Lectures 16-18 Flashcards
What is the all or none law?
an action potential fires or it doesn’t
What are two mechanisms used in the all or nothing law? (angry neurons)
1) high frequent communications by sending lots of action potentials
2) Number of neurons sending the same message
Why is there an all or none law?
To describe that an action potential either fires or it doesn’t at all, always maintains same size and stops around same point.
what is a refractory period? (speed)
Limit on how fast neuron can fire
What is the absolute refractory period and in what stage (1-3) of an action potential does it occur?
Period during an action potential when another action potential cannot fire, during rising and peak phase
What’s the relative refractory period and what makes it more difficult?
State where it is harder than normal to fire an action potential, due to needing many more milivolts due to its state.
what are the nodes of ronvier?
spaces in between myelin segments
What is saltatory conduction and it’s two benefits to the neuron? (sautè)
Action potentials being conducted at myelinated axons, jump from node to node.
1) faster action potentials
2) reduced energy
what’s a sodium potassium pump and it’s function? (take 2, release 3)
Pulls in 2 Potassium to release 3 Sodium ions, helps use less energy during saltatory conduction
Why’s saltatory conduction faster than normal conduction? (think team of tug o war, how will you win the fastest)
Only needs voltage gated channels in nodes of ronvier, makes density easier and faster to get through as its more concentrated instead of spread throughout
whys myelin important?
Several human disorders are linked with impaired myelin
What is the nature of connection between neurons?
Kajal was right, neurons aren’t connected
What are the 3 components of a synaptic structure and their functions? intro middle cliffhanger
1) pre synaptic component -send and receive mssgs
2) post synaptic component-receive mssgs
3) Synaptic cleft-space between pre and post synaptic component
What are the 3 types of synapses
(the axos…)
1) axodendritic synapse
2) axosematic synapse
3)axoaxomic synapse
functions of the 3 synapses:
(axos..)
Axodendritic- majority of synapses
Axosematic: synapses between brain and body
Axoaxomic: synapses between one axon to another
What did sherrington find in their expirement?
(the dog toe pincher)
speed as a hint
Synapse Speed was lower than expected, whatever happens in it must be slower than an action potential
What did Elliot find in Elliot and Loewis frog heart expirements?
Accelerator nerves mimick same effect as adrenaline
What did Loewi find in Elliot and Loewis frog heart expirements?
Fluid transferred from one heart beaker to another, could increase/decrease the other heart rates beats
What does synaptic transmission involve and release?
Involves release of neurotransmitters
What are neurotransmitters?
Internal chemicals that transmit signals from neuron to target cell across the synapse
What are the 4 Chemical structures of neuro transmitters ? (BANO)
Biogenic amines
amino acids
neuropeptides
other
What is an amine, and how many amines do bio amines and mono amines have in them biologically?
An amine is a type of chemical grouping
Bio amines have 1 or more amine in them biologically
Mono amines have only 1 amine in them biologically
What type neurotransmitters fall under the biogenic amine group ? and name all 5…
happy.. cliff jumping…turkey meat has..
NEADS
The catecholomines and mono amines sub grouping
Norepinephrine
Epinephrine
Acetylcholine
Dopamine
Serotonin
What are the functions of serotonin and dopamine?
(zzz, haha!) (hmm, how do i deal with this?)
Serotonin aids in sleep and mood
Dopamine helps process info in the brain and regulates movement
What are the functions of norepinephrine and epinephrine and what else can they be known as to the average person?
Roles in arousal and mood
Norepinephrine : nor adrenaline
epinephrine: adrenaline
What are the two neurotransmitters that fall under the Amino acids chemical structure and what are their functions ? (opposites, double G’s, highs and lows)
Glutamate: main excitatory neurotransmitter
GABA: main inhibitory neurotransmitter(decrease activity)
What are neuropeptides and what two neurotransmitters fall under this chemical structure ? (pain and blocking, the only cool name for a neurotransmitter)
def: shorter chains of amino acids
1) Substance p
2) endorphins
What are the functions of substance P (1) and endorphins(2)?
(What did michaels cousin do when he broke his leg … what could this be known as?)
substance P: process pain messages
Endorphins: block pain messages, regulate breathing
What does it mean by “others” in Chemical structure 4? And what neurotransmitter (1) falls under this category?
Don’t fit it neatly with others, weird things
1) nitric oxide
What are the 5 steps in neurotransmission? think about it as baking a cake, 1) you get your ingredients ready, 2) prep everything for the bake,3) put it in the oven 4) beep beep on the oven 5) it’s done! everyone eats
1) synthesis: making neurotransmitter
2) Preparation for release
3) Release
4) Signalling
5) Termination of actions
Where(2) and what does the synthesis stage do and involve(2 things it involves) ( in the 5 steps of making neurotransmitters )
Can be made in pre synaptic terminal or cell body
Makes the neurotransmitter using precursors and synthetic enzymes
What happens during the preparation for release phase (2 steps)? Think about it like going on a boat, what are the three steps to it… boarding…. what’s the next two?
Synaptic vesicles fill with neurotransmitters
1) Loading neurotransmitters
2) Transporting and docking neurotransmitters to active zone
What is a quanta and quantal release? (goes in 2 step cycle) (quant-quantity)
Quanta: amount of neurotransmitters in a synaptic vesicle
Quantal release : Synaptic vesicles release as a group of neurotransmitters
What causes neurotransmitters to move into the synaptic cleft? (queues of arrival)
The arrival of an action potential is the queue for neurotransmitters to move into the synaptic cleft.
What is a snare complex and in what step of neurotransmission does it occur? Like creating a monkey bridge, to form soemthing…)
Occurs in the release step(3rd)
It’s proteins holding vesicles in place to form a protein complex in the active zones
What occurs chemically in the release step (number 3, in five steps of neurotransmission) (3 steps, who comes, changes, fuses and then is pushed into somewhere)
Calcium comes,
protein changes shape and pulls synaptic vesicles into synaptic membrane,
Synaptic vesicle then fuses with synaptic membrane and gets pushed into synaptic cleft
Why was the first (old) dales law incorrect and how did we change it? (wrong numbers dale)
Stated each neuron can only synthesize and release one type of neurotransmitter when they can really synthesize and release 1-3.
