Neurobiology Exam 1

resting membrane potential

constant, negative voltage occurring when a neuron is at rest

receptor potential

graded change in membrane potential due to a sensory stimulus

synaptic potential

graded change in membrane potential due to a synaptic stimulus

action potential

activation of axons due to sensory or synaptic stimulus; frequency of firing reflects strength of stimulus

passive responses

graded changes in polarization that do NOT result in an action potential

passive conduction

signal decays as it travels along the axon

active conduction

signal remains constant as it travels along the axon

active transporters

move ions across the cell membrane against their natural gradient to maintain disequilibrium

ion channels

allow certain ions to move freely across the cell membrane towards equilibrium

resting membrane potential is determined by _____

K+ concentration

resting membrane is nearly impermeable to _____, so its concentration doesn’t really affect resting potential

Na+

electrochemical equilobrium

when electrical force across the membrane exactly balances the concentration gradient, causing ions to stay put

equilibrium potential

voltage at which a specific ion is at electrochemical equilibrium

Nernst equation

used to predict an ion’s equilibrium potential

Goldman’s equation

used to predict an ion’s membrane potential when it is permeable to multiple ions

endoderm

interior germ layer; turns into digestive tract

mesoderm

middle germ layer; turns into skeleton & organs

ectoderm

exterior germ layer; turns into epidermis & nervous system

prosencephalon

forerunner subdivision that becomes the forebrain

mesencephalon

forerunner subdivision that becomes the midbrain; conserved areas include tectum & tegmentum; associated with cerebral aquaduct

rhombencephalon

forerunner subdivision that becomes the hindbrain

telencephalon

major subdivision formed from prosencephalon; conserved areas include olfactory bulb, pallium, & subpallium; associated with lateral ventricles & 3rd ventricle

diencephalon

major subdivision formed from prosencephalon; conserved areas include thalamus & hypothalamus; associated with 3rd ventricle

metencephalon

major subdivision formed from rhombencephalon; conserved areas include isthmus, cerebellum, & pons; associated with anterior 4th ventricle

myelencephalon

major subdivision formed from rhombencephalon; conserved areas include medulla; associated with posterior 4th ventricle

notochord

cylinder of mesodermal cells underneath the neural plate/tube responsible for inductive signals during neural development

neuroectoderm

section of ectoderm on neural plate above the notochord that will turn into the nervous system

neuromeres

segments of neural crest/tube that differentiate into distinct regions, determined by hox genes

endomembrane system

group of organelles (nuclear envelope, endoplasmic reticulum, golgi apparatus, ribosomes) that work together to modify, package, & transport lipids & proteins

glial cells

promote synaptogenesis and maintain neuronal signaling

astrocytes

form blood-brain-barrier on capillaries and maintain ionic environment

radial glia

guides migration of new cells, later differentiate into astrocytes

microglia

macrophages of the nervous system: phagocytic & cytotoxic

oligodendrocytes

form myelin sheaths around multiple axons in CNS & can impede injury recovery

ependymal cells

line the ventricles to produce & circulate CSF

schwann cells

form myelin sheath around single axons in PNS & aid in injury recovery

satellite cells

promotes cell survival in PNS & may maintain neuronal environment

subventricular zone astrocytes

type of glial stem cell that can form more stem cells, neurons, astrocytes, or oligodendrocytes

oligodendrocyte precursor cell

type of glial stem cell that mainly forms oligodendrocytes

Ohm’s law

I=V/R; I= current in amperes (coulombs per second), V= voltage in volts, R= resistance in ohms

V₀

point of stimulus

λ (lambda)

where V₀ decays to 37% of its value

V∞

steady state

T (tau)

time it takes to reach 63% of V∞