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Chapter 4: Pregnancy Conception • • • • • ________ is the smallest unit of life that is able to reproduce itself ___________ is the male germ cell _____________ is the female germ cell ___________________ occurs when ovum and sperm combine __________________ is a single cell formed at conception – also called a fertilized egg • ______________________ extend from the sides of the uterus • ____________________ is the organ in which the baby develops – where the ovum is fertilized Genetic Factors and the Unborn Baby • • • • • • Genetic factors are traits passed through the genes – _____________________ all stages of growth and development ________________________ is a genetic blueprint that guides growth and development during pregnancy – gives cells instructions for family-like traits that will unfold throughout life ___________________________ is the center of the cell Genetic code is a set of instructions for development _______________________ store the genetic code Chromosomes carry the DNA Chromosomes and Genes 1 Chapter 4: Pregnancy • Chromosomes • Genes – each person has ____________, pairs of 23 – half from sperm, half from egg – contains _____,000 genes – each human cell contains about ________ million genes – a gene, or group of genes, decides a trait Dominant and Recessive Traits • • ______________________________ traits always show in a person even if only one gene of the pair is inherited for that trait ______________________________ traits typically do not show in a person unless both genes for the trait are inherited – one from each parent – person who inherits only one recessive gene for a trait becomes a carrier of that trait Sex Chromosomes • Sex chromosomes determine genetic sex of baby – _________ female • ovum always carries only _____ chromosomes – _____________ male • • sperm can carry either X or Y chromosome boys’ sex-linked traits are determined only by their ________________ Multiple Pregnancy 2 Chapter 4: Pregnancy • • • • ______________________ pregnancy occurs when two or more babies develop in the same pregnancy ____________________ children develop from two or more ova – most common – each baby has own chorion (which is: ) _________________________ children develop from same ova and sperm Mixed types of pregnancy must include fraternal and identical babies Stages in Prenatal Development • • • • • Prenatal development takes place between conception and birth – – – ______________________________ stage ________________________________stage ________________________________ stage Germinal Stage Germinal stage is the ___________ stage of development ______________________ is a fluid-filled sac that surrounds the baby in the uterus ______________________ is an organ filled with blood vessels that nourish the baby in the uterus Umbilical cord is a cord that connects the baby to the placenta Embryonic Stage • Embryonic stage is the second stage of development, lasts about six weeks – most _____________________ to development – baby is called an ___________________ 3 Chapter 4: Pregnancy – development of most _______________________ systems – ______________________ begins to beat – ___________________________ is present before bones form – substances pass from mother’s placenta through the umbilical cord Fetal Stage • • Fetal stage is the third stage of pregnancy, lasts from about nine weeks after conception until birth – _____________________ starts to replace cartilage – baby is known as a ______________________ During the fetal stage, – all parts of the body mature – overall size increases quickly – hear heartbeat in the third month – ____________________________ begins between the fourth and fifth months; which is ____________________________________________ • • Age of ___________________________ is the age at which a baby could survive if born, 28 weeks – still need extensive medical care – better chance of survival each week the baby is not born During last two months of pregnancy, – inner layer of ______________ produces substance that allows for breathing air – receives immunities from mother in the ninth month 4
