Early Influences on Development - Prenatal Development Flashcards
Prenatal Development
list the 3 periods, 3 trimesters, & timeframes for prenatal development
periods
1) germinal period: conception to end of the 2nd week
2) embryonic period: 3 to 8 weeks
3) fetal period: week 9 through birth
trimesters
1) first trimester: week 1 to week 13
2) second trimester: week 14 to week 27
3) third trimester: week 28 through birth
Prenatal Development
characteristics of the germinal period
- zygote impants in the uterine wall
- exposure to toxic chemicals, drugs, or other teratogens typically have an “all-or-none” effect
- meaning that if exposure causes significant damage, implantation will not occur
- if implantation occurs, it suggests that exposure had little to no effect
Prenatal Development
characteristics of the embryonic period
- major organs & structures are forming
- exposure to teratogens is most likely to cause major defects
Prenatal Development
characteristics of the fetal period
- major organs & structures grow and msture
- exposure to teratogens is most likely to cause minor defects or abnormalities
- an exception is the central nervous system, which is susceptible to major damage from teratogens during both the embryonic & fetal periods
Prenatal Development
____ is the earliest age at which a premature baby can survive outside the womb and occurs between ____ and ____ weeks.
viability; 22 adn 26 weeks
Chromosomal Abnormalities
define & list 3 disorders due to a chromosomal deletion
a change in chromosome structure that involves the loss of one or more segments of a chromosome
- Prader-Willi Syndrome
- Angelman Syndrome
- Cri-Du-Chat Syndrome
Chromosomal Abnormalities
Prader-Willi
1. caused by a deletion on what chromosome
2. symptoms
- paternal chromosome 15
- symptoms include:
* narrow forehead
* almond-shaped eyes
* short statue
* small hands & feet
* poor muscle tone (hypotonia)
* global developmental delays
* chronic overeating (hyperphagia)
* obesity
* hypogonadism
* intellectual disabilities
* skin-picking & other self-injurious behaviors
Chromosomal Abnormalities
Angelman Syndrome
1. due to deletion on what chromosome
2. symtoms
- maternal chromosome 15
- symptoms include:
* small head & brain (microcephaly)
* wide jaw & pointed chin
* severe developmental delays
* communication & intellectual disabilities
* hyperactivity
* tendency to be unhappy
* ataxia
* seizures
* hand-flapping
Chromosomal Abnormalities
Cri-Du-Chat Syndrome
1. due to a deletion of what chromosome
2. symptoms
- chromosome 5
- symptoms range from mild to severe depending on the extent & location of the deletion & include:
* high-pitched (cat-like) cry
* low birth weight
* weak muscle tone
* characteristic facial features - widely set eyes, low-set ears, round face)
Chromosomal Abnormalities
list the 3 chromosomal disorders that are due to sex chromosome abnormalities
- Klinefelter Syndrome
- Turner Syndrome
- Rett Syndrome
Chromosomal Abnormalities
Klinefelter Syndrome
1. due to what chromosomal abnormality
2. effects males or females
3. symptoms
- the presence of 2 or more X chromosomes and a single Y chromosome
- males
- develop normal male identitiy but incomplete secondary sex characteristics and symptoms include:
- breast enlargement (gynecomastia)
- low testosterone
- disproportionately long arms & legs
- taller than normal
- delays in language development
- learning disabilities
- impaired problem-solving & social skills
Chromosomal Abnormalities
Turner Syndrome
1. due to what chromosomal abnormality
2. effects males or females
3. symptoms
- partial or complete deletion of one of the X chromosomes
- females
- don’t develop secondary sex characteristics & are infertile; symptoms include:
* short stature
* stubby fingers
* drooping eyelids
* receding or small lower jaw
* web-like neck
* learning disabilities
* heart defects
* kidney & urinary tract abnormalities
Chromosomal Abnormalities
Rett Syndrome
1. due to what chromosomal abnormality
2. effects males or females
3. symptoms
- X-linked dominant disorder that is usually caused by mutations in the MECP2 gene
- almost exclusively females
- infants appear to develop normally during first 6 to 18 months but then develop characteristic symptoms including:
* slowed head & brain growth
* loss of speech & motor skills
* abnormal hand movements
* sleep disturbances
* breathing abnormalities
* seizures
children with Rett Syndrom may also have autistic-like traits (e.g., deficits in social interactions) during early stages of the disorder
Chromosomal Abnormalities
Down Syndrome is a(n) ____ disorder. List the 3 types.
autosomal
1) Trisomy 21
2) Mosaic trisomy 21
3) Translocation trisomy 21
Chromosomal Abnormalities
The most common type of Down Syndrome is ____, which accounts for about ____% of all cases
trisomy 21; 95%
