Biopsychology
The divisions of the nervous system
The nervous - The nervous system is a specialised network of cells in the
system human body and is our primary internal communication
system
- It has two main functions
1. To collect, process and respond to information in the
environment
2. To co-ordinate the working of different organs and cells
in the body
- It is divided into two sub-systems: the central nervous
system (CNS) and the peripheral nervous system (PNS)
The central - The CNS is made up of the brain and the spinal cord
nervous - Passes messages to and from the brain and connects
system nerves to the PNS
Brain
- Centre of all conscious awareness
- The outer layer, the cerebral cortex, is highly developed in
humans and what distinguishes our mental functions from
those of animals
- Divided into two hemispheres
Spinal cord
- Extension of the brain
- Responsible for reflex actions
The - Transmits messages, via millions of neurons, to and from
peripheral the CNS
nervous - Subdivided into the autonomic nervous system (ANS) and
system the somatic nervous system (SNS
- ANS – governs vital functions in the body such as
breathing, heart rate and digestion
- SNS – controls muscle movement and receives information
from sensory receptors
The structure and function of neurons
Types of - Neurons are nerve cells that process and transmit
neuron messages through electrical and chemical signals
- Three types of neurons
- Motor neurons – connect the CNS to effectors such as
muscles, they have short dendrites and long axons
- Sensory neurons – carry messages from the PNS to the
CNS, they have long dendrites and short axons
- Relay neurons – connect the sensory neurons to the motor
or other relay neurons, they have short dendrites and short
axons
, Biopsychology
The structure - Neurons vary in size from less than a mm to up to a metre,
of a neuron but all share the same basic structure
- The cell body includes a nucleus which contains all the
genetic material
- Dendrites are branch-like structures which extend from the
cell body and carry nerve impulses from neighbouring
neurons towards the cell body
- The axon carries the impulses away from the cell body
down the length of the neuron. It is covered in a fatty layer
of myelin sheath that protects the axon and speeds up
electrical transmission of the impulse.
- The myelin sheath is segmented by gaps – nodes of
Ranvier, which speed up the transmission of the impulse
by forcing it to ‘jump’ across the gaps along the axon
- Terminal buttons are at the end of the axon and
communicate with the next neuron in the chain across a
gap called the synapse
Electric - When a neuron is in its resting state the inside of the cell is
transmission negatively charged compared to the outside
- When the neuron is activated by a stimulus, the inside of
the cell becomes positively charged for a second causing
an action potential to occur
- This creates an electrical impulse that travels down the
axon towards the end of the neuron
The process of synaptic transmission
Synaptic - The process by which neighbouring neurons communicate
transmission with each other by sending chemical messages across the
gap (the synaptic cleft) that separates them
Chemical - Neurons communicate with each other within groups called
transmission neural networks
- Each neuron is separated from the next by a synapse
which includes the space between them (the synaptic cleft)
as well as the presynaptic terminal and postsynaptic
receptor sight
- Signals within neurons are transmitted electrically;
however, signals between neurons are transmitted
chemically by synaptic transmission
- When the electrical impulse reaches the end of the neuron
(the presynaptic terminal) it triggers the release of
neurotransmitter from tiny sacs called synaptic vesicles
Neurotransmit - Chemicals that diffuse across the synapse to the next
ter neuron in the chain
The divisions of the nervous system
The nervous - The nervous system is a specialised network of cells in the
system human body and is our primary internal communication
system
- It has two main functions
1. To collect, process and respond to information in the
environment
2. To co-ordinate the working of different organs and cells
in the body
- It is divided into two sub-systems: the central nervous
system (CNS) and the peripheral nervous system (PNS)
The central - The CNS is made up of the brain and the spinal cord
nervous - Passes messages to and from the brain and connects
system nerves to the PNS
Brain
- Centre of all conscious awareness
- The outer layer, the cerebral cortex, is highly developed in
humans and what distinguishes our mental functions from
those of animals
- Divided into two hemispheres
Spinal cord
- Extension of the brain
- Responsible for reflex actions
The - Transmits messages, via millions of neurons, to and from
peripheral the CNS
nervous - Subdivided into the autonomic nervous system (ANS) and
system the somatic nervous system (SNS
- ANS – governs vital functions in the body such as
breathing, heart rate and digestion
- SNS – controls muscle movement and receives information
from sensory receptors
The structure and function of neurons
Types of - Neurons are nerve cells that process and transmit
neuron messages through electrical and chemical signals
- Three types of neurons
- Motor neurons – connect the CNS to effectors such as
muscles, they have short dendrites and long axons
- Sensory neurons – carry messages from the PNS to the
CNS, they have long dendrites and short axons
- Relay neurons – connect the sensory neurons to the motor
or other relay neurons, they have short dendrites and short
axons
, Biopsychology
The structure - Neurons vary in size from less than a mm to up to a metre,
of a neuron but all share the same basic structure
- The cell body includes a nucleus which contains all the
genetic material
- Dendrites are branch-like structures which extend from the
cell body and carry nerve impulses from neighbouring
neurons towards the cell body
- The axon carries the impulses away from the cell body
down the length of the neuron. It is covered in a fatty layer
of myelin sheath that protects the axon and speeds up
electrical transmission of the impulse.
- The myelin sheath is segmented by gaps – nodes of
Ranvier, which speed up the transmission of the impulse
by forcing it to ‘jump’ across the gaps along the axon
- Terminal buttons are at the end of the axon and
communicate with the next neuron in the chain across a
gap called the synapse
Electric - When a neuron is in its resting state the inside of the cell is
transmission negatively charged compared to the outside
- When the neuron is activated by a stimulus, the inside of
the cell becomes positively charged for a second causing
an action potential to occur
- This creates an electrical impulse that travels down the
axon towards the end of the neuron
The process of synaptic transmission
Synaptic - The process by which neighbouring neurons communicate
transmission with each other by sending chemical messages across the
gap (the synaptic cleft) that separates them
Chemical - Neurons communicate with each other within groups called
transmission neural networks
- Each neuron is separated from the next by a synapse
which includes the space between them (the synaptic cleft)
as well as the presynaptic terminal and postsynaptic
receptor sight
- Signals within neurons are transmitted electrically;
however, signals between neurons are transmitted
chemically by synaptic transmission
- When the electrical impulse reaches the end of the neuron
(the presynaptic terminal) it triggers the release of
neurotransmitter from tiny sacs called synaptic vesicles
Neurotransmit - Chemicals that diffuse across the synapse to the next
ter neuron in the chain
