Neural
Control
and
Coordination
o
Coordination
is
the
process
through
which
two
or
more
organs
interact
and
complement
the
functions
of
one
another
to
maintain
homeostasis
in
our
body.
(1)
INTRODUCTION
The
neural
system
and
the
endocrine
system
jointly
coordinate
and
integrate
all
the
activities
of
the
organs
so
that
they
function
in
a
synchronised
fashion.
(4)
TYPES
OF
AXONSINERVE
FIBRES
Parameters
Myelinated
Non-myelinated
Myelin
sheath
Node
of
Ranvier
Location
Cranial
&
spinal
nerves
o
Schwann
cells
surround
both
myelinated
and
non-myelinated
nerve
fibres
but
they
form
myelin
sheath
only
in
myelinated
fibres.
Autonomic
and
somatic
neural
system
5)
CONCENTRATION
GRADIENT
ACROSS
AXONAL
MEMBRANE
o
Excitability
of
neurons
is
attributed
to
polarised
state
of
neural
membranes.
o
It
has
selectively
permeable
ionic
channels
responsible
for
differential
concentration
gradient
across
the
axonal
membrane
ICF
o
At
rest,
axonal
membranes
are
more
permeable
for
K,
neariy
impermeable
to
Na
and
impermeable
to
negatively
charged
proteins.
Composition
Types
of
fluids
SEGE
K't,
Nat
(
o
lonic
gradients
across
resting
membrane
are
maintained
by
the
active
transport
of
ions
by
the
sodium-potassium
pump
which
pumps
3Na
outwards
and
2K
into
the
cell
(2)SYSTEMS
MAINTAINING
HOMEOSTASIS
PARAMETERS
o
Integration
Through
hormones
Coordination
Slower
Neural
system
provides
an
organised
network
of
point
to
point
connections
with
target
cells.
NEURAL
SYSTEM
Through
o
Cycle
of
events:
neurotransmitters
6)
GENERATION
OF
IMPULSE
Resting
state
(This
state
is
maintained
by
Na'IK
pump)
Quicker
o
The
electrical
potential
difference
across
the
resting
plasma
membrane
is
called
the
resting
potential
o
The
electrical
potential
difference
across
the
axonal
membrane
after
receiving
threshold
stimulus
is
called
action
potential/nerve
impulse.
Threshold
stimulus
Change
in
permeability
of
axolemma
for
Na
B
K'etmuox
Repolarisation
ENDOCRINE
SYSTEM
(
cONDUCTION
OF
IMPULSE
(0
Depolarisation
o
Flow
of
charge
is
from
A?outer
Na
influx
o
Impulse
generated
at
a
site
arrives
at
another
site
and
same
sequence
is
repeated
along
the
length
of
axon.
Change
in
permeability
of
axolemma
for
K
o
Current
flows
in
a
circuit
when
it
moves
from
A
to
B
site.
Inner
R
membrane
o
Neuron
is
the
structural
and
functional
unit
of
the
neural
system
o
Composed
of
a
cell
body,
dendrites
and
axon
Types
o
o
Dendrites
Multipolar
2
or
more
Cerebral
cortex
Bipolar
Retina
of
eye
Unipolar
Embryonic
stage|
o
No.
of
Above
given
neurons
have
only
one
axon.
1
Cell
body
contains
cell
organelles.
Impulse
from
dendrite
moves
towards
cell
body
and
in
axon
away
from
cell
body.
-Neurotransmitters
released
in
synaptic
cleft
Features
oSBind
to
receptors
on
post
synaptic
neuronal
(PSN)
cmembrane
oOpening
of
ion
channels
in
PSN
oGenerates
a
new
potential
in
PSN
o
Flow
of
impulse
lo
Transmission
NEURON
Location
lo
Pre&
post
neuron
o
Nature
o
Existence
(8)
TRANSMISSION
OF
IMPULSE
Neuroranernictors
Types
of
Synapse
Electrical
synapse
Close
proximity
through
gap
junctions
Direct
Faster
Rare
Nucleus
Schwann¢
cell
o
Neve
impulse
is
transmitted
from
one
neuron
to
another
across
a
synapse.
Events
observed:
Myelin
sheath
Node
of
4
Ranvier
Axon
torminal
9A
Chapter
NissIs
grnosls
→Axon
Neurotransniters
are
stored
i
synaptic
vesiclos
o
Synaptic
lnobe
Fig.:
Structure
of
a
neuron
→Aon
Axon
terminal
HSynaptic
vesices
+Pre-synaptic
membrane
Synapic
clet
Post-synaptic
membr
orane
Receptors
Chemical
synapse
Separated
by
fuid-filled
synaptic
cleft
Through
neurotransmitters
Slower
Excitatory
or
inhibitory
Common
Transmission
of
impulse
across
electrical
synapse
is
very
similar
to
impulse
conduction
along
a
single
axon.
