week2 intro to human dev

Page 1: The Beginning of Development

  • Instructor: Hyunji Kim

  • Overview of developmental stages:

    • Prenatal

    • Infancy and toddlerhood (Birth – 2 years)

    • Early childhood (2-6 years)

    • Middle childhood (6-11 years)

    • Adolescence (11-18 years)

    • Early adulthood (18-40 years)

    • Middle adulthood (40-65 years)

    • Late adulthood (65 years-death)

Page 2: Learning Objectives

  1. Characterize the course of prenatal development.

  2. Describe the symptoms of an expectant mother.

  3. Identify harmful substances during pregnancy.

  4. Summarize where and how birth takes place and describe the postpartum period.

Page 3: The Beginning of Life

  • Gametes: Reproductive cells (sperm and ova).

    • Each gamete consists of 23 chromosomes.

  • Zygote: Formation from the combination of two gametes (sperm and ovum), producing a new individual with 23 chromosomes from each parent.

Page 4: Down Syndrome (Trisomy -21)

  • Caused by an extra chromosome at the 21st site.

  • Occurs in approximately 1:700 births.

  • Characteristic features include:

    • Thick tongue

    • Round face

    • Slanted eyes

Page 5: Germinal Period

  • Lasts for the first 14 days after conception.

  • The zygote begins to duplicate and divide soon after conception.

  • Development of the placenta occurs.

  • Implantation: About 10 days after conception.

Page 6: Developmental Stages

  • Germinal Period: 0-2 weeks

  • Embryonic Period: 3-8 weeks

  • Fetal Period: 9 weeks to birth

Page 7: Embryonic Period (3rd-8th Week)

  • Embryo development includes:

    • Formation of the brain and spine.

    • Shape of the head begins to form.

    • Development of facial features (eyes, ears, nose, mouth).

    • Heart pulsation starts.

    • Development of extremities, including differentiation of webbed fingers and toes.

  • Cephalocaudal Development: Development from head to toe.

  • Proximodistal Development: Development from the center to the periphery.

Page 8: Early Miscarriages

  • Approximately 20 percent of embryos are spontaneously aborted, often termed an early miscarriage.

  • The leading cause is typically chromosomal abnormalities, not indicative of issues with the mother.

Page 9: Fetal Period (Weeks 9-40)

  • Lasts about seven months until birth, referred to as the fetus.

  • Key developments:

    • 16 weeks: Muscle movements begin.

    • 20 weeks: Quickening felt; external genitalia formation.

    • 4th month onward: Significant brain growth, development of reflexes (sucking, swallowing, hiccupping).

    • 7th to 9th months: Maturation of organ systems, preparation for life outside the womb.

    • By the final 12 weeks, fat develops under skin; rapid growth in length and weight.

Page 10: Age of Viability

  • Around week 22, the preterm newborn has the potential to survive outside the mother's uterus with proper medical care.

  • By 22 weeks post-conception, the brain can regulate essential body functions such as breathing.

Page 11: Biological Mothers During Pregnancy

  • This section highlights physical and emotional changes experienced by biological mothers during pregnancy.

Page 12: Trimester Symptoms

  • Couvade Syndrome: Men experience pregnancy-like symptoms while their partner is expecting.

  • Common symptoms include: fatigue, sore breasts, constipation, bloating, headaches, food cravings & aversions, frequent urination, vaginal discharge, feelings of fetal movement, pressure on organs, weight gain, backaches, heartburn, swelling, Braxton Hicks contractions, and anxiety as focus shifts to birth.

Page 13: Teratogens

  • Teratogens: Any agent or condition (viruses, chemicals, drugs) leading to birth defects or potentially death.

  • Critical time for teratogen effects: damage occurs primarily during specific developmental periods.

  • Threshold effect: Teratogens are generally harmless until a specific level of exposure is reached.

  • Example: Fetal Alcohol Syndrome (FAS).

Page 14: Fetal Alcohol Syndrome (FAS)

  • A cluster of abnormalities resulting from excessive alcohol consumption during pregnancy, which can cause:

    • Slowed physical growth.

    • Reduced intellectual abilities.

    • Abnormal facial characteristics.

Page 15: Preterm vs. Small for Gestational Age (SGA)

  • Preterm: Birth occurring two or more weeks early, usually linked to low birth weight (average newborn weight ~7 lbs).

  • Small for Gestational Age (SGA): Significantly lower birth weight relative to gestational age (e.g., 30-week-old fetus weighing only 1,000 grams).

    • Indicates potential impairments throughout prenatal development and serious health issues, influenced by maternal nutrition, drug use, and multiple births.

Page 16: Birth Stages

  • Stage 1: Dilation & Effacement.

  • Stage 2: Birth.

  • Stage 3: Expulsion of the placenta.

Page 17: Home Birth Statistics

  • A chart detailing the percentages of home births categorized by race and Hispanic origin of mothers in the U.S. from 2019-2021, indicating shifts in home birth rates from 2004 to 2009.

Page 18: Delivery Assistants

  • Obstetrician-Gynecologist (OBGYN): A medical doctor specializing in reproductive health and management of pregnancy and childbirth.

  • Certified Nurse Midwife: Healthcare professional trained to provide pregnancy care; they are nurses with specialized education in midwifery.

  • Doula: Trained professional who offers emotional and physical support during pregnancy but does not perform clinical tasks.

Page 19: Cesarean Section (C-Section)

  • Procedure: Baby is delivered through an incision in the mother's abdomen.

  • Advantages: Can be scheduled, safer for certain cases, and allows for rapid delivery.

  • Disadvantages: May complicate breastfeeding and can lead to higher incidence of asthma or obesity due to lack of beneficial microbiome exposure.

Page 20: Postpartum Period

  • Lasts about 6 weeks post childbirth, during which the mother undergoes physical and emotional adjustments:

    • Physical changes: fatigue and hormonal shifts.

    • Emotional changes: Baby blues (transitory mood swings) and postpartum depression (more persistent and severe emotional distress).

Page 21: Postpartum Symptoms

  • Postpartum Blues: Symptoms appear 2-3 days after delivery, usually resolving within 1-2 weeks.

  • Postpartum Depression: Symptoms may last weeks or months, significantly impacting daily functioning. Symptoms vary in prevalence from 0% up to about 70%.