Human lung
Frontal view of lungs cut open Trachea branches into bronchi
Latin	pulmo
Gray's	subject #240 1093
MeSH	Lung

The human lungs are the human organs of respiration. Drawing of human lungs cut open, from Grays Anatomy, 1918. ... For other uses, see Latins and Latin (disambiguation). ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... In animal physiology, respiration is the transport of oxygen from the ambient air to the tissue cells and the transport of carbon dioxide in the opposite direction. ...

Humans have two lungs, with the left being divided into two lobes and the right into three lobes. Together, the lungs contain approximately 1500 miles (2,400 km) of airways and 300 to 500 million alveoli, having a total surface area of about 75 m² in adults — roughly the same area as a tennis court.^[1] Furthermore, if all of the capillaries that surround the alveoli were unwound and laid end to end, they would extend for about 620 miles. For the village in Tibet, see Lung, Tibet. ... The alveoli (singular:alveolus), tiny hollow sacs which are continuous with the airways, are the sites of gas exchange with the blood. ... This article does not cite any references or sources. ...

Organization

• The conducting zone contains the trachea, the bronchi, the bronchioles, and the terminal bronchioles
• The respiratory zone contains the respiratory bronchioles, the alveolar ducts, and the alveoli.

The conducting zone and the respiratory zone (but not the alveoli) are made up of airways. Windpipe redirects here. ... A bronchus (plural bronchi, adjective bronchial) is a caliber of airways in the the respiratory tract that conducts air into the lungs. ... The bronchioles are the first airway branches that no longer contain cartilage. ... A terminal bronchiole is a bronchiole at the end of the respiratory zone. ... The bronchioles are the first airway branches that no longer contain cartilage. ... Alveolar ducts are the tiny end tubules of the branching airways that fill the lungs. ... The alveoli (singular:alveolus), tiny hollow sacs which are continuous with the airways, are the sites of gas exchange with the blood. ... The airways are those parts of the respiratory system through which air flows, to get from the external environment to the alveoli. ...

The conducting zone has no gas exchange with the blood, and is reinforced with cartilage and smooth muscle, which are very strong. Smooth muscle has variable resistance to air flow. The conducting zone warms the air to 37 degrees Celsius and humidifies the air. It also cleanses the air by removing particles.

The respiratory zone is the site of gas exchange with blood. Gas exchange or respiration takes place at a respiratory surface—a boundary between the external environment and the interior of the body. ...

The smooth muscle tone in bronchioles, and therefore bronchiolar diameter, is controlled by:

• the sympathetic nervous system via noradrenaline acting on the beta receptors and causes bronchodilation
• the parasympathetic nervous system via acetylcholine which acts on the muscarinic receptors and causes bronchoconstriction
• many other non-autonomic nervous and biochemical stimuli including, for example, carbon dioxide.

The intrapleural space is the potential space between the pleura lining the inner wall of the thoracic cage and the pleura lining the lungs. The Sympathetic Nervous System (SNS) is a branch of the autonomic nervous system. ... Norepinephrine, known as noradrenaline outside the USA, is a catecholamine and a phenethylamine with chemical formula C8H11NO3. ... Epinephrine Norepinephrine The adrenergic receptors (or adrenoceptors) are a class of G protein-coupled receptors that are targets of the catecholamines. ... A bronchodilator is a medication intended to improve bronchial airflow. ... Autonomic nervous system innervation, showing the sympathetic and parasympathetic (craniosacral) systems, in red and blue, respectively The parasympathetic nervous system is one of three divisions of the autonomic nervous system. ... The chemical compound acetylcholine (often abbreviated ACh) is a neurotransmitter in both the peripheral nervous system (PNS) and central nervous system (CNS) in many organisms including humans. ... Muscarinic receptors are those membrane bound acetylcholine receptors that are more sensitive to muscarine than to nicotine. ... Bronchoconstriction is the constriction of the airways in the lungs due to the tighting of surrounding smooth muscle, with consequent coughing, wheezing, and shortness of breath. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... In anatomy, the pleural cavity is the potential space between the lungs and the chest wall. ... In anatomy, the pleural cavity is the potential space between the lungs and the chest wall. ...

Physiology

Total lung capacity (TLC) includes inspiratory reserve volume, tidal volume, expiratory reserve volume, and residual volume.^[2] The total lung capacity depends on the person's age, height, weight, sex, and normally ranges between 4,000 and 6,000 cm³ (4 to 6 L). For example, females tend to have a 20–25% lower capacity than males. Tall people tend to have a larger total lung capacity than shorter people. Smokers have a lower capacity than nonsmokers. Lung capacity is also affected by altitude. People who are born and live at sea level will have a smaller lung capacity than people who spend their lives at a high altitude. In addition to the total lung capacity, one also measures the tidal volume, the volume breathed in with an average breath, which is about 500 cm³. For a detailed discussion of the various lung volumes, see the article on lung volumes.^[3] This page may meet Wikipedias criteria for speedy deletion. ... The average pair of human lungs can hold about 6 litres of air, but only a small amount is used during normal breathing. ... The average pair of human lungs can hold about 6 litres of air, but only a small amount is used during normal breathing. ... The average pair of human lungs can hold about 6 litres of air, but only a small amount is used during normal breathing. ... The average pair of human lungs can hold about 6 litres of air, but only a small amount is used during normal breathing. ... The cigarette is the most common method of smoking tobacco. ... For considerations of sea level change, in particular rise associated with possible global warming, see sea level rise. ... Altitude is the elevation of an object from a known level or datum. ... The average pair of human lungs can hold about 6 litres of air, but only a small amount is used during normal breathing. ... Lung Volumes Lung volumeizing refer to physical differences in lung volume, while lung capacities represent different combinations of lung volumes, usually in relation to inhalation and exhalation. ...

Typical resting adult respiratory rates are 10–20 breaths per minute with 1/3 of the breath time in inspiration.

Human lungs are to a certain extent 'overbuilt' and have a tremendous reserve volume as compared to the oxygen exchange requirements when at rest. This is the reason that individuals can smoke for years without having a noticeable decrease in lung function while still or moving slowly; in situations like these only a small portion of the lungs are actually perfused with blood for gas exchange. As oxygen requirements increase due to exercise, a greater volume of the lungs is perfused, allowing the body to reach its CO₂/O₂ exchange requirements. The term Exercise can refer to: Physical exercise such as running or strength training Exercise (options), the financial term for enacting and terminating a contract Category: ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... This article is about the chemical element and its most stable form, or dioxygen. ...

Diseases

Diseases of the human lung belong to respiratory diseases. The following is a list of important medical conditions involving the lung. Many of these are caused or worsened by smoking. Diseases of the mammalian respiratory system are classified under one of two broad categories: physiologic, where disease states are characterised by alterations in physiology, or anatomical, where disease states are defined by the anatomical location/level affected, or by the layers of the respiratory system affected by disease. ... The cigarette is the most common method of smoking tobacco. ...

• Lung cancer
• Emphysema is an enlargement of the air spaces in the lung, making it hard to breathe.
• Asthma is an immunological disease which causes the bronchioles to narrow by inflammation and spasm of the lining of the airway wall.
• Cystic fibrosis is a hereditary disease which causes the lung to produce abnormally viscous mucus.
• A pulmonary embolism occurs when a blood clot obstructs an artery leading to the lung.
• Tuberculosis is a transmittable bacterial infection of the lung, the most common infectious disease today.
• Pneumonia is an infection of the lung, caused by bacteria, viruses or fungi.
• Pneumoconiosis, an occupational lung disease caused by the inhalation of dust.
• Bronchitis is an inflammation of the bronchi.
• A collapsed lung (pneumothorax) can occur when one or both walls of the pleural cavity are penetrated by injury, allowing air to enter.
• In pulmonary edema fluid from the capillaries enters the alveoli. This can be caused by weakness of the left side of the heart (resulting in a blood holdup in the lung), altitude sickness, or rarely inhaling toxic gases.
• Lung pinprick condition is a hereditary disease which results in decreased lung capacity and occasional shortness of breath.

Transplantation now allows for a person to have a single lung transplant, a double-lung transplant, or a transplant of both the heart and lungs. Lung cancer is a disease of uncontrolled cell growth in tissues of the lung. ... A genetic disorder, or genetic disease is a disease caused, at least in part, by the genes of the person with the disease. ... Mucus cells. ... For other uses, see Artery (disambiguation). ... Tuberculosis (abbreviated as TB for tubercle bacillus or Tuberculosis) is a common and deadly infectious disease caused by mycobacteria, mainly Mycobacterium tuberculosis. ... This article is about human pneumonia. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... This article is about biological infectious particles. ... For the fictional character, see Fungus the Bogeyman. ... Pneumoconiosis, also known as coal workers pneumoconiosis, miners asthma, or black lung disease, is a lung condition caused by the inhalation of dust, characterized by formation of nodular fibrotic changes in lungs. ... These are a specific branch of Occupational Diseases concerned primarily with work related exposures to harmful substances, be they dusts or gases, and the subsequent pulmonary disorders that may occur as a result. ... Bronchitis is an inflammation of the bronchi and may specifically refer to: Acute bronchitis, caused by viruses or bacteria and lasting several days or weeks Chronic bronchitis, a persistent, productive cough lasting at least three months in two consecutive years. ... An abscess on the skin, showing the redness and swelling characteristic of inflammation. ... In medicine (pulmonology), a pneumothorax or collapsed lung is a medical emergency that can result from a penetrating chest wound or barotrauma to the lungs. ... Pulmonary edema is swelling and/or fluid accumulation in the lungs. ... Altitude sickness, also known as acute mountain sickness (AMS), altitude illness, or soroche, is a pathological condition that is caused by acute exposure to low air pressure (usually outdoors at high altitudes). ... Toxic redirects here, but this is also the name of a song by Britney Spears; see Toxic (song) Look up toxic and toxicity in Wiktionary, the free dictionary. ... Lung Pinprick Condition (LPC) is a rare, autosomal recessive, respirative condition. ... A genetic disorder, or genetic disease is a disease caused, at least in part, by the genes of the person with the disease. ... An organ transplant is the transplantation of a whole or partial organ from one body to another, for the purpose of replacing the recipients damaged or failing organ with a working one from the donor. ... A heart-lung transplant is a procedure carried out to replace both heart and lungs in a single operation. ...

Modification of substances

The lungs convert angiotensin I to angiotensin II. In addition, they remove several blood-bourne substances, e.g. PGE₁, PGE₂, PGF_2α, leukotrienes, serotonin, bradykinin. ^[4] Angiotensinogen, angiotensin I and angiotensin II are peptides involved in maintenance of blood volume and pressure. ... Angiotensinogen, angiotensin I and angiotensin II are peptides involved in maintenance of blood volume and pressure. ... For other uses, see Blood (disambiguation). ... E1 - Alprostadil I2 - Prostacyclin A prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body. ... Leukotrienes are autocrine and paracrine eicosanoid lipid mediators derived from arachidonic acid by 5-lipoxygenase. ... For the professional wrestling stable, see Ravens Nest#Serotonin. ... Spacefilling model of bradykinin Bradykinin is a physiologically and pharmacologically active peptide of the kinin group of proteins, consisting of nine amino acids. ...

References

Additional images

Detailed diagram of the lungs Image File history File links Lungs_diagram_detailed. ...

Bronchi, bronchial tree, and lungs. Image File history File links Illu_bronchi_lungs. ... A bronchus (plural bronchi, adjective bronchial) is a caliber of airways in the the respiratory tract that conducts air into the lungs. ... The heart and lungs (from an older edition of Grays Anatomy) The lung is an organ belonging to the respiratory system and interfacing to the circulatory system of air-breathing vertebrates. ...