AP Psych Unit 2: Neurons

multipolar neuron

neuron with many pathways

bipolar neuron

neuron with two pathways: common sensory neurons

pesudo-unipolar nueron

the combination of uni and bipolar neurons (technically one pathway but it looks like two)

resting membrane potential

the normal charge inside the cyctoplasm (-70mV)

nonpenetrating ions

negative ions that require ion channels

ligand-gated ion channels

chemical binds to the channel and it opens

mechanically-gated ion channels

physical stimulus opens the channel

“leak” channels

ion channels that are always open

voltage-gated channels

ion channels that open/close in response to changes in voltage

sodium-potassium pump

active transport pump that pushes 3Na+ out of the cell per 2 K+ being let in, which keeps the inside of the cell more negative than the outside

nernst potential

voltage where the electrical force is equal to the diffusion force, meaning no ions travel in and out of the cell (different for each ion in each environment) (the ions will do everything in their power to strive for this)

graded potential

only a few ion channels open up but the cell never reaches the excitation threshold

action potential

the excitation threshold is reached and all the Na+ channels open up

excitation threshold

-50 mV; minimum voltage a cell needs to reach before an action potential occurs

depolarization

the cell becomes more and more positive as Na+ enters

absolute refractory period

30 mv; the sodium channels go inactive as the K+ channels open and those ions start leaving

repolarization

K+ ions are leaving and the cell is become more negative

hyperpolarization

the cell becomes more negative than the resting membrane potential until the K+ channels close again

passive conduction

Na+ goes down the axon

two factors preventing axons from leaking Na+

diameter (thicker+shorter), myelin sheath

continuous conduction

unmylenated axons

saltatory conduction

mylenated axons

oligodendrocytes

add myelin to CNS neurons; many extensions

swhann cells

mylenate PNS neurons; only one extension

white brain matter

mylenated axons make up this part of the brain

excitatory signal

Signal that increases the likelihood of a neuron firing an action potential.

inhibitory signal

Signal that prevents or reduces the activity of a neuron or a specific target. It acts by decreasing the likelihood of an action potential being generated and transmitted.

signal summation

axon hillox adds up all the signals a neuron receivevs from other neurons and decides whether or not to action potential

reuptake

Process where neurotransmitters are taken back up into the presynaptic neuron, reducing their concentration in the synaptic cleft.

reuptake inhibitors

Reuptake inhibitors are drugs that block the reabsorption of neurotransmitters by the sending neuron, increasing their concentration in the synaptic cleft. This enhances neurotransmission and helps regulate mood, cognition, and other brain functions. Examples include SSRIs and SNRIs.

agonist

enhance the effect of a neurotransmitter

antagonist

counteract the effect of a neurotransmitter

spatial summation

many neurons trigger one action potentialt

temporal summation

one neuron triggers an action potential

lipid-based hormones

hydrophobic/lipid-soluable; diffuse across membranes to bind to receptors inside cells

protein-based hormones

hydrophillic/not lipid soluable; can’t diffuse through membrane so attach to cell membrane receptor protein and trigger secondary messanger pathway

HPA axis

hypothalamus releases CRH, pituitary releases ACTH, adrenal releases cortisol