exam 2- chapter 7

Question 1

Zygote

Answer 1

A fertilized egg cell containing 46 chromosomes (23 from each parent).

Question 2

Blastocyst

Answer 2

Stage after several cell divisions (~32 cells, day 5) that implants in the uterus.

Question 3

Morula

Answer 3

Early solid ball of 16 cells formed by rapid cell divisions (day 4).

Question 4

Three embryonic layers

Answer 4

Ectoderm, Mesoderm, and Endoderm.

Question 5

Ectoderm

Answer 5

Outer layer that forms the skin and nervous system.

Question 6

Mesoderm

Answer 6

Middle layer that forms muscles, bones, and the circulatory system.

Question 7

Endoderm

Answer 7

Inner layer that forms the digestive system and internal organs.

Question 8

Neural groove

Answer 8

Structure that forms between ridges of the ectoderm and becomes the midline of the nervous system.

Question 9

Neural tube

Answer 9

Structure formed from the neural groove that develops into the central nervous system.

Question 10

Neural crest

Answer 10

Cells along the neural tube that form the peripheral nervous system.

Question 11

Embryo to fetus

Answer 11

At 8 weeks the embryo has organs forming

Question 12

Forebrain, midbrain, hindbrain

Answer 12

The three major brain regions that develop from the neural tube.

Question 13

6 stages of neural development

Answer 13

Neurogenesis, Cell Migration, Differentiation, Synaptogenesis, Neuronal Cell Death, and Synapse Rearrangement.

Question 14

Neurogenesis

Answer 14

The birth of new neurons through mitotic division of progenitor cells in the ventricular zone.

Question 15

Cell migration

Answer 15

Movement of newly formed neurons along radial glia to their proper locations.

Question 16

Differentiation

Answer 16

Process where cells become specialized neuron or glial types.

Question 17

Autonomous differentiation

Answer 17

Cell develops independently of other cells based on internal genetic programming.

Question 18

Neural environment differentiation

Answer 18

Cells are influenced by chemical signals from neighboring cells (induction).

Question 19

Induction

Answer 19

Process where one cell group releases factors that direct neighboring cells’ development.

Question 20

Synaptogenesis

Answer 20

Formation of synaptic connections between neurons.

Question 21

Process outgrowth

Answer 21

Development of axons and dendrites during synaptogenesis.

Question 22

Growth cone

Answer 22

The growing tip of an axon or dendrite.

Question 23

Filopodia

Answer 23

Fine extensions from growth cones that sense the environment and guide growth.

Question 24

Chemoattractant

Answer 24

Chemical that attracts specific classes of axonal growth cones.

Question 25

Chemorepellent

Answer 25

Chemical that repels specific axonal growth cones.

Question 26

Apoptosis

Answer 26

Programmed cell death that removes unnecessary neurons during development.

Question 27

Death genes

Answer 27

Genes activated only during apoptosis to help dismantle the cell.

Question 28

Caspases

Answer 28

Proteins that cut up other proteins and DNA during apoptosis.

Question 29

Apoptosis cascade

Answer 29

Ca²⁺ enters cell → mitochondria release Diablo → Diablo binds IAPs → caspases activate → cell death (blocked by Bcl-2).

Question 30

Diablo

Answer 30

Protein released by mitochondria that triggers apoptosis by binding IAPs.

Question 31

Bcl-2

Answer 31

Protein that blocks apoptosis by preventing Diablo release.

Question 32

Neurotrophic factors

Answer 32

Chemicals that promote survival of neurons (e.g., NGF, BDNF).

Question 33

Nerve Growth Factor (NGF)

Answer 33

Neurotrophic factor that keeps target neurons alive.

Question 34

Brain-Derived Neurotrophic Factor (BDNF)

Answer 34

Neurotrophin family member supporting neuron survival and synapse formation.

Question 35

Synapse rearrangement

Answer 35

Process where synapses are refined—some are eliminated, others strengthened.

Question 36

Synaptic pruning

Answer 36

Elimination of weaker synapses to strengthen more active connections.

Question 37

Prefrontal cortex maturation

Answer 37

Last brain region to fully mature, associated with planning and judgment.

Question 38

Environmental developmental disorders

Answer 38

Problems like hypoxia, maternal malnutrition, or drug exposure causing intellectual disability.

Question 39

Fetal Alcohol Syndrome (FAS)

Answer 39

Disorder caused by prenatal alcohol exposure leading to brain damage and behavioral issues.

Question 40

Genetic developmental disorders

Answer 40

Disorders caused by mutations, e.g., Fragile X Syndrome.

Question 41

Fragile X Syndrome

Answer 41

Genetic disorder with intellectual disability caused by excessive repeats in FMR1 gene on X chromosome.

Question 42

Visual deprivation

Answer 42

Reduced visual input during early life disrupts normal visual cortex development.

Question 43

Amblyopia

Answer 43

Impaired vision in one eye due to misalignment or deprivation during the sensitive period.

Question 44

Sensitive period

Answer 44

Specific window in development when experience strongly shapes neural circuits.

Question 45

Monocular deprivation

Answer 45

Blocking vision in one eye during development reduces cortical response permanently.

Question 46

Binocular deprivation

Answer 46

Blocking both eyes causes widespread synapse loss and reduced cortical development.

Question 47

Hebbian synapse

Answer 47

Synapses that strengthen when presynaptic and postsynaptic cells are active together (“cells that fire together, wire together”).

Question 48

Gene expression and experience

Answer 48

Environmental factors can alter which genes are expressed without changing DNA sequence.

Question 49

Epigenetics

Answer 49

Study of heritable changes in gene expression due to chemical modifications like DNA methylation.

Question 50

Methylation

Answer 50

Process that suppresses gene expression by adding methyl groups to DNA.

Question 51

Maternal care and epigenetics

Answer 51

High maternal care reduces stress responses

Question 52

Aging and the brain

Answer 52

Aging causes synaptic loss and shrinkage in brain regions, especially the hippocampus.

Question 53

Memory decline and hippocampus

Answer 53

Reduced hippocampal volume is linked with age-related memory loss.