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PRENATAL DEVELOPMENT

PRENATAL DEVELOPMENT. Semester 2, 2015/2016. Female anatomy. The uterus - is a major female hormone-responsive reproductive sex organ Within the uterus  fetus develops during gestation . The term uterus =womb.

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PRENATAL DEVELOPMENT

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  1. PRENATAL DEVELOPMENT Semester 2, 2015/2016

  2. Female anatomy • The uterus - is a major female hormone-responsive reproductive sex organ • Within the uterus  fetus develops during gestation. • The term uterus =womb. • One end, the cervix, opens into the vagina; the other is connected on both sides to the Fallopian tubes.

  3. The Female Reproductive System • Uterus • A muscular chamber about the size and shape of a pear. • Located in a woman's abdomen, is a hollow, elastic reproductive organ, where a baby develops during pregnancy.

  4. Ovum (Egg) • The ovum is the female reproductive cell Chief Characteristics: • Round • .01 mm in diameter • Consistency of stiff jelly • Contributes 23 chromosomes Fact: • Females already have 1-2 million primal eggs at birth • Eggs usually fertilized about 12 hours after discharged from the ovary or they die within 12-24 hours

  5. Sperm • Sperm is the male reproductive cell Chief Characteristics: • Tightly packed tip (acrosome) that contains 23 chromosomes that carry genetic information • Short neck region • Trail to propel it in its search for the ovum • Microscopic Fact: • Remains capable of fertilizing egg for 24-48 hours after ejaculation • Of 200 million sperm that enter the vagina, only about 200 survive the journey to the fallopian tubes, where fertilization occurs • Males, at birth, have in their testes those cells that will eventually produce sperm

  6. Pregnancy • If the egg is fertilized by a sperm cell as it travels down the fallopian tube, then pregnancy occurs, it becomes attached to the lining of the uterus

  7. In order for conception to occur, there must be three factors present: • the egg, • the sperm • a medium in which the sperm can travel to reach the fallopian tubes. • Women produce cervical fluid under the influence of increasing levels of estrogen in the first part of the cycle. • Sperms can live up to five days in fertile quality cervical fluid

  8. 3 Stages in prenatal development: • Germinal stage • Embryonic stage • Fetal stage • Principles: • Cephalocaudal principle • Proximodistal principle

  9. PRENATAL DEVELOPMENT: Bapa (sperma) Ibu (Ovum) ½ sel (23 kromosom X or Y) ½ sel (23 kromosom X) Stage 1: Germinal Persenyawaan zigot Stage 2: Embryonic Embrio Stage 3: Fetal Fetus Baby

  10. First Stage: Germinal • Starts at conception (fertilization) until implantation  14 days. • Conception process  When the sperms meets the egg (ovum) in the fallopian tube  travel down into the uterus where it implants in the uterine lining and begin to grow (implantation).

  11. Conception • Conception occurs when the sperm meets and penetrates the ovum, or egg sperm ovum

  12. Normally, only one sperms will succeed penetrating through the ovum wall.

  13. When one sperms succeeded penetrating the ovum wall, a protective lining will form around it preventing other sperms to enter/penetrate. • The combination of ovum & sperms  form zygote (with one nucleus). • Zygote will later develop into blastocyst a complex organism with millions of cells  with various functions. • Rapid cell division, increasing complexity and differentiation, and implantation

  14. Fertilization: the sperm and egg join in the fallopian tube to form a unique human being. • a fertilized egg, only thirty hours after conception.

  15. Zygotic Period(Conception - 1st Week) • A zygote is a fertilized egg with 46 chromosomes • Genetic potential determined at this time • Egg is 2.5 mm in diameter at end of 1st week • Mitosis, a process of cell division, occurs during this period • A human zygote exists as a single cell before undergoing cleavage  becomes a blastocyst  on the fifth day

  16. Early Development Of A HumanEmbryo

  17. Early development of a human embryo

  18. Embrio : blastosis burrows into the uterine lining

  19. As soon as the fertilized egg burrows into the lining, it starts releasing a pregnancy hormone, HCG (Human Chorionic Gonadotropin) which sends a message back to the corpus luteum left behind on the ovarian wall. • HCG signals the corpus luteum to remain alive beyond its usual maximum of 16 days and continuing to release progesterone long enough to sustain the nourishing lining. • After several months, the placenta takes over, not only maintaining the endometrium, but providing all the oxygen and nutrients the fetus needs to thrive.

  20. Cells Division • There are two type of cell division • Mitosis and meiosis • Mitosis - division & multiplication of other body cells • Meiosis process - Division of Reproductive cells

  21. Cells Division • Mitosis is cell division that results in the duplication of cells  genetic copies of the parent cell. This cell multiplication allows for replacement of old cells, tissue repair, growth and development. • Mitosis • The creation of new cells through duplication & divisions of cells  cells duplicates (From 1 24  16 32, etc) • Cells developed into organs, brain, heart etc.

  22. Meiosis is Sex Cell (Gamete) Formation • Meiosis is a complex process by which gametes form; involves duplication and division of reproductive cells and their chromosomes. • The number of chromosomes in cells divide into two’s, and each set of cell will receive 1 from each sets of chromosomes  makes up 23 sets. • This type of cell division results in the production of gametes (eggs or sperm). • Meiosis is much more complex than mitosis involves the duplication and subsequent division of chromosomes.

  23. What's the Difference between Mitosis & Meiosis • Mitosis is how the cells of our body make more cells for growth, development and repair. • Meiosis is how our body makes sex cells, or gametes (eggs or sperm).

  24. Mechanisms Of Heredity • The Genetic Code • Basis of heredity is a chemical called deoxyribonucleic acid (DNA), which contains all the inherited material passed from biological parents to children • Every cell except the sex cells has 23 pairs of chromosomes, 23 (M) + 23 (F) = 46 in all • Genetic action that triggers growth of body and brain is often regulated by hormones

  25. Genetic Code • Genetic information are kept in chromosomes  ie. A long & complex set of DNA molecules. • Genes is a segment of DNA molecules  contains instructions for making protein. • Human being is said to have 100 trillions of cells in the body  with specific functions; and is distributed through 46 chromosomes, ie. 23 from father & 23 from mother. • Genetic Foundation • Genotype (genetic makeup) • Phenotype (observable characteristics)

  26. Hereditary composition of the zygote

  27. What determines sex? • Boy or girl? • Chromosomes determine sex : • 23 pairs of sex chromosomes • Female : XX pairs of sex chromosomes • Male : XY pairs of sex chromosomes • When an ovum (X) is fertilized by an X-carrying sperm, the zygote formed is XX, a female • When an ovum (X) is fertilized by a Y-carrying sperm, the resulting zygote is XY, a male AYAH=XYIBU=XX XY (anaklelaki)XX (anakPerempuan)

  28. What Causes Multiple Births? Dizygotic (two-egg) twins=fraternal twins Monozygotic (one-egg) twins=identical twins The rise in multiple births is due in part to a trend toward delayed childbearing Infertility Inability to conceive a baby after 12 to 18 months of trying

  29. 2nd Stage in prenatal development stage Embryonic Stage

  30. 2nd Stage: Embryonic Period (2nd Week – 8th week) • The phase after implantation  after the development of zygote  and developing its blastosist. • Embryo composed of millions of cells with various functions (week 3-8) • Rapid growth and development of major body systems and organs • A critical period • Trimesters • Spontaneous abortion (miscarriage) • Stillborn

  31. Phases in pregnancy: • First trimester (week 1-12) • 2nd Trimester (week 13 -24) • 3rd Trimester (week 25 & above)

  32. 2nd Stage: Embryonic Period(2nd Week - 2nd Month) • The differentiation of embryonic cells into layers marks the beginning of the embryo, or embryonic period • Period when all body systems form • Highly sensitive for susceptibility of congenital malformations, or abnormal conditions with which an infant is born

  33. Embryonic Period: End of the 1st Month • 1/4 inch (6 mm) long • 1 oz. Weight • Crescent-shaped with small limb buds on sides • Tail with tiny ridges • Rudimentary circulatory system is forming • Heart begins to beat • Growth acceleration

  34. 7 weeks • Facial features are visible, including a mouth and tongue. • The eyes have a retina and lens. • The major muscle system is developed, and the unborn child practices moving. • The child has its own blood type, distinct from the mother's. • These blood cells are produced by the liver now instead of the yolk sac.

  35. Embryonic Period:End of 2nd Month • 1.5 inches long • Beginning of face, neck, fingers, toes develop • Limb buds lengthen • Muscles enlarge • Sex organs begin to form • Rapid brain development • Embryo is firmly planted on uterine wall and is receiving nourishment from placenta and umbilical cord

  36. 3rd Stage in prenatal development stage Fetal Stage

  37. 3rd stage: Fetal Stage(8 weeks to birth) • Embryo develops  fetus (baby in the uterus). • Cells that represents eyes, head, body, hands, legs  further develops  larger. • The period of consumption until baby is born  40 weeks (sometimes 38-36 weeks). • Increased detail of body parts and greatly enlarged body size • Finishing touches • Fetal behavior • Ultrasound

  38. Early Fetal Period: 3rd - 6th Month • Period of the fetus begins around the 3rd month and continues until delivery • Movement first becomes apparent to mother at this time • No new anatomical features appear during this period, yet still critical time

  39. Early Fetal Period: 3rd Month • Rapid growth, 3 inches long at end of 3rd month • Sexual differentiation continues • Teeth buds emerge • Stomach and kidneys begin to function • Vocal cords appear • Reflex actions felt: opens/closes mouth, clenches fist, sucks thumb

  40. Early Fetal Period:4th Month • Most rapid growth rate (doubles in length to 6-8 inches) • 6 oz. Weight • Hands fully shaped • Bony tissue begins to form

  41. Early Fetal Period:5th Month • Reaches 1/2 of birth length (8-10 inches) • Only 10% of birth weight • Skin, hair, nails appear • Internal organs grow and assume proper anatomical positions • Pigmented hair on head & eyebrows appears

  42. Early Fetal Period: 6th Month • 13 inches long • ½ kg • Eyelids reopen and are completed • Structurally complete but functionally immature

  43. Later Fetal Period: 7th-9th Month/Birth • From the 7th month to birth, the fetus triples in weight • This is a period of filling out • Preparation for birth

  44. Later Fetal Period:7th Month • A layer of adipose tissue begins to form under skin (serves as both insulator & food supplier) • Rapid Weight gain (1-1.8 kg) • 14-16 inches long • Fetus is quiet for long periods of time • Brain more active and is increasing control over body systems

  45. Later Fetal Period:8th Month • Fetus is more active (frequent changes in position) • Fatty deposits distributed • 16-18 inches long • 1.8- 2.7 kg

  46. Later Fetal Period:9th Month (Birth) • 19-21 inches long • 2.7 - 3.5 kg. • Birth process is initiated by placenta and contraction of uterine muscles • Birth generally occurs after week 40 of gestation (normal is 38-42 wks.)

  47. Important parts in the uterus • Amniotic Sac • Placenta • Amniotic fluid • Umbilical cord

  48. Factors Influencing Prenatal Development: • Maternal factors • Prescription and Nonprescription Drugs • Medical drugs [Thalidomide/DES/Aspirin] • Caffeine • Cocaine, heroin, or methadone • Tobacco/Nicotine • Alcohol • Other Maternal factors • Maternal Diseases • Exercise & Physical activity • Mother’s Diet/Nutrition • Emotional Stress • Rh Incompartibility • Maternal age (Too young/too old) • Mother’s Physical condition (size: too fat/ thin) • Mother’s Emotion • Mother’s Pregnancy history (Frequent pregnancy/miscarriage/abortion)

  49. Factors Influencing Prenatal Development: • Paternal factors • Environmentally caused defects • Cocaine use • Age (Too Young/Too Old) • Smoking • Environmental Influences (Teratogens - capable of causing birth defects) • Teratogenic • Radiation • Environmental Polution

  50. Prenatal care • Why is prenatal care important? • How can it be improved? • What is the relationship between prenatal care and low birthweight and premature births? • How can we tell whether a new baby is healthy and is developing normally? • What complications of childbirth can endanger newborn babies, and what can be done to increase the chances of a positive outcome?

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