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we 're told to solve and graph the solution for the system of equations right here . and the first thing that jumps out at me , is that we might be able to eliminate one of the variables . and if we just focus on the x , we have a 4x here and we have a 2x right here . if we were to just add them right now , we would ge...
any point on this line , which is both of those lines , will satisfy both of these equations . you give me an arbitrary y , solve for x in the top equation , that x and y will also satisfy the bottom equation . so this actually has an infinite number of solutions .
how do i solve : y= x-4 y= -4x+26 using elimination ?
we 're told to solve and graph the solution for the system of equations right here . and the first thing that jumps out at me , is that we might be able to eliminate one of the variables . and if we just focus on the x , we have a 4x here and we have a 2x right here . if we were to just add them right now , we would ge...
you try to graph this , the y-intercept is at negative 2.5 , right there . the slope is 2 . so it 's going to be this exact same line .
if you know that if 2 lines have the same slope and y-intercept , could n't you have multiplied the bottom equation by 2 and figured out that there are infinite solutions ?
we 're told to solve and graph the solution for the system of equations right here . and the first thing that jumps out at me , is that we might be able to eliminate one of the variables . and if we just focus on the x , we have a 4x here and we have a 2x right here . if we were to just add them right now , we would ge...
we can say , hey , look , the negative 4x and the positive 4x should cancel out , or they will cancel out . so let 's add these two equations . let 's add the left side to the left side , the right side to the right side , and we can do that because these two things are equal .
how is zero the same as two point five ?
we 're told to solve and graph the solution for the system of equations right here . and the first thing that jumps out at me , is that we might be able to eliminate one of the variables . and if we just focus on the x , we have a 4x here and we have a 2x right here . if we were to just add them right now , we would ge...
any point on this line , which is both of those lines , will satisfy both of these equations . you give me an arbitrary y , solve for x in the top equation , that x and y will also satisfy the bottom equation . so this actually has an infinite number of solutions .
what happens if you get one equation like 'x + 3y - 4 = 0 ' ?
- for every work of art on paper that survives today intact or relatively intact , it 's hard to estimate , but there are probably many , many more works on paper that did n't survive . our department cares for the collections of drawings , manuscripts , and photographs . i personally am a conservator of photographs . ...
i personally am a conservator of photographs . the conservation of drawings , manuscripts , and photographs is grouped together because they all have physically similar types of objects . these three collections and the materials that compose them share a common vulnerability to the environment .
how is paper conservation different from photograph conservation ?
- for every work of art on paper that survives today intact or relatively intact , it 's hard to estimate , but there are probably many , many more works on paper that did n't survive . our department cares for the collections of drawings , manuscripts , and photographs . i personally am a conservator of photographs . ...
when this happens , gelatin will first begin to lift away from its paper support and then flake away , resulting in losses . we change our displays of works of art on paper every 12 weeks . we do this to limit their exposure to light .
how does one become art conservationist ?
- for every work of art on paper that survives today intact or relatively intact , it 's hard to estimate , but there are probably many , many more works on paper that did n't survive . our department cares for the collections of drawings , manuscripts , and photographs . i personally am a conservator of photographs . ...
this red chalk drawing by guilio romano entitled `` the sacrifice of isaac '' from the early 16th century came into our collection a victim of insect infestation . there were numerous small worm holes scattered throughout the paper support . a restorer had well-meaningly placed small squares of paper in behind each wor...
is there a certain type of light that slows down or prevents paper/photograph degredation ?
- for every work of art on paper that survives today intact or relatively intact , it 's hard to estimate , but there are probably many , many more works on paper that did n't survive . our department cares for the collections of drawings , manuscripts , and photographs . i personally am a conservator of photographs . ...
we change our displays of works of art on paper every 12 weeks . we do this to limit their exposure to light . you 'll find that the galleries in the museum are lit significantly low in the drawings , manuscripts , and photo galleries , significantly lower than the other areas , such as sculpture and painting .
the light in the exhibit they showed seems a bit yellowish , is that a factor ?
: the cozy car company ships some of their new cars to japan and vietnam . the number of cars that will be shipped to japan during the next t months is modeled by the function j of t is equal to 2 to the tth power . the number of cars that will be shipped to vietnam during the next t months is modeled by the function ...
based on these 2 models for how much they 're going to receive after t months , after 5 months , vietnam is going to receive , vietnam is going to receive more cars . i guess the answer to that is vietnam . vietnam will have received more cars after 5 months . which country had received more cars from the cozy car comp...
how is vietnam not exponential growth ?
: the cozy car company ships some of their new cars to japan and vietnam . the number of cars that will be shipped to japan during the next t months is modeled by the function j of t is equal to 2 to the tth power . the number of cars that will be shipped to vietnam during the next t months is modeled by the function ...
2 to the 6th is going to be 32 times ... we can read this as 2 to the 5th times 2 times 2 , which is going to be equal to , this is going to be equal to 32 times 4 , which is 128 cars after 7 months will have gone to japan , and to vietnam , v of 7 is going to be equal to 2 times 7 squared , so that 's equal to 2 times...
how could we have proved that japan will have received more cars after the 7th month ?
: the cozy car company ships some of their new cars to japan and vietnam . the number of cars that will be shipped to japan during the next t months is modeled by the function j of t is equal to 2 to the tth power . the number of cars that will be shipped to vietnam during the next t months is modeled by the function ...
we 'll say x is our independent variable here , so 2 to the x power . then let 's do the quadratic one . this is y of 2 , although it will be v of 2 .
how does the quadratic equation have a linear graphing even though it has an exponent ?
: the cozy car company ships some of their new cars to japan and vietnam . the number of cars that will be shipped to japan during the next t months is modeled by the function j of t is equal to 2 to the tth power . the number of cars that will be shipped to vietnam during the next t months is modeled by the function ...
: the cozy car company ships some of their new cars to japan and vietnam . the number of cars that will be shipped to japan during the next t months is modeled by the function j of t is equal to 2 to the tth power .
does the equation form a parabola ?
: the cozy car company ships some of their new cars to japan and vietnam . the number of cars that will be shipped to japan during the next t months is modeled by the function j of t is equal to 2 to the tth power . the number of cars that will be shipped to vietnam during the next t months is modeled by the function ...
2 to the 6th is going to be 32 times ... we can read this as 2 to the 5th times 2 times 2 , which is going to be equal to , this is going to be equal to 32 times 4 , which is 128 cars after 7 months will have gone to japan , and to vietnam , v of 7 is going to be equal to 2 times 7 squared , so that 's equal to 2 times...
why the answer is not the number of the total number of cars japan or vietnam received ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and so if a channel gets opened up because of some stimulus , that would allow positive ions to flow in . and the primary positive ions we 've been talking about are the sodium ions . maybe this is some type of sodium gate that gets opened up because of this stimulus .
how the nodes can boast the signal of ions ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
you say , ok . i like having this myelin sheath . but why do n't we put gaps in the myelin sheath every so often ?
is myelin sheath same as schwann cells ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
you say , ok . i like having this myelin sheath . but why do n't we put gaps in the myelin sheath every so often ?
what disease occurs when the myelin sheath is damaged or missing ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and then it gets boosted at the nodes of ranvier , because it triggers these voltage-gated channels again . that triggers an action potential . and then your signal gets boosted , and then it dissipates -- boosted , dissipates , boosted , dissipates , boosted , dissipates .
when the action potential is initiated at the axon hillock , what prevents the inflow of ions from migrating ( diffusing ) back towards the cell body/dendrites ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so we 've already talked about the dendrites as being where the neuron can be stimulated from multiple inputs . if we 're in the brain , these dendrites might be near the terminal ends of axons of other neurons . if we 're some type of sensory cell , these dendrites could be stimulated by some type of sensory input .
what other organs are near the brain , and what type of tissue makes up the brain ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
you say , ok . i like having this myelin sheath . but why do n't we put gaps in the myelin sheath every so often ?
is myelin sheath same as schwann cells ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and so if a channel gets opened up because of some stimulus , that would allow positive ions to flow in . and the primary positive ions we 've been talking about are the sodium ions . maybe this is some type of sodium gate that gets opened up because of this stimulus .
how do positively charged ions carry a signal ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so then you say , ok , well then why do n't we try to boost the signal ? well , how would you boost the signal ? you say , ok .
would n't the signal be diluted at the nodes of ranvier when it just gets flooded with more ions ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
but right at time 0 , we have n't really noticed it with our voltmeter . our voltage right across the membrane right over there is at that equilibrium , negative 70 millivolts . but after some small amount of time , this electrotonic potential has gotten to this point , because all of these positive charges are trying ...
how does the transmission goes in the right direction ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so then you say , ok , well then why do n't we try to boost the signal ? well , how would you boost the signal ? you say , ok .
sal explains that we have gaps in our myelin sheath so that we could `` boost '' the signal with voltage gated channels , so if we intake extra calcium , would it be that this would boost the signal even more ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
how are the k= that are lost during the stimulation re-supplemented ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
you say , ok . i like having this myelin sheath . but why do n't we put gaps in the myelin sheath every so often ?
what is exactly a myelin ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
these are nodes of ran-veer , or ranvier . and right in those little nodes , right in those nodes , right where the myelin sheath is n't , we can put these voltage-gated channels to essentially boost the signal . if the signal had to go electrotonically all the way over here , it 'd be very weak .
and why ca n't voltage-gated channels be placed on the surface of myelin ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
you say , ok . i like having this myelin sheath . but why do n't we put gaps in the myelin sheath every so often ?
is myelin sheath same as schwann cells ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so now all sorts of positive charge gets flushed into the neuron . and then purely through electrotonic spread , you will have this electrotonic potential spread down the axon . now , this is the interesting part , because we can think a little bit about , what is the best way for an axon to be designed ?
electrotonic spread happens in the axon , right ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and you 're going several feet , or even whatever , you want to go a reasonable distance purely with electrotonic spread , your signal , remember , it dissipates . your signal is going to be really weak right over here . you 're going to have a weak signal on the other end . it might not be even strong enough to make a...
so , what keeps the signal from going back into the receptor instead of going on to the terminal , especially when the signal receives the boost ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and so if a channel gets opened up because of some stimulus , that would allow positive ions to flow in . and the primary positive ions we 've been talking about are the sodium ions . maybe this is some type of sodium gate that gets opened up because of this stimulus .
during a boosting of action potential ( in nodes of ranvier ) , how come that there 's always an influx of sodium ions when there 's too many na ions inside the cell ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
it 's more negative inside of the neuron than outside of the neuron . and so if a channel gets opened up because of some stimulus , that would allow positive ions to flow in . and the primary positive ions we 've been talking about are the sodium ions . maybe this is some type of sodium gate that gets opened up because...
is n't it that the natural flow of ions should be from a higher concentration to lower concentration gradient ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
your signal is going to be really weak right over here . you 're going to have a weak signal on the other end . it might not be even strong enough to make anything interesting happen at these terminals , which would n't be strong enough to trigger , maybe , other neurons , or whatever else might need to happen at this ...
do neurons have any calcium channels anywhere else besides the end of the axon ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and you have the myelin sheath around it to make sure it goes as fast as possible , and you get very little loss of signal . and then it gets boosted at the nodes of ranvier , because it triggers these voltage-gated channels again . that triggers an action potential .
is there a name for the voltage gated channels in the nodes of ranvier ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and you have the myelin sheath around it to make sure it goes as fast as possible , and you get very little loss of signal . and then it gets boosted at the nodes of ranvier , because it triggers these voltage-gated channels again . that triggers an action potential .
what is the mv needed to stimulate the voltage gated ions at the node or ranvier ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
that is what the myelin sheath is . so let 's say we want to surround this whole thing with just one big grouping of schwann 's cells , so one big myelin sheath -- which is a good insulator . it does not conduct current well .
one last question , are there any ion channels and na/k pumps under the schwann cells ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and then it gets boosted at the nodes of ranvier , because it triggers these voltage-gated channels again . that triggers an action potential . and then your signal gets boosted , and then it dissipates -- boosted , dissipates , boosted , dissipates , boosted , dissipates .
does an action potential travel along an axon or does it stimulate the production of a new action potential in the membrane ahead of it ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
it gets triggered here , then it gets triggered , here then it gets triggered here , then it gets triggered here , then it gets triggered here . this is called saltatory conduction . it comes from the latin word saltare -- once again , i do n't know how to pronounce .
if there is no stimulus , does the saltatory conduction happens ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so we 've already talked about the dendrites as being where the neuron can be stimulated from multiple inputs . if we 're in the brain , these dendrites might be near the terminal ends of axons of other neurons . if we 're some type of sensory cell , these dendrites could be stimulated by some type of sensory input .
what comprises the extracellular space of neurons ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and this right over here is a node of ranvier . these are nodes of ran-veer , or ranvier . and right in those little nodes , right in those nodes , right where the myelin sheath is n't , we can put these voltage-gated channels to essentially boost the signal .
why these nodes are called as nodes of ranvier ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
that triggers an action potential . and then your signal gets boosted , and then it dissipates -- boosted , dissipates , boosted , dissipates , boosted , dissipates . maybe it could even get boosted again .
i am still confused on how the signal gets boosted at nodes of ranvier ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
you want it to be surrounded . so if this was a cross section , you want it to be surrounded by an insulator that has high resistance . and the reason is because you do n't want the potential to leak across your membrane -- high resistance right over here . if you did n't have something high resistance around it , your...
what does high resistance mean ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and then it gets boosted at the nodes of ranvier , because it triggers these voltage-gated channels again . that triggers an action potential . and then your signal gets boosted , and then it dissipates -- boosted , dissipates , boosted , dissipates , boosted , dissipates .
why is mostly sodium and potassium ions affect the action potential ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
you want it to be surrounded . so if this was a cross section , you want it to be surrounded by an insulator that has high resistance . and the reason is because you do n't want the potential to leak across your membrane -- high resistance right over here . if you did n't have something high resistance around it , your...
why do we need high resistance of myelin sheaths ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and for the most part , that is true . it is surrounded by a good insulator . that is what the myelin sheath is .
is n't the phospholipid layer already a good insulator ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
as we know , there 's a potential difference . it 's more negative inside of the neuron than outside of the neuron . and so if a channel gets opened up because of some stimulus , that would allow positive ions to flow in . and the primary positive ions we 've been talking about are the sodium ions . maybe this is some ...
can positive ions only go inside the neuron ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and this right over here is a node of ranvier . these are nodes of ran-veer , or ranvier . and right in those little nodes , right in those nodes , right where the myelin sheath is n't , we can put these voltage-gated channels to essentially boost the signal .
why are the nodes called nodes of ranvier ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and so if a channel gets opened up because of some stimulus , that would allow positive ions to flow in . and the primary positive ions we 've been talking about are the sodium ions . maybe this is some type of sodium gate that gets opened up because of this stimulus .
sal drew the sodium ions entering the the cell itself , but the cells atucally enter and travel along the membrane ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and so that 's what you have to get the voltage up to , the voltage difference up to , in order to trigger the ion channels right over there . so those are the sodium channels to get positive charge in . here 's the potassium channels to get the positive charge out .
dont the pumps for the potassium pump potassium out when there 's alot of positive charge making the the sodium dicipate before it reaches the next sodium pump ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so let 's say we want to surround this whole thing with just one big grouping of schwann 's cells , so one big myelin sheath -- which is a good insulator . it does not conduct current well . so this right over here is just one big myelin sheath right over here .
can anyone please explain to me how the current flows from dendrites to axon ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so we 've already talked about the dendrites as being where the neuron can be stimulated from multiple inputs . if we 're in the brain , these dendrites might be near the terminal ends of axons of other neurons . if we 're some type of sensory cell , these dendrites could be stimulated by some type of sensory input .
if some of our axons can be up to 1 meter , how does it fit in our head ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and on its own , that might have caused a similar type of bump right over here . but when you add the two together and they 're happening at the same time , their combined bumps are enough to trigger an action potential in the hillock , or a series of action potentials in the hillock . and so then , you really have , e...
does the voltage required to fire the action potentials between the hillock and each individual node differ ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
but that 's not exactly what 's happening . the signal is traveling passively through . it gets triggered here in the axon hillock .
how long does it take for the signal to get from the soma to the terminal ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
but after some small amount of time , this electrotonic potential has gotten to this point , because all of these positive charges are trying to get away from each other . it 's gotten to that point . and you might see a bump in the voltage -- in the voltage difference , i guess i should say .
what 's special about the hillock beside being the `` convergent point '' of the graded signals ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and then it gets boosted at the nodes of ranvier , because it triggers these voltage-gated channels again . that triggers an action potential . and then your signal gets boosted , and then it dissipates -- boosted , dissipates , boosted , dissipates , boosted , dissipates .
can an action potential be generated at some point before the hillock if two signals happen to meet there and pass the threshold ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
you say , ok . i like having this myelin sheath . but why do n't we put gaps in the myelin sheath every so often ?
does this meant that people who have less nodes of ranvier and more myelin sheath have slower reflexes , since the more myelin sheath there is , the slower the signal carries ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and this right over here is a node of ranvier . these are nodes of ran-veer , or ranvier . and right in those little nodes , right in those nodes , right where the myelin sheath is n't , we can put these voltage-gated channels to essentially boost the signal .
do nodes of ranvier appear only in the pns , cns or both ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and then it gets boosted at the nodes of ranvier , because it triggers these voltage-gated channels again . that triggers an action potential . and then your signal gets boosted , and then it dissipates -- boosted , dissipates , boosted , dissipates , boosted , dissipates .
is n't the purpose of the myelin sheath to prevent action potential from repeatedly generating along the whole axon thus slowing the signal down ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and then it gets boosted at the nodes of ranvier , because it triggers these voltage-gated channels again . that triggers an action potential . and then your signal gets boosted , and then it dissipates -- boosted , dissipates , boosted , dissipates , boosted , dissipates .
if all the signals and informations transmit by stimulation of ion gates , and there is a uniform threshold to initiate the action potential , so what deferintiate one information from another ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and you have the myelin sheath around it to make sure it goes as fast as possible , and you get very little loss of signal . and then it gets boosted at the nodes of ranvier , because it triggers these voltage-gated channels again . that triggers an action potential .
at the node of ranvier , there are gated channels to boost the signals transmitted through axons , are those gated channels are always in pair ( 1 na + 1 k gated channels ) ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and then it gets boosted at the nodes of ranvier , because it triggers these voltage-gated channels again . that triggers an action potential . and then your signal gets boosted , and then it dissipates -- boosted , dissipates , boosted , dissipates , boosted , dissipates .
how is action potential triggered at nerve endings where there is no nerve to give the signal to the receiving nerve ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
it gets triggered here , then it gets triggered , here then it gets triggered here , then it gets triggered here , then it gets triggered here . this is called saltatory conduction . it comes from the latin word saltare -- once again , i do n't know how to pronounce .
does the saltatory conduction conserve energy for the axon ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
now , that by itself might not be -- we might have gotten the voltage difference low enough , i guess we could say . or we might not have gotten the voltage inside of the cell positive enough in order to trigger the voltage-gated ion channels . and so maybe nothing happens .
are the voltage gated channels between the myelin the schwann cells ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and you 're going several feet , or even whatever , you want to go a reasonable distance purely with electrotonic spread , your signal , remember , it dissipates . your signal is going to be really weak right over here . you 're going to have a weak signal on the other end . it might not be even strong enough to make a...
is that because of the signal from one end of the nerve to the next does n't get amplified enough to have a strong signal ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
if you just had a bunch of copper wires on one side , and you had some copper wires that were surrounded by a really good insulator , a really good resistor -- for example , plastic or rubber of some kind . the current is actually going to have less energy loss . it 's going to travel faster when it 's surrounded by an...
for clarification , do stimuli cause the sodium to pass over the membrane for the first burst of energy ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and then it gets boosted at the nodes of ranvier , because it triggers these voltage-gated channels again . that triggers an action potential . and then your signal gets boosted , and then it dissipates -- boosted , dissipates , boosted , dissipates , boosted , dissipates .
why will an action potential be stopped if the nodes of ranvier are wide apart ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and then it gets boosted at the nodes of ranvier , because it triggers these voltage-gated channels again . that triggers an action potential . and then your signal gets boosted , and then it dissipates -- boosted , dissipates , boosted , dissipates , boosted , dissipates .
are n't action potentials constant and will not be attenuated ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so then you say , ok , well then why do n't we try to boost the signal ? well , how would you boost the signal ? you say , ok .
so the nodes of ranvier essentially boost the signal using a method somewhat like pressure ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
it 's gotten to that point . and you might see a bump in the voltage -- in the voltage difference , i guess i should say . this thing might go up .
why is the voltage increase only a temporary bump as opposed to lasting longer ( as now the voltage of the inside is increasing due to the rush of sodium ) ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so now all sorts of positive charge gets flushed into the neuron . and then purely through electrotonic spread , you will have this electrotonic potential spread down the axon . now , this is the interesting part , because we can think a little bit about , what is the best way for an axon to be designed ?
how can electrotonic conduction happen ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and so that 's what you have to get the voltage up to , the voltage difference up to , in order to trigger the ion channels right over there . so those are the sodium channels to get positive charge in . here 's the potassium channels to get the positive charge out .
if the sodium potassium pump is random , why can you control your actions ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
i 'm not really sure how to pronounce it . so let me put those gaps in here . so you put those gaps in here , so these are the myelin sheath .
how large are the gaps between the schwann cells in real life ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
that is what the myelin sheath is . so let 's say we want to surround this whole thing with just one big grouping of schwann 's cells , so one big myelin sheath -- which is a good insulator . it does not conduct current well .
how long are the schwann cells ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and then those gaps would allow the membrane to interface with the outside . and in those areas , we could put some voltage-gated channels that can release action potentials , in order to essentially boost the signal . and that 's is exactly what the anatomy of a typical neuron is like .
could n't the action/ electrical potential maintain itself while traveling down the axon without the myelin sheath via means of the voltage gated channels ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so then you say , ok , well then why do n't we try to boost the signal ? well , how would you boost the signal ? you say , ok .
i know there would be significantly more energy loss , but would n't the voltage gated channels dispersed across the axon make up for it , `` boosting '' the charge/potential all the way to the terminals ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so we 've already talked about the dendrites as being where the neuron can be stimulated from multiple inputs . if we 're in the brain , these dendrites might be near the terminal ends of axons of other neurons . if we 're some type of sensory cell , these dendrites could be stimulated by some type of sensory input .
what is the brain made out of ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and this right over here is a node of ranvier . these are nodes of ran-veer , or ranvier . and right in those little nodes , right in those nodes , right where the myelin sheath is n't , we can put these voltage-gated channels to essentially boost the signal .
how many nodes of ranvier per axon ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and this right over here is a node of ranvier . these are nodes of ran-veer , or ranvier . and right in those little nodes , right in those nodes , right where the myelin sheath is n't , we can put these voltage-gated channels to essentially boost the signal .
what diseases could occur if nodes of ranvier are not present ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
as we know , there 's a potential difference . it 's more negative inside of the neuron than outside of the neuron . and so if a channel gets opened up because of some stimulus , that would allow positive ions to flow in .
why is it usually negative inside the cell ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
and so if a channel gets opened up because of some stimulus , that would allow positive ions to flow in . and the primary positive ions we 've been talking about are the sodium ions . maybe this is some type of sodium gate that gets opened up because of this stimulus .
why do we use ions instead of some sort of conductive fibre ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
it comes from the latin word saltare -- once again , i do n't know how to pronounce . my latin is n't too good . but it comes from the latin word saltare , which means to jump around or to hop around .
are n't chemicals too slow to allow the sort of fast paced thinking that neurons are capable of ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so then you say , ok , well then why do n't we try to boost the signal ? well , how would you boost the signal ? you say , ok .
is there a disease that causes the nodes of ranvier not to be able to boost the signal , or is that just instant death ?
now that we know how a signal can spread through a neuron , through an electrotonic potential and action potential and combinations of the two , let 's put it all together by looking again at the structure of a neuron , the anatomy of a neuron , and thinking about why it has that anatomy and how it all can work . so we...
so now all sorts of positive charge gets flushed into the neuron . and then purely through electrotonic spread , you will have this electrotonic potential spread down the axon . now , this is the interesting part , because we can think a little bit about , what is the best way for an axon to be designed ?
what is the initial impulse which triggers the signal spread down the axon ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it .
when you divide decimals is it the same as when you divide numbers above 1 ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
and we know that when we have a fraction like this we 're not changing the value of the fraction if we multiple the numerator and the denominator by the same quantity . and so what could we multiply this denominator by to make it a whole number ? well we can multiply it by 10 and then another 10 .
why do you make the numbers diffrent colers ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
2 minus 2 is 0 . so what i got left over is less than 42 , so i know that 7 is the right number . i want to go as many times as possible into 302 without going over .
when we divide and theres a number that keeps going when do we know when to stop putting that number after the decimal point ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it .
how do you use remainders in decimals ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
and if we move that two to the right , then we can move this two to the right . or we need to move this two to the right . and so this is where , now the decimal place is .
when will we need to divid decimals in real life ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
you subtract , and we have no remainder . so 3,042 divided by 42 is the same thing as 30.42 divided by 0.42 . and it 's going to be equal to 72 .
how do you divide a decimal by a whole number for example 4.3 divided by 10 ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ?
when you write 30 x 42 x 100 =3,024 why do you leave off the .24 ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
the decimal is now there if you care about it . and , 0.42 times 100 . once again move the decimal one , two places to the right , it is now 42 .
how come sal switched up the numbers ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
so we 're not changing the value of this fraction . or , you could view this , this division problem . so this is going to be 30.42 times 100 .
why did n't sal put the zeroes during the division problem ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
this is equal to 72 . just like that .
why exactly when working with decimals like this , does multiplying the factors give the same answe r as not doing so ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
but what do you do now ? well the important realization is , is when you 're doing a division problem like this , you will get the same answer as long as you multiply or divide both numbers by the same thing . and to understand that , rewrite this division as 30.42 over 0.42 .
why did you put the numbers wrong ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it .
when you divide decimals ca n't you just divide normally and and the decimal point ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
2 minus 2 is 0 . so what i got left over is less than 42 , so i know that 7 is the right number . i want to go as many times as possible into 302 without going over .
who even got the idea of decimals ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it .
how do you divide the 30.24 by 0.42 ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ?
when sal accidentally switched the numbers from 30.24 to 30.42 , would n't that affect the outcome ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it .
what would be a way of overlapping and justifying a solution to the equation ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it .
what would /are equations for colors ?
let 's see if we can divide 30.24 divided by 0.42 . and try pausing the video and solving it on your own before i work through it . so there is a couple of ways you can think about it . we could just write it as 30.24 divided by 0.42 . but what do you do now ? well the important realization is , is when you 're doing a...
and so what could we multiply this denominator by to make it a whole number ? well we can multiply it by 10 and then another 10 . so we can multiply it by a 100 .
say i had 34.4 but also had 0.00534 and multiplied the second one by 10,000 does 34.4 have to be multiplied by 10,000 too ?