Lesson 2 Flashcards
There are so many things that your mind and brain does. Can you name three?
- sense, perceive, understand the world
- learn and remember
- plan, organize, and perform complex actions
- love, hate, fear, appreciate music
- strive for world peace
What is the brain made of?
89 billion cells called neurons, the wiring that connects them and alot of glial cells
what are the molecules called that are present in your brain?
neurotransmitters
What are the cells of the brain called?
neurons
what is a collections of neurons called?
assemblies or neural circuits
what do larger collections of neurons make up?
brain areas
Brain areas connect to each other in _______ forming _________
networks; neural systems
fill in the blanks
where does the communication between other neurons occur?
the terminal buttons
What kind of process is neural activity?
an electro-chemical process
which part of neural activity refers to the flow of ions
(charged particles) in/out of the cell, or through the cell?
the electrical part
which part of neural activity refers to the flow of
neurotransmitters between neurons?
the chemical part
what are the key ions for a neuron membrane?
sodium (Na+)
potassium (K+)
chloride (Cl-)
what is the charged value of the neuron membrane?
-70mv
what is something a neuron membrane is able to do that involves ions?
is able to decide what to keep in and out of the cell
how do you describe a neuron membrane?
semi-permeable
what is the resting membrane potential?
the difference in charge across the membrane at equilibrium (about -70mv)
what are the three stages of computation in a neuron?
stage 1: input stage
stage 2: “processing” stage
stage 3: output stage
between two neurons, there is a ______ where the axon of one neuron connects to the dendrite of another neuron
synapse
the neuron before the synapse is called?
presynaptic neuron
the neuron after the synapse is called?
postsynaptic neuron
what do we called when a neuron fires?
the action potential
before a transmitter release the postsynaptic neuron is ___ at rest
polarized meaning it has a negative charge
after a transmitter release, ion channels are influenced and the postsynaptic cell has been _____
depolarized meaning it ends up with a less negative charge
What type of potential describes when the cell is less polarized because it has a less negative charge?
Excitatory postsynaptic potential (EPSP)
What type of potential describes when the cell can also become more polarized so it has a more negative charge?
Inhibitory postsynaptic potential (IPSP)
What is the word for when a cell is less polarized?
depolarized
What is the word for when a cell is more polarized?
hyper polarized
Why is depolarization is excitation?
because it makes it more likely the cell will reach threshold (e.g., -50mv) and trigger an action potential
Why is hyperpolarized inhibition?
because it makes it less likely the cell will reach threshold and transmit a signal (via an action potential)
What are examples of excitatory neurotransmitters?
ACh, catecholamines, glutamate, serotonin
What are examples of inhibitory neurotransmitters?
GABA, glycine, some peptides
How do neurotransmitters fit post-synaptic receptors?
in a ‘lock and key’ fashion
True or False? if false, correct the statement
specific neurotranmitters fit with specific receptors
true
What are the four steps of the input stage?
- Presynaptic neuron releases neurotransmitters into synaptic cleft
- Neurotransmitters bind with receptor of the post-synaptic cell in a lock and key fashion
3.Ion channels in the post-synaptic cell open at the receptor site allowing specific ions to enter the cell - Depending on the neurotransmitter and receptor, post-synaptic cell becomes depolarized or hyperpolarized
Fill in the blank:
the right neurotransmitter must be with the right ____to have influence on the post-synaptic cell
Receptor
Fill in the blank:
The synapse is where the ____
of one neuron connects to the ____ of another neuron
terminal button; dendrite
Where do signals from other neurons enter?
dendrites
What stage matches this description: many “signals” come in at the dendrites
the input stage
What stage matches this description: signals summate, adding and canceling, possibly reaching critical threshold within the cell body
the “processing” stage
What stage matches this description: if the input is strong enough (exceeds threshold) then the neuron passes the
signal along via it’s axon
Output stage
where does evaluation process happen? with importance to which region?
the cell body; the axon hillock
As more information comes into the post synaptic neuron?
the overall charge of the neuron increases
When the threshold of -50mv is reached, what happens?
voltage sensitive gates
open up, triggering a
positive spike in voltage
(an “action potential”)
Which region of the neruon is where the axon connects to the cell body?
axon hillock
What word is defined as the value of the membrane potential?
the threhold
What word is defined as a dramatic change in voltage to a
positive potential (+40mv),
to below resting potential,
then back to resting
potential (-70mv)
the action potential
True or false? if false, correct the statement
Action potentials do vary in strength, but can’t vary in rate
False; action potentials do not vary in strength, but they can vary in rate
True or false? if false, correct the statement
All-or-none is defined as the value of the action potential is always the same, regardless of the
amplitude of the depolarizing current
true
True or false? if false, explain why
A threshold of -50mv is a weak action potential and a threshold of -30mv is a strong action potential
action potential don’t vary in strength. there are no “strong” or “weak” action potentials
Fill in the blank:
Signals are transmitted along the ______, until they reach _______,
where they connect to the next ______
axon; terminal buttons; neuron
True or false? if false, explain why
When more information is coming in resulting in more frequent action potentials, this is an example of the rate changes and is not characterized by strengths
true, actions potential aren’t characterized as strong or weak but the rates can change
what is the purpose of myelin sheath?
provides electrical insulation, alters the flow of current
down the axon
Since action potentials cannot be generated where there are myelin sheaths, where do action potentials happen?
the nodes of Ranvier, breaks in the myelin sheaths
What is saltatory conduction?
in myelinated action potentials “jump” from node to node, enabling fast propagation of the signal down the axon, with a signal that never loses strength at any distance
During saltatory conduction, does a signal lose strength at any distance?
No
What is the threshold reached at the axon hillock to open voltage sensitive gates and trigger an action potential?
-50mv
True or false? if false explain why
An action potential triggered by a value of membrane potential of -35mv is stronger than an action potential triggered by a membrane potential of -50mv
false; action potentials aren’t described as strong or weak
