Chapter 8 Synaptic Communication

When a neuron communicates with another cell it is called a

synapse

Neurons communicate with:

another neuron, glial cells, effector organs

There are two types of synapses

chemical and electrical

In a chemical synapse the neuron that is sending a neurotransmitter is the ___________ neuron

presynaptic

in a chemical synapse the neuron that is receiving is the ___________ neuron

post synaptic

in a chemical synapse the place where a presynaptic and postsynaptic neuron get close is the

synaptic cleft

Vesicles found in presynaptic neuron are derived by the ___________, these vesicles are packed with _________

Golgi complex; neurotransmitter

On the presynaptic neuron there is a ________________, and reuptake transporter

voltage gated calcium channel

on the post synaptic neuron there is:

a receptor and enzymes

voltage gated calcium channels open when membrane potential Vm is ________ above resting

depolarized

on the presynaptic axon calcium is higher _______

outside

When calcium enters the axon it binds with _________ on the membrane

protein complexes

The increase of calcium concentration triggers ________ of neurotransmitter from __________

exocytosis; synaptic vesicles

_______ diffusion causes the neurotransmitters to go from presynaptic cleft to postsynaptic

simple

the postsynaptic cell has ______ for the neurotransmitter

receptor

After the neurotransmitter does its job they are broken down by _______ on the postsynaptic cell

enzymes

some neurotransmitters are taken back by the presynaptic neuron through

• another way to remove neurotransmitter

reuptake transporters

Aside from enzymes and reuptake transporters, another way neurotransmitters are removed is through ______

diffusion

time between the neurotransmitter being sent from presynaptic neuron to receptor on postsynaptic is called

synaptic delay

during the synaptic delay the ___________ machinery does its thing

exocytosis

another name for G protein coupled receptors is

• these are slow compared to ionotropic receptors

• amplify signals

metabotropic receptors

receptors on the postsynaptic neuron have ___________ allowing ions to pass through when open and closes after neurotransmitter unbinds. These are fast

ionotropic receptors

ionotropic receptors are:

ligand gated ion channels

when a neurotransmitter binds to a metabotropic receptor the G protein can go and bind to a:

ion channel

another thing the G protein does in a metabotropic receptor is bind to a _______ and a __________ is produced

amplifying enzyme; second messenger

Metabotropic receptor

• the second messenger can find an __________ to open or close

or

• the second messenger can produce _________

ion channel; other cell responses

when a neurotransmitter binding to a receptor changes the membrane potential on the post synaptic neuron it is called

postsynaptic potentials PSP

postsynaptic potentials PSP is a response to a __________ opening or movement of _______

ion channel; ions causing Vm change

postsynaptic potentials are ______ potentials

• subthreshold to ac action potential

graded

When a post synaptic depolarizes a neuron it is called an

• caused by Na+ or Ca++ entering cell

excitatory postsynaptic potential

most common neurotransmitters that trigger excitatory postsynaptic potential ESPS are

glutamate, acetylcholine

some postsynaptic potentials are hyperpolarizing

• cause Vm to be more negative than rest

these are called

inhibitory postsynaptic potentials

inhibitory postsynaptic potential IPSP are generated when ________ enters cell or ________ leave cell

chloride; potassium

a common neurotransmitter that cause IPSP is

GABA

excitatory vs inhibitory

• most likely to cause action potential

• depolarization

excitatory

excitatory vs inhibitory

• less likely to cause action potential

• hyperpolarization

• stabilize membrane

inhibitory

the type of postsynaptic potential that occurs depends on the

postsynaptic receptor

Ionotropic receptor is an __________ type receptor

excitatory

during a ionotropic receptor the driving force for _____ entry is much greater causing a depolarization

sodium

A net depolarization is a ____, it is fast

EPSP

Sodium enters the cell because the resting potential is ________ while potassium’s is _______

farther away; closer

why is the inside of a cell more negative than outside when resting?

nucleotides have a negative charge

EPSPs can be generated by ___________ receptors as well. This response is ______

metabotropic; slow

receptors are?

proteins

When cAMP activated protein kinase A, it phosphorylates the ________ causing it to close

potassium channel

When potassium channels close and prevent potassium from leaving the cell, it causes _________________ because the ____________ was reduced.

net depolarization; hyperpolarization

with sodium coming in and potassium going out of the cell leads to a ______________ of the cell, which is an ______, a slow

net depolarization; EPSP

the channel linked receptors on the postsynaptic receptors allow __________

both sodium and potassium

the resting potential is closer to ____ so there is a higher driving force for it

Ek

an inhibitory synapse generates an _________, which makes it difficult to get to AP threshold

IPSC

When a neurotransmitter from inhibitory synapse binds to a receptor, it opens channels for __________ or ___________

potassium; chloride

if an inhibitory synapse neurotransmitter opens a K+ channel it will ____________ the membrane inducing an ________

• Potassium will leave cell

hyperpolarize; IPSP

if an inhibitory synapse neurotransmitter open a Cl- channel allowing chloride _____ the cell, causing an ______

into; IPSP

Potassium leaves cell causing a __________ or an IPSP

hyperpolarization

The reason why the membrane potential goes back up to rest is because the neurotransmitter will _________ randomly, causing the channel to _______

unbind; close

what is the all or none principle

an action potential occurs when it membrane potential reaches threshold and if it doesn’t there is no action potential

How does a neuron’s membrane potential reach/exceed threshold?

multiple synaptic inputs to the same neuron

what is summation

adding effects of graded potentials

IPSPs and EPSPs are both ________ potentials and can be summed

graded

graded potentials can be big, tiny or somewhere in between

• depolarization

EPSP

graded potentials can be big, tiny, or somewhere in between

• hyperpolarized

IPSP