Prenatal Development

1. Prenatal Development Chapter 5 The Developing Child Priscilla Evans DHS TEKS: 1.A; 1.C; 1.D; 2.B

2. Outline • 5-1: The Developing Baby • 5-2: A Closer Look at Conception • 5-3: Problems in Prenatal Development • 5-4: Avoiding Dangers to the Baby

3. Section 5-1 Objectives • Distinguish among the three stages of pregnancy. • Describe the prenatal development during each stage of pregnancy. • Explain why changes affect a woman during each stage of pregnancy.

4. The Developing Baby • Prenatal Development • a single cell grows and develops into a human being capable of life • Takes about 9 months

5. Conception • Ovum – a female cell or egg • Released once a month by one of a woman’s ovaries • The egg moves through the Fallopian tube to the uterus, where the baby develops during pregnancy. • Journey takes about 2-3 days.

6. Conception • The egg meets, and is fertilized by a sperm, male cell. • Conception – when the ovum and sperm unite and pregnancy begins!!

7. Conception Diagram

8. Conception • Fertilization can take place only 2-3 days after the ovum has been released. • Sperm can live up to 7 days. • There’s a period of about 10 days each month during which a female can become pregnant.

9. Baby’s Development Three Stages: • Zygote • Embryo • Fetus

10. Period of the Zygote • Zygote – fertilized egg • Last about 2 weeks • Attaches itself to the lining of the uterus and draws nourishment from the mother. • Grows by cell division • The size of a pinhead

11. Period of the Embryo • Second stage of pregnancy • 3rd – 8th weeks of pregnancy • Grows rapidly 5 – 6 weeks

12. Period of the Embryo First Stage: • Mass of cells develop into major systems – heart, lungs, bones and muscle. • Internal organs unable to function. • Brain begins to take control of these body systems.

13. Period of the Embryo Second Stage: • A sac filled with fluid forms around the embryo. • Amniotic fluid – protects the developing baby • cushions it from falls or bumps

14. Period of the Embryo Third Stage: • Placenta • Tissue • Rich in blood vessels • Mother’s bloodstream carries food and oxygen here

15. Period of the Embryo Fourth Stage: • Umbilical cord • Long tube that connects to the placenta • Carries food and oxygen • Provides nourishment • Takes away waste products

16. Period of the Fetus • 8th/9th week – birth • 4th-5th month – kicks and other movements touch the wall of the uterus • “Quickening” occurs • As the fetus grows, so does the amniotic fluid.

17. Period of the Fetus • The uterus expands, and the abdomen grows. • Just before delivery, the amniotic fluid decreases. • Baby is in the fetal position.

18. Period of the Fetus • By 7th month, fetus is capable of living outside but not without a medical help. • The fetus gains weight rapidly. • Stores nutrients and builds immunity to diseases and infections.

19. Period of the Fetus It can do surprising things! • Sucks its thumb • Cough • Sneeze • Yawn • Kick • Hiccup • Cry

20. Preparing for Birth • 9th month • “ Lightening” - the baby’s weight seems to shift down and the mother feels more comfortable in her upper abdomen. • the baby drops • might not occur until just before labor

21. Preparing for Birth • The fetus is upside down, the head is nestled in the mother’s pelvis. • The baby is less active • The mother’s skin and abdomen muscles stretch. • After 37-42 weeks of preparation, the baby is ready to be born.

22. Section 5-2 Objectives • Describe how personal characteristics are inherited. • Explain the cause of multiple births. • Evaluate different possible solutions for infertility.

23. The Genetic Package Each person inherits personal characteristics from his/her parents.

24. The Genetic Package • At conception, every human baby receives 46 chromosomes, tiny threadlike particles on the nucleus of every cell. • These chromosomes come in 23 pairs.

25. The Genetic Package • Each chromosome has thousands of genes, the units that determine the child’s inherited characteristics. • For ever inherited characteristic, a person receives two copies of one gene. • When both are the same, the child has that characteristic.

26. The Genetic Package What happens if a person receives two different genes? • dominant – stronger gene • recessive – weaker gene, it will not be expressed

27. Making a Unique Person • Each sperm or egg cell contains a different combination of genes. • Personal traits are determined by the particular combinations of genes brought together at conception.

28. Making a Unique Person: Sex Chromosomes • X – egg cell/female • X or Y – sperm/male • XX = girl • XY = boy So who determines the sex of a child? THE FATHER!!

29. Multiple Births • Identical • began as one zygote • always the same sex • have very similar characteristics

30. Multiple Births • Fraternal • two eggs are released at the same time and each is fertilized. • they grow side by side in the uterus • may be opposite sexes

31. Multiple Births • When more than two babies are born, they may be identical or fraternal – or a combination. • It depends on whether one fertilized egg splits or more than one egg is fertilized at the same time.

32. Multiple Births • In the U.S., about 2 ½ % of births are twins. • Fraternal twins occur 3 times more often than identical twins. • Multiple births are happening at a growing rate because people are getting treatments.

33. Infertility • Infertility – inability to become pregnant • Couples may feel abnormal and/or alone. • Medical advances have helped many of these couples. • Surgery or medication may solve the problem.

34. Infertility • Fertility drugs stimulates a woman’s ovaries to release eggs. • Drawbacks • lung problems • abdominal pain • nausea • dizziness • multiple births

35. Options for Infertile Couples • Adoption • couple legally takes all responsibilities for raising a child already born • Artificial insemination • a doctor injects sperm into a woman’s uterus with a special needle

36. Options for Infertile Couples • In vitro fertilization • a woman has damaged Fallopian tubes • in a small glass, a doctor combines a mature egg from the woman and sperm from her husband • the doctor places the zygote in the woman’s uterus

37. Options for Infertile Couples • Ovum transfer • this procedure uses an egg taken from female donor and in vitro fertilization • it may used by women who lack ovaries or who has inherited disorders

38. Options for Infertile Couples • Surrogate mother • substitute • mother is a woman who becomes pregnant for another couple • she may carry a couple’s fertilized egg, removed from the mother

39. Options for Infertile Couples • Surrogate cont. • artificially inseminated w/ sperm from the husband • include legal arrangements and must meet state laws

40. Questions Raised • Technology advances offer options • Not everyone thinks these alternatives are acceptable. • The use of ovum transfers/surrogate mothers is controversial. • Raises ethical questions.

41. Section 5-3 • Contrast miscarriage and stillbirth. • Identify some major birth defects. • Explain the 4 causes of birth defects. • Describe how birth defects can be diagnosed and prevented.

42. Losing a Baby • Miscarriage • baby dies before 20 weeks of pregnancy • Stillbirth • baby dies after 20 weeks of pregnancy

43. Losing a Baby • As many as 20% of all pregnancies end in a miscarriage. • These loses can be severe shocks and bring pain. • Parents go through the same grief as does anyone who has had a family member die. • Most couples are able to have a successful pregnancy later.

44. Types of Birth Defects • Birth Defects – babies born with serious problems that threaten their health or ability to live. • About 3 out of every 100 children born in the U.S. have a birth defect. • Some can be mild or can be corrected. • Others result in severe lifelong disabilities or even death.

45. Types of Birth Defects • Some birth defects affect the shape or size of the body or of certain parts of the body. • Not all birth defects are apparent.

46. Causes of Birth Defects • Scientist don’t yet understand the cause of about 60% of all birth defects. • They have found four main causes for birth defects.

47. Causes of Birth Defects: Environmental • Many choices the mother makes can affect the development of the baby: • The nutritional balance of her diet • Diseases/infections the mother has during pregnancy. • Harmful substances the mother takes in, including alcohol, tobacco, and drugs.

48. Causes of Birth Defects: Environmental • Some medicines that benefit the mother, but which can hurt the baby. • Exposure to outside hazards such as radiation, especially early pregnancy.

49. Causes of Birth Defects: Environmental • A father’s exposure to alcohol, drugs, and other substances can also affect the baby. • Sperm take three months to develop. • Alcohol , drugs, and tobacco affect the way the sperm forms; they produce changes in the chromosomes.

50. Causes of Birth Defects: Environmental • Cocaine has been found to adhere to the sperm and affect the baby from the moment of conception. • What responsibilities does a future father have?