Chapter 5 Flashcards
Proliferation
Growth and development of neurons step 1: the production of new cells / neurons in the brain primarily occurring early in life
migration
Growth and development of neurons step 2: movement of the newly formed neurons and glia to their eventual locations guided by immunoglobulins and chemokines - some move quickly, some not until adult hood; movement can be radial, tangential or both
differentiation
Growth and development of neurons step 3: the process of axon and dendrite formation; migrating neurons tow axon so tip remains at target or axon grows toward target, dendrites grow at destination
myelination
Growth and development of neurons step 4: glia produce insulating fatty sheaths that excellerate transmission and continue to grow gradually for decades
synaptogenesis
Growth and development of neurons step 5: formation of synapses begin before birth and continue throughout life as neurons form new synapses and discard old synapses
Stem Cells
undifferentiated cells found in the interior of the brain and generate “daughter cells” which can transform into glia or neurons
chemical gradient
growing axons follow a path of cell surface molecules and a chemical gradient (navigate by attraction and repulsion) and connect to cells with same concentration as them
neural darwinism
selection process of neural connections - successful axon connections and combinations survive while the others fail to sustain active synapses
Nerve Growth Factor
a type of neurotrophin released by muscles that promotes the survival and growth of axons
Neurotrophin
a chemical that promotes the survival and activity of neurons (eg NGF)
BDNF
Brain Derived Neurotrophic Factor (a neuroptrophin)
Apoptosis
programmed mechanism of cell death (often as a result of lack of NGF) as compared to necrosis (death by injury/toxic substances)
Fetal Alcohol Syndrome
a condition marked by hyperactivity, implusiveness, difficulty maintaining attention, varying degrees of mental retardation, motor problems, heart defects, and facial abnormalaties (occurs when fetus is exposed to alchohol during pregnancy)
Focal Hand Dystonia
musician’s cramp, a condition in which the reorganization of the brain goes too far, causes musician to become clumsy, fatigue easily and make involuntary movements due to overlapping signals
Antisaccade Task
looking away from a powerful attention-getter
Stroke (Cerebrovasular accident)
is temporary loss of blood flow to the brain; ischemic - resulting from a blood clot or obstruction of an artery, neurons lose their oxygen and glucose supply or hemmorhagic - resulting from a ruptured artery. Neurons are flooded with excess blood, calcium, oxygen, and other chemicals; both types cause edema
Edema
the accumulation of fluid in the brain resulting in increased pressure on the brain and increasing the probability of further strokes
Tissue Plasminogen Activator (tPA)
a drug that breaks up blood clots and can reduce the effects of an ischemic strokes (administered preferably within 3 hrs)
Penumbra
region that surrounds the immediate damage
What methods have researches found to save cells in the penumbra?
blocking glutamate synapses and opening potassium channels; cooling the brain to 34-35 degrees
Diaschisis
decreased activity of surviving neurons after damage to other neurons
Collateral Sprouts
after a cell loses input from an axon it secretes neurotrophins that induce other axons to form new branches and take over vacant synapses (esp in 1st 2 weeks)
Denervation Supersensitivity (Receptor Supersensitivity)
the heightened sensitivity of a neuron to a neurotransmitter after the destruction of an incoming axon (helps compensate for decreased input)
Phantom Limb
continued sensation in an amputated body part
Deafferenated Limb
limbs that have lost their afferent sensory input (sensory neurons can’t communicate with CNS)
