Neuro CH6

Moving across the synapse

how does the electrical signal jump across a gap (what are the three parts of the synpase)

presynaptic - neuron transmits

postsynaptic - cell receives signal

synaptic cleft - gap between the two

sequence of transmission at chemical synapse

what is step 1

action potential travels down axon to the terminal

sequence of transmission at chemical synapse

what is step 2

voltage gated calcium channels open and Ca2+ enters

sequence of transmission at chemical synapse

what is step 3

synaptic vesicles fuse with membrane and release neurotransmitter into cleft

sequence of transmission at chemical synapse

what is step 4

transmitter binds to postsynaptic receptor causing EPSP or IPSP

what is an EPSP

excitatory postsynaptic potential

small local depolarization, pushing cell closer to threshold

what causes an EPSP

what is one neurotransmitter that causes this

Na+ ions entering cell making inside more positive

Glutamate

what is an IPSP

Inhibitory postsynaptic potential

small local hyperpolarization, pushing cell away from threshold

what causes IPSP

what is a neurotransmitter that does this

Cl- ions entering cell, making inside negative

GABA

sequence of transmission at chemical synapse

what is step 5

EPSPs and IPSPs are summed at the axon hillock, determines if threshold is reached

sequence of transmission at chemical synapse

what is step 6

Synaptic transmission is rapidly stopped

transmitter may bind to presynaptic autoreceptors, decreasing release

sequence of transmission at chemical synapse

what is step 7

after binding to receptors, neurotransmitters are inactivated by: degradation, reuptake, or recycling

what occurs during neurotransmitter recycling

astrocytes actively participate at the synapse to gather NTs and recycle them for reuse

what is neurotransmitter degradation and give an example

breakdown/inactivation of transmitter by enzyme

acetylcholinesterase (AChE) breaks down acetylcholine (Ach)

how does electrical synapse occur

ions flow directly through large channels into adjacent neurons with no time delay

whats the benefit of electrical synapses

faster, allows neurons to sync, saves energy

what are the amino acid NTs

GABA

Glutamate

what are the peptide NTs

endorphins

what are the Amine NTs (5)

acetylcholine, dopamine, serotonin, epinephrine, norepinephrine

what does adrenaline do

fight or flight

incr HR + blood flow → stat boost

what does noradrenaline do

concentration NT

contracts vessels to incr blood flow

affects attention + responding actions

also part of fight or flight

what does dopamine do

pleasure NT

pleasure/addiction
movement+motivation

what does serotonin do (3 parts)

mood transmitter

wellbeing + happiness
helps sleep cycle + GI regulation
affected by exercise+light exposure

what does GABA do (3)

calming NT

calms firing nerves in CNS
high lvls improve focus
low lvls cause anxiety

what does acetylcholine do (3)

learning NT

involved in thought, learning, memory
activates muscle action
associated w attention+awakening

what does glutamate do

memory NT

most common NT
part of learning+memory
regulates dev+creation of nerve contacts

what do endorphins do

euphoria NT

released during exercise, excitement, sex
reduces pain

what are seizures

wave of abnormally synchronous electrical activity in the brain

what is channelopathy

genetic abnormality of ion channels, can lead to epilepsy, migraine, weakness

what is an EEG

electroencephalogram

recording of brain potentials (functional test)

regarding types of seizure disorders

what are generalized convulsions

abnormal activity throughout the brain

what are characteristics of generalized convulsions

tonic(stiffening) and clonic (rhythmic jerking) contractions

seizure is followed by confusion and sleep

regarding types of seizure disorders

what are absence “attacks”

brain waves show generalized rhythmic activities for a few seconds, but hundreds of times a day

no muscle activity, except for stopping and staring

previously called petit mal

regarding types of seizure disorders

what is complex partial seizure

awareness is impaired during

unusual activity in only part of the brain

most common type of seizure in kids and teens

what seizures are in partial onset

simple partial seizures (normal awareness)

complex partial seizures (awareness impaired)

what seizures are in generlized onset

absence seizures (petit mal)

tonic clonic seizures (grand mal)