- Lung Anatomy: How the Lungs Work Center
- Understanding COPD Slideshow
- COPD (Chronic Obstructive Pulmonary Disease) Quiz
- Energy Foods for COPD Slideshow Pictures
- Patient Comments: Lung Anatomy - Disease
Human lung anatomy definition and facts
- The lungs exchange oxygen and carbon dioxide between the air we breathe and the blood.
- The tracheobronchial tree is the passage way from the mouth to the interior of the lung.
- Gas exchange occurs in the alveoli deep in the lungs.
- Breathing air in (inhalation) requires muscular effort.
- Air is warmed, humidified, and cleaned by the nose and lungs.
What are the lungs?
What is carbon dioxide poisoning? What are the symptoms?
The cells in the body constantly need a new supply of oxygen to produce energy. With lack of oxygen, cellular function is impaired and damage or cell death may occur. As energy is utilized, waste products are created, one of which is the gas carbon dioxide. Eliminating carbon dioxide from the body is just as important as breathing in oxygen from the air. If carbon dioxide builds up in the blood it will lead to headaches, drowsiness, coma, and eventually even death.
What is the structure of the respiratory system?
Air enters the body via the nose (preferably) or the mouth. The air enters the main windpipe, called the trachea, and continues en route to each lung via either the right or left bronchus (plural=bronchi). The lungs are separated into sections called lobes, two on the left and three on the right. The air passages continue to divide into ever smaller tubes, which finally connect with tiny air sacs called alveoli. This gradually branching array of tubes is referred to as the tracheobronchial "tree" because of the remarkable similarity to the branching pattern of a tree.
The other half of the respiratory system involves blood circulation. Venous blood from the body is returned to the right side of the heart and then pumped out via the pulmonary artery. This artery splits in two for the left and right lungs and then continues to branch much like the tracheobronchial tree. These vessels branch into a fine network of very tiny tubes called capillaries. The capillaries are situated adjacent to the alveoli and are so small that only one red blood cell at a time can pass through their openings. It is during this passage that gases are exchanged between the blood and the air in the nearby alveoli. After passing the alveoli, capillaries then join together to begin forming the pulmonary veins, which carry the blood back to the left side of the heart.
Inhalation and exhalation
Respiration is divided into two components, inhalation and exhalation.
Inhalation is active, because it requires muscle contraction. The major muscle of respiration is a sheet-like dome shaped muscle called the diaphragm that is located below the lungs. The diaphragm separates the chest and abdominal cavities. As the diaphragm contracts, it flattens out, moving toward the abdominal cavity. This action causes an increase in the size of the chest cavity, thus creating a vacuum. Air is then sucked in through the mouth or nose. When physical activity increases dramatically, or with some lung conditions, other muscles like those of the neck and those between the ribs also assist in the increase in size of the chest cavity. These muscles are referred to as accessory muscles of respiration.
Exhalation is passive because it does not require muscle contraction. During this phase, the expanded lung acts like a stretched rubber band and simply contracts to its resting position. This contraction forces air out of the lungs and through the mouth.
How does gas exchange occur?
As energy is utilized by cells, one of the waste products is the gas carbon dioxide. Oxygen-enriched red blood cells release oxygen to the cells of the body and then pick up the waste carbon dioxide. This oxygen- deprived, dark blue blood is then delivered to the blood vessels of the lungs. Carbon dioxide is released by the red cells, easily passes through the capillary wall into the space in the air sac of the adjacent alveoli, and is then eliminated with each breath out of the mouth (exhalation). Oxygen present in the air sac easily passes into the capillaries and into the red blood cells. The capillary network carrying this oxygen-rich, bright red blood flows to larger vessels and eventually empties into the left side of the heart where it is pumped to all the tissues of the body. Thus, the cycle or circle of blood is complete; hence, the name circulation.
What are other important events during the breathing cycle?
Outside air needs to be heated and moistened to match the body's temperature and humidity. As air passes down the tracheobronchial tree, it is warmed and water is added. Contaminants must also be removed. Nose hairs and tiny microscopic hairs called cilia, along with sticky mucus produced by the lining membrane help cleanse the air of impurities. Cilia beat in a synchronized fashion brushing any collected dirt and mucus up toward the mouth. The accumulated material is then coughed out or swallowed. By the time the air reaches the alveoli, it is virtually sterile.
Health Solutions From Our Sponsors
MedscapeReference.com. Lung Anatomy.
Top Lungs Design And Purpose Related Articles
Alpha 1 Antitrypsin Deficiency
Alpha-1 antitrypsin deficiency (AATD) is an inherited disorder caused by mutations in the SERPINA1 gene. People with the condition are at risk for developing serious lung and liver disease. Symptoms and signs of lung disease caused by this condition include:
The earliest symptoms and signs of lung disease usually develop between 20 and 50 years of age, and are
- The reduced ability to exercise
- Shortness of breath (dyspnea) following mild activity
Other symptoms and signs of alpha-1 antitrypsin deficiency are:
- Rapid heartbeat when going from sitting to standing
- Recurring respiratory infections
- Unintentional weight loss
Lung disease: People with this condition often develop emphysema, with symptoms of a hacking cough, barrel-shaped chest, and difficulty breathing. If you have this condition and smoke or are exposed to tobacco smoke, it accelerates the appearance of emphysema symptoms and lung damage.
Liver disease: Alpha-1 antitrypsin deficiency also cause liver disease in some people with the condition, that include liver cancer, cirrhosis of the liver, an abnormally large liver (hepatomegaly), liver failure, and hepatitis. Liver damage from alpha-1 antitrypsin deficiency causes symptom of a swollen abdomen, swollen legs or feet, and jaundice.
Treatment of AATD depends upon the severity of symptoms. FDA approved drug for AATD is an orphan product called alpha-1-proteinase inhibitor (human), sold under the brand name "Prolastin."
Asthma Myths SlideshowThere is currently no cure for asthma, and no specific, single cause for asthma has been identified. Take this quiz on asthma myths to test your asthma IQ and take an active role in your own health.
Asthma OverviewAsthma is a condition in which hyperreactive airways constrict and result in symptoms like wheezing, coughing, and shortness of breath. Causes of asthma include genetics, environmental factors, personal history of allergies, and other factors. Asthma is diagnosed by a physician based on a patient's family history and results from lung function tests and other exams. Inhaled corticosteroids (ICS) and long-acting bronchodilators (LABAs) are used in the treatment of asthma. Generally, the prognosis for a patient with asthma is good. Exposure to allergens found on farms may protect against asthma symptoms.
Asthma SlideshowWhat is asthma? Learn about asthma, a chronic inflammation disorder of the bronchiole tubes (airways). Discover information about an asthma attack, asthma symptoms, prevention and treatments such as asthma medications and inhalers.
Take the Asthma QuizAsthma is a chronic disease of the airways of the lungs, which can be managed with proper treatment. Triggered by two main causes, asthma symptoms can be brought on by environmental factors and surprising allergens.
Bronchitis SlideshowIs bronchitis contagious? Learn about bronchitis, an inflammation of the lining of the lungs. Bronchitis can be aggravated from colds, cigarette smoking, COPD, and other lung conditions. Explore bronchitis symptoms and treatments.
Bronchitis QuizWhat happens within the body when a person develops bronchitis? Take this quick quiz to learn the causes, symptoms, treatments, and complications of this common respiratory illness.
Chest X-rayChest X-Ray is a type of X-Ray commonly used to detect abnormalities in the lungs. A chest X-ray can also detect some abnormalitites in the heart, aorta, and the bones of the thoracic area. A chest X-ray can be used to define abnormalities of the lungs such as:
- excessive fluid (fluid overload or pulmonary edema),
- fluid around the lung (pleural effusion),
- and cancers.
Take the COPD QuizCOPD is a combination of three conditions? Take this quiz to learn the three conditions that make up the pulmonary disease called chronic obstructive pulmonary disease (COPD).
Cystic FibrosisCystic fibrosis is a disease of the mucus and sweat glands. Cystic fibrosis is an inherited disease. The outcome of the disease leaves the body malnourished, with bulky and fouls smelling stools, vitamin insufficiency, gas, painful or swollen abdomen, infertility, susceptible to heat emergencies, and respiratory failure. There is no cure for cystic fibrosis, treatment of symptoms is used to manage the disease.
Endotracheal IntubationEndotracheal intubation is a procedure by which a tube is inserted through the mouth down into the trachea. Intubation is done under deep sedation, or in emergency situations (the patient is often unconscious at the time of the procedures. The purpose of the endotracheal tube is to allow air to pass to and from the lungs for ventilation. Potential complications of intubation include:
- brain damage,
- cardiac arrest,
- or death.
Lung CancerLung cancer kills more men and women than any other form of cancer. Eight out of 10 lung cancers are due to tobacco smoke. Lung cancers are classified as either small cell or non-small cell cancers.
Lungs PictureThe lungs are a pair of spongy, air-filled organs located on either side of the chest (thorax). See a picture of the Lungs and learn more about the health topic.
Marfan syndrome is hereditary (genetic) condition affecting connective tissue. A person with Marfan syndrome may exhibit the following symptoms and characteristics:
- Dislocation of one or both lenses of the eye
- A protruding or indented breastbone
- Flat feet
- Aortic dilatation
- Dural ectasia (a problem with the sac surrounding the spinal cord)
- Stretch marks
- Collapsed lung
Though there is no cure for Marfan syndrome, there are treatments that can minimize and sometimes prevent some complications.
Nasal Airway SurgeryDeviated septum surgery (septoplasty) and turbinectomy (nasal airway surgery) is performed on individuals who have a deviated or crooked septum or enlarged tissues (turbinates) within the nose. The goal of surgery is to improve breathing, control nosebleeds, relieve sinus headaches, and promote drainage of the sinus cavities. Risks and complications of surgery should be discussed with the surgeon prior to surgery.
OximetryOximetry is a procedure used to measure the concentration of oxygen in the blood. Oximetry is used in the evaluation of various medical conditions that affect the function of the heart and lungs. Pulse oximeters are the most common oximeter used because they respond only to pulsations. Oximetry can also be done on blood within the heart, or on whole blood that has been removed from the body. Similar technology to oximetry is currently used to measure carbon dioxide levels at the skin.
Secondhand SmokeThe effects of secondhand smoke can be hazardous to your health. Secondhand smoke can lead to lung cancer, heart disease, and respiratory illnesses. Get the facts about how to protect yourself and your family from the effects of secondhand smoke.
TracheostomyA tracheostomy is a surgically created opening in the neck leading directly to the trachea (the breathing tube). It is maintained open with a hollow tube called a tracheostomy tube. Tracheostomies are used to:
- bypass an obstructed airway,
- remove airway secretions, and
- easily deliver oxygen to the lungs.