Chapter 10 Neural Development and Neuroplasticity Flashcards
human genome
46 chromosomes (23 from each parent) - 23 chromosomes of the haploid human genome contains approximately 3 billion nucleotide base pairs
transcribed >85%
translated
transcription factors
proteins involved in the process of converting, or transcribing, DNA into RNA
stem cells
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
cell differentiation
stem cells differentiate and become different types of cells
neural progenitor cells
differentiated from embryonic stem cells in the developing nervous system; are on track to become various types of neurons or glia
neural tube
structure formed by a group of cells folding within three weeks of conception
growth cone
progresses via the extension of fingerlike structures called filopodia - propelled by actions of the internal cytoskeletal structure of the cell
cytoskeleton
cytoskeletal microtubules and microfilaments orchestrate the insertion and removal of membrane proteins such as ion channels, transporters, and neurotransmitter receptors
microtubule
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
microfilament
long polymers of action proteins
actin
globular multi-functional protein that forms microfilaments
tubulin
polymerize into microtubules
Roger Sperry (1913-1994)
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
chemoaffinity hypothesis
forumlated by Roger Sperry; proposes that nerve cells use specific chemical signals to guide their wring during development and during neural regeneration
neurotrophins
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)
guidance factors
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)
pruning
a process in which synapses that are not used are eliminated
neuroplasticity
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)
embryonic and adult neurogenesis
neurogenesis occurs in limited but measurable ways in the adult vertebrate brain (particularly with the hippocampus)
neurogenesis
growth and development of neural tissue
hippocampus
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
