Class notes
Developmental Psychology notes
- Course
- Institution
The notes I made for my developmental psychology classes in first year. I got a grade 8.
[Show more]
Seller
Follow
brunacfda
Content preview
Problem 1 – Prenatal DevelopmentThe basics of genetics
- Nucleus of each cell in humans contains 46 chromosomes arranged in 23 pairs
- Only cells that do not have 46 are gametes
- Chromosomes made up of DNA
- String of DNA that makes up each chromo can be further divided into genes
- Each gene controls/influences a particular feature of an organism
o A gene controlling a specific characteristic always appears in the same place (locus) on the same
chromosome in every individual
- 2 types of chromosomes: autosomal & sex chromosomes
o 22 autosomal pairs of chromosomes – normal chromos
o 23rd pair = sex chromo – either X or Y
- Normal female has XX normal male has XY
o Sex is determined by which gene is received from sperm bcuz women only have X chromos
- Genotype = characteristics and developmental sequences mapped in the genes of a specific individual
o Can be modified by individual experience into the phenotype
- Phenotype = the expression of a set of genetic info in a specific environment
o The observable joint result of genetic and environmental influences
- If one gene of a pair always exerts its effects = dominant (AA, Aa, aA)
o Dominant genes override the potential influence of the other recessive gene (aa)
o If you inherit a recessive gene for a trait from each parent, you will show the trait
o If you inherit a recessive gene from only one parent, you may never know you carry the gene
- Sex linked genes = genes located on one of the sex chromos
o X-linked inheritance = when a gene is carried on the X chromo
o Males only have 1 X = if they have the gene for an X-linked disease = they have the disease
o Females have 2 X so they would have to have the gene on both chromos to have the disease
Cell division:
- Mitosis: the process by which a single parent cell divides to make 2 new daughter cells
o Each daughter cell receives a complete set of chromos from the parent = genetically identical
o Cell’s nucleus (including chromos) duplicates itself & cell divides
- Meiosis: a type of cell division in sexually reproducing organisms that reduces the number of chromosomes in
gametes
o Cell duplicates its chromos but the divides twice = forms 4 cells
o Each daughter has only half the genetic material of the parent cell = 23 unpaired chromos
Genetic disorders:
- Down syndrome: caused by the presence of an extra copy of chromo 21 because of failure to separate during
meiosis
o Causes physical abnormalities e.g., flattened skull, short limbs & a protruding tongue
o Also causes disabilities involving motor and intellectual development
- Sex-linked chromosomal abnormalities – most common involve and extra X or Y chromo, or absence of one of
the X chromos in females
o Klinefelter syndrome: males have an extra X – making them XXY
▪ Undeveloped testes, enlarged breasts
▪ Impairments in language, academic, attentional and motor abilities
▪ 1/700 male births
o Fragile X syndrome: results from abnormality in the X chromo, which becomes constricted and often
breaks
▪ Prominent ears, long face, high-arched palate & soft skin
▪ Intellectual disability, learning disability or short attention span
▪ More common in males
o Turner syndrome (only females): either an X chromo is missing or part of one X is deleted
, ▪ Short, webbed neck, infertile
▪ Difficulty in math but verbal ability is good
▪ 1/2000 female births
o XYY syndrome: male has an extra Y
o Poly X: triple X- pattern (XXX) – normal in appearance
▪ 1/1000 female births
o Poly Y: triple Y- pattern (YYY)
▪ 1/1000 male births
- Genetic abnormalities
o phenylketonuria (PKU): individual cannot properly metabolize an amino acid
▪ easily detected but, if left untreated, results in intellectual disability and hyperactivity
▪ results from a recessive gene
▪ 1/10,000 – 20,000 births
o sickle-cell anemia: genetic disorder that affects the red blood cells and occurs most often in people of
African descent
▪ recessive gene causes the red blood cell to become a hook-shaped “sickle” that cannot carry
oxygen properly and dies quickly = body’s cells do not receive enough oxygen = anemia and
early death
▪ 1/500 African American children
o Huntington’s disease: dominant disease that causes CNS to deteriorate – causes muscle coordination
problems and mental deterioration
▪ Symptoms typically only appear until 35 or older
▪ 1/18,000-25,000 births
Prenatal development
- Begins with fertilization and ends with birth
- Lasts between 38 to 40 weeks
- Can be divided into 3 periods: germinal, embryonic & fetal
- The germinal period
o Begins at conception and ends when zygote is implanted in the uterus wall (implantation) - first 2 weeks
o Includes creation of fertilized egg (zygote), cell division & attachment of zygote to wall
o Approx. 1 week cell differentiation begins
o Blastocyst develops = a cluster of dividing cells made by a fertilized egg - the early stage of an embryo
o Trophoblast also develops = the outer layer of cells that later provides nutrition and support for the
embryo
o Implantation occurs after about 11-15 days
- The embryonic period
o Begins when implantation is complete – 3 to 8 weeks
o Rate of cell differentiation intensifies, support systems for cells form & organs appear
o 3 layers of cells form:
▪ Endoderm – the inner layer – develops into digestive & respiratory systems
▪ Mesoderm – middle layer – develops into the circulatory system, bones, muscles, excretory
system & reproductive system
▪ Ectoderm – outermost layer – becomes the nervous system, brain, sensory receptors & skin parts
o Life-support systems for the embryo develop rapidly
▪ Amnion – an envelope that contains amniotic fluid in which the embryo floats & provides temp &
humidity controlled env
▪ Umbilical cord – contains 2 arteries & 1 vein – connects embryo to placenta
▪ Placenta – a disk-shaped group of tissues – small blood vessels from the mother & offspring
intertwine but do not join
o Organogenesis = the process of organ formation during first 2 months of prenatal development
▪ While being formed, organs are very vulnerable to env changes
o 3rd week:
▪ neural tube that becomes spinal cord forms
▪ eyes begin to appear
▪ cells for the heart start to differentiate
o 4 week:
th
, ▪ Urogenital system becomes apparent
▪ Arm & leg buds emerge
▪ 4 chambers of the heart take shape
▪ Blood vessels appear
o 5th – 8th week:
▪ Arms & legs differentiate further
▪ Face starts to form & facial structures fuse
▪ Intestinal tract develops
- The fetal period
o Lasts about 7 months – from 2 months after conception to birth
o A lot of growth and development
o 3 months:
▪ Fetus becomes more active – moves arms, legs & head - opens & closes mouth
▪ Most facial features and limbs are distinguishable
▪ Genitals can be identified
o 4 months:
▪ Growth spurt occurs in body’s lower parts
▪ Mother can feel arm and leg movements
o 5 months:
▪ Skin structures (e.g. nails) have formed
▪ Fetus is more active
o 6 months:
▪ Eyes and eyelids are completely formed
▪ Fine layer of hair covers head
▪ Grasping reflex is present
▪ Irregular breathing movements occur
o Last 2 months:
▪ Fatty tissues develop
▪ Function of various organ systems step up
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller brunacfda. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $11.24. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
71498 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now