chapter 4: development of the brain

Question 1

ectoderm

Answer 1

outer layer of the developing embryo, giving rise to the skin and the nervous system

Question 2

neural tube

Answer 2

embryonic structure with subdivisions that correspond to the future forebrain, midbrain, and hindbrain

Question 3

neurogenesis

Answer 3

production of neurons

Question 4

mitosis

Answer 4

cell division

Question 5

ventricular zone

Answer 5

a region lining the cerebral ventricles from which new neurons and glial cells are born throughout life, via mitosis

Question 6

cell migration

Answer 6

movement of cells from site of origin, out of the ventricular zone, to final location, where they express particular genes

Question 7

gene expression

Answer 7

the way a cell makes an mRNA transcript of a gene. cells begin to use, or express, particular genes

Question 8

cell differentiation

Answer 8

cells become distinctive types of neurons or glial cells through cell-cell interactions

Question 9

synaptogenesis

Answer 9

establishment of synaptic connections as axons and dendrites grow

Question 10

cell-cell interactions

Answer 10

process during development in which one cell affects the differentiation of other cells

Question 11

stem cells

Answer 11

undifferentiated and therefor can take on the fate of any cell that a donor organism can produce

Question 12

cell death (apoptosis)

Answer 12

surplus cells die (needs to happen)

Question 13

neurotrophic factors

Answer 13

target-deprived chemical that induces innervating neurons to survive

Question 14

synapse rearrangement (synaptic remodeling)

Answer 14

loss of synapses and the development of others

Question 15

fragile X syndrome

Answer 15

intellectual disability produced by a fragile site on the X chromosome that seems prone to breaking because the DNA there is unstable

Question 16

amblyopia

Answer 16

reduced visual acuity of one eye that is not caused by optical or retinal impairments

Question 17

binocular deprivation

Answer 17

depriving both eyes of form vision, as by sealing the eyelids

Question 18

monocular deprivation

Answer 18

depriving only one eye of light during the developmental sensitivity period, resulting in structural and functional changes in the thalamus and visual cortexo

Question 19

ocular dominance histogram

Answer 19

portrays the strength response of a brain neuron to stimuli presented to the eyes

Question 20

Hebbian synapse

Answer 20

a synapse that is strengthened when it successfully drives the postsynaptic cell

Question 21

radial glial cells

Answer 21

scaffold for neurons to follow to reach target destination

Question 22

holoprosencephaly

Answer 22

atypical separation of the two hemispheres of the forebrain and can disrupt development of midline facial structures

Question 23

growth cone

Answer 23

specialized structure at the end of a growing axon deciding where to grow

Question 24

lamellipodium

Answer 24

sheet like expansion of the growing axon

Question 25

filopodia

Answer 25

numerous fine processes in the tip of the axon

Question 26

genotype

Answer 26

all genetic information that one specific individual has inherited (intrinsic, since birth)

Question 27

phenotype

Answer 27

anatomical, physiological and behavioral characteristics (extrinsic, changes constantly)

Question 28

phenylketonuria(PKU)

Answer 28

absence of the enzyme necessary to metabolize phenylalanine resulting in a buildup of phenylalanine, which becomes toxic

Question 29

epigenetics

Answer 29

study of factors that affect gene expression without making any changes in the nucleotide sequence of the genes

Question 30

methylation

Answer 30

a chemical modification of DNA that does not affect the nucleotide sequence of a gene but makes that gene less likely to be expressed

Question 31

Alzheimer’s disease

Answer 31

form of dementia that may appear in middle age but is more frequent among the aged

Question 32

dementia

Answer 32

drastic failure of cognitive ability, including memory failure and disorientation

Question 33

amyloid plaques

Answer 33

buildup of beta-amyloid (proteins)

Question 34

neurofibrillary tangles

Answer 34

abnormal whorls of neurofilaments that form a tangled array inside the cell