fertility Ability of an individual or couple to reproduce through normal sexual activity. About 80% of healthy, fertile women are able to conceive within one year if they have intercourse regularly without contraception. Normal fertility requires the production of enough healthy sperm by the male and viable eggs by the female, successful passage of the sperm through open ducts from the male testes to the female fallopian tubes, penetration of a healthy egg, and implantation of the fertilized egg in the lining of the uterus (see reproductive system). A problem with any of these steps can cause infertility.
fertilization Reproductive process in which a male sex cell (sperm) unites with a female sex cell (egg). During the process, the chromosomes of the egg and sperm will merge to form a zygote, which will divide to form an embryo. In humans, sperm travel from the vagina through the uterus to a fallopian tube, where they surround an egg released from an ovary usually two or three days earlier. Once one sperm has fused with the egg cell membrane, the outer layer becomes impenetrable to other sperm. See also cross-fertilization, self-fertilization. See illustration oppo¬ site on following page.
fertilizer Natural or artificial substance containing the chemical ele¬ ments that improve growth and productiveness of plants. Fertilizers enhance the natural fertility of the soil or replace the chemical elements taken from the soil by previous crops. The use of manure and composts as fertilizers is probably almost as old as agriculture. Modern chemical fer¬ tilizers include one or more of the three elements most important in plant nutrition: nitrogen, phosphorus, and potassium. Of secondary importance are the elements sulfur, magnesium, and calcium.
Fes \'fes\ or Fez Vfez \ Arabic Fas \'fas\ City (pop., 1994: 541,162), northern Morocco. The oldest of Morocco’s four imperial cities, it was founded on opposite banks of the Wadi Fes by Idris I c. 789 and Idris II c. 809. The two parts were united by the Almoravid dynasty in the 11th cen¬ tury to become a major Islamic city. Fes reached its zenith under the Marinid dynasty as a centre of learning and commerce in the mid-14th century and has kept its religious primacy through the ages. The site of the oldest mosque in northern Africa, it is also the seat of an Islamic uni¬ versity founded in 859. A centre for trade and traditional crafts, it was until the late 19th century the only place where the fez hat was made.
fescue Any of about 100 species of grasses that make up the genus Fes- tuca (family Poaceae, or Gramineae), native to temperate and cold regions of the Northern Hemisphere. Several species are important pasture and fodder grasses, and a few are used in lawn mixtures. One variety, blue fescue (F. ovina ‘glauca’), has smooth, silvery leaves and is planted in ornamental borders.
Fessenden, William Pitt (b. Oct. 16, 1806, Boscawen, N.H., U.S.—d. Sept. 8, 1869, Portland, Maine) U.S. politician. He practiced law in Maine before serving in the U.S. House of Representatives (1841—43)
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fetal alcohol syndrome ► Feuillants I 669
Fertilization of a human egg. (1) The sperm release enzymes that help disperse the corona radiata and bind to the zona pellucida. (2) The outer sperm head layer is sloughed off, exposing enzymes that digest a path through the zona pellucida. (3) The sperm fuses with the egg cell membrane, causing the zona pellucida to become impenetrable to other sperm. (4) The tail separates from the sperm head, and the male pronucleus enlarges and travels to the female pronucleus in the center of the cell. Chromosomes merge to form a fertilized egg.
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and Senate (1854-64, 1865-69). Originally a Whig, he opposed the exten¬ sion of slavery to the territories, and he was one of the leaders of the movement that resulted in the formation of the Republican Party (1854). Despite his personal dislike for Pres. Andrew Johnson, he voted for acquit¬ tal in Johnson’s Senate impeachment trial.
fetal alcohol syndrome (FAS) Various congenital disorders in a newborn caused by the mother drinking alcohol during pregnancy. The main symptoms are retarded growth, abnormalities of the central nervous system, and certain face and head abnormalities. The child may be men¬ tally retarded. Behavioral problems (e.g., poor concentration, impulsive¬ ness) are sometimes the only obvious symptoms. The syndrome is common in babies born to chronic alcoholics, but health care organiza¬ tions now commonly recommend that women cease drinking alcohol entirely while pregnant. Other disorders have been linked to alcohol in breast milk.
fetial Vfe-shol\ Any of a group of 20 Roman priestly officials who dealt with foreign relations. Selected from noble families and appointed for life, they acted as emissaries to foreign lands in times of conflict. When Rome was offended by another city-state, the fetials would visit the city-state and demand satisfaction. They also delivered treaties and made formal
declarations of war, based on the decisions of the Senate. This priesthood had faded by the late republic, but was later revived by Augustus.
fetish Object believed to have magical power to protect or aid its owner, and by extension, an object regarded with superstitious or extravagant trust or reverence. In the 18th century it was applied to West African amulets; it has also been used for various items in American Indian reli¬ gion. In psychology, a fetish is an object that substitutes for a person as the focus of sexual desire. See also fetishism.
fetishism In psychology, erotic attachment to an inanimate object or a nongenital body part whose real or fantasized presence is necessary for sexual gratification. The object is most commonly some other body part or an article of clothing. From the time of its identification by Sigmund Freud in 1927, fetishism was thought to occur almost exclusively among men, but in the late 20th century that notion was challenged by several new studies. See also fetish.
fetus \'fet-os\ Unborn young of any vertebrate, particularly mammals, after it has acquired its basic form. In humans, this stage begins about eight weeks after conception (see embryo). The fetal stage, marked by increased growth and full development of the organ systems, climaxes in birth (see pregnancy, parturition). By the end of the third month, the arms and legs of the human fetus begin to move and reflexive movements (such as sucking) begin. Four months after conception, the fetus is about 5.3 in. (135 mm) long and weighs about 6 oz (170 g). During the fifth month, downy hairs (lanugo) cover the body and the skin becomes less transpar¬ ent. At seven months, a protective greasy substance (vemix caseosa) cov¬ ers the reddish, wrinkled skin. Fat is deposited under the skin during the eighth month, when the fetus typically weighs about 5 lbs (2.2 kg). A full-term fetus is about 266 days old.
feudal land tenure System by which land was held by tenants from lords. In England and France, the king was lord paramount and master of the realm. He granted land to his lords, who granted land to their vassals and so on down to the occupying tenant. Tenures were divided into free and unfree. Free tenure included tenure in chivalry, as in the case of knight service, and socage (tenure by agricultural service fixed in amount and kind). The main type of unfree tenancy was villenage, a limited form of servitude. See also feudalism, fief, landlord and tenant, manorialism.
feudalism Term that emerged in the 17th century that has been used to describe economic, legal, political, social, and economic relationships in the European Middle Ages. Derived from the Latin word feudum (fief) but unknown to people of the Middle Ages, the term “feudalism” has been used most broadly to refer to medieval society as a whole, and in this way may be understood as a socio-economic system that is often called mano¬ rialism. It has been used most narrowly to describe relations between lords and vassals that involve the exchange of land for military service. Feu¬ dalism in this sense is thought to have emerged in a time of political dis¬ order in the 11th century as a means to restore order, and it was later a key element in the establishment of strong monarchies. “Feudalism” also has been applied, often inappropriately, to non-Western societies where institutions similar to those of medieval Europe are thought to have existed. The many ways “feudalism” has been used have drained it of specific meaning, however, and caused some scholars to reject it as a use¬ ful concept for understanding medieval society.