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Chapter 3

chapter 3 text.notes - only imp. things u need to know for test

4 Pages
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Department
Psychology
Course Code
PSY100H1
Professor
Michael Inzlicht

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Psychology Notes: Chapter 3
GENETIC AND BIOLOGICAL FOUNDATIONS
- 23 pairs of chromosomes in all
ACTION POTENTIALS CAUSE NEURONAL COMMUNICATION
- Action potential: (i.e. neuronal firing) is the electrical signal that passes along the axon and
causes release of chemicals that transmit signals to other neurons
- Resting membrane potential: when not active the inside and outside of a neuron differ
electrically cuz of the balance of ions in the intracellular fluid Æ negatively charged
o Microelectrode: measure neuron[]vP}v]olÆuoÇ]vÇÀ]ZP]
electric currents
o Polarization: diff of charge inside and outside of neuron/creates electrical energy
necessary to power action potential
o Due to selective permeability, there is more potassium inside the neuron than sodium,
which contributes to polarization
CHARGES IN ELECTRICAL POTENTIAL LEAD TO ACTION
- Signals arrive at dendrites
o Excitatory t stimulates neuron to fire
o Inhibitory t reduce likelihood of neuron firing
o How they work: by affecting polarization Æ either it depolarizes or hyperpolarizes cell
membrane
- Depolarization and hyperpolarization
o Neurons fire when cell membrane is depolarized past certain threshold Æ causes
change in permeability of cell membrane= opens gates of sodium channels and allows
sodium to rush into neuron(inside = slightly more positively charged)
o Hyperpolarization: sodium channels become even more resistant to passage of sodium
- Action Potentials Spread along the Axon
o
o Once gating stops flow of sodium into neuron, potassium stops leaving Æ momentarily
creating state of hyperpolarization
Absolute refractory period: during this time it is impossible for the neuron to
fire, which keeps action potential from repeating up and down the axon in a
kind of ripple effect
Relative refractory period: when neuron can fire, but only in response to an
especially strong signal
Normally action potentials move along the axon in only one direction
o All or none principle: a neuron cannot partially fire, it fires with same potency each time,
but at diff intervals of diff frequency depending on the strength of stimulation
o Myelin sheath: makes it go faster
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Description
Psychology Notes: Chapter 3 GENETIC AND BIOLOGICAL FOUNDATIONS - 23 pairs of chromosomes in all ACTION POTENTIALS CAUSE NEURONAL COMMUNICATION - Action potential: (i.e. neuronal firing) is the electrical signal that passes along the axon and causes release of chemicals that transmit signals to other neurons - Resting membrane potential: when not active the inside and outside of a neuron differ electrically cuz of the balance of ions in the intracellular fluid negatively charged o Microelectrode: measure neuron[ZZ]L2}L]olKo]L] ZZ2]Z electric currents o Polarization: diff of charge inside and outside of neuroncreates electrical energy necessary to power action potential o Due to selective permeability, there is more potassium inside the neuron than sodium, which contributes to polarization CHARGES IN ELECTRICAL POTENTIAL LEAD TO ACTION - Signals arrive at dendrites o Excitatory J stimulates neuron to fire o Inhibitory J reduce likelihood of neuron firing o How they work: by affecting polarization either it depolarizes or hyperpolarizes cell membrane - Depolarization and hyperpolarization o Neurons fire when cell membrane is depolarized past certain threshold causes change in permeability of cell membrane= opens gates of sodium channels and allows sodium to rush into neuron(inside = slightly more positively charged) o Hyperpolarization: sodium channels become even more resistant to passage of sodium - Action Potentials Spread along the Axon o o Once gating stops flow of sodium into neuron, potassium stops leaving momentarily creating state of hyperpolarization Absolute refractory period: during this time it is impossible for the neuron to fire, which keeps action potential from repeating up and down the axon in a kind of ripple effect Relative refractory period: when neuron can fire, but only in response to an especially strong signal Normally action potentials move along the axon in only one direction o All or none principle: a neuron cannot partially fire, it fires with same potency each time, but at diff intervals of diff frequency depending on the strength of stimulation o Myelin sheath: makes it go faster www.notesolution.com
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