The central nervous system, neurotransmitters and their role in in human
behaviour and mental functioning
NEURONS
Dendrites:
Dendrites means ‘tree’ in Greek ‐ they are like extensive tree branches
The dendrite collects information from another nerve cell and sends the
information to the soma
The more branches, the more information a neuron can receive
Soma:
The cell body (soma) sums and subtracts the information it receives from the
dendrites
It provides energy for the neurons to carry out their function
The nucleus in the cell body contains chromosomes
Axon:
The axon carries messages to other neurons and parts of body (i.e. glands,
muscles)
There is only one axon, which varies in length
Myelin sheath insulates the axon and speeds up the neural impulse
Myelinated axons are responsible for making our bodily movements smooth
Myelin Sheath:
The larger the myelin sheath, the greater the speed of electrical signal
The myelin is produced by a particular type of glia cells: Oligodendrocytes
The gaps between myelinated sections of an axon are called nodes of
Ranvier
White matter of the brain: myelinated fibres
Grey matter: unmyelinated fibres
Neural Communication:
Each neuron is an individual unit separated from its neighbour by a very small
gap ‐ a synapse
Pre‐synaptic neuron sends an electrical impulse to post‐synaptic neuron
The firing of the electrical impulse down the axon is called an “action
potential”
Action Potentials:
Transfer information by means of a combination of electrical and chemical
processes
The electrical charge within a neuron is 70 mV less than the electrical charge
outside the neuron
This difference is called resting potential and is maintained by a mechanism
known as sodium-potassium pump
behaviour and mental functioning
NEURONS
Dendrites:
Dendrites means ‘tree’ in Greek ‐ they are like extensive tree branches
The dendrite collects information from another nerve cell and sends the
information to the soma
The more branches, the more information a neuron can receive
Soma:
The cell body (soma) sums and subtracts the information it receives from the
dendrites
It provides energy for the neurons to carry out their function
The nucleus in the cell body contains chromosomes
Axon:
The axon carries messages to other neurons and parts of body (i.e. glands,
muscles)
There is only one axon, which varies in length
Myelin sheath insulates the axon and speeds up the neural impulse
Myelinated axons are responsible for making our bodily movements smooth
Myelin Sheath:
The larger the myelin sheath, the greater the speed of electrical signal
The myelin is produced by a particular type of glia cells: Oligodendrocytes
The gaps between myelinated sections of an axon are called nodes of
Ranvier
White matter of the brain: myelinated fibres
Grey matter: unmyelinated fibres
Neural Communication:
Each neuron is an individual unit separated from its neighbour by a very small
gap ‐ a synapse
Pre‐synaptic neuron sends an electrical impulse to post‐synaptic neuron
The firing of the electrical impulse down the axon is called an “action
potential”
Action Potentials:
Transfer information by means of a combination of electrical and chemical
processes
The electrical charge within a neuron is 70 mV less than the electrical charge
outside the neuron
This difference is called resting potential and is maintained by a mechanism
known as sodium-potassium pump
