labyrinth
inner ear system of fluid-filled passages which provides the sense of balance (semicircular canals, vestibule). Named by analogy with the Greek mythology maze that imprisoned the Minotaur.
lactation
(Latin lactans = suckling) production of milk through action of prolactin and other hormones on breast tissue. Therefore associated mainly with mammals. (More? Normal Development - Milk | Integumentary Development - Mammary Glands)
lacunae
blood-filled spaces within endometrium, formed following blastocyst implantation and trophoblast erosion of the maternal sinusoids. (More? Week 2 Notes | Placenta Notes)
lanugo
fine coat of body hair found on the fetus. (More? Integumentary Development | Integumentary Development - Hair)
laparoscopy
A surgical procedure in which a fiber optic instrument (a laparoscope) is inserted through a small incision in the abdomen to view the inside of the pelvis.
large intestine
gastrointestinal tract between the end of the ileum (cecum) and anus. The large intestine can be further subdivided into parts: cecum, colon (ascending, transverse, descending, and sigmoid), and rectum. Functions in the resorption of water, vitamin K metabolism, and the formation of faeces. (More? GIT Notes)
laryngotracheal groove
forms on anterior (ventral) wall of pharynx, gives rise to larynx, trachea, respiratory tree. (More? Respiratory Notes | Head Notes | Stage 13/14 Embryo Section B3 Section B4)
(LGL1) a glycoprotein secreted by fetal lung mesenchyme and fetal kidney, involved in retinoic acid stimulated branching morphogenesis. (PMID: 17670908)
lateral cervical anomaly
also known as branchial cleft anomaly, which can be four different types: first, second, third and fourth. (More? Head Notes - Abnormalities)
lead
an environmental heavy metal linked to developmental defects. (More? Defects - Chemical Notes | Defects - Heavy Metals )
lectins
carbohydrate-binding proteins originally found in plants. Can be used to specifically bind/identify glycoproteins.
leiomyoma
(= uterine fibroids) a benign smooth muscle tumor of the uterus. These are also one of the most common gynecologic neoplasm in women, often detected on pelvic examination or by a range of diagnostic tools (endovaginal sonography, sonohysterography, hysterosalpingography, magnetic resonance imaging, computerized tomography, radionucleotide scanning, serum markers). The condition is difficult to distinguish from another uterine disease adenomyosis. (More? Reproductive System - Abnormalities | Medlineplus - uterine fibroids)
leptin
(Greek, leptos = thin) a polypeptide hormone (16 kDa) produced in adipose and many other tissues. Hormone receptor (OB-R, leptin receptors) found in many different tissues. Hormone levels associated with fertility and reproductive maturity in many species. Other hormonal roles include: satiety, adiposity, and metabolism, body mass control, angiogenesis, immunity, wound healing, bone remodelling cardiovascular function, and specific metabolic pathways. (More? Endocrine Adipose Endocrine Notes | Henson MC, Castracane VD. Leptin in pregnancy: an update. Biol Reprod. 2006 Feb;74(2):218-29.)
lesser omentum
the stomach has 2 peritoneal folds attached to each of the stomach curvatures. The lesser omentum is the peritoneal fold extending from lesser curvature of the stomach to liver. The greater omentum is the peritoneal fold extending from the greater curvature of the stomach to the colon, and hanging down over the small intestine. (More? GIT Notes)
synthetic progesterone used in oral contraceptives and as an emergency contraceptive. (Other Progestins: 3-keto-desogestrel, dienogest, drospirenone, Nestorone, nomegestrol acetate and trimegestone) Note that Trimegestone and Nestorone are currently the most potent fourth-generation progestins with no androgenic or estrogenic actions. (More? Human Menstrual Cycle)
Leydig cells
(interstitial cells) of the testes (male gonad) which secrete testosterone, beginning in the fetus. Named after Franz von Leydig (1821 - 1908) a German scientist. (More? Genital Notes | Urogenital Notes)
Leydig cell hypoplasia
(LCH) or male pseudohermaphroditism is an autosomal recessive disorder in individuals with a 46,XY karyotype with a predominantly female phenotype (More? Hermaphroditism | Reproductive System - Abnormalities)
acronym for Late-Gestation Lung Protein 1, a glycoprotein secreted by fetal lung mesenchyme and fetal kidney, involved in retinoic acid stimulated branching morphogenesis. (PMID: 17670908)
lin-35
(lin-35 Rb) only retinoblastoma tumor suppressor (Rb) related gene in worm C. elegans, identified as a synthetic multivulva (synMuv) class B gene. (More? Other Embryo - Worm)
lipophorin
(Lp) lipoprotein particle formed in insect cells that has been identified as having a role in Hedgehog (Hh) signaling during development. Lipophorins (Lp) contain two apolipophorins I and II (ApoLI and ApoLII). Similar lipoprotein particles can be found in vertebrates and consist of a phospholipid monolayer surrounding a core of esterified cholesterol and triglycerides which is scaffolded by apolipoproteins. Reference: Callejo A, Culi J, Guerrero I. Patched, the receptor of Hedgehog, is a lipoprotein receptor. Proc Natl Acad Sci U S A. 2008 Jan 15 (More? Molecular Development - Sonic Hedgehog | Molecular Development - Patched Receptor)
smooth brain, developmental brain abnormality resulting from an absence (agyria) or the paucity (pachygyria) of cerebral convolutions. (More? Neural Notes | Fetal Neural)
a large family of bacteria found throughout the environment (soil, dust, water, unwashed raw produce, fish, undercooked poultry, prepared meats such as hot dogs and deli meats, and faeces of domestic and wild animals). Listeria monocytogenes is the specific bacteria form that causes the infection "listeriosis". The most common human source of infection is contaminated foods: delicatessan meats, unpasteurized milk or dairy products, soft cheeses, and paté. Once infected, Listeria lives in the gastrointestinal Maternal listeriosis with symptoms has a risk (2-14 days after maternal infection) of for miscarriage, stillbirth, uterine infection, premature labor, and death in the newborn period. (More? Abnormal Development)
live birth
The delivery of one or more babies with any sign of life. World Health Organization (WHO) definition: "Live birth is the complete expulsion or extraction from its mother of a product of conception, irrespective ot the duration of pregancy, which, after separation, breathes or shows evidence of life, such as the beating of the heart, pulsation of the umbilical cord, or definite movement of voluntary muscles, whether or not the umbilical cord has been cut or the placenta is attached; each product of such a birth is considered liveborn."
lobule
term used to describe a small lobe. Can be used to describe part of a gland, ear, organ structure.
lunatic fringe
gene encodes a secreted signaling protein that signals formation of boundaries between groups of cells during development. One mechanism is by modifying Notch and inhibits signaling through the Notch pathway. In neural tube, regulates early neural crest differentiation. In mesoderm, regulates somite formation (segmentation). (More? Neural Crest - Molecular | Molecular Development - Notch | OMIM - lunatic fringe)
luteinizing hormone
(gonadotropin) an anterior pituitary hormone that triggers female ovulation. (More? Human Menstrual Cycle | Genital Notes)
lutenizing hormone
alternative spelling, (gonadotropin) an anterior pituitary hormone that triggers female ovulation. (More? Human Menstrual Cycle | Genital Notes)
luteinizing hormone/chorionic gonadotropin receptor
(LHCGR) a G protein-coupled receptor expressed in male testis (Leydig cells) and female ovary (granulosa-lutein and theca cells) (More? Genital Notes)
Lyme disease
caused by a bacterium, Borrelia burgdorferi, which was cultured from the midgut of Ixodes ticks in the mid-1980s. Named after a small town of Lyme in Connecticut where in the mid-1970s this diesease was initially identified. (More? NCBI Coffee Break Lyme Disease)
lymphangioma
a disfiguring vascular malformation of early childhood (mostly before 2 years of age) occuring in soft tissues of the head and neck or axilla, may also occur in the limbs, trunk, viscera and serous cavities. (More? Lymphatic Notes)
lymphedema
abnormal accumulation of interstitial fluid in tissues due to a lack of lymphatic drainage, which in turn leads to localized swelling. (More? Lymphatic Notes)
lymphopoiesis
(lymphoid hematopoiesis, lymphocytopoiesis) the process of generating lymphocytes (the immune cells) in various tissues (bone marrow, lymph nodes, thymus and spleen). (More? Blood Notes | Lymphatic Notes)
lyssavirus
a form of virus closely related to classical rabies (though genetically and serologically distinct). A form of this virus carried in bats (Australian bat lyssavirus) has been associated with two human fatalities. Effects on embryonic development are unknown. (More? Abnormal Development - Virus)
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Search the NIH Medlineplus Medical Dictionary Type the word that you would like to find. If unsure of spelling, type the first few letters, followed by an asterisk(*). |
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Use this page to access brief definitions of specific alphabetically listed embryology terms. Additional information can be accessed from links listed at the end of each definition. Glossary from the UNSW Embryology program compiled and written by Dr Mark Hill. Reference Material used in preparing Glossary List: Texts listed on page 1 Reading of each notes section, Department of Anatomy Publications, WWW resources from NCBI, AMA (USA), Office of Rare Diseases (USA), PubMed Medline Dictionaries, MSDS, Merck Manual home edn., NHMRC (Australia). These notes are for Educational Purposes Only. Please email Dr Mark Hill if you wish to make a comment about this current project. |
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