Teratogen simple english wikipedia, the free encyclopedia. Heavy amounts associated with fetal alcohol syndrome fas, reported to be a cause of mental retardation, facial deformities, and defects of limbs and heart. Teratogens act via a specific mechanism on developing cells and tissues to initiate a cascade of altered developmental events. The aim of experimental teratology in the postthalidomide period has been the exact explanation of causes and mechanisms of the rise of cdds. Moderate amounts 12 drinks per day may result in attention deficit disorder add. During the first two weeks of gestation, teratogenic agents usually kill the embryo rather than cause congenital malformations. If a teratogen has the potential to interfere with the closure of the neural tube, for example, the exposure to the teratogen must occur in the first 3.
Teratogens and their effects columbia university pages 1. As teratogenic agent, the effect of any kind of drugs on the unborn babies depends of the types, the dosage and the developmental stage of the fetus. The epub format uses ebook readers, which have several ease of. Effects of teratogens on prenatal development by andrea. Following meckel, scientists in the nineteenth century began experimental studies to detect the effect of different teratogens on chicken eggs. The effects of teratogens during this period can cause physiological defects and less severe structural problems. Rabbits were susceptible to cyclopamine administered on the seventh day of gestation, exhibiting doubleglobe cyclopia and cebocephaly. Teratogens are thought to have the ability to effect the fetus about 10 to14 days after conception. Chapter 23, p 231 238, columbia university medical center, new york. Some things can be teratogens, including some chemicals, medications, and infectious diseases. This multiauthor work deals with the practical aspects of teratogens chemicals which cause birth defects. Five viruses are known to be teratogenic in humans. The first human teratogen identified in 1941 by an ophthalmologist, norman gregg, was maternal rubella infection in pregnancy, which produced a triad of defects cataracts, heart malformations, and deafness in the infants.
Other viruses which can infect and produce disease in the fetus are influenza, rubeola, western equine encephalitis, variola, vaccinia, hepatitis b, echoviruses, and poliovirus. A more comprehensive definition is that teratology is the science dealing. Varicella or chickenpox is a highly infectious disease, usually associated with childhood. Tens of thousands of excellent, educational videos in a huge, intuitive directory. The likelihood that some drugs will cause fetal ab. The effects of teratogens on the health of developing.
Congenital malformations may be caused by genetic factors or environmental insults or a combination of the two that occur during prenatal development. Common teratogens drug effects depressants alcohol small amounts increase risk of spontaneous abortion. Teratogenic agents and related conditions texila international. A free powerpoint ppt presentation displayed as a flash slide show on id. Eightyfive to ninetyfive percent of pregnant women are immune to chickenpox, which means that there is no need to be concerned about this during pregnancy, even if the woman is. Ideal as a supplement to a curriculum or for independent study. It is designed for use as a unique guide to these chemicals in which one can find all relevant information. During the development of a baby, there are certain organs forming at certain times. Their occurrence, structural relationship, and biologic effects. Principles causes and effects of teratology essay 1453.
Zygote germinal stage conceptiontwo weeks biological teratogen. Many harmful agents cause damage only if exposure occurs during a sensitive period of prenatal development. Moreover, we report on brazilian cases of teratogenesis due to the. Teratogens and their effects on pregnancy by allie pail on. Cases involving congenital anomalies from 2008 to 20. During weeks nine through thirtyeight, exposure to teratogens can still have a large damaging effect on external features and a diminished, yet significant effect on the central nervous system. Their teratogenic effect will depend on the intracellular balance.
A human teratogen is an agent that alters the growth or structure of the developing embryo or fetus, thereby causing birth defects. Wilson defined teratology as a science dealing with adverse effects of the environment on developing systems, namely on germ cells, embryos, foetuses, and immature individuals. Alcoholsmoking when teratogens are introduced at such a delicate time, severe consequences sometimes. The effects of teratogens on the health of developing human beings. The effect of teratogens on the baby is based on the period of pregnancy the mother is in. The author of this research has no financial or other interests which post a conflict ofor other interests which post a conflict of interest.
Teratogens are environmental agents that cause developmental defects in the fetus. Effects of teratogens during this period of developmental often times results in an all or none effect. Child growth and development pregnancy and prenatal. A teratogen is defined as any agent that acts during embryonic or fetal development to produce an alteration of form or function. Teratology is the scientific study of causes and mechanisms of malformation during the human development.
This teratogenic effect is produced by certain steroidal alkaloid teratogens from. Alcohol effects on executive functions function in brain effects on behavior inhibition socially inappropriate behavior, as if inebriated planning inability to apply consequences from past actions time perception difficulty with abstract concepts time and money internal ordering like files out of order, difficulty processing information. There is a threshold below which no teratogenic effect will be observed. Download as pptx, pdf, txt or read online from scribd. During pregnancy, the embryo or fetus is very sensitive and. That is, the effect of the teratogen, if it is to have any effect, will be so profound as to cause a spontaneous abortion.
A teratogen is a material that can cause congenital defects. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Any substance, organism, or process that causes harm to a fetus i. Pdf the effects of teratogens on the health of developing human. Teratogens are defined as any environmental factor that can produce a permanent abnormality in structure or function, restriction of growth, or death of the embryo or fetus. Learn what a teratogen in pregnancy is, relevant time lines during gestation, the most common examples, their effects on developing fetuses, and ways to avoid them. Environmental influences cont maternal factors nutrition and maternal weight need 300 500 more calories a day need extra protein weight gain of 25 35 pounds less likely to have birth complications overweight before pregnancy highest risk of. Some examples of teratogens known to cause human malformations are listed in the table below table 232.
Definition of a teratogen an exposure in pregnancy that. By adulthood, more than 95 percent of americans have had chickenpox. Download pdf introduction teratology is the study of the causes and biological processes leading to abnormal development and birth defects and of the appropriate measures for prevention. Fetal diseases, mechanical effects and retarded development of the embryo and the fetus are some of the causes of cdds congenital developmental disorders according to. This is a permanent mental condition that will affect your child through out their entire life. Congenital malformations may be caused by genetic factors orenvironmental insults or a combination of the two that occur during prenataldevelopment. If you need to print pages from this book, we recommend downloading it as a pdf. It is usually something in the environment that the mother may be exposed to during. Teratogens and their effects columbia university fliphtml5. Neurology for the speechlanguage pathologist sixth edition, 2017.
Designed for teachers, students, parents, homeschoolers, educators and all lifelong learners. Read teratogens free essay and over 89,000 other research documents. The word teratogen originates from the greek word for monster, teratos. Teratogenic effects are dependent on the nature of the teratogen, including chemical properties of the chemical, route of exposure, maternalfetal bioactivation, placental transport, etc. Genetics unit massgeneral hospital for children holmes. Effects of teratogens on prenatal development stage 1 conclusion.
Unfortunately, this book cant be printed from the openbook. Unlimited viewing of the articlechapter pdf and any associated supplements and figures. Teratogens and their effects on pregnancy and development. Teratogen is an agent that can disturb the development of the embryo or fetus teratogens halt the pregnancy or produce a congenital malformation include radiation, maternal infections, chemicals, and drugs. About 75% of all congenital disfectants are caused by teratogens. Definitions and statistics a teratogen is an agent, which can cause a birth defect. The study that would be conducted would involve women during their fetal stage of pregnancy. Teratogens teratogens are any agents from the environment that can cause harm to the developing fetus. Developmental toxicology drugs, and fetal teratogenesis core. Children who have been exposed to teratogens in utero will not pass their defect on to their children. The side effects of alcohol to an unborn child can range from something as simple as low birth weight to a more severe problem like fetal alcohol syndrome.
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