3 Pregnancy Learning Outcomes 1. Describe fertilization and the early development of the fertilized egg.2. Describe the structure and function of the placenta.3. Describe how fetal circulation differs from adult circulation.4. Briefly describe changes that occur in the embryo, fetus, and mother during pregnancy.
5 Pregnancy Gestation begins with fertilization and ends with delivery Approximately 38 weeksAll fetal tissues differentiate from single fertilized egg
6 Fertilization and the Start of Pregnancy Vagina receives semenSperm dissolve egg cell coating, penetrate plasma membraneSperm, egg combine in single cell (zygote)Zygote divides into cell cluster, moves to uterusCluster becomes embryo
7 Figure 24-1 The female reproductive system. Where is the ovum fertilized?
8 The PlacentaOrgan of nutrition, respiration, excretion for developing offspringEmbryonic cluster forms villi (projections)Projections invade uterine wall, maternal blood channels (venous sinuses)Embryonic layer and uterine lining form placenta
9 The Umbilical Cord Connects embryo to placenta Carries blood to and from fetusFetus has special circulatory features
10 Fetal CirculationCirculatory adaptations to bypass nonfunctional lungsUmbilical vein from mother carries blood to liverMost blood added to deoxygenated blood in inferior vena cava via ductus venosusForamen ovale in atrial septum bypasses right ventricle and pulmonary circuitDuctus arteriosus connects pulmonary artery to descending aortaTwo umbilical arteries return blood to placenta for oxygenationAdaptations close after birth of baby. Failure to close results in congenital defects.
11 Figure 24-2 Fetal circulation and section of placenta. What is signified by thepurple color in this illustration?11
13 ✓PregnancyCheckpoints 24-1 What structure is formed by the union of an ovum and a spermatozoon? 24-2 What organ nourishes the developing fetus? 24-3 What is the function of the umbilical cord? 24-4 Fetal circulation is adapted to bypass what organs?13
14 Hormones and Pregnancy Human chorionic gonadotropin (hCG)ProgesteroneEstrogenHuman placental lactogen (hPL, Relaxin)
16 Development of the Embryo Embryology is study of growth during first 8 weeks of lifeNervous system begins to formHeart and blood vessels originateLimb buds formHuman appearance
17 Development of the Fetus Offspring from month 3 until birthOrgans grow and matureOvaries formMost rapid growth months four to six (second trimester)Can determine sexAmniotic sacVernix caseosa
18 Figure 24-3 Development of an embryo and early fetus. 18
19 Figure 24-4 Human embryos at different stages and early fetus. 19
20 Metabolic Changes in the Mother Heart pumps more bloodLungs increase respirationKidneys excrete waste from fetus and motherDigestive system supplies additional nutrientsNausea and vomiting commonUrinary frequency and constipation common
21 Figure 24-5 Midsagittal section of a pregnant uterus with intact fetus. What structure connects thefetus to the placenta?21
22 The Use of Ultrasound in Obstetrics Safe, painless, noninvasive method used toDiagnose pregnancyJudge fetal ageDetermine location of placentaShow presence of excess amniotic fluid and fetal abnormalities
24 Figure 24-7 Comparison of positive and negative feedback. What possible forces can stopa positive feedback system?24
25 ✓PregnancyCheckpoints 24-5 At about what time in gestation does the heartbeat first appear? 24-6 What is the name of the fluid-filled sac that holds the fetus? 24-7 What is the approximate duration of pregnancy in days from the time of fertilization?25
30 Cesarean SectionIncision made in abdominal wall and uterine wall for fetal deliveryMay be required forPlacental abnormalityAbnormal fetal positionDisproportion between head of fetus and mother’s pelvis
31 Multiple Births Two Types of Twins Fraternal Two different ova Two placentas and surrounding sacsIdenticalSingle ovumEmbryonic cells separate into two unitsUsually single placentaSeparate umbilical cordsAlways same sex
32 Pregnancy Outcomes Live birth Immature (premature) infant Loss of fetusAbortionFetal deathStillbirth
34 ✓ChildbirthCheckpoints 24-8 What is parturition? 24-9 What is a cesarean section?34
35 The Mammary Glands and Lactation Learning Outcomes5. Name the hormones active in lactation and describe the action of each.6. Cite the advantages of breastfeeding.
36 The Mammary Glands and Lactation Structure of the Mammary GlandsLobesLactiferous ductsFunction of the Mammary GlandsMilk secretionColostrum; first mammary secretion
37 Figure 24-9 Section of the breast (mammary gland). What muscle underliesthe breast?37
38 The Mammary Glands and Lactation Hormones of LactationHuman placental lactogen (hpl)ProlactinOxytocinBenefits of BreastfeedingReduces infectionsTransfers antibodiesProvides optimal nutritionProvides emotional satisfaction
39 The Mammary Glands and Lactation ✓The Mammary Glands and LactationCheckpoint What is lactation?39
40 Disorders of Pregnancy, Childbirth, and Lactation Learning Outcome7. Describe several disorders associated with pregnancy, childbirth, and lactation.
46 Disorders of Pregnancy, Childbirth, and Lactation ✓Disorders of Pregnancy, Childbirth, and LactationCheckpoints What is an ectopic pregnancy? What is puerperal infection?46
47 Case Study Learning Outcome 8. Referring to the case study, describe some of the events that occur during each phase of labor.47
48 Case Study Events That Occur During the Phases of Labor Stage 1: Cervix dilates, contractions beginStage 2: Cervix is fully dilated, contractions severe, baby is deliveredStage 3: Delivery of placentaStage 4: Uterine contractions to return uterus to pre- pregnancy size and shape
49 Word Anatomy Learning Outcome 9. Show how word parts are used to build words related to development and birth49
50 Word Anatomy Word Part Meaning Example zyg/o joined An ovum and spermatozoon join to form a zygote.chori/omembrane, chorionHuman chorionic gonadotropin is produced by the chorion (outermost cells) of the embryo.ox/ysharp, acuteOxytocin is a hormone that stimulates labor.toc/olaborSee preceding example.ect/ooutside, externalAn ectopic pregnancy occurs outside of the uterine cavity.