lecture 4 notes

Depolarization

An excitatory process that makes the membrane potential more positive.

Hyperpolarization

An inhibitory process that makes the membrane potential more negative.

Resting membrane potential

The membrane potential that is more positive than the potassium equilibrium potential (Ek) due to sodium permeability.

Local potentials

Small, graded, localized changes in membrane potential that can be either depolarizing or hyperpolarizing.

Graded local potentials

Local potentials that vary in size and duration in relation to the strength and duration of the stimulus.

Decremental local potentials

Local potentials that decrease in size with distance away from the site of initiation.

Summation of local potentials

The capability of local potentials to add together over time (temporal summation) or space (spatial summation).

Electrotonic spread

The passive spread of local potentials, which dissipate exponentially within the cell.

Precursors of action potentials

Local potentials are crucial for initiating action potentials, enabling rapid long-distance neural communication.

Integration of information

The ability of local potentials to be excitatory or inhibitory and summate, allowing the nervous system to filter information.

Causes of local potentials

Local potentials are caused by the opening of ion channels.

Sites of local potentials

Local potentials arise at synapses on dendrites and cell bodies or at sensory reception sites.