a rapid electrical signal that travels along the axon of a neuron

- always the same strength

electrically charged molecules

anions - negatively charged

cations - positively charged

-50 to -80 mV

inside of a cell has a negative polarity

two layers of lipid molecules with their tails facing inside that create the cell membrane

only allow certain non-polar things in (tails hydrophobic - charged particles and water not allowed to pass)

proteins that span the membrane and allow ions to pass

channels that open and close in response to voltage changes, chemicals, or mechanical action

opened by certain molecules (voltage-gated, ligand-gated) and only let certain things in (K+, Na+)

moves three Na+ ions out of the cell and two K+ ions in against their concentration gradients to maintain the negative resting potential

- uses energy

predicts the voltage needed to counterbalance the diffusion force pushing an ion across a membrane

predicts the resting membrane potential for that ion

the part of the neuron where action potentials originate from

the beginning of the axon

an increase in membrane potential

- the interior of the membrane becomes even more negative

a decrease in membrane potential

- the interior of the cell becomes less negative

responses that travel down the dendrites

- response size varies with intensity of stimulus 

when a neuron reaches this, it triggers an action potential

-40 mV

causes the cell's ability to fire another action potential to be decreased; at the end of an action potential

the speed of propagation of action potentials

varies with diameter and thickness of myelin sheath

the action potential can jump directly to the postsynaptic region without being transformed into a chemical signal in these regions

- ions flow directly through large channels into adjacent cells, no time delay

a graded potential that produces a small hyperpolarization, pushing the cell further away from threshold

- result from Cl- ions entering the cell

the summing of potentials that come from different parts of the cell

- receiving action potentials from multiple neighboring cells

the summing of potentials that arrive at the axon hillock at different times

- receiving multiple action potential signals from a neighboring cell

the creation of new vesicles after intense activity

- repackage of neurotransmitters

1. phagocytosis in the synapse

2. brought back to the transporter and destroyed

3. brought back to the transporter and put back into vesicles (pinocytosis)

fits in a specific receptor but does not activate it

- blocks neurotransmitters from binding to receptor and causing a reaction

Ex: Curare and Bungarotoxin (from poison darts) block cholinergic receptors and keep ACh from opening those channels

substances that can bind to a receptor and cause a reaction

Ex: nicotine and muscarine can bind to cholinergic receptors and cause the same effects as ACh

the rapid breakdown and inactivation of transmitter by an enzyme

Ex: acetylcholineesterase (AChE) breaks down ACh

a simple series of neurons

Ex: reflexes