Template:Respiratory terms

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Respiratory Terms (expand to view) 
  • adenovirus - A Class I virus containing a single double-stranded DNA (dsDNA), which can cause infections in the upper respiratory tract in many animals. (More? viral infection)
  • alveolar duct - Anatomical short region lying between the end of the respiratory bronchioles and the final alveolar sacs. Term is also used in the mammary gland, to describe the smallest of the intralobular ducts into which the secretory alveoli open.
  • alveolar sac - (alveolus), Latin alveolus = little cavity) Anatomical and functional end of the mammalian lung respiratory tree where gas exchange occurs. In humans, during lung development these are the last features to form from 7 months onwards.
  • alveolar - Term used in relation to the alveoli of the lungs. The final functional sac of the respiratory tree where gas exchange occurs between the alveolar space and the pulmonary capillaries.
  • alveolar stage - Term used to describe lung development, the final histological/developmental stage (Pseudoglandular, Fetal Canalicular, Terminal sac, Alveolar). This stage occurs from late fetal/neonate with alveoli formation, the final functional sac of the respiratory tree exists, where gas exchange occurs between the alveolar space and the pulmonary capillaries. (embryonic stage - pseudoglandular stage - canalicular stage - saccular stage - alveolar stage)
  • alveolus - (alveolar sacs, plural alveoli, Latin alveolus = little cavity) Anatomical and functional end of the mammalian lung respiratory tree where gas exchange occurs. In humans, during lung development these are the last features to form from 7 months onwards. The acinus starts approximately 3 to 4 generations proximal of the bronchioalveolar duct junction and ends about 4 generations of alveolar ducts distal of the bronchioalveolar duct junction.
  • angiogenesis - vascular growth by direct extension from pre-existing blood vessels. (see also vasculogenesis).
  • apgar - Non-invasive clinical test designed by Dr Virginia Apgar (1953) carried out immediately on newborn. The name is also an acronym for: Activity (Muscle Tone), Pulse, Grimace (Reflex Irritability), Appearance (Skin Color), Respiration. A score is given for each sign at one minute and five minutes after the birth. (More? Apgar test)
  • apnea - Respiratory term meaning the cessation of breathing.
  • assisted ventilation - Clinical term referring to newborn (perinatal) respiration assistance required immediately following delivery, the infant given minimal breaths for any duration with bag and mask or bag and endotracheal tube within the first several minutes from birth. Excludes free flow oxygen only and laryngoscopy for aspiration of meconium.
  • asthma - Flow limitation during tidal expiration in early life significantly associated with the development of physician-diagnosed asthma by the age of 2 years. Infants with abnormal lung function soon after birth may have a genetic predisposition to asthma or other airway abnormalities that predict the risk of subsequent lower respiratory tract illness. Asthma phenotypes have a number of different classifications; allergic asthma, intrinsic or nonallergic asthma, infectious asthma, and aspirin-exacerbated asthma, and environmental exposures (occupational agents, smoking, air pollution, cold dry air) (More? PMID 5439356)
  • azygos lobe - Common condition (0.5% of population). The right lung upper lobe expands either side of the posterior cardinal. There is also some course variability of the phrenic nerve in the presence of an azygos lobe.
  • Bochdalek hernia - The most common form (80-85%) of the Congenital Diaphragmatic Hernia (CDH) types occurring mainly on the postero-lateral (left) side of the respiratory diaphragm. (More? Congenital Diaphragmatic Hernia)
  • bronchi - (Latin, bronchos = windpipe) Plural of bronchus, the two subdivisions of the trachea carrying air to the lungs. Embryologically form as an endodermal outpocket of the foregut which branch (bronchiole, subdivision of the bronchus) as they grow.
  • bronchiole - A smaller branch subdivision of the respiratory tract bronchus.
  • bronchopulmonary dysplasia - (chronic lung disease in preterm infants) Clinical term for a heterogeneous lung disease seen in preterm (premature) infants and diagnosed within the first months of life. Condition was first described in 1967. (More? preterm birth American Lung Association)
  • canalicular stage - (fetal canalicular, canalicular phase) Term used to describe lung development, after early embryonic the second of the histological/developmental stages (pseudoglandular, fetal canalicular, terminal sac, alveolar). This stage occurs during the fetal period from week 16 to 24. During this stage there is lung bud mesenchymal angiogenesis and cellular differentiation into different stromal cell types (fibroblasts, myoblasts and chondrocytes). (embryonic stage - pseudoglandular stage - canalicular stage - saccular stage - alveolar stage)
  • carbon monoxide - (CO) A colourless and odorless gas formed mainly as a by-product of incomplete combustion of hydrocarbons and can cause cytotoxicity by tissue hypoxia. Carbon monoxide enters circulation though the respiratory system, binding to haemoglobin to form carboxy-haemoglobin (COHb), with fetal haemoglobin binding with a greater affinity.
  • CDH - Acronym for Congenital Diaphragmatic Hernia, a musculoskeletal abnormality of the respiratory diaphragm. The most common form being the B#Bochdalek herniaBochdalek hernia.
  • chronic lung disease - (CLD) Clinical term, a neonatal chronic lung disease can be caused by prolonged mechanical ventilation (MV) and oxygen-rich gas with premature infants.
  • Clara cells - Respiratory tract epithelial cells on the luminal surface of airways. These cells have a dome shaped cytoplasmic protrusion and no cilia and their function is secretory and xenobiotic. Clara cells can act as progenitor cell in small airways replacing injured terminally differentiated epithelial cells.
  • Clara cell secretory protein - (CCSP) A protective lung protein secreted from non-ciliated bronchiolar epithelial cells in the conducting airways of mammals. The protein increases in expression level post-natally and is thought to have antioxidant, immunomodulatory, and anticarcinogenic properties.
  • congenital laryngeal webs - Laryngeal abnormality due to embryonic (week 10) incomplete recanalization of the laryngotracheal tube during the fetal period. Rare abnormality occuring mainly at the level of the vocal folds (glottis).
  • corticosteroid - An endocrine steroidal hormone produced by the adrenal cortex. Clinically, corticosteroids are also used for lung maturation of the premature neonate.
  • cystic fibrosis - Inherited disease of the mucus and sweat glands, causes mucus to be thick and sticky. Clogging the lungs, causing breathing problems and encouraging bacterial grow. (Covered elsewhere in the course)
  • diaphragm - A general term for a membranous sheet, used to describe the respiratory diaphragm. The muscular sheet separating chest from abdomen with several different embryonic origins. Regular contraction of the diaphragm is required in respiration. The diaphragm forms initially at the lower end of the pleuroperitoneal canal. (Embryonic origins: transverse septum (septum transversum) - tendon of the diaphragm, 3rd to 5th somite pairs - musculature of diaphragm, ventral pleural sac - connective tissue, mesentry of oesophagus - connective tissue around oesophasus and inferior vena cava, and pleuroperitoneal membranes - connective tissue around central tendon)
  • endoderm - (Greek, endo = inside + derma = skin) One of the initial 3 germ cell layers (ectoderm, mesoderm, endoderm) formed by the process of gastrulation. The endoderm forms the epithelial lining glands and of the respiratory tract.
  • epaxial muscle - Anatomical term describing skeletal muscles which lie dorsal (posterior) to the vertebral column developing from the somite myotome. At the ribcage level the levatores costarum muscles involved with rib elevation during respiration.
  • epiglottis - (Greek, epi = above, upon) cartilaginous part of the larynx above the glottis, which in infancy directs food into the esophagus and not the trachea . Embryologically it develops in the foregut from the hypobranchial eminence, behind the undeveloped tongue, from which it separates at about 7 weeks. Postnatal anatomical development in humans involves a maturational descent in infancy (4 and 6 months of age). Contains lymphoid tissue (larynx-associated lymphoid tissue, LALT and Bronchus-associated lymphoid tissue, BALT).
  • Extracorporeal Membrane Oxygenation - (ECMO) an invasive therapy that has been investigated and utilized in newborn infants with cardiorespiratory failure.
  • fetal breathing movements - (FBM) Occur in the third trimester preparing both the skeletomuscular system and lungs mechanically for respiration.
  • fistula - An abnormal communication between 2 structures (organs, vessels, cavities) that do not normally connect, can occur between the trachea and oesophagus.
  • foregut - The first of the three part/division (foregut - midgut - hindgut) of the early forming gastrointestinal tract. The foregut runs from the buccopharyngeal membrane to the midgut and forms all the tract (esophagus and stomach) from the oral cavity to beneath the stomach. In addition, a ventral bifurcation of the foregut will also form the respiratory tract epithelium.
  • glottis - (Greek, = larynx) the boundary between pharynx to the larynx and consists of the vocal folds and their associated intervening space.
  • HIF-1 - A transcription factor that is one of the main regulators of homeostasis in human tissues exposed to hypoxia, due to inflammation and/or insufficient circulation.
  • hyaline membrane disease - (Newborn Respiratory Distress Syndrome) Abnormality due to a membrane-like substance from damaged pulmonary cells.
  • laryngeal cleft - (LC, laryngeal-tracheo-oesophageal cleft) A rare foregut abnormality allowing digestive tract and the airway to communicate causing chronic cough, aspiration and respiratory distress. The downward extension of the cleft determines the classification of the abnormality.
  • laryngeal webs - (congenital laryngeal webs) Laryngeal abnormality due to embryonic (week 10) incomplete recanalization of the laryngotracheal tube. Rare abnormality occuring mainly at the level of the vocal folds (glottis).
  • laryngotracheal groove - Early embryonic foregut developmental feature, forms on the anterior (ventral) wall of the pharynx and gives rise to larynx, trachea and entire respiratory tree. In humans, this feature is the first indication of respiratory development and appears during week 4.
  • larynx - Site of the the vocal folds in the neck. Embryologically develops from the foregut with the lining derived from endoderm and the cartilage from pharyngeal arch 4 and 6. Beginning as a simple foregut groove, the laryngotracheal groove which folds to form the laryngotracheal bud, then the larynx and trachea.
  • late-gestation lung protein 1 - (LGL1) A glycoprotein secreted by fetal lung mesenchyme and fetal kidney, involved in retinoic acid stimulated branching morphogenesis.
  • lipofibroblast - (lipid interstitial cell, pulmonary lipofibroblast) Cell involved in secondary septum formation during the alveolar stage of lung development (late fetal to postnatal). Cell is recognizable by a number of characteristic lipid droplets and contains cortical contractile filaments.
  • lobar emphysema - (overinflated lung) Abnormality of an overinflated left upper lobe There is a collapsed lower lobe The left lung is herniating across the mediastinum.
  • measles - (paramyxovirus) Measles (rubeola) is mainly a respiratory viral infection, clinically different from Rubella.
  • meconium aspiration syndrome - (MAS) Fetal stress in the third trimester, prior to/at/ or during parturition can lead to premature meconium discharge into the amniotic fluid and sunsequent ingestion by the fetus and damage to respiratory function.
  • mitochondria - Double membraned cell organelle located in the cytoplasm, a cell may contain 100's or more mitochondria, the number can relate to the metabolic activity of that cell. Functions in cell respiration, providing energy to the cell and also has a role in the process of apoptosis (programmed cell death).
  • nitrofen - A diphenyl ether herbicide teratogen used in rodent development to generate a range of developmental abnormalities, including congenital diaphragmatic hernia.
  • oropharynx - The second portion of the pharynx (throat) that is posterior to the oral cavity. The other pharynx regions are the nasopharynx and laryngopharynx (hypopharynx).
  • parathyroid hormone-related protein - (PTHrP) A protein named for its evolutionary and structural relationship to parathyroid hormone (PTH). A protein hormone produced by many fetal tissues and with a number of different functions including a possible autocrine role in lung development.
  • parietal pleura - Serous membrane which forms the outer lining of pleural cavity. mesoderm of the thoracic cavity body wall and derived from epithelia of pericardioperitoneal canals from intra-embryonic coelom. The inner pleural layer, visceral pleura, is splanchnic mesoderm in origin.
  • Pentalogy of Cantrell - A developmental abnormality of the anterior diaphragm, diaphragmatic pericardium, abdominal wall, cardiovascular and lower sternum.
  • Persistent Pulmonary Hypertension of the Newborn - (PPHN) A serious newborn condition due to due to the failure of closure one of the prenatal circulatory shunts, the ductus arteriosus. Occurs in about 1-2 newborns per 1000 live births and results in hypoxemia.
  • pharynx - (throat) embryo uppermost end of the combined gastrointestinal and respiratory tract beginning at the buccopharyngeal membrane and forms a major arched cavity within the phrayngeal arches. Also used as a respiratory term describing the initial segment of the upper respiratory tract divided anatomically into three regions: nasopharynx, oropharynx, and laryngopharynx (hypopharynx). Anatomically extends from the base of the skull to the level of the sixth cervical vertebra.
  • pleural cavity - Anatomical body cavity in which the lungs develop and lie. Forms in the lateral plate mesoderm as part of the early single intra-embryonic coelom, the pleural cavities are initially two narrow canals.
  • pleuropericardial fold - (pleuropericardial membrane) An early embryonic fold which restricts the communication between pleural cavity and pericardiac cavity, contains both the |cardinal vein and phrenic nerve.
  • pleuroperitoneal foramen - The developmental opening occurring in the intra-embryonic coelom before formation of the pleuroperitoneal membrane.
  • PLUNC - Acronym for Palate, LUng, Nasal epithelium Clone protein, related to the lipid transfer/lipopolysaccharide binding protein (LT/LBP) family. This protein is secreted by the airway conducting epithelia and acts as a surfactant that may interfere with biofilm formation by airway pathogens.
  • pulmonary acini (singular - acinus) region of the lung supplied with air from one of the terminal bronchioles, anatomical and functional end of the mammalian lung respiratory tree where gas exchange occurs. Starts approximately 3 to 4 generations proximal of the bronchio-alveolar duct junction and ends about 4 generations of alveolar ducts distal of the bronchioalveolar duct junction.
  • pulmonary arterial hypertension - (PAH) a progressive disease characterized by abnormalities of vascular tone and reactivity, vessel wall structure, growth, and thrombosis that in newborns, infants, and children can contribute to poor outcomes in cardiac, pulmonary, and systemic diseases.
  • respiratory - Term used in relation to breathing (in and out) or associated with the lungs. Anatomically used to describe the lungs, air pathways and associated muscles. In cell biology used in relation to mitochondrial use of oxygen to produce energy and carbon dioxide waste.
  • respiratory sinus arrhythmia - (RSA) Clinically used as an index of cardiac vagal activity, measured breath-by-breath by subtracting the minimum heart rate (HR) during expiration from the maximum HR during inspiration.
  • respiratory tree - Anatomical term to describe the components of the respiratory system (lungs) as they branch again and again ending in the functional units, the alveolar sacs (alveolus).
  • saccular stage - (terminal sac stage) process of lung epithelial cell differentiation, vascular remodeling and thinning of the mesenchyme. This process leads to enlargement of the diameter and surface area of the alveolar sacs. Distal epithelial cells form 2 populations: 1. cells flattens, thins, and spreads to form type I cells; 2. cells remain cuboidal, acquire surfactant filled lamellar bodies and differentiate into type II cells. Sacculation is a general anatomical term meaning to formed a series of sac-like expansions. (embryonic stage - pseudoglandular stage - canalicular stage - saccular stage - alveolar stage)
  • secondary septa - (secondary septa) process in the lung alveolar stage of development (postnatally) where the double capillary network in the immature gas-exchange region fuses to form a single capillary layer.
  • septum transversum - (transverse septum) A mesodermal region in the early embryo. Identified externally as the junctional site between amnion and yolk sacs, and internally (within the embryo) lying directly beneath the heart and at the foregut/midgut junction. This ventro-dorsal "plate" of mesoderm contributes several structures including: the central tendon of diaphragm and some of the liver.
  • stenosis - Term used to describe an abnormal narrowing, usually in relation to a tube for example: respiratory tract, blood vessel, gastrointestinal tract.
  • stomodeum - (stomadeum, stomatodeum) The primordial mouth region of the developing embryonic head.
  • surfactant - (surface active agent ; pulmonary surfactant) A mixture of lipids and proteins secreted by Type 2 alveolar cells between alveolar epithelium that reduces surface tension (detergent) at the air-liquid interface. The function is to prevent collapse of the lung at the end of expiration. In humans, these cells and their secretion develop towards the very end of the third trimester, just before birth. Clinical surfactants used for surfactant replacement therapy are animal-derived preparations, commonly bovine (beractant, bovactant, BLES) or less common porcine (butantan, poractant-α and surfacen) PMID30728009.
  • surfactant replacement therapy - (surfactant therapy) A clinical birth term referring to the endotracheal instillation of a surface-active suspension for treating surfactant deficiency due to either preterm birth or pulmonary injury resulting in respiratory distress (respiratory distress syndrome).
  • tachypnea - (Greek, tachypnea = rapid breathing) Clinical term describing an increased respiratory rate of greater than 60 breaths/minute in a quiet resting baby.
  • terminal sac stage - (saccular stage, terminal sac phase, immature alveoli) Term used to describe the second last histological/developmental stage (pseudoglandular stage, Fetal Canalicular, saccular stage, Alveolar) of lung development. This stage occurs from late fetal week 24 to 36. During this stage branching and growth of the terminal sacs occurs, with cellular differentiation of the type -II pneumonocytes and type - I pneumonocytes The final functional sac of the respiratory tree occurs at the next neonatal period, where gas exchange occurs between the alveolar space and the pulmonary capillaries. (embryonic stage - pseudoglandular stage - canalicular stage - saccular stage - alveolar stage)
  • trachea - (windpipe) In the embryo, a ventral out-pocket of pharynx endoderm that branches in week 4 stage 13 into the right and left bronchi within the lung buds. The endoderm has associated mesoderm that later differentiates to form most structures outside the respiratory epithelium. In the adult, the trachea forms the functional connection between the pharynx and larynx to the lungs.
  • tracheoesophageal fistula - Abnormal connection between the trachea and oesophagus.
  • Trisomy 21 - (Down syndrome) associated with significant cardiovascular and pulmonary mortality and morbidity of neonates, infants, and children. Infant lung histology may share features of decreased lung vascular and alveolar growth. (More? Trisomy 21 | PMID 25621156)
  • vagus - (Latin, vagus = wandering) cranial nerve X (CN X) A mixed nerve that leaves the head and neck to innervate respiratory tract (larynx, lungs), gastrointestinal tract (pharynx, esophagus, stomach), cardiac (heart) and abdominal viscera. This mixed nerve has sensory, motor and autonomic functions of viscera (glands, digestion, heart rate).
  • vasculogenesis - the formation of new blood vessels from angioblasts or endothelial progenitor cells (EPCs) that migrate, differentiate, and grow into tubes in response to signals from surrounding cells. (see also angiogenesis).
  • VEGF - (vascular endothelial growth factor) a specific mitogen and survival factor required for endothelium growth and development also required in lung vasculature development and remodelling.
  • ventilatory unit - region from a respiratory bronchiole extending to the supported alveolar ducts and alveoli.
  • visceral pleura - Serous membrane which forms the inner lining of pleural cavity, both covering and attached to the lungs. Embryonically derived from the splanchnic mesoderm. The outer pleural layer, parietal pleura, is derived from mesoderm of the thoracic cavity body wall.
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