F

UNSW Embryology Glossary F

Link to the Original UNSW Embryology Glossary F

F-factor

(fertility factor) A kind of episome in bacteria that can replicate either autonomously or in integrated form; can move from one bacterium to another during conjugation.

F1

(Latin, filial = son) first filial generation or the initial progeny of a cross-breeding (hybrid). The genetic breeding out (recombination) is said to strengthen the progeny, hence "F1 hybrid vigour".

F2

(Latin, filial = son) second filial generation The progeny of the F1 generation.

factor V Leiden

A mutation which is a heritable thrombophilia (increased tendency of blood to clot, impaired natural anticoagulant or fibrinolytic pathways) present in 5 - 8% of Caucasian populations.

falciform ligament

A sheet of parietal peritoneum between the two principal lobes of the liver. The ligamentum teres, the remnant of umbilical vein, lies within its folds.

(More? GIT Notes | Liver)

fallopian tube

(see [#uterine_tube uterine tube], uterine horn, oviducts) A pair of tubular structures designed to transport the oocyte (egg) from the ovary to the [U.htm#uterus uterus] body, named after Gabriel Fallopius (1523-1562), an anatomists and physician.

femur length

An ultrasound measurement of Femur Length (FL) is used to determine fetal age and normal development (small/large/abnormal) parameters. The femur is the longest bone in the body and measurements and reflects the longitudinal growth of the fetus (approximately 14 weeks 1.5 cm - term 7.8 cm). It is one of the four typical ultrasound assessments of fetal size and age: [B.htm#biparietal_diameter Biparietal Diameter] (BPD), [H.htm#head_circumference Head Circumference] (HC), [A.htm#abdominal_circumference Abdominal Circumference] (AC), and Femur Length (FL).

(More? Ultrasound | Head Notes) | Fetal Notes | Birth Notes)

fenestra

(Latin, fenestra = window) A small pore approximately 60–70 nm diameter in vascular bed endothelium (renal glomerular, gastrointestinal, and endocrine gland capillaries, corneal capillaries) allowing exchange between blood and tissues, plural - fenestrae.

fermentation

(Latin, fervere = to boil) The anaerobic extraction of energy from organic compounds. The "boiling", or bubbling, is easily seen in the release of carbon dioxide from aerobic yeast during brewing processes.

fertility rate

A statisical term that refers to the total number of live births, regardless of age of mother, per 1,000 women of reproductive age, 15–44 years.

(More? Statistics | Australian Statistics)

fertilization

(fertilisation) The process of penetration of the oocyte (egg) by the spermatozoa and the combining of their genetic material that initiates development of the embryo. The union of two haploid gametes to form a diploid cell or zygote.

(More? Week 1 Notes | Fertilization)

fertilization promoting peptide

(FPP) Also called Glu2TRH which is a small tripeptide (3 amino acid; pGlu-Glu-Pro-NH2) present in human seminal plasma which stimulates spermatozoa capacitation. Peptide is a structural analogue to thyrotrophin-releasing hormone (TRH; pGlu-His-Pro-NH2).

(More? Spermatozoa Capacitation | Spermatozogenesis)

fetal breathing movements

(FBM) Occur in the third trimester preparing both the skeletomuscular system and lungs mechanically for respiration.

(More? Respiratory Development - Birth | Respiratory Notes | Search Pubmed - fetal respiratory movements)

fetal death rate

A statisical term refers to the number of fetal deaths with a stated or presumed gestation of 20 weeks or more divided by the sum of live births plus fetal deaths, per 1,000 live births plus fetal deaths. Late fetal death rate shifts the stated or presumed gestational age to 28 weeks.

(More? Statistics | Australian Statistics | Search Pubmed - fetal death rate)

fetal fibronectin

(fFN) An extracellular matrix glycoprotein produced by fetal cells. Fetal fibronectin appears to act as an adhesive between the interface of the [C.htm#chorion chorion] and the [D.htm#decidua decidua] (fetal membrane and uterine lining). As a prenatal diagnostic test, a positive fetal fibronectin test result can indicate a higher risk of preterm delivery, but may also has false positive results.

(More? Prenatal Diagnosis | Normal Development - Birth | Birth - Premature |)

Fetal Origins Hypothesis

(fetal programming hypothesis, Barker Hypothesis) Originally called the Barker Hypothesis, which began as statistical analysis carried out by Barker in the UK, of low birth weight data (early 1900's) and proposes in utero influences cause permanent changes in embryo/fetus, low birth weight, predisposition to chronic disease in adult life.

(More? Fetal Origins Hypothesis | Search Pubmed - fetal origins hypothesis)

fetal length

The measurement of crown to rump length of the developing fetus. The greatest growth in length occurs in the middle second trimester, of human development. There are a number of other growth parameters that can be measured, commonly determined by ultrasound, during the fetal period.

(More? Fetal | Ultrasound Measurements | Ultrasound Movies)

fetal period

(foetal period) In humans, the development week 9 to 36 is the fetal stage (second and third trimester) and during this time organs formed in the embryonic period continue to develop and the fetus grows in size and weight. The first 8 weeks of development is considered the embryonic period and is divided into 23 Carnegie stages based upon developmental milestones. Note when searching an alternate spelling "foetal".

(More? Fetal Notes | Embryo Stages)

fetal macrosomia

A clinical description for a fetus that is too large, condition increases steadily with advancing gestational age and defined by a variety of birthweights. In pregnant women anywhere between 2 - 15% have birth weights of greater than 4000 grams (4 Kg, 8 lb 13 oz).

(More? Fetal Weight | Fetal Development | Birth)

fetal weight

The measurement of the weight of the developing fetus. The measurement is obtained by ultrasound calculation or clinically estimated by palpatation. The greatest addition of fetal weight occurs during and towards the end of the third trimester.

(More? Fetal Weight | Fetal Notes | Ultrasound Measurements | Ultrasound Movies)

fetotoxicant

A chemical that adversely affects the developing fetus, resulting in low birth weight, symptoms of poisoning at birth or stillbirth (fetus dies before it is born). Note when searching an alternate spelling "foetal".

(More?Abnormal Development - Environmental | Abnormal Development - Drugs)

fetus

(foetus) In mammals, term describes the period of development following the embryonic period. In humans, the development week 9 to 36 is the fetal stage (second and third trimester). (see [#fetalperiod fetal period] above).

FGR

Acronym for ===F===etal ===G===rowth ===R===estriction also known as Intrauterine Growth Retardation.

(More? Intrauterine Growth Retardation)

fibrillin

A connective tissue protein encoded in humans by (FBN1) gene which is associated with Marfan syndrome.

(More? Musculoskeletal Abnormalities)

fibrinoid layer

(Nitabuch's layer) A layer formed at maternal/fetal interface during placentation and is thought to act to prevent excessively deep conceptus implantation. Fibrin-type fibrinoid (maternal blood-clot product) and matrix-type fibrinoid (secreted by invasive extravillous trophoblast cells).

(More? Placenta)

fibroadenomas

Term describing in relation to the breast, a lump, both smooth and firm, made up of fibrous and glandular tissue. These are generally not cancerous and are more common in younger women and may become tender in the days before a period or grow bigger during pregnancy.

fibroid embolization

The treatment method for uterine fibroids (non-cancerous tumor that can develop within the wall of the [U.htm#uterus uterus]) involving stopping or blocking the blood flow to the tumor.

(More? Human Menstrual Cycle | Genital System - Female Uterus | Urogenital Notes | Medline Plus)

fimbriae

(Latin, fimbria = a fringe) The finger-like projections at the ovarian end of uterine tube. At ovulation they sit over the ovary to aid egg movement into the uterine tube.

(More? Week 1 Notes)

Finasteride

A chemical used to prevent male pattern baldness and enlargement of prostate glands. An anti-androgen (blocks synthesis of dihydrotestosterone) and therefore a potential endocrine disruptor, exposed pregnant women can impact on male fetus genetial development.

(More? Endocrine Abnormalities)

first polar body

The small cytoplasmic exclusion body formed when the oocyte (egg) completes meiosis 1 at ovulation. This exclusion body contains the excess DNA from the first reductive division (the second and third polar bodies are formed from meiosis 2 at [#fertilization fertilization]). These polar bodies do not contribute to the genetic complement of the zygote, embryo or fetus. Recent research in some species suggest that the space formed by the peripheral polar body (between the oocyte and the zona pellucia) can influence site of sperm [#fertilization fertilization].

(More? Week 1 Notes)

first trimester

Clinical term used to describe and divide human pregnancy period (9 months) into three equal parts of approximately three calendar months. The first trimester corresponds approximately to embryonic development (week 1 to 8) of organogenesis and early fetal. The second and third trimester correspond to the fetal period of growth in size (second trimester) and weight (third trimester), as well as continued differentiation of existing organs and tissues.

(More? Embryo Stages | Human Fetal Period | Development Week by Week)

fistula

An abnormal communication between 2 structures (organs, vessels, cavities) that do not normally connect.

(More? [/head2.htm Head Abnormalities] | [/respire2.htm Respiratory Abnormalities])

FL

Acronym for ===F===emur ===L===ength, longest bone in the body, used in clinical ultrasound measurements and reflects growth of the fetus.

(More? Ultrasound Movies)

FLASH

Acronym for ===FL===ICE-===a===ssociated ===h===uge protein, a cytoplasmic component of the apoptosis signaling pathway which also translocates to nuclear Cajal bodies.

Flt1

Gene acronym for fms-like tyrosine kinase 1, one of the membrane receptors for vascular endothelial growth factor (VEGF). A soluble form of the receptor (sFlt1) inhibits VEGF signaling in the vasculature by competing with full-length Flt1 for binding to VEGF.

fms-like tyrosine kinase 1

(Flt1) One of the membrane receptors for vascular endothelial growth factor (VEGF). A soluble form of the receptor (sFlt1) inhibits VEGF signaling in the vasculature by competing with full-length Flt1 for binding to VEGF.

foetal

Often considered the British spelling, US spelling is actually more correct, "fetus" correctly derives from the Latin fetus see alternate spelling [#fetalperiod fetal period] above.

Fog2

Acronym for Friend of Gata 2, a transcription factor required for diaphragm and lung development.

folic acid

(Latin, folium = leaf) (= Folate, Pteroylglutamic acid) A water soluble vitamin, found in many fruits (particularly oranges, berries and bananas), leafy green vegetables, cereals and legumes, which can prevent neural tube defects (NTDs). The cellular roles of folate include: DNA synthesis, amino acid metabolism and methylation of genes, proteins and lipids via S-adenosylmethionine-mediated one-carbon transfer reactions.

(More? Abnormal Development - Folic Acid and Neural Tube Defects | Neural System - Abnormal Development)

follicle

(Latin, folliculus = little bag, dim. of Latin follis) The functional unit within the ovary that includes the developing oocyte (egg) and the surrounding layers of cells that support that oocyte. Some cells within the follicle are released along with the ooctye at ovulation, while other cells are involved with female sex hormone secretion into the maternal bloodstream.

(More? Week 1 - Oogenesis | Human Menstrual Cycle | Genital System - Female)

follicle atresia

The degeneration of the developing ovarian follicle, which can occur at any stage of follicular development. Many developing follicles undergo this process in each menstrual cycle.

(More? Week 1 - Oogenesis | Human Menstrual Cycle | Genital System - Female)

follicle stimulating hormone

(FSH, gonadotropin) Glycoprotein hormone secreted by anterior pituitary and acts on gametogenesis and other systems in both males and females. In females, FSH acts on the ovary to stimulate follicle development. Negative feedback by inhibin from the developing follicle decreases FSH secretion. In males, acts on the testis Sertoli cells to increase androgen-binding protein (ABP) that binds androgens and has a role in spermatogenesis. FSH-deficientcy in females results in infertile (block in folliculogenesis prior to antral follicle formation) and in males does not affect fertility (have small testes but are fertile). FSH protein has a molecular weight 30 kDa and a 3-4 hour half-life in circulation. Gonadotrophins have been used clinically in humans for the treatment of infertility. Other glycoproetin hormones include luteinizing hormone (LH), thyroid stimulating hormone (TSH), and chorionic gonadotropin.

(More? Week 1 - Oogenesis | Human Menstrual Cycle | Endocrine Development - Pituitary | Kumar TR, Wang Y, Lu N, Matzuk MM. Follicle stimulating hormone is required for ovarian follicle maturation but not male fertility. Nat Genet. 1997 Feb;15(2):201-4.)

follicular basal lamina

The basal lamina beneath the membrana granulosa (granulosa cell) layer of the developing follicles of the ovary. It separates the stratum granulosa from the thecal layers. Thought to be synthesized by granulosa cells, but may also have a contribution from the thecal layer.

(More? Week 1 - Oogenesis)

folliculin

(FLCN) A tumor-suppressor protein with unknown functions (see PNAS). Germ line mutations in the gene lead to Birt–Hogg–Dubé syndrome, characterized by benign tumors of the hair follicle, lung cysts, and renal neoplasia.

(More? OMIM folliculin | Birt–Hogg–Dubé syndrome | PNAS Baba M, Hong SB, Sharma N, Warren MB, Nickerson ML, Iwamatsu A, Esposito D, Gillette WK, Hopkins RF 3rd, Hartley JL, Furihata M, Oishi S, Zhen W, Burke TR Jr, Linehan WM, Schmidt LS, Zbar B. Folliculin encoded by the BHD gene interacts with a binding protein, FNIP1, and AMPK, and is involved in AMPK and mTOR signaling. Proc Natl Acad Sci U S A. 2006 Oct 6)

follicular fluid

The fluid found in the antrum of a secondary follicle. Secreted by cells in the wall of the follicle. This fluid is released along with the oocyte at ovulation.

(More? Week 1 - Oogenesis | Human Menstrual Cycle | Genital System - Female)

folliculogenesis

The term used to describe the process of [#follicle follicle] development within the ovary. The follicle is the structure developing within the ovary that includes the oocyte (egg) and surrounding support cells.

(More? Week 1 - Oogenesis | Human Menstrual Cycle | Genital System - Female)

fontanel

(fontanelle) A fibrous region between flat bones of developing skull. Have a role in birth allowing the cranial vault to flex and postnatally allow the skull to enlarge. In humans, there are six fontanels; an obvious anterior (bregmatic) and posterior (occipital) fontanels, as well the less noticeable lateral fontanels (two mastoid fontanels and two sphenoidal fontanels). A month or two after birth, the posterior and lateral fontanelles are lost, the anterior is not completely closed until about the 18 months.

(More? Musculoskeletal Development - Skull Development)

4 (four) dimensional ultrasound

(4D) A term used to describe the collection of three dimensional (3D) ultrasound images over time.

(More? Ultrasound Movies)

foregut

The first of the three part/division (===foregut=== - [M.htm#midgut midgut] - [H.htm#hindgut 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.

(More? Gastrointestinal Tract - Stomach | Gastrointestinal Tract Notes | Respiratory Notes)

Forkhead Box F1

(Foxf1) A member of the forkhead gene family, a group of transcription factors originally identified in drosophila and have a role in development of the gall bladder and other tissues. The'forkhead' domain is a conserved 100 amino acid sequence.

(More? GIT Notes - Gall bladder | OMIM FORKHEAD BOX F1; FOXF1)

Fraser syndrome

(cryptophthalmos-syndactyly syndrome) An autosomal recessive congenital malformation syndrome characterized by [C.htm#cryptophthalmos cryptophthalmos], [S.htm#syndactyly syndactyly], and urogenital defects (bicornuate uterus, imperforate anus, anal stenosis or renal malformations).

(More? Eye Abnormalities | Limb Abnormalities | Urogenital Abnormalities | Urogenital Notes | OMIM - Fraser syndrome)

fusiform

(Latin, fusus = spindle-shaped) widest near the middle and tapering in toward both ends, (back in the days of smoking) often described as "cigar-shaped". For example, used to describe the shape of the early developing stomach or the shape of smooth muscle cells.

(More? GIT Notes)

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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