PSYCH 1XX3 Lecture Notes - Lecture 4: Autonomic Nervous System, Radial Glial Cell, Axon Terminal
Neuroscience 1
The Neuron
- Neural anatomy is prime for communicating information
- Messages pass through synaptic transmission
- Neuron has two zones:
o Receptive Zone: receives signals from other neurons; made up of dendrites
o Transmission Zone: passes on signals; made up of the axon and terminal ends
Receptive Zone
- Begins with the cell body
- Contains most of the vital organelles
- Branching from the cell body are dendrites that reach to other
neurons and receive signals that will be passed on through the
axons
The Axons
- Information’s gets passed down the axon until it approaches the
axon terminal (branches)
- The information reaches the terminal bouton (terminal ends);
these reach the out and make connections with the dendrites of
nearby neurons to transmit the information further
A neural Network
- Glial cells support, nourish, and provide insulation for neurons
- The glial cells and neurons work together, resting in a bath of ions, chemicals, and blood vasculature
make up the brain
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The Action Potential
- The movement of ions across a membrane dictates neural communication
- The cell membrane is selectively permeable allowing different ions to pass with ease
- Contains potassium and sodium channels that allow communication between cells
The Resting Potential
- A resting electrical imbalance exists between the two sides of a neuron
- The starting baseline for the differing concentration of ions produces an electrical imbalance between
the outside and the inside of the neuron
- The inside of the neurons starts with -70mv relative to the outside of the cell
o This voltage is maintained by the Leaky Potassium
Channel, which allows positively charged potassium
ions to constantly leave the inside of the neuron
- Chloride and Sodium ions stay outside of the cell due to the
electrostatic force of the large protein molecules
- Voltage gated sodium channels are closed in the resting state
- Also a very low concentration of sodium ions flow in during
resting state
- Once the voltage reaches -50mv ITS SHOWTIME
The Action Potential
- Once the -50mv has been reached a chain of events occur
- Sodium channels open: causing most of the sodium ions outside to flow inside, this makes the inside of
the neuron positively charged
- The electrostatic force inside the neuron causes more Potassium to flow out through the leaky channel,
then once the electrostatic force is too powerful the voltage gated potassium channel opens and more
potassium can flow outside
- After reaching a max of +40mv the sodium channels close, however the potassium ions are still
leaving the neuron through the voltage gated potassium channel and lowers the inner voltage until it
overshoots the -70mv resting potential, here the voltage potassium channels close
- Eventually, the cell returns to -70 mv, and there is a short refractory period where the neuron cannot
fire another action potential until it settles and recovers
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Document Summary
Neural anatomy is prime for communicating information. Neuron has two zones: receptive zone: receives signals from other neurons; made up of dendrites, transmission zone: passes on signals; made up of the axon and terminal ends. Branching from the cell body are dendrites that reach to other neurons and receive signals that will be passed on through the axons. Information"s gets passed down the axon until it approaches the axon terminal (branches) The information reaches the terminal bouton (terminal ends); these reach the out and make connections with the dendrites of nearby neurons to transmit the information further. Glial cells support, nourish, and provide insulation for neurons. The glial cells and neurons work together, resting in a bath of ions, chemicals, and blood vasculature make up the brain. The movement of ions across a membrane dictates neural communication. The cell membrane is selectively permeable allowing different ions to pass with ease. Contains potassium and sodium channels that allow communication between cells.
