How neurons send and receive signals

resting membrane potential

-70mV

ions

-chemical changes cause electrical changes -chemicals in the body are electrically charged

the neuron at rest

-ions move in and out through ion-specific channels -K+ and Cl- pass readily -little movement of Na+ -proteins don't move at all, trapped inside -Na+ is driven by both electrostatic forces and its concentration gradient -K+ is driven in by electrostatic forces and out by its concentration gradient -Cl- is at equilibrium

factors contributing to even distribution of ions (charged particles)

-random motion -electrostatic pressure

factors contributing to uneven distribution of ions

-selective permeability to certain ions -sodium-potassium pumps works constantly to ensure negative charge

dendrites

Branchlike parts of a neuron that are specialized to receive information.

ions contributing to resting potential

Sodium (Na+), Chloride (Cl-), Potassium (K+), and negatively charged proteins (A-)

velocity of axonal conduction

The maximum velocity of conduction in human motor neurons is about 60 meters per second.

integration

adding or combining a number of individual signals into one overall signal

terminal buttons

buttonlike endings of axon branches, release chemicals into synapses

excitatory postsynaptic potentials (EPSPs)

depolarizing

Recording the membrane potential:

difference in electrical charge between the inside and outside of the cell -inside the neuron is negative with respect to the outside -membrane is polarized (carries a charge)

relative refractory period

harder to initiate another action potential

inhibitory postsynaptic potential (IPSP)

hyperpolarizing

absolute refractory period

impossible to initiate another action potential

spatial summation

integration of events happening at different places

temporal summation

integration of events happening at different times

electrostatic pressure

like repels like, opposites attract

depolarization

making the membrane potential less negative

hyperpolarization

making the membrane potential more negative

Generation and Conduction of Postsynaptic Potentials (PSPs)

neurotransmitters bind at postsynaptic receptors, these chemical messengers bind and cause electrical changes

random motion

particles tend to move down their concentration gradient

refractory periods

prevent the backwards movement of APs and limit the rate of firing

axon hillock

the cone-shaped region at the junction between the axon and the cell body

myelin sheath

the fatty insulation around many axons

synapses

the gaps between neurons, across which chemical messages are sent

nodes of ranvier

the gaps between sections of myelin

axon

the long, narrow process that projects from the cell body

cell body

the metabolic center of the neuron; also called the soma

equilibrium potential

the potential at which there is no net movement of an ion - the electrical potential difference that exactly counterbalances diffusion due to concentration differences

cell membrane

the semipermeable membrane enclosing the neuron

decremental graded potential

they become less impactful

conduction of APS

when the threshold is reached, voltage-activated ion channels are opened - all or none - when threshold is reached the neuron "fires" and the action potential either occurs or it does not