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Pulmonary Agenesis
Pulmonary agenesis is an inborn lung underdevelopment that is rare and potentially lethal. The disorder is caused by a complete developmental arrest of the primitive lung during embryonic life, and it is often associated with other developmental defects. Bilateral and unilateral pulmonary agenesis are classified, depending on whether one side of the lung or both sides are affected. Bilateral pulmonary agenesis is lethal, while the mortality rate of unilateral pulmonary agenesis is higher than 50%. Depending on the severity, the symptom ranges from none to various respiratory complaints. It is detectable prenatally, however, its nonspecific clinical features act as the obstacle for diagnosing. The exact cause of pulmonary agenesis is still obscure. However, theories have been raised regarding the vascular, iatrogenic, viral and genetic causes of pulmonary agenesis in an attempt to explain the pathogenesis of the disorder. In most cases of pulmonary agenesis, surgical resection is pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the nervous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Hypoplasia
Pulmonary hypoplasia is incomplete development of the lungs, resulting in an abnormally low number or size of bronchopulmonary segments or alveoli. A congenital malformation, it most often occurs secondary to other fetal abnormalities that interfere with normal development of the lungs. Primary (idiopathic) pulmonary hypoplasia is rare and usually not associated with other maternal or fetal abnormalities. Incidence of pulmonary hypoplasia ranges from 9–11 per 10,000 live births and 14 per 10,000 births. Pulmonary hypoplasia is a relatively common cause of neonatal death. It also is a common finding in stillbirths, although not regarded as a cause of these. Causes Causes of pulmonary hypoplasia include a wide variety of congenital malformations and other conditions in which pulmonary hypoplasia is a complication. These include congenital diaphragmatic hernia, congenital cystic adenomatoid malformation, fetal hydronephrosis, caudal regression syndrome, mediastinal tumor, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birth Defect
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth defects are divided into two main types: structural disorders in which problems are seen with the shape of a body part and functional disorders in which problems exist with how a body part works. Functional disorders include metabolic and degenerative disorders. Some birth defects include both structural and functional disorders. Birth defects may result from genetic or chromosomal disorders, exposure to certain medications or chemicals, or certain infections during pregnancy. Risk factors include folate deficiency, drinking alcohol or smoking during pregnancy, poorly controlled diabetes, and a mother over the age of 35 years old. Many are believed to involve multiple factors. Birth defects may be visi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitamin A
Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal (also known as retinaldehyde), retinoic acid, and several provitamin A carotenoids (most notably beta-carotene ²-carotene. Vitamin A has multiple functions: it is essential for embryo development and growth, for maintenance of the immune system, and for vision, where it combines with the protein opsin to form rhodopsin the light-absorbing molecule necessary for both low-light (scotopic vision) and color vision. Vitamin A occurs as two principal forms in foods: A) retinol, found in animal-sourced foods, either as retinol or bound to a fatty acid to become a retinyl ester, and B) the carotenoids alpha-carotene, β-carotene, gamma-carotene, and the xanthophyll beta-cryptoxanthin (all of which contain β-ionone rings) that function as provitamin A in herbivore and omnivore animals which possess the enzymes that cleave and convert provi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In Vitro
''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology and its subdisciplines are traditionally done in labware such as test tubes, flasks, Petri dishes, and microtiter plates. Studies conducted using components of an organism that have been isolated from their usual biological surroundings permit a more detailed or more convenient analysis than can be done with whole organisms; however, results obtained from ''in vitro'' experiments may not fully or accurately predict the effects on a whole organism. In contrast to ''in vitro'' experiments, ''in vivo'' studies are those conducted in living organisms, including humans, and whole plants. Definition ''In vitro'' ( la, in glass; often not italicized in English usage) studies are conducted using components of an organism that have been isolated fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathogenesis
Pathogenesis is the process by which a disease or disorder develops. It can include factors which contribute not only to the onset of the disease or disorder, but also to its progression and maintenance. The word comes from Greek πάθος ''pathos'' 'suffering, disease' and γÎνεσις ''genesis'' 'creation'. Description Types of pathogenesis include microbial infection, inflammation, malignancy and tissue breakdown. For example, bacterial pathogenesis is the process by which bacteria cause infectious illness. Most diseases are caused by multiple processes. For example, certain cancers arise from dysfunction of the immune system (skin tumors and lymphoma after a renal transplant, which requires immunosuppression), Streptococcus pneumoniae is spread through contact with respiratory secretions, such as saliva, mucus, or cough droplets from an infected person and colonizes the upper respiratory tract and begins to multiply. The pathogenic mechanisms of a disease (or cond ... [...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] |
Hypoplasia
Hypoplasia (from Ancient Greek ὑπo- ''hypo-'' 'under' + πλάσις ''plasis'' 'formation'; adjective form ''hypoplastic'') is underdevelopment or incomplete development of a tissue or organ. Dictionary of Cell and Molecular Biology (11 March 2008) Although the term is not always used precisely, it properly refers to an inadequate or below-normal number of cells.Hypoplasia Stedman's Medical Dictionary. lww.com Hypoplasia is similar to |
Dysplasia
Dysplasia is any of various types of abnormal growth or development of cells (microscopic scale) or organs (macroscopic scale), and the abnormal histology or anatomical structure(s) resulting from such growth. Dysplasias on a mainly microscopic scale include epithelial dysplasia and fibrous dysplasia of bone. Dysplasias on a mainly macroscopic scale include hip dysplasia (human), hip dysplasia, myelodysplastic syndrome, and multicystic dysplastic kidney. In one of the modern histopathology, histopathological senses of the term, dysplasia is sometimes differentiated from other categories of tissue change including hyperplasia, metaplasia, and neoplasia, and dysplasias are thus generally not cancerous. An exception is that the myelodysplasias include a range of benign tumor, benign, precancerous condition, precancerous, and cancerous forms. Various other dysplasias tend to be precancerous. The word's meanings thus cover a spectrum of histopathological variations. Microscopic sca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lung Buds
The lung bud sometimes referred to as the respiratory bud forms from the respiratory diverticulum, an embryological endodermal structure that develops into the respiratory tract organs such as the larynx, trachea, bronchi and lungs. It arises from part of the laryngotracheal tube. Early stage In the fourth week of development, the respiratory diverticulum, starts to grow from the ventral (front) side of the foregut into the mesoderm that surrounds it, forming the lung bud. Around the 28th day, during the separation of the lung bud from the foregut it forms the trachea and splits into two bronchial buds, one on each side. Molecular signaling The molecular signaling involved in the specification of the respiratory bud starts with the expression of the Nkx2-1 gene, which determines the respiratory field – the area where the respiratory bud will begin to grow from. The signaling that makes the growth of the respiratory bud possible is complex and involves a number of interaction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Respiratory Tract
The respiratory tract is the subdivision of the respiratory system involved with the process of respiration in mammals. The respiratory tract is lined with respiratory epithelium as respiratory mucosa. Air is breathed in through the nose to the nasal cavity, where a layer of nasal mucosa acts as a filter and traps pollutants and other harmful substances found in the air. Next, air moves into the pharynx, a passage that contains the intersection between the oesophagus and the larynx. The opening of the larynx has a special flap of cartilage, the epiglottis, that opens to allow air to pass through but closes to prevent food from moving into the airway. From the larynx, air moves into the trachea and down to the intersection known as the carina that branches to form the right and left primary (main) bronchi. Each of these bronchi branches into a secondary (lobar) bronchus that branches into tertiary (segmental) bronchi, that branch into smaller airways called bronchioles that ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primordium
A primordium (; plural: primordia; synonym: anlage) in embryology, is an organ or tissue in its earliest recognizable stage of development. Cells of the primordium are called primordial cells. A primordium is the simplest set of cells capable of triggering growth of the would-be organ and the initial foundation from which an organ is able to grow. In flowering plants, a floral primordium gives rise to a flower. Although it is a frequently used term in plant biology, the word is used in describing the biology of all multicellular organisms (for example: a tooth primordium in animals, a leaf primordium in plants or a sporophore primordium in fungi.) Primordium development in plants Plants produce both leaf and flower primordia cells at the shoot apical meristem (SAM). Primordium development in plants is critical to the proper positioning and development of plant organs and cells. The process of primordium development is intricately regulated by a set of genes that affect the pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
