Chapter 10 Neural Development and Neuroplasticity

Question 1

human genome

Answer 1

46 chromosomes (23 from each parent) - 23 chromosomes of the haploid human genome contains approximately 3 billion nucleotide base pairs
transcribed >85%
translated

Question 2

transcription factors

Answer 2

proteins involved in the process of converting, or transcribing, DNA into RNA

Question 3

stem cells

Answer 3

has capacity to continue dividing and to do differentiate into any type of cell in the body; formed after conception, when the fertilized egg begins to divide

Question 4

cell differentiation

Answer 4

stem cells differentiate and become different types of cells

Question 5

neural progenitor cells

Answer 5

differentiated from embryonic stem cells in the developing nervous system; are on track to become various types of neurons or glia

Question 6

neural tube

Answer 6

structure formed by a group of cells folding within three weeks of conception

Question 7

growth cone

Answer 7

progresses via the extension of fingerlike structures called filopodia - propelled by actions of the internal cytoskeletal structure of the cell

Question 8

cytoskeleton

Answer 8

cytoskeletal microtubules and microfilaments orchestrate the insertion and removal of membrane proteins such as ion channels, transporters, and neurotransmitter receptors

Question 9

microtubule

Answer 9

long polymers of alpha-tubulin and beta-tubulin proteins; highly probable that microtubules are involved in aspects of cell function that are at present only dimly appreciated; structure and function have even been invoked in an important hypothesis about the nature of mind and consiousness

Question 10

microfilament

Answer 10

long polymers of action proteins

Question 11

actin

Answer 11

globular multi-functional protein that forms microfilaments

Question 12

tubulin

Answer 12

polymerize into microtubules

Question 13

Roger Sperry (1913-1994)

Answer 13

researched with frogs and salamanders b/c of their ability to regenerate after sustaining physical damage to their bodies; experiment involved cutting the optic nerve in a frog (the connection between the frog’s eye and the frog’s brain)

• frog will be blind until optic nerve regenerates, then normal vision is restored
• cut and rotated eyeball in its socket by 180 degrees resulted in upside down and backward vision when the nerve regenerated

Question 14

chemoaffinity hypothesis

Answer 14

forumlated by Roger Sperry; proposes that nerve cells use specific chemical signals to guide their wring during development and during neural regeneration

Question 15

neurotrophins

Answer 15

the first growth factor to be discovered; simply named “nerve growth factor” NGF
others now known include: BDNF, GDNF, NT3 (all proteins that have been found to somehow promote the growth/survival of neurons)

Question 16

guidance factors

Answer 16

involved in axon and dendrite guidance and other developmental processes; examples: ephrin, netrin, neurophilin, plexin, semaphorin, Slit, Robo; involves direct contact between one protein anchored to one cell and another protein anchored to another - such binding can sometimes cause cell growth in the direction of contact (or away from the direction of contact)

Question 17

pruning

Answer 17

a process in which synapses that are not used are eliminated

Question 18

neuroplasticity

Answer 18

process of strengthening and weakening synapses as a result of molecular processes taking place either presynaptically, postsynaptically, or both; example of presynaptic mechanism to strengthen synapse: prolonging state of depolarization in the axon terminal so that voltage gated Ca++ channels remain open for a longer time; retrograde signals from a postsynaptic cell strengthens synapse; postsynaptic mechanism for changing strength of a synapse: influence gene transcription so that greater/lesser numbers of neurotransmitter receptors are produced and inserted into the postsynaptic membrane (more=stronger, less=weaker)

Question 19

embryonic and adult neurogenesis

Answer 19

neurogenesis occurs in limited but measurable ways in the adult vertebrate brain (particularly with the hippocampus)

Question 20

neurogenesis

Answer 20

growth and development of neural tissue

Question 21

hippocampus

Answer 21

part of the adult vertebrate brain where neurogenesis occurs; about fourteen hundred new neurons are added each day within the two hippocampi of the brain; bilateral structure located beneath the surface of the temporal lobe known to play a pivotal role in the formation and stabilization of memories