electrical signaling by neurons part 1

how do proteins move ions across the layer

1. actively, such as through the ion pump pumping ions across the membrane 2. passively , allowing ions to diffuse across the ion channels through concentration or electrical gradients

what does selectivity mean

an ion channel's ability to only allow certain ions through

define ions

atoms or molecules that have either a positive (cation) or negative (anion) charge.

mechanically gated channels

channel opens or closes based off of movement (such as hair cells moving)

channelopathies

diseases caused by defective ion channels

in basic terms, how are electrical signals spread in a neuron?

electrical signals stem from ions moving in and out of the cell membrane, changing the electrical charge.

neurons use [blank] signals to communicate with a neuron, and [blank] signals to communicate between each other

electrical;chemical

summarize active transport

energy that is needed to move the ions across the cell membrane; this is used by sodium potassium pump

thermally gated channels

gates open or close depending on the temperature of the neuron

ions moving across a cell membrane can produce which 2 types of electric potentials?

graded, local potential: restricted to one place in the membrane (such as the postsynaptic potential) propagated potential: travels down the cell's axon (such as during an action potential)

summarize how concentration and electrical gradients work

in concentration gradients, ions are moved from areas of high concentration to low concentration passively for electric, ions are moved from areas of positive charge to negative charge

how is the resting potential of the neuron able to stay negative?

intracellular fluid contains many fixed anions, which are negative active transport used by ion pumps

which ions are heavily involved in the intracellular environment at rest versus extracellular environment

intracellular: sodium, fixed anions extracellular: sodium, calcium, chlorine

summarize sodium potassium pump

ion pumps move 3 Na+ into the extracellular space and 2 K+ ions come back into the intracellular space as a result. ATP is used to move this pump along.

what is a cell or neuronal membrane?

it is a double layer of lipids (fat) with proteins spread throughout that controls what goes in and out of the extra cellular environment

what is the lipid component of the cell membrane?

it is a double layer of phospholipids that have hydrophilic heads facing outwards the cell and hydrophobic tails facing inward to form the cell membrane

what is gating referring to ion channels?

it is the mechanism by which ion channels open or close categories: ligand gated, voltage gated, thermally gated, or mechanically gated

how do ion channels work in broad terms?

membrane proteins have a "hole", and if an ion fits in the hole because of its charge or size, then the ion can flow through the protein into the membrane, thus changing the charge of the membrane

voltage gated channels

open and close depending on the electrical changes in the membrane's potential

at -65 mV, the neuron is at rest and viewed as ...

polarized, ready to fire

what is the role of proteins in the phospholipid bilayer

regulate movement of ions across the membrane

resting membrane potential

the collective difference of electrical potential inside versus outside a neuron. RMP is -65 mV

what does term diffusion barrier mean

the phospholipid bilayer protects the cell from the extracellular environment; it is not permeable to ions, which is why proteins are also in the cell membrane

ligand gated channels

these gates open or close based off of a hormone or NT (called a ligand) binding to a specific receptor

what does term capacitor mean in terms of phospholipid bilayer

this means that the bilayer is able to store charges of opposite sign that are attracted to each other but unable to cross the membrane