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Link to the Original UNSW Embryology Glossary C

c-section

abbreviation of "caesarian section" also can be further shortened as acronym C/S (see [#caesarian caesarian section]).

caesarian

surgical delivery of fetus through abdominal incision. Named after the roman emperor Caesar who was delivered by this method. Please note the UK/Australian "Caesarean" versus USA "Cesarean" spelling differences.

(More? Birth Notes - caesarian)

cafe-au-lait spots

(French, cafe-au-lait = coffee with milk) term used to describe the appearance of a type of skin blemishes that can be associated with a neural crest disorder, Neurofibromatosis Type 1.

(More? Neural Crest Abnormalities - Neurofibromatosis)

Cajal bodies

(CB) Ramon y Cajal originally identified these small nuclear organelles in cells, they have various suggested functions and are localized to the nucleolar periphery or within the nucleoli.

Call-Exner bodies

A feature seen in the developing ovarian follicle granulosa layer of some species, including human. Appears as a spherical space staining as an eosinophilic region and contains basal lamina components (type IV collagen and laminin) similar to thiose of the follicular basal lamina.

(More? Week 1 - Oogenesis)

calvaria

The skull formed from frontal, parietal and occipital bones.

(More? Musculoskeletal Notes)

camptodactyly

A term describing abnormal development resulting in a permanent flexion contracture of a finger or toe.

(More? Abnormal Development - FAS)

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).

(More? [respire.htm Respiratory Notes])

cancelled cycle

An [A.htm#Assisted_Reproductive_Technology ART] cycle in which ovarian stimulation was carried out but which was stopped before eggs were retrieved, or in the case of frozen embryo cycles, before embryos were transferred.

(More? Week 1 - In Vitro Fertilization)

Cantrell's pentalogy

A rare human developmental syndrome involving 5 key abnormalities: midline abdominal wall defect, lower sternum defect, anterior diaphragm defect, diaphragmatic pericardium defect and congenital heart malformation.

capacitation

The process by which sperm become capable of fertilizing an egg, requires membrane changes, removal of surface glycoproteins and increased motility.

(More? Week 1 Notes - Capacitation)

cardinal vein

The name given to the initial early vessels that will form the systemic venous system. This vascular system, like most early vessels, develop initially bilaterally and symmetrical.

(More? Blood Vessel Notes | Cardiovascular Notes)

cardiocyte

(cardiomyocyte) The mature cardiac (heart) muscle cell. Cardiac muscle cells are striated, joined by specialised junctions (intercalated discs) and innervated by the autonomic nervous system.

(More? Heart Notes)

Carnegie stages

Carnegie stages are a system of classifying embryonic development based on the external features and related internal changes that affect appearance and growth of the embryo. Note that the stages are not directly dependent on either age or size, but upon the appearance of specific embryonic features. Early human and other species embryos can be classified by these stages. The term "carnegie stages" are named after the famous USA Institute which began collecting and classifying embryos in the early 1900's.

(More? Carnegie Stages | Carnegie Stages - Scanning Electron Micrography | About the Carnegie Institute | Carnegie Stage Comparision)

cartilage

The connective tissue formed from mesoderm by the process of chondrogenesis. In the embryo cartilage initially forms most of the skeleton and is later replaced by bone (ossification). In the adult, cartilage is found in many skeletal regions including the surface of bone joints.

(More? Musculoskeletal Development - Cartilage Development | Musculoskeletal Development)

catabolism

(Greek, cata = down + ballein = to throw) The reactions of metabolism that break down complex molecules, such as those in food.

catagen

The end of active growing phase of the life cycle of the hair, between growing phase (anagen) and resting stage (telogen).

(More? Integumentary Development - Hair)

cauda equina

(Latin, cauda equina = horse's tail) The lower end, caudal, extension of the mature spinal cord. This anatomical feature develops due to the growth, in length, of the vertebral column while the spinal cord does not elongate at the same rate.

caudal

(Latin, caudal = tail) Anatomical term referring to structures that are more towards the tail.

cavitates

Term used to describe the process of formation of a space within an existing solid object. This process occurs developmentally in a number of different structures: in the early blastocyst forming the blastocoel, within early somites forming the somitocoel.

CBU

Acronym for Cord Blood Units, used in defining quantities of placental cord blood collected.

(More? Stem Cells - Cord Blood)

cell division

The process by which a parent cell gives rise to two daughter cells that carry the same genetic information as the parent cell. All body cells divide by the process called mitosis, except germ cells which undergo meiosis. Meiosis is a DNA reductive cell division (diploid to haploid).

(More? Week 1 Notes | Mitosis | Meiosis)

Cell Theory

The historic theory that states: (1) All organisms are composed of one or more cells; (2) cells themselves are alive and are the basic living unit of function and organization of all organisms; (3) all cells come from other cells.

(More? UNSW Cell Biology)

cellular oncogene

A normal gene (proto-oncogene) which when mutated can cause unregulated cellular growth and proliferation, cancer.

central canal

The lumen or cavity of neural tube lying within the spinal cord. This space is continuous with ventricular system of the brain.

(More? Neural Notes)

Central Dogma

The theory that states "DNA specifies RNA, which specifies proteins."

central nervous system

(CNS) The part of the nervous system made up of the brain and spinal cord. Both structures form from the neural tube which is ectoderm in origin.

(More? Neural Notes)

centre of ossification

(ossification centre) The region where bone formation commences within embryonic connective tissue. In endochondrial ossification, this process occurs within cartilage. In membranous ossification, this process occurs within a membrane.

(More? Musculoskeletal Notes)

centriole

A pair of small cylindrical structures each about 0.2 micron in diameter and 0.4 micron long, that lie at right angles to one another; present at each pole of the mitotic spindle in animal cells and in some other eukaryotes.

centripetal

(Latin, centripetal = center seeking) Term used to describe the direction of growth, movement or migration.

centromere

The point at which the two chromatids of a single chromosome are joined.

cephalic

(Greek, kephale = head) Term used to relate to the head or sometimes towards the upper body.

(More? Head Notes | Neural Abnormalities - Cephalic)

cerebellum

(Latin, cerebellum = little brain) A central nervous system component formed from the rhombencephalon (hindbrain) region of the neural tube. The cerebellum is required for coordinated motor activities. Cells within the cerebellum are formed by the ventricular zone of the roof of the fourth ventricle and the second germinal zone (Rhombic lip).

(More? Neural Notes)

cerebral aqueduct

A narrow ventricular cavity within the mesencephalon formed from the cavity within the neural tube.

(More? Neural Notes)

cerumen

The ear wax which is secreted by apocrine glands in the ear canal (external auditory meatus).

(More? Hearing Notes | Head Notes)

cervical flexure

The most caudal brain flexure (of 3) between spinal cord and rhompencephalon.

(More? Neural Notes)

cervical sinus

An ectodermal depression visible externally during embryonic development (approx carnegie stage 14-16), which marks the region where 2nd pharyngeal arch has grown over 3rd and 4th arches.

cesarean

The surgical delivery of fetus through abdominal incision. Named after the roman emperor Caesar who was delivered by this method. Please note the UK/Australian "Caesarean" versus USA "Cesarean" spelling differences.

(More? Birth Notes - caesarian)

CHARGE Syndrome

Each letter sands for an associated disorder of the syndrome: Coloboma on the eye , Heart, Atresia of choane , Retardation of growth , Genital malformations, Ear malformations and/or deafness. CHARGE syndrome has an estimated birth incidence of 1 in 12,000 and is a common cause of congenital anomalies. Most affected individuals with CHARGE syndrome have mutations involving the chromodomain helicase DNA-binding protein-7

chemotaxis

The movement of a cell toward a higher (or, in some cases, a lower) concentration of a particular chemical.

chiasma

(Greek, chiasma = cross; plural, chiasmata) The sites of exchange of DNA between homologous chromosomes during meiosis; visible during prophase of meiosis I.

(More? Week 1 Notes - Meiosis)

chimera

(Greek, pronounced ky-MIR-uhs) A mythical monster with the head of a lion, the body of a goat, and the tail of a serpent. Today used to describe a mixing of biological molecules either: 1. animals that have been genetically engineered 2. development studies where different species cells have been mixed, example chick-quail chimera, 3. Modified proteins containing parts of 2 different proteins.

(More? Neural Crest Notes)

cholangiocyte

Bile duct epithelial cell derived from hepatoblasts during embryonic liver development. These cells line the bile duct system and have apical cilia. Cholangiocytes function (mechano-, osmo-, and chemo-sensory) to regulate the fluidity and alkalinity of canalicular bile by reabsorptive and secretory events adjusting the final secreted bile composition. Abnormalities associated with these cells development or function are called cholangiociliopathies (polycystin-1, polycystin-2, and fibrocystin).

(More? Gastrointestinal Tract - Liver)

cholecystitis

inflammation of the gall bladder generally caused by gallstones obstructing the duct from gall bladder to common bile duct and can occur in maternal gall bladder during pregnancy.

(More? GIT Notes- gall bladder | Medline Plus Acute cholecystitis (Gallstones) | The Merck Manual Cholecystitis)

chondrodysplasia

Term used to describe skeletal malformation due to perturbation of chondrocyte differentiation program at the growth plate.

(More? Musculoskeletal Development - Cartilage Development | Musculoskeletal Development)

chondrogenesis

the process of forming cartilage, which is a connective tissue formed from from mesoderm (or neural crest in the head region). In the embryo, cartilage initially forms most of the skeleton and is later replaced by bone (ossification). In the adult, cartilage is found in many skeletal regions including the surface of bone joints.

(More? Musculoskeletal Development - Cartilage Development | Musculoskeletal Development)

chordae tendineae

Within the heart ventricles, a series of tendinous chords connecting the ventricular papillary musclular walls with the atrioventricular valves (bicuspid, tricuspid). The ventricular wall attachment is through the trabeculae (trabeculae carneae).

(More? Heart Development)

chorioamnionitis

(CA) An intraamniotic puerperal infection described as having 3 forms: histologic, clinical (clinical chorioamnionitis, IAI), and subclinical. Intraamniotic infection is a common (2-4%) event in labor and the systemic inflammatory response can also lead to preterm birth and neonatal complications.

(More? Placenta Notes)

chorion

An [E.htm#extraembryonic_membrane extraembryonic membrane] generated from trophoblast and extraembryonic mesoderm that forms placenta. chorion and amnion are made by the somatopleure. The chorion becomes incorporated into placental development. The avian and reptilian chorion lies beside the egg shell and allows gas exchange.

(More? Placenta Notes)

chorion frondosum

(frondosum = leafy) The chorion found on conceptus oriented towards maternal blood supply where the majority of villi form and proliferate, will contribute the fetal component of the future placenta.

(More? Placenta Notes | Week 2 Notes | Week 3 Notes)

chorion laeve

(laeve = smooth) The smooth chorion found on conceptus away from maternal blood supply (towards uterine epithelium and cavity) with very few villi present.

(More? Placenta Notes | Week 2 Notes | Week 3 Notes)

chorionic somatomammotropin

(CSH, human lactogen) A hormone synthesized within the placenta by syncytiotrophoblast cells. This protein hormone (190 amino acid) has a structure is similar to pituitary growth hormone.

(More? Placenta Notes | OMIM - chorionic somatomammotropin hormone)

chronic lung disease

(CLD) Neonatal chronic lung disease can be caused by prolonged mechanical ventilation (MV) and oxygen-rich gas with premature infants.

(More? Normal Development - Birth | Respiratory Notes)

chronic histiocytic intervillositis

(massive chronic intervillositis, chronic intervillositis) Rare placental abnormality and pathology defined by inflammatory placental lesions, mainly in the intervillous space (IVS), with a maternal infiltrate of mononuclear cells (monocytes, lymphocytes, histiocytes) and intervillous fibrinoid deposition.

(More? Placenta Abnormalities)

chronic intervillositis

(massive chronic intervillositis, chronic histiocytic intervillositis) Rare placental abnormality and pathology defined by inflammatory placental lesions, mainly in the intervillous space (IVS), with a maternal infiltrate of mononuclear cells (monocytes, lymphocytes, histiocytes) and intervillous fibrinoid deposition.

(More? Placenta Abnormalities)

chronic villitis

Placental pathology which can occur following placental infection leading to maternal inflammation of the villous stroma, often with associated intervillositis.

(More? Placenta Abnormalities)

Chorionic villus sampling

(CVS) taking a biopsy of the placenta, usually at the end of the second month of pregnancy, to test the fetus for genetic abnormalities.

(More? Prenatal Diagnosis - Chorionic Villus Sampling)

choroid plexus

A vascular complex in 3rd and 4th ventricle that differentiates to act as an endorgan synthesizing and secreting cerebrospinal fluid (CSF) into the ventricular space of the brain.

(More? Ventricular System | Cerebrospinal Fluid)

chromaffin

The name given to adrenal medulla cells, due to their histological staining with potassium di===chroma===te (brown).

(More? Endocrine Notes | [endocrine9.htm Adrenal Development Notes])

chromatin

(Greek, chroma = color) A diffuse material within the nucleus of a non-dividing eukaryotic cell; consists of DNA and proteins.

chromosomes

(Greek, chroma = color + soma = body, because it is stained by certain dyes) double stranded DNA coiled around histones. Condenses during mitosis and meiosis.

chryptochid testes

A male genital abnormality where the testes remain undescended in the abdominopelvic cavity.

(More? Reproductive System - Abnormalities - Gonadal Descent)

cilia

(Latin, cilium = eyelid) Cellular extensions named from the hair-like appearance of a cilium; singular, cilium. In many tissues, cilia are found as epithelial cell apical surface motile specializations. In the uterine tube epithelium, after ovulation used to move the unfertilized egg, then the fertilized zygote, then blastocyst during the first week of development.

ciliated epithelium

(Latin, cilium = eyelid) An epithelium named on the basis of the cells having surface hair-like appearance of a cilium; singular, cilium. In many tissues, cilia are found as epithelial cell apical surface motile specializations. In the uterine tube epithelium, after ovulation used to move the unfertilized egg, then the fertilized zygote, then blastocyst during the first week of development.

cilium

(Latin, cilium = eyelid) Cellular extension named from the hair-like appearance of a cilium; plural, cilia. In many tissues, cilia are found as epithelial cell apical surface motile specializations. In the uterine tube epithelium, after ovulation used to move the unfertilized egg, then the fertilized zygote, then blastocyst during the first week of development.

circular DNAs

Genetic material structure found in bacteria, energy-producing organelles (mitochondria, chloroplasts), and many viruses.

cis-regulatory element

(Latin, cis = on the same side) Gene expression regulation, named because the regulatory element is on the same piece of DNA that is being regulated.

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.

(More? Respiratory Notes)

claudin

A protein family which forms a component of tight junctions located between cells in the subapical region of the lateral membranes. These proteins in epithelial cells can interact with Eph/ephrin proteins during development to affect cell migration and allow cell sorting to occur.

clavicle

(Latin, clavis = key, -cula = small, "collar bone") The bone which locks shoulder to body. In mammals, the clavicle is one of the first bones to ossify by a mix of intramembranous and endochondral ossification from two centres of ossification within a single condensation. The suggested bird equilivant, the furculae (wishbone), ossifies only by intramembranous within a single center in each condensation.

(More? Musculoskeletal Development- Bone | Casselman's- Clavis)

cleavage

A series of rapid cell divisions following [F.htm#fertilization fertilization] in many early embryos; cleavage divides the embryo without increasing its mass.

cleavage furrow

A structure, groove, formed from the cell membrane in a dividing cell as the contractile ring tightens.

(More? Week 1 Notes)

cleft

An anatomical gap or space occuring in abnormal development in or between structures. Most commonly associated with cleft lip and cleft palate. Term is also used to describe the groove that forms between each pharyngeal arch during their formation.

(More? Face - Abnormalities | Face Notes | | Head Notes | Medline Plus - Cleft Lip and Palate)

cleft lip

An abnormality of face development leading to an opening in the upper lip. Clefting of the lip and or palate occurs with 300+ different abnormalities. Depending on many factors, this cleft may extend further into the oral cavity leading to a cleft palate. In most cases clefting of the lip and palate can be repaired by surgery.

(More? Face - Abnormalities | Face Notes | | Head Notes | Medline Plus - Cleft Lip and Palate)

cleft palate

An abnormality of face development leading to an opening in the [P.htm#palate palate], the roof of the oral cavity between the mouth and the nose. Clefting of the lip and or palate occurs with 300+ different abnormalities. In most cases clefting of the lip and palate can be repaired by surgery.

(More? Face - Abnormalities | Face Notes | | Head Notes | Medline Plus - Cleft Lip and Palate)

cleidocranial dysplasia

A human genetic bone disease due to a heterozygous mutation in Runx2.

(More? Bone Development)

clinodactyly

(Greek, klinein = to bend, slope or incline and dactylos = digit, finger or toe) a curving of the fifth (little) finger toward the fourth (ring) finger. Can be associated with a number of genetic syndromes (trisomy 21 Down syndrome and Klinefelter (XXY) syndrome) or other skeletal abnormalities.

(More? Limb Abnormalities)

clinical trials

Clinical experimentation on patients and are designated as phase I, II, or III, based on the type of question and number of people in the study.

Phase I clinical trials researchers test a new drug or treatment in a small group of people (20-80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.

Phase II clinical trials the study drug or treatment is given to a larger group of people (100-300) to see if it is effective and to further evaluate its safety.

Phase III clinical trials the study drug or treatment is given to large groups of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely. (text modified from NIH Clinical Trials site)

clinodactyly

A musculoskeletal abnormality of development resulting in permanent curving of the fifth finger, usually toward other fingers and can also be seen for other fingers or toes.

(More? Abnormal Development - FAS)

cloacal membrane

Forms the external lower membrane limit (caudal end) of the early gastrointestinal tract (GIT). This membrane is formed during gastrulation by ectoderm and endoderm without a middle (intervening) layer of mesoderm. The membrane breaks down to form the initial "anal opening" of the gastrointestinal tract.

(More? [B.htm#buccopharyngeal_membrane buccopharyngeal membrane] | GIT Notes)

clockface

A term used to describe the appearance of plasma cell nuclei due to the clumping of the chromatin at the nucleus periphery. More clearly seen in tissue plasma cells that the bone marrow smear, where they are sometimes confused with the basophilic erythroblasts.

(More? [heart20.htm Blood Notes] | GIT Notes)

clomiphene citrate

(CC) A fertility drug taken orally to promote the process of follicle/egg maturation in superovulation therapy. (CC) an anti-estrogen (MRL-41) therapy for WHO group II (eu-oestrogenic) infertility associated with polycystic ovary syndrome. Used for more than 40 years it is a simple, cheap treatment, with low side effects and yields a 25% live birth rate. Alternative therapeutics being considered are metformin, aromatase inhibitors and low-dose FSH.

(More? Greenblatt RB, Barfield WE, Jungck EC, Ray AW. Induction of ovulation with MRL/41. Preliminary report. JAMA. 1961 Oct 14;178:101-4. | Homburg R. Clomiphene citrate--end of an era? A mini-review. Hum Reprod. 2005 Aug;20(8):2043-51.) | Notes - Ovary | Week 1 - In Vivo Fertilization | Week 1 - In Vitro Fertilization | Week 1 - Abnormalities)

clone

(Greek, klon = twig) A population of genetically identical individuals or cells descended from a single ancestor.

club foot

The historic common (slang) term for [T.htm#talipes_equinovarus talipes equinovarus] a congenital deformity of the foot (occurs approximately 1 in 1,000 births).

(More? [T.htm#talipes_equinovarus talipes equinovarus])

CNS

Acronym for Central Nervous System. The structures formed from the neural tube, the brain and spinal cord.

(More? Neural Notes)

coacervate

(Latin, coacervatus = heaped up) Discrete tiny droplet into which proteins and polysaccharides can spontaneously concentrate.

coagulation plug

The uterine epithelium feature located where the blastocyst had entered the uterine wall. In humans, seen approximately day 12 following [F.htm#fertilization fertilization].

(More? Week 2 Notes)

coarctation

(Latin coartare = to press together) Term used to describe a narrowing (stricture, constriction) associated with aortic arch developmental abnormality.

(More? Cardiovascular Abnormalities)

coarctation of the aorta

(Latin coartare = to press together) Term used to describe a developmental abnormality of narrowing (stricture, constriction) of the aortic arch.

(More? Cardiovascular Abnormalities | Coarctation of Aorta)

coated pit

A depression in the plasma membrane, lined with clathrin molecules; an intermediate structure in receptor-mediated endocytosis

codominant

Refers to two alleles that each contribute to the phenotype of a heterozygote.

codon

A group of three nucleotides that specifies a single amino acid residue.

coelom

Term used to describe a space. There are extraembryonic and intraembryonic coeloms that form during vertebrate development. The single intraembryonic coelom will form the 3 major body cavities: pleural, pericardial and peritoneal.

(More? Coelom Notes)

coelocentesis

A sampling of extracoelomic fluid usually for an early prenatal diagnostic technique.

(More? Coelom Notes | Prenatal Diagnosis)

coenzyme

An organic molecule (but not a protein) that is a necessary participant in an enzyme reaction.

collagen

===helix ===A regular structure found principally in the structural protein collagen; the collagen helix consists of three polypeptide chains.

colostrum

The maternal mammary gland secretion that occurs at birth which precedes the secretion of milk.

(More? Normal Development - Milk | Integumentary Development - Mammary Glands)

column chromatography

A type of chromatography in which the stationary phase is an insoluble material packed into a glass or metal column.

commensalism

An association between individuals of two species in which one organism benefits without harming the other one.

communicating junctions

Membrane-associated structures that allow small molecules to pass freely between two adjacent cells.

competitive inhibitor

A molecule whose inhibitory effects on an enzyme can be overcome by increased substrate concentration.

complement

A set of blood proteins that attack microbial invaders.

complementarity determining region

(CDR) The segment of an immunoglobulin molecule most involved in binding antigen; so called because its shape is complementary to that of the antigen.

complex disease

Types of diseases which aggregate in families but do not segregate in a Mendelian fashion.

conceptus

The entire product of conception, that is all the structures derived from the zygote and includes not only the embryo, but also the placental and membrane components.

(More? Week 1 Notes)

congenital

Already present at birth, often used to describe defects present at birth, congenital defects.

(More? Abnormal Development)

congenital adrenal hyperplasia

(CAH, adrenal virilism===) ===Abnormality of the fetal adrenal cortex, alters cortisol and androgens with different effects dependent upon sex: in females masculization of the external genitalia; in males, disorder often unnoticed until postnatally. In both sexes, accelerated skeletal growth and sexual maturation is seen in late childhood. Caused by a deficiency or absence of the enzyme 21-hydroxylase in the adrenal cortex.

(More? Endocrine Adrenal - congenital adrenal hyperplasia | Reproductive System - Abnormalities)

Coombs test

A diagnostic test named after Robin Coombs (1921-), a British immunologist who developed a technique of using antibodies that are targeted against other antibodies used in the test for erythroblastosis fetalis (Haemolytic disease of the newborn).

(More? Placenta Development- Abnormalities | Blood Groups and Red Cell Antigens Hemolytic disease of the newborn)

cord blood

(human umbilical cord blood, HUCB) A term used to describe blood collected from the placenta usually after birth. Has been identified as a source of stem cells with potential therapeutic uses and is stored in Cord Blood Banks throughout the world.

(More? Placenta Development | Stem Cell)

cord presentation

A term used to describe at birth the presence of the umbilical cord between the fetal presenting part and the cervix, with or without membrane rupture.

(More? Birth Notes | Placenta Development- Abnormalities)

cord prolapse

A term used to describe at birth the descent of the umbilical cord through the cervix alongside (occult) or past (overt) the presenting part in the presence of ruptured membranes (incidence of 0.1% to 0.6%).

(More? Birth Notes | Placenta Development- Abnormalities)

corneal stroma

An eye structural component of the cornea. In chicken, formed by a two-stage process of collagen fibril deposition, a primary stroma secreted by epithelial cells and a secondary stroma by the invading neural crest cells (corneal keratocytes).

(More? Eye Notes)

corona radiata

The granulosa cells that directly surround the oocyte, within the antral follicle of the ovary. These cells are released along with the oocyte at ovulation and provide physical protection and the initial structural barrier that spermatazoa must penetrate during fertilization. Other granulosa cells within the follicle include: [M.htm#membrana_granulosa membrana granulosa] and [#cumulus_oophorus cumulus oophorus].

(More? Week 1 - Oogenesis)

corpus albicans

(Latin, corpus = body, albicans = whitish) The histological structure formed by the degenerating corpus luteum in the ovary if implantation does not occur and the hormone hCG is not released. The structure is white, not yellow, because of the absence of steroid hormone synthesis/accumulation.

(More? Week 2 Ovary | Week 1 Notes)

corpus luteum

(Latin, corpus = body, luteum = yellow) The remains of ovarian follicle after ovulation that acts as an endocrine organ (produce progesterone and oestrogens) supporting pregnancy and preventing menstruation (loss of the endometrial lining). Formed by proliferation of both follicular granulosa cells (granulosa lutein cells) and thecal cells (theca lutein cells) after ovulation, which produce progesterone and oestrogens. de Graaf first observed it in the ovary of a cow as a yellow structure, caused by accumulation of steroidal hormones.

(More? Week 2 Ovary | Week 1 - Oogenesis)

cortex

(Latin, corticalis = at the outside) outer layer, used in association with medulla (innner layer or core) a general description that can be applied to describing an organ with a layered structure. Also used to describe the outer cellular (grey matter) layer of the central nervous system.

cortical

(Latin, corticalis = at the outside) like the bark of a tree, usually combined with medulla meaning the core. Also used to describe the outer cellular layer of the central nervous system.

cortical plate

The outer neural tube region which post-mitotic neuroblasts migrate too along radial glia to form adult cortical layers.

(More? Neural Notes)

corticosteroid

A steroidal hormone produced by the adrenal cortex.

(More? Endocrine Notes)

corticotropin-releasing hormone

(CRH) A hypothalamic neuropeptide hormone, which is also produced by embryonic trophoblast and maternal decidua cells, with receptors in several reproductive organs. Thought to have a role in endometrial decidualization, blastocyst implantation and early maternal tolerance.

cotyledon

(Greek, kotyle = a deep cup) In the embryos of seed plants, the "seed leaves," in which nutrients are stored for use after germination. Used also to describe the structure of the placenta.

(More? Placenta Notes)

cranial flexure

(= midbrain flexure) The most cranial brain flexure, between mesencephalon and prosencephalon, of the three flexures (bends) that develop as the nueral tube grows and elongates.

(More? Neural Notes)

craniofrontonasal syndrome

(CFNS) A human X-linked developmental disorder caused by a mutation in ephrin-B1 affecting mainly females. Characterised by abnormal development of cranial and nasal bones, craniosynostosis (premature coronal suture fusion), and other extracranial anomalies (limb polydactyly and syndactyly).

(More? Musculoskeletal Development - Skull Development)

craniopharyngioma

A common destructive tumorogenic lesions of the hypothalamus and pituitary gland. Can occur when remnant cells from Rathke's pouch remain forming a tumour.

(More? Endocrine - Hypothalamus | Endocrine - Pituitary )

craniosynostosis

The term describing the premature closure of the skull sutures, or fusion of skull bones. May cause skull and brain abnormalities. There are at least 8 different disorders with six related to the fibroblast growth factor receptor (FGFR); Pfeiffer syndrome, Apert syndrome, Crouzon syndrome, Beare-Stevenson syndrome, FGFR2-related isolated coronal synostosis, Jackson-Weiss syndrome, Crouzon syndrome with acanthosis nigricans (AN), and Muenke syndrome.

(More? Head Notes | Head Abnormalities | Bone Notes | Bookshelf - GeneReviews)

CREB

Acronym for ===C===yclic-AMP ===r===esponse ===e===lement=== b===inding protein.

CREB is a member of the basic region leucine zipper (bZIP) family of transcription factors and requires phosphorylation to become a biologically active transcriptional activator. CREB binds to CRE (===c===AMP ===r===esponse ===e===lement) which is the final target of many extracellular and intracellular signals (e.g. cAMP, calcium, neurotrophins).

(More? Molecular Development)

CrebA

Acronym for ===C===yclic-AMP ===r===esponse ===e===lement=== b===inding protein ===A=== involved in gene activation.

Drosophila have two genes (A and B-17A) encoding the cAMP response element binding (CREB) protein family members. These proteins have mammalian equilivants with RNA polymerase II transcription factor activity, DNA binding, transcription factor activity, protein homodimerization activity.

(More? Molecular Development)

cretinism

The term describing a neurological abnormality due to insufficient thyroid hormone during neural development. The main cause of this disorder is an insufficiency or lack of iodine in the diet.

(More? Endocrine Development - Thyroid | Abnormal Development - Iodine Deficiency)

cribiform plate

Anatomical structure of the head, describing the perforated portion of ethmoid bone of skull allows passage of olefactory axons from nasal epithelium to olefactory bulb.

(More? Senses Notes)

CRISP

Acronym for cysteine-rich secretory protein, a group of proteins (CRISP1, CRISP2) recently suggested to have a role in sperm-egg fusion through binding to egg-complementary sites.

(More? Fertilization)

critical period

(critical period of development) The term used to describe a developmental time when exposure to a teratogen can lead to a developmental abnormality, which can be further divided into an early major and later minor developmental abnormality. The defined critical period will differ in timing and length for different systems.

(More? Abnormal Development - Environmental)

CRL

Acronym for ===C===rown-===R===ump=== L===ength. Used in embryology to accurately stage the early embryo. Used in clinical ultrasound as a measurement between the periods of 7 to 13 weeks as an accurate estimation of the gestational age.

(More? Embryo Stages | Ultrasound Movies)

Crown-rump length

(CRL) A measurement used in embryology to more accurately stage the early embryo. Measured from the curvature at the top (crown) to the curvature at the bottom (rump) of the "C-shaped" early embryo. Used in clinical ultrasound as a measurement between the periods of 7 to 13 weeks as an accurate estimation of the gestational age.

(More? Embryo Stages | Ultrasound Movies)

cryptopatches

(CPs) An immune system structure, small clusters of lymphoid cells with an immature lymphocyte phenotype and dendritic cells found associated with the gastrointestinal tract.

cryopreservation

A technique for freezing tissue or cells to preserve for use at a later date. In this report, cryopreserved embryos are referred to as frozen embryos.

cryptophthalmos

The term describing an anomaly of eye development, with a continuity of the skin from the forehead to the cheek over a malformed eye. Classified into three types: complete, incomplete and abortive.

(More? Eye Abnormalities)

cryptorchidism

An abnormality of either unilateral or bilateral testicular descent, occurring in < 30% premature and 3-4% term males. Descent may complete postnatally in the first year, failure to descend can result in sterility.

(More? Urogenital Notes | Genital Abnormalities)

CSH

Acronym for [#chorionic_somatomammotropin chorionic somatomammotropin hormone], a placental hormone.

cuboidal epithelium

An epithelial layer formed by cells with a cuboidal shape (morphology), compared to the other two main hsitological cell shapes (squamous, columnar). Cuboidal, equal height and width, for example, endodermal or peripheral ectodermal layers of the trilaminar embryo.

cumulus oophorus

(Latin cumulus = a little mound G. oon = egg + phorus = bearing) The granulosa cells that form a column of cells that attaches the oocyte to the antral follicle wall within follicles of the ovary. This column of cells is broken or separates during ovulation to release the oocyte from its follicle attachment. Other granulosa cells within the follicle include: membrana granulosa and [#corona_radiata corona radiata].

(More? Week 1 - Oogenesis)

cyst

The pathological term describing a fibrous capsule containing fluid.

cyto-

(Greek, kytos = hollow vessel or container) Prefix referring to a "cell" or "cellular", as is the the suffix "-cyte".

cytochrome

(Greek, kytos = hollow vessel + chroma = color) One of a set of heme-containing electron carrier proteins that change color as they accept or donate electrons.

cytokinesis

(Greek, kytos = hollow vessel + kinesis = movement) The division of the cytoplasm and formation of two separate plasma membranes.

(More? Week 1 Notes)

cytomegalovirus

An infection of early embryos is fatal, infection of later fetuses can lead to blindness, deafness, cerebral palsy, and mental retardation.

(More? Abnormal Development- Virus)

cytotrophoblast

The "cellular" trophoblast layer surrounding (forming a "shell") the early implanting conceptus. Beginning at uterine adplantation, proliferation and fusion of these cells is thought to form a second outer trophoblast layer, the [S.htm#syncytiotrophoblast syncytiotrophoblast]. The cytotrophoblast layer contributes to formation of the placental villi, the functional component of the fetal placenta.

(More? Week 2 Notes | Placenta Notes | [C.htm#human_chorionic_gonadotrophin human Chorionic Gonadotrophin])

cytosine

(cytosine triphosphate) One of the four types of nucleotides (AT===C===G) that make up DNA. Base pairs with guanine by 3 hydrogen bonds.

Comments

Use this page to access brief definitions of specific 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 this glossary list includes: texts listed on page 1 Reading of each notes section, Department of Anatomy Publications, WWW resources from NCBI, NIH, OMIM, NHMRC (Australia), AMA (USA), Office of Rare Diseases (USA), PubMed Medline Dictionaries, MSDS, Merck Manual home edn.

These notes are for Educational Purposes Only Please email Dr Mark Hill if you wish to make a comment about this current project.

Copyright: Dr Mark Hill Created: 01.06.1997 Updated: 11.05.2009

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