Lecture 7 Flashcards
What are neurons?
Basic wiring of the brain & nervous system.
What can neurons be compared to?
They are like information messengers that use electrical impulses and chemical signals to transmit info. to different parts of the brain.
What does an action potential do?
action potential denotes a change in the relative electric charge from inside to outside the cell.
What is the difference between transmission and conduction?
Conduction allows the transmission of an impulse, first step of an action potential. Transmission is the process where one neuron communicates with another.
What is an action potential like? Why?
An action potential is like dominoes, no single one travels all the way through the cell, it takes a bunch of them to transmit an impulse.
What is a sodium potassium pump?
A sodium-potassium pump is an information processing element in brain computation.
How can brain neurons transmit signals?
Brain neurons can transmit signals using a flow of Na+ & K+ ions, which produce an electrical spike called an action potential.
What are neurotransmitters? What do they do?
Chemical messengers that your body cannot function without. Carries chemical messages from on neuron to the next target cell.
What are the names of the neurotransmitters?
Noradrenaline, dopamine, seratonin, gaba, acetylcholine
What does noradrenaline do?
fight/flight (also has to do with concentration)
What does Dopamine do?
mood/sleep/learning (good mood, responds well to positive reinforcement)
What does seratonin do?
Mood/ Sleep (one of the biggest neurotransmitters involved w/ mood and sleep)
What does Gaba do?
Sleep/ anxiety (people with anxiety disorders have too little gaba)
What does acetylcholine do?
muscle/ memory
What does glutamate do?
Memory/ learning (found in 95% of the brain)
What do endorphines do?
Pain/ Pressure (blocks pain and makes you feel happy)
What do excitatory neurotransmitters do? What are they?
Increases positive charge (Dopamine, Norepinephrine, Glutamate, Acetylcholine).
What is an agonist? Examples?
Agonists increase the function of a neurotransmitter. Cocaine increases amount of dopamine & norepinephrine which are both agnonists.
What is an antagonist?
Antagonists decrease the function of a neurotransmitter. Caffeine is an adenosine antagonist.
What happens with calcium ions?
Calcium ions entering the cell initiate a signalling cascade that causes small membrane-bound vesicles, called synaptic vesicles, containing neurotransmitter molecules to fuse with the presynaptic membrane.
What are inhibitory transmitters? Examples?
Decreases positive charge (Serotonin, GABA, Endorphins).
What happens at the peak of an action potential graph?
It activates the next action potential.
What happens when you don’t need a neuron anymore?
It starts to degrade.
What are vesicles? What do they do?
Filled w/ neurotransmitters that unlock gates & release then into synapse, once gate is open sodium flows into dendrite & action potential occurs.
What happens to left over neurotransmitters?
They are either sucked back in (re-uptake), others stay & some float away & are broken down
What is Heterochromia?
One form (congenital) is that a person has two sets of DNA in their cells, absorbs fraternal twin.
What is a disease relating to the degradation of myelin sheath?
Multiple sclerosis (immune systems attack the myelin sheath).
Where is the nucleus of the neuron located?
The soma/cell body.
What are the branching extensions called on the soma?
Dendrites
Why do we need the myelin sheath?
Crucial for the normal operation of neurons within the nervous system: the loss of the insulation it provides can be detrimental to normal function.
What are receptors?
Proteins on the cell surface where neurotransmitters attach, vary in shape, w/ diff shapes “matching” different neurotransmitters.
What is the lock-and-key relationship?
Specific neurotransmitters fit specific receptors (neurotransmitter binds to any receptor that it fits).
What do synaptic gates do?
pick up neurotransmitters
What is the flow of information across neurons?
one neuron’s axon releases neurotransmitters into the synapse and the synaptic gates of the next neuron pick them up.
What does sodium do?
Increases the likelihood of an action potential
What does chlorine do?
decreases the likelihood of an action potential
What are the excitatory neurotransmitters?
Dopamine, norepinepherine, glutamate, acetylcholine
What are the inhibitory neurotransmitters?
Seratonin, GABA, Endorphins
how does action potential lead to the transfer of information?
When the action potential comes, it stimulates the vesicles to release the neurotransmitters which go to the gate and unlock it. When we unlock the gate, sodium, chlorine and potassium walk through.
How many action potential occur within a neuron?
several
When do we start forgetting things?
when we don’t use the neuron as much and the myelin sheath degrades
how do we get the Na+ and Cl- into the dendrite?
neurotransmitters
Where does most of our functioning happen?
in the gap called our synapse
How do we learn stuff?
based on how we connect our neurons together
What is the dotted line on an action potential graph?
the threshold of excitation
What is the first increase (hill)on the action potential graph? What is happening?
depolarization? sodium is flowing into dendrites (soma)
What is the peak of the action potential graph? What is happening?
the action potential (light turns on) (40mv)
What is the down hill part of the action potential graph?
repolarization. Cell gets rid of
sodium and potassium, volts go down
What is the dip in the action potential graph? What is happening?
hyper-polarization. Cell has overcorrected, then gets more sodium and potassium and returns to resting state.
What acronym can you use for exhitatory neurotransmitters?
DANG
WHat acronym can you use for inhibitory neurotransmitters?
SEG
If we are talking about dormant genes what process is responsible for it being expressed?
Epigentics
