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Tracheoesophageal Septum
The tracheoesophageal septum is an embryological structure. It is formed from the tracheoesophageal folds or ridges which fuse in the midline. It divides the oesophagus from the trachea during prenatal development. Developmental abnormalities can lead to a tracheoesophageal fistula. Structure The tracheoesophageal septum is formed from the tracheoesophageal folds laterally (longitudinal ridges), which fuse in the midline. It divides the oesophagus from the trachea. This is complete by 6 weeks of gestation. It divides the foregut tube: the laryngotracheal tube ventrally and oesophagus dorsally.Development of the Digestive System Function The tracheoesophageal septum divides the |
Tracheoesophageal Folds
The tracheoesophageal septum is an embryological structure. It is formed from the tracheoesophageal folds or ridges which fuse in the midline. It divides the oesophagus from the trachea during prenatal development. Developmental abnormalities can lead to a tracheoesophageal fistula. Structure The tracheoesophageal septum is formed from the tracheoesophageal folds laterally (longitudinal ridges), which fuse in the midline. It divides the oesophagus from the trachea. This is complete by 6 weeks of gestation. It divides the foregut tube: the laryngotracheal tube ventrally and oesophagus dorsally.Development of the Digestive System Function The tracheoesophageal septum divides the oesophagus from the trachea during prenatal development. ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oesophagus
The esophagus (American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. The esophagus is a fibromuscular tube, about long in adults, that travels behind the trachea and heart, passes through the diaphragm, and empties into the uppermost region of the stomach. During swallowing, the epiglottis tilts backwards to prevent food from going down the larynx and lungs. The word ''oesophagus'' is from Ancient Greek οἰσοφάγος (oisophágos), from οἴσω (oísō), future form of φέρω (phérō, “I carry”) + ἔφαγον (éphagon, “I ate”). The wall of the esophagus from the lumen outwards consists of mucosa, submucosa (connective tissue), layers of muscle fibers between layers of fibrous tissue, and an outer layer of connective tissue. The mucosa is a stratified squamous epithel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trachea
The trachea, also known as the windpipe, is a Cartilage, cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends from the larynx and branches into the two primary bronchi. At the top of the trachea the cricoid cartilage attaches it to the larynx. The trachea is formed by a number of horseshoe-shaped rings, joined together vertically by overlying annular ligaments of trachea, ligaments, and by the trachealis muscle at their ends. The epiglottis closes the opening to the larynx during swallowing. The trachea begins to form in the second month of embryo development, becoming longer and more fixed in its position over time. It is epithelium lined with columnar epithelium, column-shaped cells that have hair-like extensions called cilia, with scattered goblet cells that produce protective mucins. The trachea can be affected by inflammation or infection, us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prenatal Development
Prenatal development () includes the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal development until birth. In human pregnancy, prenatal development is also called antenatal development. The development of the human embryo follows fertilization, and continues as fetal development. By the end of the tenth week of gestational age the embryo has acquired its basic form and is referred to as a fetus. The next period is that of fetal development where many organs become fully developed. This fetal period is described both topically (by organ) and chronologically (by time) with major occurrences being listed by gestational age. The very early stages of embryonic development are the same in all mammals, but later stages of development, and the length of gestation varies. Terminology In the human: Different terms are used to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tracheoesophageal Fistula
A tracheoesophageal fistula (TEF, or TOF; see spelling differences) is an abnormal connection (fistula) between the esophagus and the trachea. TEF is a common congenital abnormality, but when occurring late in life is usually the sequela of surgical procedures such as a laryngectomy. Presentation Tracheoesophageal fistula is suggested in a newborn by copious salivation associated with choking, coughing, vomiting, and cyanosis coincident with the onset of feeding. Esophageal atresia and the subsequent inability to swallow typically cause polyhydramnios in utero. Rarely it may present in an adult. Complications Surgical repair can sometimes result in complications, including: * Stricture, due to gastric acid erosion of the shortened esophagus * Leak of contents at the point of anastomosis * Recurrence of fistula * Gastro-esophageal reflux disease * Dysphagia * Asthma-like symptoms, such as persistent coughing/wheezing * Recurrent chest infections * Tracheomalacia Associations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saunders (imprint)
Saunders is an American academic publisher based in the United States. It is currently an imprint of Elsevier. Formerly independent, the W. B. Saunders company was acquired by CBS in 1968, who added it to their publishing division Holt, Rinehart & Winston. When CBS left the publishing field in 1986, it sold the academic publishing units to Harcourt Brace Jovanovich. Harcourt was acquired by Reed Elsevier in 2001. . . Retrieved May 2, 2015. W. B. Saunders published the Kinsey Reports and |
Elsevier
Elsevier () is a Dutch academic publishing company specializing in scientific, technical, and medical content. Its products include journals such as ''The Lancet'', ''Cell'', the ScienceDirect collection of electronic journals, '' Trends'', the '' Current Opinion'' series, the online citation database Scopus, the SciVal tool for measuring research performance, the ClinicalKey search engine for clinicians, and the ClinicalPath evidence-based cancer care service. Elsevier's products and services also include digital tools for data management, instruction, research analytics and assessment. Elsevier is part of the RELX Group (known until 2015 as Reed Elsevier), a publicly traded company. According to RELX reports, in 2021 Elsevier published more than 600,000 articles annually in over 2,700 journals; as of 2018 its archives contained over 17 million documents and 40,000 e-books, with over one billion annual downloads. Researchers have criticized Elsevier for its high profit marg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregnancy can have one or more gestations at the same time, for example in a multiple birth. The time interval of a gestation is called the '' gestation period''. In obstetrics, ''gestational age'' refers to the time since the onset of the last menses, which on average is fertilization age plus two weeks. Mammals In mammals, pregnancy begins when a zygote (fertilized ovum) implants in the female's uterus and ends once the fetus leaves the uterus during labor or an abortion (whether induced or spontaneous). Humans In humans, pregnancy can be defined clinically or biochemically. Clinically, pregnancy starts from first day of the mother's last period. Biochemically, pregnancy starts when a woman's human chorionic gonadotropin (hCG) levels ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foregut Tube
The foregut is the anterior part of the alimentary canal, from the mouth to the duodenum at the entrance of the bile duct. Beyond the stomach, the foregut is attached to the abdominal walls by mesentery. The foregut arises from the endoderm, developing from the folding primitive gut, and is developmentally distinct from the midgut and hindgut. Although the term “foregut” is typically used in reference to the anterior section of the primitive gut, components of the adult gut can also be described with this designation. Pain in the epigastric region, just below the intersection of the ribs, typically refers to structures in the adult foregut. Adult foregut Components * Esophagus * Respiratory tract (lower respiratory tract) * Stomach * Duodenum (up to ampulla of vater) * Liver * Gallbladder * Pancreas * Spleen – The spleen arises from the mesodermal dorsal mesentery (the foregut arises from the endoderm not mesoderm). But the spleen shares the same blood supply as many of the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laryngotracheal Tube
The laryngotracheal groove is a precursor for the larynx and trachea. The rudiment of the respiratory organs appears as a median longitudinal groove in the ventral wall of the pharynx. The groove deepens and its lips fuse to form a septum which grows from below upward and converts the groove into a tube, the laryngotracheal tube. The cephalic end opens into the pharynx by a slit-like aperture formed by the persistent anterior part of the groove. Initially the cephalic end is in open communication with the foregut but eventually it becomes separated by indentations of mesoderm, the tracheoesophageal folds. When the tracheoesophageal folds fuse in the midline to form the tracheoesophageal septum, the foregut is divided into trachea ventrally and the esophagus dorsally. The tube is lined by endoderm from which the epithelial lining of the respiratory tract is developed. The cephalic part of the tube becomes the larynx, and its next succeeding part the trachea, while from its caudal e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers caused by exposure to ultraviolet radiation), which then may undergo error-prone repair (especially microhomology-mediated end joining), cause an error during other forms of repair, or cause an error during replication (translesion synthesis). Mutations may also result from insertion or deletion of segments of DNA due to mobile genetic elements. Mutations may or may not produce detectable changes in the observable characteristics (phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity. Mutation is the ultimate source o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
