Introduction to psychology
24/01/20 Introduction to the nervous system
Peripheral nervous system
Somatic nervous system
- Controls movement of skeletal muscles/transmits somatosensory information to
the central nervous system
Autonomic nervous system
- Body’s vegetative function (primarily involuntary)
o Sympathetic
o Parasympathetic.
Central nervous system
Brain
Spinal cord
- Carries commands from (efferent) the brain to muscles and organs; carries
sensory info to (afferent) the brain
- Locked In syndrome
o Complete paralysis of voluntary muscles (exception – eyes).
Brain and spinal cord -> communicate with body via nerves (bundle of axons)
Spinal nerves
Cranial nerves
Neurons
Higher cortical areas
- 26-29 billion
Cerebellum
, - 70 billion
Spinal cord
- 1 billion
“Specialised cells that convey sensory information into the brain; carry out the
operations involved in thought, feeling and action; and transmit commands out into
the body to control muscles and organs” – Garrett (2008).
Components of a neuron:
Dendrite
- Branching extensions that receive messages; send impulses toward the cell body
Axon
- The extension of a neuron, ending in branching terminal fibres, through which
messages are sent to other neurons or to muscles or glands
Myelin sheath
- A layer of fatty cells encasing many neurons; increases transmission speed.
Types of a neuron:
Motor neuron
- Efferent
Sensory neuron
- Afferent
Interneuron
- Within CNS.
Internal structure of a neuron:
Membrane
- Phospholipid bilayer
o “Fat sandwich”; fatty acids between 2 slices of polar (phosphate) ‘bread’
o Pierced with protein ‘straws’
- Detect substances
- Control access
- Transport.
Neuronal signalling: electrochemical process
Within a neuron
- Local potentials
o In dendrites and soma
o Passive propagation; gets smaller as they go
- Action potentials
o All-or-none; signals travels down the axon
o Active propagation; maintains intensity
Between neurons
- Synaptic transmission (chemical neurotransmitters).
Membrane potential
Axon is charged
- Cell membrane controls environment (selective permeability)
24/01/20 Introduction to the nervous system
Peripheral nervous system
Somatic nervous system
- Controls movement of skeletal muscles/transmits somatosensory information to
the central nervous system
Autonomic nervous system
- Body’s vegetative function (primarily involuntary)
o Sympathetic
o Parasympathetic.
Central nervous system
Brain
Spinal cord
- Carries commands from (efferent) the brain to muscles and organs; carries
sensory info to (afferent) the brain
- Locked In syndrome
o Complete paralysis of voluntary muscles (exception – eyes).
Brain and spinal cord -> communicate with body via nerves (bundle of axons)
Spinal nerves
Cranial nerves
Neurons
Higher cortical areas
- 26-29 billion
Cerebellum
, - 70 billion
Spinal cord
- 1 billion
“Specialised cells that convey sensory information into the brain; carry out the
operations involved in thought, feeling and action; and transmit commands out into
the body to control muscles and organs” – Garrett (2008).
Components of a neuron:
Dendrite
- Branching extensions that receive messages; send impulses toward the cell body
Axon
- The extension of a neuron, ending in branching terminal fibres, through which
messages are sent to other neurons or to muscles or glands
Myelin sheath
- A layer of fatty cells encasing many neurons; increases transmission speed.
Types of a neuron:
Motor neuron
- Efferent
Sensory neuron
- Afferent
Interneuron
- Within CNS.
Internal structure of a neuron:
Membrane
- Phospholipid bilayer
o “Fat sandwich”; fatty acids between 2 slices of polar (phosphate) ‘bread’
o Pierced with protein ‘straws’
- Detect substances
- Control access
- Transport.
Neuronal signalling: electrochemical process
Within a neuron
- Local potentials
o In dendrites and soma
o Passive propagation; gets smaller as they go
- Action potentials
o All-or-none; signals travels down the axon
o Active propagation; maintains intensity
Between neurons
- Synaptic transmission (chemical neurotransmitters).
Membrane potential
Axon is charged
- Cell membrane controls environment (selective permeability)
