The Nervous System
The body control centre
Functions of the Nervous
System


Receives, stores & interpret information e.g. from
eyes & ears
Controls activities of all body systems to maintain
homeostasis within the body
Homeo = combining form meaning the same

Controls all muscle movements including speech
Divisions of Nervous System
1. Central Nervous System (CNS)

Brain

Spinal cord
Divisions of the Nervous
System cont’d
2. Peripheral Nervous System (PNS)


These nerves branch out from the CNS to all
parts of body
There are:
12 pairs of cranial nerves
31 pairs of spinal nerves
Peripheral Nervous System
Nerves of PNS function in a voluntary
Manner
Peripheral nerves carry impulses from receptors in skin,
eyes, ears nose to CNS.

These peripheral nerves are called sensory or afferent nerves
Peripheral nerves also carry impulses from CNS to body
organs

These nerves are called motor or efferent nerves
Division of the Nervous
System cont’d
3. Autonomic System (ANS)

Nerves carry involuntary impulses to
smooth muscle, cardiac muscle & some
glands
Divisions of Nervous System
Central Nervous System
Peripheral Nervous System
Afferent (sensory) neurons from
organs muscles & glands
Efferent (Motor) neurons
to
Muscle & glands
Autonomic Nervous System
Word component
Word Root
Neur
Combining
Form
Neuro
Meaning
nerve
Neurons and their Function


Specialised cells of the Nervous System
Cells responsible for transmission of
nerve impulses
What does a neuron look like?
Network of nerves or neurons
pg1
Word Components
Word Root Combining
form
Plex
Plex/o
Meaning
Cephal
Cephal/o
head
Encephal
Encephal/o brain
cerebr
cerebr/o
network of nerves
cerebrum of the brain
Act 2
The Brain

Cerebrum – large brain

Cerebellum – Little brain
Cerebral Vascular Accident
(CVA)

Is a result of disruption to blood supply (i.e.
ischaemia) to part of the brain

Ischaemia to cerebrum can cause brain cells to die
and is known as an infarct

Paralysis and loss of speech can occur because cells
of the cerebrum control many body movements

Severity depends on what part of the brain is
affected
Cerebral Cortex

Is the outer layer of cerebrum

Contains motor and sensory areas

Responsible for consciousness and
intelligence
Word Components
Word
Root
Combining
form
Meaning
ventricul ventricul/o
Ventricle
crani
crani/o
bones of the skull
(cranium)
gangli
gangli/o
knot of group of nerve cell
bodies
More word components
Mening
mening/o, mening/i
membrane
Radicul
radicul/o
spinal nerve roots
Myel
myel/o
marrow, spinal cord
Pleg
-plegia
paralysis
Aesthesi
aesthesi/o
sensation
Narc
Narc/o
stupor – abnormal sleep
induced by a drug
Alges
Algesi/o, -algesia
sense of pain
Rachi
rachi/o
spine
Act 3
Part
Other parts of brain
Combining
form
Function
Cerebrum
cerebr/o
responsible for
thoughts,judgements,memory,sensation
cerebellum
cerebell/o
coordinates voluntary movement
Thalamus
thalam/o
grey matter; neurons relays sensory
messages e.g. pain to cerebral cortex
Hypothalamus
has neurons that control body
temperature, sleep, appetite, &
emotions
Brain Stem –
pons
medulla oblongata
relays messages to cerebrum,
cerebellum, & spinal cord
responsible for breathing, heart rate,
and heat
CRANIUM
CEREBRUM
Thalamus
Hypothalamus
PONS
CEREBELLUM
MEDULLA OBLONGATA
THE BRAIN
Spinal Cord

Extends from the medulla oblongata to the second
lumbar vertebra

Carries nerves that affect limbs &lower parts of body

Is the pathway for impulses to & from brain

Inner section composed of grey matter

Outer section composed of white matter
Meninges
What are the layers surrounding brain & spinal
Cord?
1.
Dura mater – outer membrane contains channels
for blood to enter brain tissue. Subdural space is
below the dura & contains blood vessels
2.
3.
Arachnoid membrane – next layer. Subarachnoid
space contains cerebrospinal fluid (CSF)
Pia mater – layer closest to brain
Rachiocentesis


Procedure to take sample of CSF from
spinal cord fro testing
Also known as a lumbar puncture or
spinal tap
Act 4
Conditions of Nervous System
Condition
Meaning
Alziemers Disease
deterioration of mental capacity causing degeneration of neurons in
cerebral cortex
Palsy
Bells Palsy
Cerebral Palsy
unilateral facial paralysis due to disorder of facial nerve
partial paralysis & lack of muscular coordination due to damage to
cerebrum during birth
Parkinson’s Disease
degeneration of brain nerves leading to tremors, weakness, &
slowness of movement
Multiple Sclerosis
conduction of nerve impulses is prevented due to parasthesia,
leading to muscle weakness, unsteady gait & paralysis
Epilepsy
recurrent seizures & /or fitting
Word Components
Word part Meaning
-lexia
condition of speech/ words
mening/o
meninges
myel/o
spinal cord or bone marrow
occipit/o
occipit, posterior region of the skull
-paresis
weakness, slight paralysis
-plegia
paralysis
plexus
network of vessels or nerves
synapse
membrane to membrane contact of one nerve cell to
another
Abbreviations
CAT or
CT Scan
Computerized Axial Tomographyx rays are beamed at different angles to produce images and
examine soft tissues of the body
EEG
Electroencephalogram – recording of brain waves
MRI
Magnetic Resonance Imaging – uses movement of hydrogen
to a large magnetic field to produce images of internal soft
tissues
Conditions & Terms
anaesthesia
loss of sensation resulting from medication
analgesia
loss or reduction of pain sensation
encephalitis
inflammation of the brain
hemiparesis
weakness on one side (half) of body
hemiplegia
paralysis of one side (half ) of body
hydrocephalus
excessive amount of cerebrospinal fluid around the
brain
paralysis
complete or partial loss of controlled movement
sciatica
pain that radiates down the sciatic nerve, affecting
buttock, thigh, and foot