9-2 Neuron Pt 2

axon hillock

connects the cell body to the axon

synapse

neurons talk to each other through electrical and chemical signals called _____.

difference in electrical charge inside and outside cell

synapse signals are made possible by what?

movement of charged particles (ions)

sending information from one neuron to another involves the ____________ in and out of the cell

electrochemical potential

the difference in charge inside and outside the cell is called what?

resting membrane potential

charge at rest

-70mV

resting membrane potential number (inside of membrane is ___ compared to outside)

action potentials

when ion channels open and close, neurons talk to each other through ____ which are quick changes in the membrane potential

more sodium (Na+) outside and more potassium (K+) and negatively charged proteins inside

at resting membrane potential, where Na+ and K+ ions?

presynaptic cell

sending neuron

postsynaptic cell

receiving neuron

synapse

connection between neurons (microscopic space where two neurons meet) (1 neuron can receive input from thousands of neurons and send output to thousands more)

axodendritic, axosomatic, axoaxonic

types of synapses

axodendritic

neurons connect by axon to dendrites

axosomatic

neurons connect by axon to soma

axoaxonic

neurons connect by axon to axon

cell membrane

what seperates the inside and outside of a cell? (phospholipid bilayer)

selectively permeable

the cell membrane is what? (only small things can get in, big things cannot)

passive, active

2 ways molecules can get through plasma membrane?

diffusion, ion channels

types of passive ways molecules can get through plasma membrane (does not require additional energy, moves from area of high concentration to low concentration)

create pores or holes in the membrane that can open and close

what do ion channels do?

pumps

type of active way molecules can get through plasma membrane

use energy to carry ions through the membrane

what do pumps do?

charged particles

what are ions? (Na2+, Ca2+, K+)

voltage gated, mechanically gated, ligand gated, leak channels

4 types of ion channels

voltage gated Na+ channel

which ion channel opens in response to changes in distribution of ions/charge across the membrane (ex: voltage changes from -70 to -50)
-passive

-gated

-generates and propogates the action potential

mechanically gated

which ion channel gets physically pulled open? (some form of external physical stimulus opens the gate) (this is what happens in inner hair cells)

ligand gated

which ion channel acts like a lock and key, a certain neurotransmitter must attach itself to the ion channel to open it?

-passive

-gated

-many different types of ions

-produces graded potentials at the postsynaptic membrane

Na+ leak channel

which ion channel randomly opens and closes?

-passive

-explains why resting potential sits slightly above the K+ equilibrium potential rather than exactly at it

voltage gated & ligand gated

which ion channels wait for binding to be able to open?

neurotransmitter ligands

chemical messengers that bind to specific receptor sites on neurons to alter brain activity

excitatory neurotransmitters

Signals the receiving neuron to fire an action potential (turns activity on).

inhibitory neurotransmitters

Prevents or reduces the likelihood that the receiving neuron will fire (turns activity down).

glutamate, gamma amino butyric acid, dopamine, serotonin, acetylcholine

key neurotransmitters

glutamate

main excitatory neurotransmitter (involved in synaptic plasticity, learning, memory -- pretty much everything!)

gamma amino butyric acid

the main inhibitory neurotransmitter (alcohol activates GABA receptors)

dopamine

neurotransmitter involved in pleasure/reward, motivation, reward-driven learning

serotonin

neurotransmitter involved in mood, appetite, sleep, memory, learning -- target for anti-depressants

acetylcholine

neurotransmitter involved in motor movement, attention, learning, memory

active transport pumps

how do you get ions back once equalized?

against concentration gradient (from low to high)

in active transport pumps how do ions transport?

sodium potassium pump (Na+/K+ ATPase)

one important pump where it pumps 2 K+ ions into the cell and 3 Na+ out of the cell for every molecule of ATP

-active (uses ATP)

-always working

-maintains the concentration gradients long term

K+ leak channel

-passive

-always open

-main river of resting membrane potential

sodium potassium pump because The pump moves 3$ positive charges out for every 2 it pulls in, which directly helps keep the inside negative. Stopping it causes an instant drop in voltage.

which single channel or pump would cause the most damage to the neuron’s resting potential if it stopped working? Why?