Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Slide 1 4 Prenatal Development John W. Santrock © 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 2 Prenatal Development • What Is the Course of Prenatal Development? • What Are Expectant Parents’ Experiences Like During Prenatal Development? • What Are Some Potential Hazards to Prenatal Development? © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Is the Course of Prenatal Development? Slide 3 The Germinal Period • First two weeks after conception – Creation of zygote – Continued cell division – Attachment of zygote to uterine wall – Differentiation of cells has begun © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Is the Course of Prenatal Development? Slide 4 Parts of the Zygote • Blastocyst: inner layer of cells that develops during the germinal period – Later develops into embryo • Trophoblast: outer layer of cells that develops during germinal period – Provides embryo nutrition and support © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Is the Course of Prenatal Development? Slide 5 The Embryonic Period • Two to eight weeks after conception – Rate of cell differentiation intensifies – Support systems for cells form – Organogenesis: organ formation – Embryo has three layers of cells © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Is the Course of Prenatal Development? Slide 6 Parts of the Embryo • Endoderm: inner layer of cells forming digestive and respiratory systems • Ectoderm: outermost layer of cells forming nervous system, sensory receptors, and skin parts © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Is the Course of Prenatal Development? Slide 7 Parts of the Embryo • Mesoderm: middle layer of cells forming circulatory system, bones, muscles, excretory and reproductive systems © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Is the Course of Prenatal Development? Slide 8 Embryo’s Life-Support System • Placenta: intertwines but does not join mother and baby • Umbilical cord: connects baby to placenta • Amnion and amniotic fluid: provides baby’s environment © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Is the Course of Prenatal Development? Slide 9 The Placenta and the Umbilical Cord Uterus Umbilical cord Placenta Fig. 4.1 Umbilical vein Umbilical arteries Fetal portion of placenta Maternal portion of placenta © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Is the Course of Prenatal Development? Slide 10 The Fetal Period • Begins two months after conception; lasts about seven months, until birth • Largest prenatal size and weight gains • Fingers, toes, skin, features, lungs, other structures, and reflexes all develop to prepare for birth © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Is the Course of Prenatal Development? Slide 11 The Fetal Period • The three trimesters are not same as the three prenatal periods • At birth, average baby weighs 7.5 pounds and is about 20 inches long © 2007 The McGraw-Hill Companies, Inc. All rights reserved. Third trimester begins About 16.518 inches long, weighs 4 to 5 pounds 32 weeks About 14-17 inches long, weighs 2.5 to 3 pounds 19 inches long, weighs 6 pounds Less than 1/10th of an inch long About 11-14 inches long, weighs 1 to 1.5 pounds About 10-12 inches long, weighs 1/2 to 1 pound First trimester begins Slide 12 The three trimesters of prenatal development Less than 1 inch long About 5.5 inches long, weighs about 4 ounces About 3 inches long, weighs about 1 ounce Second trimester begins © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Expectant Parents’ Experiences Like During Prenatal Development? Slide 13 Confirming the Pregnancy and Calculating the Due Date • Pregnancy test checks for human chorionic gonadotropin (HCG) • Pregnancy calculated from first day of the woman’s last menstrual period – Lasts about 280 days or 40 weeks • Fetal life begins at ovum fertilization © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Expectant Parents’ Experiences Like During Prenatal Development? Slide 14 Early Signs and Symptoms of Pregnancy Fig. 4.4 © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Expectant Parents’ Experiences Like During Prenatal Development? Slide 15 Three Trimesters and Preparation for Birth First trimester Very tired; nausea and pregnancy sickness; breasts change; emotional changes Second trimester Less fatigue and nausea; uterus expands into abdominal cavity Third trimester Anticipates end; uterus expands to point below breastbone © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Expectant Parents’ Experiences Like During Prenatal Development? Slide 16 Preparation for the Baby’s Birth • Braxton Hicks contractions increase • Cervix becomes softer and thinner • Awkwardness • Fatigue and desire for pregnancy to end • Nesting urge and spurts of energy © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Expectant Parents’ Experiences Like During Prenatal Development? Slide 17 Expectant Mother’s Nutrition and Weight Gain • Nutrition – Need for protein, iron, vitamin D, calcium, phosphorus, magnesium increases 50 percent, water is essential • Weight Gain – 25 to 35 pounds associated with best reproductive outcomes © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Expectant Parents’ Experiences Like During Prenatal Development? Slide 18 Expectant Mother’s Nutrition and Weight Gain • Weight Gain – Maternal obesity adversely impacts pregnancy outcomes; carries risks • Hypertension • Diabetes • Respiratory complications • Infections © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Expectant Parents’ Experiences Like During Prenatal Development? Slide 19 Exercise During Pregnancy • Exercise for shorter time intervals • Decrease intensity as pregnancy progresses • Avoid prolonged overheating • Avoid high-risk activities • Warm up, stretch, cool down • After exercise, lie on left side 10 minutes • Wear supportive shoes and bra • Reduce exercise significantly in the last four weeks © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Expectant Parents’ Experiences Like During Prenatal Development? Slide 20 Culture and Prenatal Care • Prenatal care in the United States and around the world – U.S. does not provide uniform prenatal care – In developing countries: poverty is rampant, health and nutrition of mothers is poor, and percentage of low birthweight reaches 50% © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Expectant Parents’ Experiences Like During Prenatal Development? Slide 21 Cultural Beliefs About Pregnancy and Development • Specific actions in pregnancy often determined by cultural beliefs • Health care providers need to assess if cultural practices pose threat – Home care remedies and folk beliefs – Religious beliefs and healers © 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 22 1990 2001 Percentage of U.S. women using timely prenatal care 100 90 80 70 60 50 40 30 20 10 0 Non-Latino White women African American women Latino women Fig. 4.6 © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Some Potential Hazards to Prenatal Development? Slide 23 Some General Principles • Teratogen – Any agent that causes a birth defect – Only about half of potential effects appear at birth • Severity and type of defect affected by – Dose – Genetic susceptibility – Time of exposure © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Some Potential Hazards to Prenatal Development? Slide 24 Prescription and Nonprescription Drugs •Damage discovered after a cluster of deformed babies is born – Specific antibiotics – Some antidepressants – Certain hormones – Diet pills – Aspirin – Caffeine © 2007 The McGraw-Hill Companies, Inc. All rights reserved. Terogens and Timing of Their Effects on Prenatal Development Slide 25 Zygote 1 2 Embryonic period (wks) Fetal Period (wks) 3 4 5 6 7 8 9 16 32 38 Central nervous system Most Heart serious Arms damage Eyes from teratogens Legs in first 2–8 Ears weeks Teeth Period of susceptibility Palate to structural defects External genitalia Period of susceptibility to functional defects Fig. 4.7 (modified) © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Some Potential Hazards to Prenatal Development? Slide 26 Psychoactive Drugs • Psychoactive drugs – Act on nervous system – Alter states of conscious – Modify perceptions – Change moods © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Some Potential Hazards to Prenatal Development? Slide 27 Psychoactive Drugs • Alcohol – Fetal alcohol syndrome (FAS) • • • • • Nicotine Cocaine Marijuana Methamphetamine Heroin © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Some Potential Hazards to Prenatal Development? Slide 28 Environmental Hazards • Fathers’ exposure to lead and radiation • Certain pesticides • Petrochemicals • Environmental pollutants and toxins • Toxic waste • Manufactured chemicals © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Some Potential Hazards to Prenatal Development? Slide 29 Infectious Diseases • Rubella • Sexually transmitted infections – Syphilis – Genital herpes – AIDS, HIV infection © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Some Potential Hazards to Prenatal Development? Slide 30 Incompatible Blood Types • Between mother and father • Between mother and baby – Blood group (A, B, O, AB) – Rh factor (positive, negative) – Vaccine within 3 days of birth © 2007 The McGraw-Hill Companies, Inc. All rights reserved. What Are Some Potential Hazards to Prenatal Development? Slide 31 Other Parental Factors • Maternal nutrition and low birthweight • Obesity during pregnancy • Maternal age—too young, too old • Paternal age and risks • Emotional states and stress • Maternal hormonal treatments © 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 32 4 The End © 2007 The McGraw-Hill Companies, Inc. All rights reserved.