2 What you should know when we are done with this chapter! Describe what happens during conceptionExplain how genetic factors affect prenatal developmentDescribe how a person inherits traits through genesList the three different types of multiple pregnanciesDescribe the three main stages of prenatal development
3 The prenatal period lasts from about 270-280 days The prenatal period lasts from about days. It is the shortest stage in the life span.
4 What is Pregnancy?The process through which a new human prepares to enter the world.
5 Conception:Cell- the smallest unit of life that is able to reproduce itself. Life begins with the joining of two separate cells one from the male and one from the femaleSperm- the male germ cellOvum or egg- the female germ cellConception- the joining of these two cells- at conception, ovum and sperm combine to form a single cell called a zygote or fertilized egg
6 Egg informationEggs produced and stored by the woman’s ovaries in a small sac called the follicle. Each month hormones cause some follicles to grow and fill with fluid. Around the middle of the menstrual cycle, one ovum is released from the follicle and the other follicles become inactive- yet sometimes more than one ovum or egg is released. The release of the ovum from the ovary is called ovulation.
8 When the egg is released it travels to the fallopian tubes- these are two hollow tubes that extend from the right and left sides of the uterus. Once inside the FT- the ovum or egg is ready and available to be joined by a sperm. Semen may carry over 100 million sperm as it enters the woman. Many of the sperm do not survive. Sperm may meet the ovum at any point. Only one sperm successfully enters or fertilizes the egg. Once one sperm enters- no others can enter and CONCEPTION HAS OCCURRED AND A ZYGOTE IS FORMED!
9 Uterus- the organ is which the baby develops and is protected until birth
10 GENETICS- traits passed through genes GENETICS- traits passed through genes. These affect ALL stages of development.Because of genetics the unborn baby will:come to look like other family memberslikely have the same interestshave similar personalities
11 Genetics affect the prenatal period- and sets forth the blueprint for the developing fetus. These blueprints will give information to the fetus later in life.For example- during the prenatal period- the blueprint is put down whether the baby boy will become bald later in life- sorry Rogaine!
12 Chromosomes and GenesEach baby is given 23 pairs of chromosomes- for a total of 46½ from mom and ½ from dad- What are they? threadlike structures that carry genes in living cells.
14 Each chromosome contains about 20,000 genes - these genes determine traits each person will have Humans cells have about a million genes- sometimes one gene will determine a trait- other times it a group of genes that do
15 TraitsDOMINANT TRAITS- traits that always show in a person even if only one gene of the pair is inherited for that trait.RECESSIVE TRAIT- traits that typically do not show in a person unless both genes for the trait are inherited
18 Sex Chromosomes- 22 of the chromosomes the same in men and women- the last pair is the sex chromosome
19 How are we doing? Did we? Describe what happens during conception Explain how genetic factors affect prenatal developmentDescribe how a person inherits traits through genesList the three different types of multiple pregnanciesDescribe the three main stages of prenatal development
20 What can be affected by sex chromosomes: HeightEye color
21 Multiple Pregnancy-If 2 or more babies develop in the same pregnancy becoming more common due to fertility drugs
23 Multiples According to the text: frequency of twins 1 in 35 3 or more babies in the same pregnancy 1 in 540Dr.’s often concerned with the health of multiplesMost of these babies are born early and are underweightRisks can include:severe vision issueshearing issuesmental and developmental disabilitiestwins are also 5 times more likely to die in their first year (triplets 10 times)
24 Fraternal Births- most common when multiple babies develop from two or more ova- each fertilized with a different spermFraternal Facts:may or may not look alikemay or may not be the same gendereach fraternal twin has their own chorion- a membrane that surrounds the baby in the uterusno more similar than any other sibling
25 Identical Births-children develop from a single ovum that was fertilized by a single sperm. This happens early on and Dr.’s do not know why it splits.
26 Identical Facts:if ovum does not totally split, the babies will be conjoinedidentical babies have the identical genetic makeupthey are the result of one fertilized eggsimilar in appearancefingerprints, footprints, and palm prints are similar-but not exact
27 Mixed Types- can be both identical and fraternal if three or more children are born. In order to be a mixed type, the babies must be fraternal and identical. It works with quadruplets as well. There could even be two identical pairs.
28 Stages in Prenatal Development: Many things happen between conception and birth. All these changes are called prenatal development. There are 3 stages:Germinal/ZygoteEmbryonic/EmbryoFetal/Fetus
29 Germinal Stage: this is the first stage Germinal Stage: this is the first stage. Conception starts the beginning of this stage.
30 Germinal/Zygote highlights: Lasts the first 2 weeks of pregnancy.The fertilized egg remains a single cell for about a day and ½By day 3 it is a hollow ball of 32 cellsThis ball of cells then enters the uterus and floats freelyAbout days after conception the ball of cell embed in the uterus wallThe cells continue to divideThe chorion and the amnion(amniotic sac) begin to formThe placenta begins to develop against the wall of the uterus
31 Germinal/Zygote highlights: The umbilical cord grows out of the developing child at the site of the navel and connects with the placentaThe umbilical cord contains three blood vessels that connect the child with the placentaThe placenta will develop it will begin to nourish the baby, remove the baby’s wastes, exchange gases between mom and babyIt also provides hormones for the babyThis stage ends when the baby can receive nourishment from the mom
32 The Embryonic Stage this is the 2nd stage of prenatal development The Embryonic Stage this is the 2nd stage of prenatal development. Experts say that this is the most important stage since almost all body systems develop during this stage.
33 Embryo Highlights Lasts until the 8th week When this stage ends, the embryo looks like a small humanThe embryo has tiny arms, legs, fingers, toes, and a faceAll major organs such as heart, brain, and lungs are thereHeart begins beatingNo bones only cartilageBaby now receives both good and bad substances from the mom through the umbilical cordBaby’s body parts are developing quickly, so passing harmful substances to the child can affect them for lifeThe mom’s diet needs to full of vitamins and nutrientsMom should avoid: alcohol, drugs, excess caffeine, smoke, and x-rays
34 Fetal Stage: this is the 3rd stage Fetal Stage: this is the 3rd stage. This is when the bone starts to replace cartilage. This stage starts about week 9 up to delivery.https://drive.google.com/a/d155.org/?tab=oo#owner/khester%40d155.org
35 Fetal highlights: All body parts start to mature Overall size increasesBy the 4th month the fetus has grown enough to give the mom’s growing abdomen a pregnant lookTwo major milestones- in the 3rd month the parents may be able to hear the heart of the baby and by the 4th -5th month the mom can start to feel the baby(quickening)The fetus can turn, swallow, and even suck its thumb
36 Fetal highlights:Another important milestone- 28 weeks/7 months= the age of viability- when the fetus has a strong chance of surviving outside of the mom if it were to be born nowThey still may need special help- yet they have a strong chance of survivalLast 2 months the lungs become stronger and the baby becomes larger9th month the baby receives immunities from the mom- ex: if mom had chicken pox- the baby will have the chicken pox immunity from the momFinally the baby will start to turn head down to prepare for birth
38 So, did we get it all? Describe what happens during conception Explain how genetic factors affect prenatal developmentDescribe how a person inherits traits through genesList the three different types of multiple pregnanciesDescribe the three main stages of prenatal development