BIOPSYCHOLOGY LECTURE 2
Communication in the Nervous System
Nervous System
CNS: brain and spinal cord
PNS: all nervous tissue outside the CNS. Includes nerves, ganglia,
enteric, plexuses & sensory receptors.
Divided into:
- SNS
- ANS
- ENS
Neural Communication: insulation & info transfer
Hardware:
Neurons – communication
o Dendrites receive
o Soma cell body
o Axon transmit away
Glial Cells – structural support & insulation
Myelin Sheath – speeds up transmission
(Axon) Terminal Button – end of axon; secretes neurotransmitters
Neurotransmitters – chemical messengers
Synapse – point at which neurons interconnect
Demyelination disrupts transmission of neural impulse… myelin speeds up
electrical transmission & insulates axon – prevents dissipation of electrical
signal
The Neural Impulse: Electrochemical Beginnings
Hodgkin & Huxley (1952) – giant squid
Fluids in/outside neuron
Electrically charged particles (ions)
Neuron at rest – negative charge on inside compared to
outside
-70 millivolts = resting potential
The Neural Impulse: Action Potential
Stimulation causes cell membrane to open briefly
Positively charged Na (sodium) ions flow in
Shift in electrical charge travels along neuron
All-or-None law
, Absolute refractory period
The Synapse: Chemicals as Signal Couriers
Synaptic gap/cleft
Presynaptic Neuron
Synaptic vesicles
Neurotransmitters
Postsynaptic Neuron
Receptor sites
The Postsynaptic Potential (PSP)
Voltage change at receptor site – PSP
Not all-or-none
Changes the probability of the postsynaptic neuron firing
Positive shift = excitatory PSP
Negative shift = inhibitory PSP
Signals: From Postsynaptic Potentials to Neural Networks
Communication in the Nervous System
Nervous System
CNS: brain and spinal cord
PNS: all nervous tissue outside the CNS. Includes nerves, ganglia,
enteric, plexuses & sensory receptors.
Divided into:
- SNS
- ANS
- ENS
Neural Communication: insulation & info transfer
Hardware:
Neurons – communication
o Dendrites receive
o Soma cell body
o Axon transmit away
Glial Cells – structural support & insulation
Myelin Sheath – speeds up transmission
(Axon) Terminal Button – end of axon; secretes neurotransmitters
Neurotransmitters – chemical messengers
Synapse – point at which neurons interconnect
Demyelination disrupts transmission of neural impulse… myelin speeds up
electrical transmission & insulates axon – prevents dissipation of electrical
signal
The Neural Impulse: Electrochemical Beginnings
Hodgkin & Huxley (1952) – giant squid
Fluids in/outside neuron
Electrically charged particles (ions)
Neuron at rest – negative charge on inside compared to
outside
-70 millivolts = resting potential
The Neural Impulse: Action Potential
Stimulation causes cell membrane to open briefly
Positively charged Na (sodium) ions flow in
Shift in electrical charge travels along neuron
All-or-None law
, Absolute refractory period
The Synapse: Chemicals as Signal Couriers
Synaptic gap/cleft
Presynaptic Neuron
Synaptic vesicles
Neurotransmitters
Postsynaptic Neuron
Receptor sites
The Postsynaptic Potential (PSP)
Voltage change at receptor site – PSP
Not all-or-none
Changes the probability of the postsynaptic neuron firing
Positive shift = excitatory PSP
Negative shift = inhibitory PSP
Signals: From Postsynaptic Potentials to Neural Networks
