Biopsychology
Biopsychology
The nervous system
The nervous system is made of a
specialised network of cells and is our
primary communication system
(control centre).
Functions
‣ To collect, process and respond to
information in the environment
‣ To coordinate the workings of di erent organs and cells in the body
The central nervous system (CNS)
Functions
‣ Controls behaviour
‣ Regulates the body’s physiological process
The brain
‣ The cerebral cortex (outer layer) is highly developed in humans due to higher cognitive
functioning ability
‣ Motor and sensory neurones travel through the brain to pass impulses between the
brain and spinal cord
Brain stem: This is responsible for regulating automatic functions (breathing, heartbeat)
Cerebrum: The largest part which is divided into 4 lobes (Frontal, Parietal, Occipital and
Temporal) each with di erent functions. The cerebrum is split into 2 halves - cerebral
hemispheres which are specialised for particular behaviours which communicate via the
corpus callosum.
Cerebellum: Beneath back of the cerebrum which controls motor skills,
balance and controls muscles.
Diencephalon: Above the brain stem, underneath the cerebrum. Includes
the hypothalamus (regulation of body temp, hunger, release of hormones)
and the thalamus (relay station for nerve impulses from senses)
The spinal cord
‣ Receives and transmits information to and from the brain to the PNS
‣ Allows brain to regulate bodily processes
‣ Allows the brain to coordinate voluntary movements
‣ Responsible for re ex actions without involving the brain
The peripheral nervous system (PNS)
‣ Main function is to connect the CNS to the limbs and organs, serving as a relay
between the brain and spinal cord and rest of the body
‣ Messages in the PNS transfer from the CNS to the rest of the body and vice versa
Page 1 of 26 A Level Psychology Paper 2
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,Biopsychology
Divisions of the peripheral nervous system
The somatic nervous system (SNS)
‣ In charge of voluntary actions (consciously)
‣ Controls skeletal muscles and connects with
the senses
‣ Is connected to the CNS and sensory organs
by motor and sensory neurones
‣ It also allows re ex actions to occur very quickly without the CNS via sensory, relay and
motor neurones
The autonomic nervous system (ANS)
‣ Regulates involuntary actions (unconsciously)
‣ Controls smooth muscles and glands such as organs that are vital to the body
‣ Made up of a collection of motor neurones doesn’t contain any
sensory neurones
‣ The brainstem controls communication
The sympathetic system
‣ Has stimulating e ects by sending neurotransmitters to parts of
the body (e.g. increasing heart rate)
‣ Involved in responses that help deal with emergencies
‣ Neurones from the SNS travel to all the body ready for rapid
action
The parasympathetic system
‣ Has inhibiting e ects by sending inhibiting neurotransmitters to
the body (e.g. slowing heart rate)
‣ Relaxes individuals when a treat has passed
‣ Slows does heartbeat and the PNS initiates digestion again
The structure and function of sensory, relay and
motor neurones
Cell body: Has a nucleus which contains genetic material of a call. The control centre.
Dendrites: Branch-like structures which protrude from the cell body, they carry nerve
impulses from neurones or sensory receptors to the cell body.
Axon: Carries the impulse away from the cell body down the length of the neuron.
Myelin sheath: Fatty layer that protects the axon and speeds up synaptic transmission.
Node of Ranvier: Gaps in the myelin sheath that speed up
transmission impulses by forcing it to jump across the gaps.
Axon terminal: At the end of the axon, communicate with the
next neuron in the chain.
Synapse: A gap between pre-and post-synaptic neuron.
Page 2 of 26 A Level Psychology Paper 2
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, Biopsychology
Type of Structure Function
neuron
Sensory ‣ Dendrites in groups ‣ Carry messages from the receptors to the CNS
neuron called ganglia ‣ Cause re ex actions
‣ Long dendrites and ‣ Carry sensory information from receptors to the CNS/brain
short axon
Relay ‣ Short dendrites and ‣ Connect the sensory neurones to the motor neurones or other
neuron axon relay neurones within the CNS
‣ Responsible for communication between di erent brain regions
‣ The brain is entirely composed of relay neurones
Motor ‣ Largest cell body ‣ Carry messages from the CNS to the e ectors such as muscles
neron ‣ Short dendrites and and glands
a single, projecting, ‣ Cause muscles to contract or relax and keep the heart beating
long axon ‣ Axon exists in groups from stem cells to muscles
Synaptic transmission
Electric transmission
‣ When a neuron is in resting state it is negatively (-70mv) charged compared to outside
‣ If it is activated by a stimulus the cell body becomes more positively charged for a split
second
‣ This causes an action potential which is when an electrical impulse travels down the
axon towards the end of the neuron (terminal buttons)
Between pre and post-synaptic neurones
‣ When an action potential arrives at the terminal button, it is
transferred across the synoptic cleft by synaptic transmission
‣ It triggers the release of neurotransmitters from synaptic vesicles in
the pre-synaptic neuron terminal button (chemical messengers that
assist in the transfer of the impulse through a process called
exocytosis
‣ Neurotransmitters di use across the synaptic gap (from a high
conc. to a low conc.) and bind to specialised receptor sites on the
post-synaptic cell dendrites
‣ The binding of the neurotransmitter to the receptor causes the
chemical message to convert back to an electrical impulse where
information is passed onto this neurone
Page 3 of 26 A Level Psychology Paper 2
fl ff ff ff
Biopsychology
The nervous system
The nervous system is made of a
specialised network of cells and is our
primary communication system
(control centre).
Functions
‣ To collect, process and respond to
information in the environment
‣ To coordinate the workings of di erent organs and cells in the body
The central nervous system (CNS)
Functions
‣ Controls behaviour
‣ Regulates the body’s physiological process
The brain
‣ The cerebral cortex (outer layer) is highly developed in humans due to higher cognitive
functioning ability
‣ Motor and sensory neurones travel through the brain to pass impulses between the
brain and spinal cord
Brain stem: This is responsible for regulating automatic functions (breathing, heartbeat)
Cerebrum: The largest part which is divided into 4 lobes (Frontal, Parietal, Occipital and
Temporal) each with di erent functions. The cerebrum is split into 2 halves - cerebral
hemispheres which are specialised for particular behaviours which communicate via the
corpus callosum.
Cerebellum: Beneath back of the cerebrum which controls motor skills,
balance and controls muscles.
Diencephalon: Above the brain stem, underneath the cerebrum. Includes
the hypothalamus (regulation of body temp, hunger, release of hormones)
and the thalamus (relay station for nerve impulses from senses)
The spinal cord
‣ Receives and transmits information to and from the brain to the PNS
‣ Allows brain to regulate bodily processes
‣ Allows the brain to coordinate voluntary movements
‣ Responsible for re ex actions without involving the brain
The peripheral nervous system (PNS)
‣ Main function is to connect the CNS to the limbs and organs, serving as a relay
between the brain and spinal cord and rest of the body
‣ Messages in the PNS transfer from the CNS to the rest of the body and vice versa
Page 1 of 26 A Level Psychology Paper 2
fl ff ff
,Biopsychology
Divisions of the peripheral nervous system
The somatic nervous system (SNS)
‣ In charge of voluntary actions (consciously)
‣ Controls skeletal muscles and connects with
the senses
‣ Is connected to the CNS and sensory organs
by motor and sensory neurones
‣ It also allows re ex actions to occur very quickly without the CNS via sensory, relay and
motor neurones
The autonomic nervous system (ANS)
‣ Regulates involuntary actions (unconsciously)
‣ Controls smooth muscles and glands such as organs that are vital to the body
‣ Made up of a collection of motor neurones doesn’t contain any
sensory neurones
‣ The brainstem controls communication
The sympathetic system
‣ Has stimulating e ects by sending neurotransmitters to parts of
the body (e.g. increasing heart rate)
‣ Involved in responses that help deal with emergencies
‣ Neurones from the SNS travel to all the body ready for rapid
action
The parasympathetic system
‣ Has inhibiting e ects by sending inhibiting neurotransmitters to
the body (e.g. slowing heart rate)
‣ Relaxes individuals when a treat has passed
‣ Slows does heartbeat and the PNS initiates digestion again
The structure and function of sensory, relay and
motor neurones
Cell body: Has a nucleus which contains genetic material of a call. The control centre.
Dendrites: Branch-like structures which protrude from the cell body, they carry nerve
impulses from neurones or sensory receptors to the cell body.
Axon: Carries the impulse away from the cell body down the length of the neuron.
Myelin sheath: Fatty layer that protects the axon and speeds up synaptic transmission.
Node of Ranvier: Gaps in the myelin sheath that speed up
transmission impulses by forcing it to jump across the gaps.
Axon terminal: At the end of the axon, communicate with the
next neuron in the chain.
Synapse: A gap between pre-and post-synaptic neuron.
Page 2 of 26 A Level Psychology Paper 2
ff
fl ff
, Biopsychology
Type of Structure Function
neuron
Sensory ‣ Dendrites in groups ‣ Carry messages from the receptors to the CNS
neuron called ganglia ‣ Cause re ex actions
‣ Long dendrites and ‣ Carry sensory information from receptors to the CNS/brain
short axon
Relay ‣ Short dendrites and ‣ Connect the sensory neurones to the motor neurones or other
neuron axon relay neurones within the CNS
‣ Responsible for communication between di erent brain regions
‣ The brain is entirely composed of relay neurones
Motor ‣ Largest cell body ‣ Carry messages from the CNS to the e ectors such as muscles
neron ‣ Short dendrites and and glands
a single, projecting, ‣ Cause muscles to contract or relax and keep the heart beating
long axon ‣ Axon exists in groups from stem cells to muscles
Synaptic transmission
Electric transmission
‣ When a neuron is in resting state it is negatively (-70mv) charged compared to outside
‣ If it is activated by a stimulus the cell body becomes more positively charged for a split
second
‣ This causes an action potential which is when an electrical impulse travels down the
axon towards the end of the neuron (terminal buttons)
Between pre and post-synaptic neurones
‣ When an action potential arrives at the terminal button, it is
transferred across the synoptic cleft by synaptic transmission
‣ It triggers the release of neurotransmitters from synaptic vesicles in
the pre-synaptic neuron terminal button (chemical messengers that
assist in the transfer of the impulse through a process called
exocytosis
‣ Neurotransmitters di use across the synaptic gap (from a high
conc. to a low conc.) and bind to specialised receptor sites on the
post-synaptic cell dendrites
‣ The binding of the neurotransmitter to the receptor causes the
chemical message to convert back to an electrical impulse where
information is passed onto this neurone
Page 3 of 26 A Level Psychology Paper 2
fl ff ff ff
