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Nervous System Functioning (Persistant Vegetative States (PVS) (Patients…
Nervous System Functioning
The Nervous System
Central Nervous System (CNS)
Brain
Receives all incoming information, process' this information and then responds to it
#
Spinal Chord
Transmits sensory messages from the body up to the brain and sends motor messages from the brain out to the rest of the body
#
White Matter
= Myelinated axons (part of neuron that sends information away from cell body or soma) Myelin is a protective coating that helps speed up transmission of information
Gray matter
= Neuron bodies, mainly located near the centre of the spinal chord
Levels
? Ask Powrie if we will need to know them
Reflexes
Unconscious
Spinal Reflexes
Do
not
involve the brain
Where survival is threatened, the spinal cord will operate without the instruction of the cerebral Cortex
Most spinal reflexes are polysynaptic however, some simple reflexes are monosynaptic
Peripheral Nervous System (PNS)
Is to carry sensory information to, and motor information away from, the central nervous system
Somatic Nervous System
Voluntary control of skeletal muscles
Skeletal Muscles
The somatic branch of the NS is primarily involved in
voluntary movements
of the body
Autonomic Nervous System
Is responsible for the body’s involuntary/physiological functions
Parasympathetic Nervous System
Calms the body after times of vigorous activity or the need for high arousal has passed, and maintains the body in a state of homeostasis
Calms back down, keeps at stable level, maintains homeostasis
Brain Stem
Responsible for a large amount of unconscious response, particularly those regulated by the Autonomic Nervous System
Located at the top of the spinal chord, explains why quadriplegics are still able to maintain autonomic functions
Roles Include
maintaining and controlling
:
Breathing, regulation of PH and Acidity levels, digestion, fight-flight-freeze responses
Sympathetic Nervous System
Regulates the activity of internal muscles, organs and glands so the body is energised and prepared for action in times of high arousal
Branch controls arousal, fight –flight-freeze response
Sensory Division (
Afferent
)
Motor Division (
Efferent
)
#
Cerebral Cortex
FPOT
(Frontal, Parietal, Occipital, Temporal
Primary Motor Cortex
Voluntary Movements
Motor Areas
Receive and process information about voluntary bodily movements
Only
one
primary motor area in the brain, located in the frontal Lobe
The motor area mostly controls
conscious response
Primary Somatosensory Cortex
Bodily Sensations
Sensory Areas
Receive and process information from sensory receptors in the body
Convert the ‘
raw
’ sensory information into
neural impulses
and transmit it to the sensory areas in the brain via neural pathways
Primary
visual cortex
– Occipital lobe
Primary
auditory cortex
- Temporal lobe
Primary
somatosensory cortex
- Parietal lobe
Association areas
Do
not
have any specialised sensory or motor function
Allow the brain to
integrate
information and link this with pre-existing ideas, concepts and memories
Also involved in complex mental abilities
All Lobes
Neurons
Central Nervous System
Motor Neurons
Sensory Neurons
Interneurons
Peripheral Nervous System
Motor Neurons
Sensory Neurons
Parts of a Neuron
Dendrites
Cell Body
Axon
Axon Terminals
Terminal Buttons
Synapse
Role of Neurotransmitters
The gap between neurons is called the
synapse
#
When the
neural impulse
reaches the end of each axon, the terminal buttons
releases chemicals called neurotransmitters
Sometimes the neurotransmitter
triggers or activates
a neural impulse on the connecting neuron. We refer to this type of neurotransmitter as
excitatory
At other times, the neurotransmitter
prevents or stops
the connecting neuron from firing. We refer to this type of neurotransmitter as
inhibitory
When the neurotransmitter has done its job it is either taken back by the terminal buttons or disposed of
The
synapse
is an
actual physical space
that exists between any two neurons. It is here that neurotransmitter begins and completes its journey from its presynaptic creator to its postsynaptic receiver
#
A post-synaptic neuron
must
reach its
action potential
before it can continue the sequence
Persistant Vegetative States (PVS)
Patients in a vegetative state may have
physiologically ‘awoken’
from a coma
Patient has NOT regained awareness, ergo they are not attentive or aware of their surroundings.
Patients can open their eyelids occasionally and demonstrate sleep-wake cycles
Completely lack cognitive function
Diagnosis is made after numerous
neurological
and other tests.