The nervous system
AO1 – The nervous system
Divisions of Central nervous system Peripheral nervous system
the nervous Brain Spinal cord Somatic
system Autonomic
Sympat
hetic Parasympathetic
AO1 – the The spinal cord:
central - Relays information between the brain and the rest
nervous of the body
system - Allows the brain to monitor and regulate bodily
processes and coordinate voluntary movements
- Contains circuits of nerve cells which enable us to
perform simple reflexes without the brain’s
involvement
- If damaged, the associated areas will be cut off
from the brain
The brain:
- The cerebrum: divided into four lobes (frontal,
parietal, occipital, temporal), split into two
hemispheres which communicate via the corpus
callosum
- The cerebellum: involved in controlling a person’s
motor skills and balance, abnormalities can lead
to problems such as speech and motor problems
or epilepsy
- The diencephalon: contains the thalamus and
hypothalamus – the thalamus relays nerve
impulses to the correct part of the brain to be
processes, the hypothalamus regulates body
temperature, hunger and thirst, and links the
nervous system to the endocrine system
- The brain stem: regulates automatic life functions
e.g. heartbeat, breathing and swallowing
AO1 – the The somatic nervous system:
peripheral - Made up of 12 pairs of cranial nerves and 31 pairs
nervous of spinal nerves
system - Responsible for carrying sensory and motor
information to and from the central nervous
system
- Involved in reflex actions
The autonomic nervous system:
- Governs involuntary and self-regulating functions
- The sympathetic nervous system:
- Involved in preparing the body for emergencies
(fight or flight) so increases heart rate, breathing
rate, dilates pupils, slows digestion and urination
etc.
, - The parasympathetic nervous system:
- Returns the body back to normal after entering a
state of fight or flight (often called rest and
digest)
- Restarts digestion and urination, slows the heart
rate, breathing rate etc, stops excess perspiration,
lowers blood pressure etc.
Neurons and synaptic transmission
AO1 – the Sensory neurons:
structure and - Carry nerve impulses from sensory receptors to
function of the central nervous system
neurons - Found in the eyes, ears, tongue, skin etc. and
convert information from sensory receptors into
neural impulses which are translated into heat,
pain etc
- Some sensory information terminates at the
spinal cord and is expressed as a reflex
Relay neurons:
- Allow sensory and motor neurons to
communicate with each other, and only exist
within the brain and spinal cord
Motor neurons:
- Conduct signals from the CNS to effector muscles
by forming synapses with muscles to control their
contractions
- cell bodies are in the CNS, but the axons extend
to and form part of the PNS
- When stimulated, motor neurons release
neurotransmitters to bind to the receptors on the
muscle to trigger muscle movement
- Muscle relaxation is caused by inhibition of motor
neurons
AO1 – synaptic - An action potential arrives at the terminal button
transmission at the end of an axon
- At the end of the axon if of the presynaptic nerve
cell are synaptic vesicles, which secrete
neurotransmitters into the synaptic gap
- The released neurotransmitters bind to
specialised receptors on the dendrites of the post
synaptic neuron, which then produce either an
excitatory or inhibitory effect on the post
synaptic neuron
- Reuptake often occurs, where the longer it takes
for the neurotransmitters to re-enter the
presynaptic vesicles, the greater effect the
neurotransmitters have on the post synaptic
neuron
AO1 – - Excitatory neurotransmitters e.g. noradrenaline
AO1 – The nervous system
Divisions of Central nervous system Peripheral nervous system
the nervous Brain Spinal cord Somatic
system Autonomic
Sympat
hetic Parasympathetic
AO1 – the The spinal cord:
central - Relays information between the brain and the rest
nervous of the body
system - Allows the brain to monitor and regulate bodily
processes and coordinate voluntary movements
- Contains circuits of nerve cells which enable us to
perform simple reflexes without the brain’s
involvement
- If damaged, the associated areas will be cut off
from the brain
The brain:
- The cerebrum: divided into four lobes (frontal,
parietal, occipital, temporal), split into two
hemispheres which communicate via the corpus
callosum
- The cerebellum: involved in controlling a person’s
motor skills and balance, abnormalities can lead
to problems such as speech and motor problems
or epilepsy
- The diencephalon: contains the thalamus and
hypothalamus – the thalamus relays nerve
impulses to the correct part of the brain to be
processes, the hypothalamus regulates body
temperature, hunger and thirst, and links the
nervous system to the endocrine system
- The brain stem: regulates automatic life functions
e.g. heartbeat, breathing and swallowing
AO1 – the The somatic nervous system:
peripheral - Made up of 12 pairs of cranial nerves and 31 pairs
nervous of spinal nerves
system - Responsible for carrying sensory and motor
information to and from the central nervous
system
- Involved in reflex actions
The autonomic nervous system:
- Governs involuntary and self-regulating functions
- The sympathetic nervous system:
- Involved in preparing the body for emergencies
(fight or flight) so increases heart rate, breathing
rate, dilates pupils, slows digestion and urination
etc.
, - The parasympathetic nervous system:
- Returns the body back to normal after entering a
state of fight or flight (often called rest and
digest)
- Restarts digestion and urination, slows the heart
rate, breathing rate etc, stops excess perspiration,
lowers blood pressure etc.
Neurons and synaptic transmission
AO1 – the Sensory neurons:
structure and - Carry nerve impulses from sensory receptors to
function of the central nervous system
neurons - Found in the eyes, ears, tongue, skin etc. and
convert information from sensory receptors into
neural impulses which are translated into heat,
pain etc
- Some sensory information terminates at the
spinal cord and is expressed as a reflex
Relay neurons:
- Allow sensory and motor neurons to
communicate with each other, and only exist
within the brain and spinal cord
Motor neurons:
- Conduct signals from the CNS to effector muscles
by forming synapses with muscles to control their
contractions
- cell bodies are in the CNS, but the axons extend
to and form part of the PNS
- When stimulated, motor neurons release
neurotransmitters to bind to the receptors on the
muscle to trigger muscle movement
- Muscle relaxation is caused by inhibition of motor
neurons
AO1 – synaptic - An action potential arrives at the terminal button
transmission at the end of an axon
- At the end of the axon if of the presynaptic nerve
cell are synaptic vesicles, which secrete
neurotransmitters into the synaptic gap
- The released neurotransmitters bind to
specialised receptors on the dendrites of the post
synaptic neuron, which then produce either an
excitatory or inhibitory effect on the post
synaptic neuron
- Reuptake often occurs, where the longer it takes
for the neurotransmitters to re-enter the
presynaptic vesicles, the greater effect the
neurotransmitters have on the post synaptic
neuron
AO1 – - Excitatory neurotransmitters e.g. noradrenaline
