CHAPTER 3: Prenatal Development and Birth

Healthy Height and Weight

-Newborns (USA) I20"long and 7lbs -Most typically they are 18 to 22"long and between 5-10lbs -Grow about 1"per month during the first year -By 2 yearsoInfants weigh approx.26-32lbso -Average 32-35"(height)

Synergistic efforts

-Tobacco and other drugs -Physiological maternal characteristics -Context of drinking: landscape secondary risks -Secondary risks: Getting into a car accident with drunk driving, Not having safe sex, Using your grocery money for drugs

Principles of Prenatal Development

-proximodistal=inner to outer, ex: spinal cord out -cephalocaudal=top to bottom, ex: head first -mass to specific=gross to fine, ex: fingers and toes are last

second trimester (middle 3 months) of Prenatal Development

16 weeks -6 inches long and weighs about 4 to 7 ounces -heartbeat is strong -skin is thin, transparent -downy hair (lanugo) covers body -fingernails and toenails are forming -has coordinated movements, able to roll over in amniotic fluid 20 weeks -12 inches long and weighs about 1 pound -heartbeat is audible with stethoscope -sucks thumb -hiccups -hair, eyelashes, eyebrows are present 24 weeks -14 inches long and weighs 1 to 1 1/2 pounds -skin is wrinkled and covered with protective coating -eyes are open -waste matter is collected in bowel -has strong grip

third trimester (last 3 months) of Prenatal Development

28 weeks -is about 16 inches long and weighs about 3 pounds -is adding body fat -very active -rudimentary breathing movements are present 32 weeks -is 16 1/2 to 18 inches long and weighs 4 to 5 pounds -has periods of sleep and wakefulness -responds to sounds -may assume the birth position -bones of head are sot and flexible -iron is being stored in liver 36 to 38 weeks -is 19 to 20 inches longhand weighs 6 to 7 1/2 pounds -skin is wrinkled -vernix caseosa is thick -lanugo is mostly gone -is less active -gaining immunities from mother

first trimester (first 3 months) of Prenatal Development

Conception to 4 weeks -called a zygote -less than 1/10 inch long -beginning development of spinal cord, nervous system, gastrointestinal system, heart, lungs -amniotic sac envelops the preliminary tissues of entire body 8 weeks -called an embryo -just over 1 inch long -face is forming with rudimentary eyes, ears, mouth, and tooth buds -arms and legs are moving -brain is forming -fetal heartbeat is detectable with ultrasound 12 weeks -called a fetus -is about 3 inches long and weighs about 1 ounce -can move arms, legs, fingers, and toes -fingerprints are present -can smile, frown, suck, and swallow -sex is distinguishable -can urinate

time of exposure

Exposure to teratogens does more damage when it occurs at some points in development than at others. (embryonic period is more vulnerable than the fetal period)

Brain Mapping

Mapping the brain -Forebrain:cerebralcortex and structures beneath it -Brain has two hemispheres, each with four lobes ▪Lateralization ▪Frontal ▪Parietal ▪Occipital -Temporal -Corpus Collisum- attaches both hemispheres

Maternal diseases of Pregnancy:

Maternal diseases and infections can produce defects in offspring by crossing the placental barrier or can cause damage during birth. ex)Syphilis-still birth, eye tensions, skin lesions, congenital syphilis ex)Herpes-brain damage thru birth canal ex)AIDS-destroys immune system, can be transmitted in 3 ways; 1.during gestation across the placenta 2.during delivery through contact wit maternal bloods or fluids 3. postpartum through breast feeding

paternal factors on prenatal development

Men's exposure to lead, radiation, certain pesticides, petrochemicals may cause abnormalities in sperm that can lead to miscarriages. Also a father smoking can also cause problems to offspring, can risk early pregnancy loss

Heroin

Narcotic. Infants whose mothers are addicted to heroin show several behavioral difficulties at birth. ex) withdrawal symptoms, tumors, irritability, disturbed sleep, impaired motor control.

Neurons

Nerve cells that handle information processing at the cellular level of the brain. By the time baby is born it has 20 to 100 billion neurons

umbilical cord

Part of the prenatal life-support system that contains two arteries and one vein that connect the baby to the placenta

Marijuana

Prenatal marijuana exposure was related to lower intelligence, alters brain function in the fetus, still birth

The Germinal Period

The first two weeks of prenatal development after conception, characterized by rapid cell division and the beginning of cell differentiation. It includes the creation of the fertilized egg, called a zygote; cell division; and the attachment of the zygote to the uterine wall 1)single egg cell from ovary is drawn into Fallopian tube at 9-16 days of 28-day menstrual cycle 2)fertilization usually occurs in upper third of tube within 24 hrs after ovulation 3)24-30 hrs after fertilization: Male and female chromosome material unite 4)first egg cell division 5)36 hours: 2 cells 6)48 hours: 4 cells 7)3 days: a small compact ball of 16-32 cells 8)4 days: a hollow ball of 64-128 cells (a blastocyst) 9)4-5 days: inner cell mass formed; blastocyst still free in uterus 10) 6-7 days: blastocyst attaching to wall of uterus 11) 11-15 days: blastocyst invading into uterine wall and becoming implanted in it

Bonding

The formation of a close connection, especially a physical bond, between parents and their newborn in the period shortly after birth.

trophoblast

The outer layer of cells that develops in the germinal period. These cells provide nutrition and support for the embryo.

Environmental Hazards

X-ray radiation can affect developing embryo or fetus, especially in first several weeks after conception. Environmental pollutants and toxic wastes (carbon monoxide, mercury, lead)

postpartum depression

a new mother's feelings of inadequacy and sadness in the days and weeks after giving birth

postpartum period

a period of adjustment for parents and their newborn during the six weeks after birth

Methamphetamine

a powerfully addictive drug that stimulates the central nervous system. Mothers who use meth have a high infant mortality rate, low birth weight, developmental and behavioral problems, less brain development in frontal lobe, and children are likely to develop ADHD

Placenta

a prenatal life-support system that consists of a disk-shaped group of tissues in which small blood vessels from the mother and offspring intertwine

Caffeine

a stimulant drug found in coffee, tea, cola drinks, chocolate, and many over-the-counter medications

neural tube

an embryonic structure that gives rise to the central nervous system from the ectoderm, forms about 18 to 24 days after conception.

Teratogen

any agent that can potentially cause a birth defect or negatively alter cognitive and behavioral outcomes -greatest sensitivity to teratogens is in the organogenesis time period

neuronal migration

approximately 6 to 24 weeks after conception This involves cells moving outward from their point of origin to their appropriate locations and creating different levels, structures, and regions of the brain

psychoactive drugs

drugs that act on the nervous system to alter consciousness, modify perception, and change mood

Blastocyst

group of cells, consists of an inner mass of cells the will eventually develop into the embryo

Alcohol

heavy drinking by woman can be devastating to their offspring. Consumption of alcohol from both men and woman during weeks of conception increase the risks of early pregnancy loss

cell death

in brain development, normal elimination of excess cells to achieve more efficient functioning

Endoderm

inner layer of cells, which will develop into digestive and respiratory systems

Mesoderm

middle layer, which will become the circulatory system, bones, muscles, excretory system and reproductive system

Brain Development

occurs during the prenatal period

Organogenesis

organ formation that takes place during the first two months of prenatal development.(embryonic period) While organs are being formed, the organs are especially vulnerable to environmental changes

Ectoderm

outermost layer, which will become the nervous system and brain, sensory receptors and skin parts

neural connectivity

physical links between areas of the brain that share common developmental trajectories, 23rd prenatal week

Emotional States and Stress

pregnant women with high levels of stress are at increased risk for having a child with emotional or cognitive problems, attention deficit hyperactivity disorder, and language delay. it creates risk of having very low birth weight infant

Differentiation

process in which cells become specialized in structure and function. Takes places approx. one week after conception

Cocaine

quickly crosses the placenta to reach the fetus. Cocaine exposure during prenatal development is associated with reduced birth weight, length, and head circumference, lower arousal, less affective self-regulation, lower quality of reflexes

Nicotine

smoking by woman can also adversely influence prenatal development, birth, and postnatal development. ex) preterm births, low birth weights, fetal and neonatal deaths, respiratory problems, and sudden infant death syndrome (SIDS) , attention deficit hyperactivity disorder, can alternate neurotransmitters in offspring

neurogenesis

the formation of new neurons 5th prenatal week

dose

the greater the dose, the greater the effect on the embryo

fetal alcohol spectrum disorder (FASD)

the harmful effects of maternal alcohol consumption on a developing fetus. Fetal alcohol syndrome (FAS) involves a range of effects, including deficiencies in brain pathways that effect working memory, blow average intelligence, facial abnormalities, defective limbs and heart

amnion

the part of the prenatal life-support system that consists of a bag or envelope that contains a clear fluid in which the developing embryo floats

The Embryonic Period

the period from two to eight weeks after fertilization, during which the major organs and structures of the organism develop

The Fetal Period

the time from about eight weeks after conception until the birth of the child fetal "breathing" and "hearing" moms voice & responding, can see bright light

Genetic Susceptibility

the type or severity of abnormalities caused by a teratogen is linked to the genotype of the pregnant woman and the genotype of the embryo or fetus