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Chapter 24: Development and Birth

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Presentation on theme: "Chapter 24: Development and Birth"— Presentation transcript:

1 Chapter 24: Development and Birth

2 Overview

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.

4 Key Terms abortion fetus obstetrics amniotic sac gestation oxytocin
chorion human chorionic parturition colostrum gonadotropin (hCG) placenta embryo implantation umbilical cord fertilization lactation zygote

5 Pregnancy Gestation begins with fertilization and ends with delivery
Approximately 38 weeks All fetal tissues differentiate from single fertilized egg

6 Fertilization and the Start of Pregnancy
Vagina receives semen Sperm dissolve egg cell coating, penetrate plasma membrane Sperm, egg combine in single cell (zygote) Zygote divides into cell cluster, moves to uterus Cluster becomes embryo

7 Figure 24-1 The female reproductive system.
Where is the ovum fertilized?

8 The Placenta Organ of nutrition, respiration, excretion for developing offspring Embryonic 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 fetus Fetus has special circulatory features

10 Fetal Circulation Circulatory adaptations to bypass nonfunctional lungs Umbilical vein from mother carries blood to liver Most blood added to deoxygenated blood in inferior vena cava via ductus venosus Foramen ovale in atrial septum bypasses right ventricle and pulmonary circuit Ductus arteriosus connects pulmonary artery to descending aorta Two umbilical arteries return blood to placenta for oxygenation Adaptations 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 the purple color in this illustration? 11

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13 Pregnancy Checkpoints 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) Progesterone Estrogen Human placental lactogen (hPL, Relaxin)

15 15

16 Development of the Embryo
Embryology is study of growth during first 8 weeks of life Nervous system begins to form Heart and blood vessels originate Limb buds form Human appearance

17 Development of the Fetus
Offspring from month 3 until birth Organs grow and mature Ovaries form Most rapid growth months four to six (second trimester) Can determine sex Amniotic sac Vernix caseosa

18 Figure 24-3 Development of an embryo and early fetus.

19 Figure 24-4 Human embryos at different stages and early fetus.

20 Metabolic Changes in the Mother
Heart pumps more blood Lungs increase respiration Kidneys excrete waste from fetus and mother Digestive system supplies additional nutrients Nausea and vomiting common Urinary frequency and constipation common

21 Figure 24-5 Midsagittal section of a pregnant uterus with intact fetus.
What structure connects the fetus to the placenta? 21

22 The Use of Ultrasound in Obstetrics
Safe, painless, noninvasive method used to Diagnose pregnancy Judge fetal age Determine location of placenta Show presence of excess amniotic fluid and fetal abnormalities

23 Figure 24-6 Sonography. 23

24 Figure 24-7 Comparison of positive and negative feedback.
What possible forces can stop a positive feedback system? 24

25 Pregnancy Checkpoints 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

26 Childbirth

27 Childbirth Factors That Start Labor
Uterine muscle stretching stimulates prostaglandin production Pressure on cervix stimulates posterior pituitary to release oxytocin Placenta changes Fetal cortisol inhibits mother’s progesterone Increase of estrogen relative to progesterone

28 The Four Stages of Labor
Uterine contractions Delivery of baby Expulsion of afterbirth Contraction of the uterus

29 Figure 24-8 Stages of labor.

30 Cesarean Section Incision made in abdominal wall and uterine wall for fetal delivery May be required for Placental abnormality Abnormal fetal position Disproportion between head of fetus and mother’s pelvis

31 Multiple Births Two Types of Twins Fraternal Two different ova
Two placentas and surrounding sacs Identical Single ovum Embryonic cells separate into two units Usually single placenta Separate umbilical cords Always same sex

32 Pregnancy Outcomes Live birth Immature (premature) infant
Loss of fetus Abortion Fetal death Stillbirth

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34 Childbirth Checkpoints 24-8 What is parturition? 24-9 What is a cesarean section? 34

35 The Mammary Glands and Lactation
Learning Outcomes 5. 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 Glands Lobes Lactiferous ducts Function of the Mammary Glands Milk secretion Colostrum; first mammary secretion

37 Figure 24-9 Section of the breast (mammary gland).
What muscle underlies the breast? 37

38 The Mammary Glands and Lactation
Hormones of Lactation Human placental lactogen (hpl) Prolactin Oxytocin Benefits of Breastfeeding Reduces infections Transfers antibodies Provides optimal nutrition Provides emotional satisfaction

39 The Mammary Glands and Lactation
The Mammary Glands and Lactation Checkpoint What is lactation? 39

40 Disorders of Pregnancy, Childbirth, and Lactation
Learning Outcome 7. Describe several disorders associated with pregnancy, childbirth, and lactation.

41 Pregnancy-Related Disorders
Ectopic pregnancy Placental disorders Placenta previa Abruptio placentae Hydatidiform mole Choriocarcinoma Gestational diabetes Pregnancy-induced hypertension Preeclampsia Eclampsia

42 Figure 24-10 Ectopic pregnancy.

43 Figure 24-11 Placental abnormalities.

44 Postpartum Disorders Puerperal infection Postpartum depression

45 Lactation Disturbances
Malnutrition Emotional disturbances Mammary gland abnormalities Mastitis

46 Disorders of Pregnancy, Childbirth, and Lactation
Disorders of Pregnancy, Childbirth, and Lactation Checkpoints 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 begin Stage 2: Cervix is fully dilated, contractions severe, baby is delivered Stage 3: Delivery of placenta Stage 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 birth 49

50 Word Anatomy Word Part Meaning Example zyg/o joined
An ovum and spermatozoon join to form a zygote. chori/o membrane, chorion Human chorionic gonadotropin is produced by the chorion (outermost cells) of the embryo. ox/y sharp, acute Oxytocin is a hormone that stimulates labor. toc/o labor See preceding example. ect/o outside, external An ectopic pregnancy occurs outside of the uterine cavity.

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