chapter 3 prenatal development

a single sperm cell from the male unites with a ovum (egg)

conception

266-280

prenatal development lasts for _____ days

period of development that takes place the first two weeks after conception
Rapid cell division by the zygote

germinal period

group of cells after about 1 week

blastocyst

outer layer of cells that later provides nutrition and support for the embryo

trophoblast

attachment of the zygote to the uterine wall; occurs 10 to 14 days after conception

implantation

development from 2 to 8 weeks after conception
Begins when blastocyst attaches to uterine wall
Mass of cells is now called an embryo

embroyonic period

endoderm, mesoderm, and ectoderm

three layers of cell

a bag that contains a clear fluid (amniotic fluid) in which the embryo floats

amnion

connects the baby to the placenta

umbilical cord

group of tissues containing mother and baby's intertwined blood vessels

placenta

development from two months after conception to birth
Rapid growth and change

fetal period

the age at which a fetus has a chance of surviving outside the womb
Currently 24 weeks; changes with advances in medical technology

viability

100 billion

babies have ____ nuerons at birth

develops 18 to 24 days after conception

nuetral tube

the generation of new neurons
Begins at fifth prenatal week and continues throughout prenatal period

Neurogenesis

cells move outward from their point of origin to their appropriate locations
Occurs approximately 6 to 24 weeks after conception

Neuronal migration

any agent that can cause a birth defect or negatively alter cognitive and behavioral outcomes

teratogen

Drugs (prescription, nonprescription)
Incompatible blood types
Environmental pollutants
Infectious diseases
Nutritional deficiencies
Maternal stress
Advanced age of parent

examples of teratogen

Dose
Genetic susceptibility
Time of exposure

Severity of damage to the unborn depends on:

fixed time period during which certain experiences or events can have a long-lasting effect on development

Critical period

antibiotics, some antidepressants, some hormones, and Accutane

Known prescription teratogens

aspirin and diet pills

Non-prescription teratogens

drugs that act on the nervous system to alter states of consciousness, modify perceptions, and change moods
Includes caffeine, alcohol, nicotine

Psychoactive Drugs:

abnormalities in newborn due to mother's heavy use of alcohol in pregnancy
Facial deformities
Defective limbs, face, heart
Most have below-average intelligence; some are mentally retarded

Fetal alcohol syndrome

Preterm births and low birth weight
Fetal and neonatal death
Respiratory problems
SIDS (sudden infant death syndrome)
ADHD (attention deficit hyperactivity disorder)

Nicotine

Cocaine
Methamphetamine
Marijuana
Heroin

Illegal drugs that harm during pregnancy:

Can cause mother's immune system to produce antibodies that will attack the fetus

Incompatible blood types (Rh factor)

Radiation
Environmental pollutants and toxic wastes

enviromental hazards

Sexually transmitted diseases (syphilis, genital herpes, AIDS)
Rubella
Diabetes

Maternal Diseases

Maternal diet and nutrition
Maternal age
Emotional states and stress

maternal factors

Exposure to teratogens
Paternal age

paternal factors

Screening for manageable conditions and treatable diseases
Medical care
Educational, social, and nutritional services

Prenatal care typically includes

uterine contractions begin at 15 to 20 minutes apart and last up to 1 minute, becoming closer and more intense with time
Causes the cervix to stretch and open to about 10 cm
This stage lasts an average of 12 to 14 hours

stage 1

baby's head begins to move through dilated cervix opening and eventually emerges from the mother's body
This stage lasts approximately 45 minutes

stage 2

umbilical cord, placenta, and other membranes are detached and expelled (afterbirth)

stage 3

Typically spend more time than doctors counseling and educating patients
Provide more emotional support
Are typically present during the entire labor and delivery process

midwives

provide continuous physical, emotional, and educational support for mother before, during, and after childbirth

doula

pain relief

Analgesia

blocks sensation in an area of the body (can also block consciousness)
Epidural block

Anesthesia

synthetic hormones used to stimulate contractions

oxytoctics

aims to reduce pain by decreasing fear and using breathing/relaxation techniques

natural childbirth

special breathing techniques; education about anatomy and physiology
Basic belief is that, when information and support are provided, women know how to give birth

Prepared childbirth (Lamaze):

(next notecard)

other natural techniques

giving birth in a tub of warm water

waterbirth

...

massage

insertion of very fine needles into specific locations in the body

acupunture

the induction of a psychological state of altered attention and awareness

hypnosis

utilizes music to reduce stress and manage pain

music therapy

the baby is removed from the mother's uterus through an incision made in the abdomen

Cesarean Delivery

Often used if baby is in breech position or other complications arise
Cesareans involve a higher infection rate, longer hospital stays, and a longer recovery time
Rate of cesarean births has increased dramatically in recent years
Better identification of

facts about cesarean

a condition in which the fetus has an insufficient supply of oxygen
Baby secretes adrenaline and noradrenalin, hormones that are secreted in stressful circumstances

birth is stressful for baby, anoxia

assessed at 1 minute and 5 minutes after birth
evaluates heart rate, body color, muscle tone, respiratory effort, and reflex irritability
10 is highest, 3 or below indicates an emergency

Measuring neonatal health and responsiveness:
Apgar Scale

...

Measuring neonatal health and responsiveness:

Typically performed within 24-36 hours after birth
Assesses newborn's neurological development, reflexes, and reactions to people and objects
Low scores can indicate brain damage or other difficulties

Brazelton Neonatal Behavioral Assessment Scale (NBAS):

Provides a more comprehensive analysis of newborn's behavior, neurological and stress responses, and regulatory capacities
Assesses the "at-risk" infant

Neonatal Intensive Care Unit Network Neurobehavioral Scale (NNNS):

infants weigh less than 5 � lbs. at birth

low birth weight infants

are those born three weeks or more before full term

preterm infants

are those whose birth weight is below normal when the length of the pregnancy is considered

small for date infants

Poor health and nutrition
Cigarette smoking
Adolescent births
Use of drugs
Multiple births/reproductive technology
Improved technology and prenatal care

causes of low birth weight

Language development delays
Lower IQ scores
Brain injury
Lung or liver diseases
More behavioral problems
Learning disabilities
ADHD
Breathing problems (asthma)

consequences of low birth weight

Early speech therapy
Intensive enrichment programs
Kangaroo care, massage therapy, and breast feeding

effects can be treated by

lasts about six weeks or until the mother's body has completed its adjustment and has returned to a nearly pre-pregnant state

Postpartum period

Fatigue
Hormone changes
Return to menstruation
Involution: process by which the uterus returns to its pre-pregnant size 5-6 weeks after birth
Weight loss/return to exercise

Physical Adjustments:

Excessive sadness, anxiety, and despair that lasts for two weeks or longer
Experienced by 10% of new mothers
Hormonal changes after birth may play a role
May affect mother-child interactions

postpardum depression

Many fathers feel that the baby gets all of the mother's attention
Parents should set aside time to be together
Father's reaction is improved if he has taken childbirth classes and is an active participant in the baby's care

fathers adjustments

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

Bonding

endoderm

inner layer of cells, develop into digestive and respitory systems

mesoderm

middle layer of cells, will become the circulatory system, bones, muscles, excreatory system, and reproductive system

ectoderm

outer layer of cells, will become nervous system and brain, sensory recptors, and skin parts

organogenesis

organ formation in first two months of development