Textbook Notes (368,795)
Canada (162,165)
Psychology (2,981)
PSY100H1 (1,831)
Chapter

Ch 5 Txt Notes + Obesity Article.docx

8 Pages
44 Views
Unlock Document

Department
Psychology
Course
PSY100H1
Professor
Michael Inzlicht
Semester
Fall

Description
CHAPTER 5: GENETICS AND THE DEV OF THE HUMAN BRAIN Genetics and Behv Disorders of Brain Dev Neural Tube Defects • Anencephaly: o Rostral neural tube does not develop properly o majority die in utero or do not survive for more than a few hours after birth • Spinal Bifida o Caudal neural tube fails to close normally o Live w/ Surgery within 24 hrs after birth can correct  Nonetheless, most develop lower limb paralysis • Neural tube defects may be caused by folic acid deficiencies o Dark green leafy vegetables, fruits, juices, egg yolks, fortified cereals (nations have done this as a preventative measure) o Avg American diet is insuffifcient o Folic acid fortification  increased risk of colon cancer Genetic Disorders: • Down Syndrome: o Trisomy 21 (3 copies of chromosome 21)  Bc abnormal division/disjunction during meiosis  Related to maternal age o Symptoms: heart deformities, shorter life expectancy, high risk of Alzheimer’s • Fragile-X Syndrome: o FMR-1 gene on the X chromosome normally has 6-50 codon repeats but w/ 200 or more repeats  fragile x o Typical intelligence to moderate retardation o Low-set ears, large forehead and jaw o Males  unusual social withdrawl  Fewer than 5% are actually autistic though • Metabolic disorders: o Body is either unable to produce or overproduces important chemicals o Accounts for 3-7% of severe retardation o Best understood = PKU = phenylketonuria = 1/50 are carriers, but 1/10,000 births o recessive gene for lack of liver enzymes needed to convert amino acid phenylalanine into tyrosine  produce abnormal byproduct = phenylpyruvic acid which damages brain in early dev • can be prevented by avoiding phenylalanine until mid-20s o milk, dairy, meat, fish, chicken, eggs, beans, and nuts Environmental Toxins: • FAS: fetal alcohol syndrome o Mental retardation + growth retardation ( skin folds at corners of eyes, nose and mouth abnormalities, small head circumference, reduced IQ) o More likely to have attention deficits, poor impulse control, severe behv problems o Decreases in grey matter Redev in Response to Damage • Segment of axon that is now separated by the damage area will deteriorate in anterograde (forward) degen • The remaining attached segment regrows sometimes and other times not o Typically, damage very close to cell body  retrograde degen so everything dies • Since all neurons are connected to lots of other ones, when one dies, the others aren’t receiving input from it and so the postsynaptic cells deteriorate by transneuronal degen • Damaged PNS can regrow bc Schwann cells • Oligodendrocytes are not helpful though bc scar tissue inhibits axon regrwoth o Also proteins in growth cones in CNS do not become reactivated but they do in PNS) o CNS damage = generally permanent o But not PNS • Some research in CNS regrowth: o Antibodies to block Nogo = substance that normally prevents further sprouting by mature axons  Nogo inhibitors would promote axon regrowth Adult Nervous System • second wave of gray matter dev + pruning at puberty o cortex thickening peaks at 11 for girls, 12 for boys o followed by gradual thinning  schizo accompanied by 4 times usual thinning o myelination also continues • fully mature by 25 • few changes until about 45 o brain weight decreases o no major cog/behv deficits in healthy yet tho • ppl w/ dementia had watched more TV o compared to those w/ active hobbies + reading • neurons don’t duplicate • but some body cells DO and this is part of aging o at end of each chromosome is a telomere  doesn’t encode any proteins • each tim
More Less

Related notes for PSY100H1

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit