FSHD 3231/30-2/4/13Pre-Natal Development and BirthEpigenesist (above our genes)- development resulting from the ongoing bidirectional exchanges between hereditary genes and all levels of the environment (when some are silenced and others are activated different chemical signals)IF, THEN If Genes if enviorment, then outcomeThree stages of prenatal developmentGerminal- conception -2 weeks early cell division and differ23I. Why Study Pre-Natal Development?- to understand development, we must start at the beginning- developments during the stage of life carry implications across the life spanII. Three Stages of Pre-Natal DevelopmentA. Germinal (or 1 Zygote) Stage: (conception – two weeks)1. Major Developmentsa. cell division begins within 15 hours after fertilizationb. implantation (cell implants to mother uterus) occurs 5-9 days after fertilizationc. New structures formi.2 blastocyst- hollow, fluid-filled ball of cells that contains an inner [and outer cell mass] the embryonic disk which will eventually form the body ii. trophoblast – thin outer ring of cells that provides protection and nourishment (later forming the placenta and chorion)iii. inner cell mass – solid clump of cells in the blastocyst that later forms the embryoiv. trophoblast multiplies fast to form amnion= outer membrane that encloses the developing organism in amniotic fluid – regulates temperature and protects from maternal movement amniotic sacd. near end of 2 weeks: placenta (exchanges food, oxygen and waste) developsi. trophoblast forms chorion - protective layer that surroundsamnionii. villi – tiny hairlike blood vessels form from the chorion to form the placentaFSHD 3231/30-2/4/13iii. umbilical cord connects the placenta to the zygote– 1 large vein with blood from mother containing nutrients 2 arteries to remove waste products – eventually reaches 1-3 feetYoutube.cm miracle of life part 4UTERUS is 5 days after fertilizationB. Embryo (2-8 weeks)1. Important Characteristicsa. Most of the major body systems and structures developb. Period of rapid growth and cell differentiationc. Embryo increases in size approximately 2 million percent duringthis stage, and by the end it is roughly 1 inch long and weighs 1/30 of an ounce .kidney bean sized. Most vulnerable to teratogens .toxins – e. Frequent spontaneous abortionsf. Possibly as many as 30%2. Major Developmentsa. embryonic disc differentiates into 3 layers of cells1. ectoderm – hair, nails, teeth, outer layer of skin and nervoussystem will develop2. mesoderm – muscles, skeleton, circulatory system, excretory system, inner layer of skin will develop3. endoderm – gastrointestinal tract, glands, liver, pancreas, lungsb. nervous system develops rapidly with the closing of the neural tube (or fold) c. spinal cord, brain develops at top, neurons are produces rapidly .spins bifida when doesn’t closed. face and features, fingers, toes e. first heartbeatsyoutube.com miracle of life part 5 C. Fetus (2 months – birth)1. Primary Characteristicsa. Rapid growth and finishing2. Major Developmentsa. temporary:a. vernix (protects skin,b. lanugo – downy hair that helps vernix stickb. considerable central nervous system growth – connections and brain weight (glials=connections) c. external genitalia form (sex is evident)d. structures and systems become connected to each other (ex: HR, motor activity)e. development of individual patterns of activity –FSHD 3231/30-2/4/13f. related to temperamentg. activity in last week predicts activity in infancyh. by the end of 6 months, the fetus reacts to external stimulii. .learn tone and rhythm of mother’s voiceg. in the final weeks fetal sleep states similar to infant sleep states h. in the final month the fetus “breathes” amniotic fluid about 50% of the timej. usually flip so head first.youtube chapter 7 feeding the growing fetus*five months baby could hear III. Labor & Delivery: 3 StagesA. Stage 1usually the longest process1. Early Labor - Dilation and effacement of the Cervix - uterine contractions begin to open the cervix .to have baby come out2. Active Labora. stronger, more painful contractionsb. 3-8 hours3. Transition – 4-10 cm dilationa. rapid contractionsb. water breaks- amniotic sacc. 15 min – 3 hrsB. Stage 2: Birth it selfa. baby enters and exits the birth canalb. usually in less than an hourC. Stage 3: Expulsion of the placenta (“afterbirth”)a. usually takes 5-10 minutesIV. Neonatal HealthA. Birth Complications1. fewer than 10% of births 2. anoxia – lack of oxygen - is the most common complicationB. APGAR evaluation of all newborns @ .1 and 5 minutesImportant read and assessment of childa. heart rate, respiratory effort, muscle tone, reflex irritability, colorb. each dimension rated on 2-point scaleScore Condition0-3 Immediate medical attentio4-6 Close watch may require help7-10 BestFSHD 3231/30-2/4/13V. Fathers’ ExperiencesA. Couvade – sympathetic pregnancy in which a man experiences a variety of psychosomatic symptoms associated with pregnancy and childbirth while his partner is pregnantB. men also experience rises in estrogen and decreases in testosteroneC. Holding the newborn creates a rise in oxytocin (“the bonding hormone”) among new mothers and fathersD. Men have mixed experiences during labor and deliveryE. To note sometimes it is a good thing to be in the room and others it canbe negativeVI. Pre-Maturity and Low-Birth Weight A. Definitions - Birth weight is the best available predictor of infant survivaland healthy development. 1. low-birth weight baby (LBW) – full-term less than 5.5 poundsa. very low birth weight – less than 3.3 pounds2. Prematurity - birth before 37 weeksb. weight may still be appropriate, based on time spent in the uterus.**know there’s difference o preterm and low weight**3. Small-for-date infant - below their expected weight considering the length of the pregnancya. may be either full-term babies or preterm babies or preterm babies who are undersizedc. most at risk acros developmentd. these children have something more fundamentally wrongB. Risk Factors1. socioeconomic (poverty) factors - Other risks- Prenatal medical care2. medical factors pre-dating the pregnancy3. medical conditions associated with the pregnancy4. multiple births5.teratogen exposure toxins that are dangerous and interfere with the developing fetusC. Challenges of caring for a preterm infant1. often long hospital