carbon dioxide. Exchange of gases between the air in the lungs and the blood in the capillaries occurs across the walls of the alveolar ducts and alveoli.
Clinical significance[ edit ] Bronchial wall thickness T and diameter D. Bronchial wall thickening, as can be seen on CT scangenerally but not always implies inflammation of the bronchi. In some lung diseases, the first symptom may be a swelling of the lymph nodes that drain the affected area, particularly the small nodes above the collarbone in the neck; enlargement of the lymph nodes in these regions should always lead to a suspicion of intrathoracic disease.
Not infrequently, the presenting symptom of a lung cancer is caused by metastasisor spread of the tumour to other organs or tissues. Thus, a hip fracture from bone metastases, cerebral signs from intracranial metastases, or jaundice from liver involvement may all be the first evidence of a primary lung cancer, as may sensory changes in the legs, since a peripheral neuropathy may also be the presenting evidence of these tumours. The generally debilitating effect of many lung diseases is well recognized.
A person with active lung tuberculosis or with lung cancer, for example, may be conscious of only a general feeling of malaiseunusual fatigueor seemingly minor symptoms as the first indication of disease. Loss of appetite and loss of weight, a disinclination for physical activitygeneral psychological depressionand some symptoms apparently unrelated to the lung, such as mild indigestion or headachesmay be diverse indicators of lung disease.
Not infrequently, the patient may feel as one does when convalescent after an attack of influenza. Because the symptoms of lung disease, especially in the early stage, are variable and nonspecific, physical and radiographic examination of the chest are an essential part of the evaluation of persons with these complaints. Defenses of the respiratory system Exposed as it is to the outside environment, the respiratory tract possesses a complicated but comprehensive series of defenses against inhaled material.
The respiratory system in humans
As air passes through the noselarge particles of debris are filtered out by cilia and by mucus that is secreted from the mucous membrane lining the nasal cavity.
The air then travels through the pharynx, which is the last portion of the upper airway, through the larynx, which is the beginning portion of the lower airways, and into the trachea. Further filtration of the air occurs as it passes over cilia and sticky layers of mucus in the trachea.
In addition, lymphatic vessels in the wall of the trachea transport cells of the immune systemsuch as lymphocytes and macrophages, that act to trap and destroy foreign particles. Bands of muscle that surround the cartilage of the trachea play an important role in narrowing the airway during coughing, thus providing a forceful defense mechanism by which sputum and other substances can be quickly expelled from the respiratory tract.
In the bronchial tree, cilia beat in unison in one direction, moving substances up and out of the airways.
Covering the cilia in the bronchioles and small bronchi is a thin layer of fluid, which increases in thickness and becomes layered with mucus as the small bronchi converge into the large bronchi. When the cilia beat, foreign particles are transported along in the fluid and mucus layers. This system, known as the mucociliary escalatorcarries debris as far as the pharynx, where the fluid and mucus is then swallowed and the debris eliminated by the digestive system.
Macrophages form the first line of defense in the smaller branches of the airways. These cells, located within the alveoli of the lungs, ingest and destroy bacteria and viruses and remove small particles. They also secrete chemicals that attract other immune cells such as white blood cells to the site, and hence they can initiate an inflammatory response in the lung. Particles picked up by macrophages are carried into the lymphatic system of the lung and stored in adjacent lymph nodes in the lung and mediastinum the region between the lungs.
Soluble particles are removed into the bloodstream and are eventually excreted by the kidneys. Methods of investigation Physical examination of the chest remains important, as it may reveal the presence of an area of inflammation, a pleural effusionor an airway obstruction.
Methods of examination include physical inspection and palpation for masses, tender areas, and abnormal breathing patterns; percussion to gauge the resonance of the underlying lung; and auscultation listening with a stethoscope to determine pitch and loudness of breath sounds.
The sounds detected with a stethoscope may reveal abnormalities of the airways, the lung tissue, or the pleural space. Examination of the sputum for bacteria allows the identification of many infectious organisms and the institution of specific treatment; sputum examination for malignant cells is occasionally helpful.
The conventional radiological examination of the chest has been greatly enhanced by the technique of computed tomography CT. This technique produces a complete picture of the lungs by using X-rays to create two dimensional images that are integrated into one image by a computer.
While the resolution of computed tomography is much better than most other visualization techniques, lung ventilation and perfusion scanning can also be helpful in detecting abnormalities of the lungs.
In these techniques, a radioactive tracer molecule is either inhaled, in the case of ventilation scanning, or injected, in the case of perfusion scanning. The ventilation scan allows visualization of gas exchange in the bronchi and trachea, and the perfusion scan allows visualization of the blood vessels in the lungs.
The combined results from ventilation and perfusion scanning are important for the detection of focal occlusion of pulmonary blood vessels by pulmonary emboli. Although magnetic resonance imaging MRI plays a limited role in examination of the lung, because the technique is not well suited to imaging air-filled spaces, MRI is useful for imaging the heart and blood vessels within the thorax.
Positron emission tomography PET scanning is used to distinguish malignant lung tissue from scar tissue on tissues such as the lymph nodes. Flexible fibre-optic bronchoscopes that can be inserted into the upper airway through the mouth are used to examine the larynx, trachea, and major bronchi. By feeding a surgical instrument through a special channel of the bronchoscope, physicians can collect fluid and small tissue samples from the airways.
Tissue samples are examined for histological changes that indicate certain diseases and are cultured to determine whether harmful bacteria are present. A number of tests are available to determine the functional status of the lung and the effects of disease on pulmonary function.
Spirometry, the measurement of the rate and quantity of air exhaled forcibly from a full respiration, allows measurement of the ventilation capacity of the lungs and quantification of the degree of airflow obstruction. Ventilatory capability can be measured with a peak flow meterwhich is often used in field studies.
More complex laboratory equipment is necessary to measure the volumes of gas in the lung; the distribution of ventilation within the lung; airflow resistance; the stiffness of the lung, or the pressure required to inflate it; and the rate of gas transfer across the lung, which is commonly measured by recording the rate of absorption of carbon monoxide into the blood hemoglobin has a high affinity for carbon monoxide.
Arterial blood gases and pH values indicate the adequacy of oxygenation and ventilation and are routinely measured in patients in intensive care units. Tests of exercise capability, in which workload, total ventilation, and gas exchange are compared before, during, and after exercise, are useful in assessing functional impairment and disability. Lung transplantation Scientists performed the first single-lung transplant inthough the patient survived just 18 days.
Success with long-term survival came in for single-lung transplantation and in for double-lung transplantation. In the following decades, persons severely disabled by cystic fibrosisemphysemasarcoidosispulmonary fibrosisor severe primary pulmonary hypertension were able to achieve nearly normal lung function several months after the procedure.
By the early s, median survival for lung transplant patients had reached more than five years. The number of procedures carried out annually, however, was limited by a shortage of donor lungs. The major complication following lung transplantation is bronchiolitis obliterans.
Many recipients of single or double lung transplantation develop bronchiolitis obliterans beginning several months or years after surgery.