a b c need to think about this question 2 ways 1. within neurons – 2. between neurons-
TRANSCRIPT
![Page 1: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/1.jpg)
How do neurons communicate?
![Page 2: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/2.jpg)
a
b
c
![Page 3: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/3.jpg)
How do neurons communicate?
Need to think about this question 2 ways
![Page 4: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/4.jpg)
How do neurons communicate?
1. within neurons –
2. between neurons-
![Page 5: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/5.jpg)
Neuron receiving info
Information traveling down neuron
![Page 6: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/6.jpg)
within neurons – electrically
between neurons – chemically◦ Synapse – space between neurons
How do neurons communicate
![Page 7: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/7.jpg)
Ramon Y Cajal
developed Golgi Stain
first determined space between neurons
“synapse”
![Page 8: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/8.jpg)
the “resting” state
the “active” state◦ neuron is firing◦ action potential
the “refractory” state
Neurons can exist in one of 3 states
![Page 9: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/9.jpg)
giant squid axon
How do we know about what is happening in the neuron?
![Page 10: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/10.jpg)
![Page 11: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/11.jpg)
![Page 12: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/12.jpg)
inside of the axon has a slightly negative charge relative to outside the axon◦ called the membrane potential◦ usually around -70mV
At rest:
![Page 13: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/13.jpg)
inside of the axon has a slightly negative charge relative to outside the axon◦ called the membrane potential
why?
At rest:
![Page 14: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/14.jpg)
action potential or
spike
![Page 15: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/15.jpg)
![Page 16: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/16.jpg)
see depolarization (change from negative inside neuron to more positive)
Neuron stimulated (either electrically or by receiving a “message”
![Page 17: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/17.jpg)
action potential or
spike
![Page 18: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/18.jpg)
see depolarization (change from negative inside neuron to more positive)
◦ “threshold” – if a great enough depolarization occurs, an action potential will occur
◦ action potential – very quick – milliseconds Other terms – spike, firing, generating an AP
Neuron stimulated (either electrically or by receiving a “message”
![Page 19: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/19.jpg)
action potential or
spike
![Page 20: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/20.jpg)
Hyperpolarization return to negative this is the refractory or recovery period
![Page 21: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/21.jpg)
action potential or
spike
![Page 22: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/22.jpg)
All axons and cells have a membrane thin lipid (fat) bilayer
The membranes have channels (to allow ions in or out)
Ions – molecules with a charge These channels can be open or shut
What causes these changes in electrical potential and the action potential?
![Page 23: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/23.jpg)
![Page 24: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/24.jpg)
Ions flowing across the membrane causes the changes in the potential
Ions are molecules that contain a positive or negative charge anion – negative charge cation – positive charge
What causes these changes in electrical potential?
![Page 25: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/25.jpg)
Na+ sodium◦ HIGHER CONCENTRATION OUTSIDE THE AXON
Cl- chloride ◦ HIGHER CONCENTRATION OUTSIDE AXON
K+ potassium◦ higher concentration inside the axon
A- anions -large (-) molecules with a negative charge (stuck inside the axon)
Some important ions for neuronal communication
![Page 26: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/26.jpg)
INSIDE AXON(intracellular)
OUTSIDE AXON (EXTRACELLULAR FLUID)
Na+
Na+
Na+
Na+
Na+Na+
Na+
Na+ and Cl- are in higher concentrationin the extracellular fluid
Cl-
Cl-
Cl-
Cl-Cl- Cl-
Cl-
Neuron at Rest
Na+
Na+
Na+
Na+Na+
Na+
Cl- Cl-
Cl-
Cl-
Cl-
Cl-
Cl-Cl-
A-
A-
A-
A-
A-
A-
![Page 27: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/27.jpg)
INSIDE AXON OUTSIDE AXON (EXTRACELLULAR FLUID)
Na+
Na+
Na+
Na+
Na+A-
A-
K+ and negative anions are in higher concentrationin the intracellular or inside the axon
Cl-
Cl-
Cl-
K+K+ Cl-
K+
Neuron at Rest
K+
K+
K+
A-
A-
Na+
Cl-
K+
![Page 28: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/28.jpg)
concentration gradient –◦ ions diffuse from higher concentration to lower
concentration
Some forces that play a role in maintaining membrane potential
![Page 29: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/29.jpg)
example of concentration forces
![Page 30: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/30.jpg)
Na+
K+
Cl-
What would each ion do if the ion channel opened based on the concentration gradient?
![Page 31: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/31.jpg)
concentration gradient –◦ ions diffuse from higher concentration to lower
concentration
electrical gradient -◦ opposite charges attract so ions are attracted to
an environment that has a charge that is opposite of the charge they carry!
Some forces that play a role in maintaining membrane potential
![Page 32: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/32.jpg)
example of electrostatic forces
![Page 33: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/33.jpg)
Na+
K+
Cl-
What would each ion do if the ion channel opened based on electrostatic forces ?
![Page 34: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/34.jpg)
INSIDE AXON(intracellular)
OUTSIDE AXON (EXTRACELLULAR FLUID)
Na+
Na+
Na+
Na+
Na+Na+
Na+
Na+ and Cl- are in higher concentrationin the extracellular fluid
Cl-
Cl-
Cl-
Cl-Cl- Cl-
Cl-
Axon depolarizing
Na+
Na+
Na+
Na+Na+
Na+
Cl- Cl-
Cl-
Cl-
Cl-
Cl-
Cl-Cl-
A-
A-
A-
A-
A-
A-
![Page 35: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/35.jpg)
opening of Na+ channels and influx of Na+ ions
What drives the action potential?
![Page 36: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/36.jpg)
What happens if sodium channels are blocked?
lidocaine, novocaine, cocaine
TTX – tetrototoxin
Sagitoxin-◦ red tides
![Page 37: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/37.jpg)
![Page 38: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/38.jpg)
Na+
K+
Cl-
ConcentrationGradient
ElectricalGradient
after the AP (+ intracellular)
![Page 39: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/39.jpg)
INSIDE AXON OUTSIDE AXON (EXTRACELLULAR FLUID)
Na+
Na+
Na+
Na+
Na+A-
A-
K+ and negative anions are in higher concentrationin the intracellular or inside the axon
Cl-
Cl-
Cl-
K+K+ Cl-
K+
Neuron at Rest
K+
K+
K+
A-
A-
Na+
Cl-
K+
![Page 40: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/40.jpg)
Sodium-potassium pump – active force that exchanges 3 Na+ inside for 2 K+ outside
![Page 41: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/41.jpg)
INSIDE AXON OUTSIDE AXON (EXTRACELLULAR FLUID)
Na+
Na+
Na+
Na+
Na+A-
A-
K+ and negative anions are in higher concentrationin the intracellular or inside the axon
Cl-
Cl-
Cl-
K+
K+
Cl-
K+
After the action potential
K+
K+
K+
A-
A-
Na+
Cl-
K+Na+
Na+
Na+
Na+
Na+
![Page 42: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/42.jpg)
![Page 43: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/43.jpg)
myelin sheath (80% fat and 20% protein)◦ produced by glia
conduction or propogation of the action potential
![Page 44: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/44.jpg)
http://www.blackwellpublishing.com/matthews/channel.html
![Page 45: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/45.jpg)
nodes of ranvier
![Page 46: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/46.jpg)
myelin sheath (80% fat and 20% protein)◦ produced by glia
◦ nodes of ranvier
conduction or propogation of the action potential
![Page 47: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/47.jpg)
nodes of ranvier
![Page 48: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/48.jpg)
myelin sheath (80% fat and 20% protein)◦ produced by glia
◦ nodes of ranvier
◦ saltatory conduction (200 ft/sec)
conduction or propogation of the action potential
![Page 49: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/49.jpg)
![Page 50: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/50.jpg)
![Page 51: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/51.jpg)
http://www.blackwellpublishing.com/matthews/actionp.html
![Page 52: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/52.jpg)
speed, efficiency of neurotransmission
Advantages of Saltatory Conduction
![Page 53: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/53.jpg)
speed, efficiency of neurotransmission
disease: Multiple Sclerosis progressive, autoimmune disease onset ~ 20 years of age early symptoms: motor symptoms, such as
weakness, leg dragging, stiffness, a tendency to drop things, a feeling of heaviness, clumsiness,
Advantages of Saltatory Conduction
![Page 54: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/54.jpg)
![Page 55: a b c Need to think about this question 2 ways 1. within neurons – 2. between neurons-](https://reader036.vdocuments.mx/reader036/viewer/2022062511/5516c3c9550346f0208b59d6/html5/thumbnails/55.jpg)
What about communication between neurons?