Psychology 1000 Lecture Notes - Lecture 1: Drug Resistance, Multiple Sclerosis, Myelin

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PSYC 1000
The biology of brain and behaviour.
CELLS
Nervous system has two kinds of cells.
Neurons.
Glia.
The Neuron (Brain has 100 Billion):
Receives information
Sends signals
Processes signals
Signals are chemical (between neurons) and electrical (within neurons, except for gap junctions, when
it’s between neurons) in nature.
Neurons can be sensory, motor, and inter. There are other types but this lecture will focus on those.
Terms:
Afferent = Into.
Efferent = Out. (Think “exit”)
NERVE IMPULSE
A nerve impulse is an electrical message transmitted down the axon of a neuron. The impulse does not
travel all the way to the end of the axon, but gets renewed and boosted at the nodes of ranvier. They
move at 100m/s.
Terms:
Resting Potential = Characterized by more positive charges outside than inside, it is the
neuron’s charge when it is “at rest” (not “firing”).
Action Potential = the “firing”.
The threshold for the sodium-potassium pumps has been exceeded.
Ions flow through the chanels in-membrane
on-off nature (you are either firing or not-- note, this can get more complicated later)
Myelin = Acts as an insulator. Allows the signal to travel more efficiently (Multiple Sclerosis
involves myelin problems)
Neurons’ cell membranes are selectively permeable. Sodium and potassium ions can come in.
THE SODIUM-POTASSIUM PUMP
The sodium-potassium pump is a protein that pumps 3 sodium ions per 2 potassium ions. Positive
sodium charges move through the axon (which weaken over time and are renewed at the cell gradient at
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Document Summary

Nervous system has two kinds of cells: neurons, glia. The neuron (brain has 100 billion): receives information. Signals are chemical (between neurons) and electrical (within neurons, except for gap junctions, when it"s between neurons) in nature. There are other types but this lecture will focus on those. Terms: afferent = into, efferent = out. (think exit ) A nerve impulse is an electrical message transmitted down the axon of a neuron. The impulse does not travel all the way to the end of the axon, but gets renewed and boosted at the nodes of ranvier. Allows the signal to travel more efficiently (multiple sclerosis involves myelin problems) The sodium-potassium pump is a protein that pumps 3 sodium ions per 2 potassium ions. Positive sodium charges move through the axon (which weaken over time and are renewed at the cell gradient at the nodes of ranvier).

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