Please enable JavaScript.
Coggle requires JavaScript to display documents.
NERVOUS SYSTEM, most sympatheitc - Coggle Diagram
NERVOUS SYSTEM
cell membrane potential
polarized as result
unequal distribution of ions
on either side
channels in membrane
allow passage of some ions
but not others
control ion distribution
distribution of ions
membrane ion channels
formed by proteins
may be
always open
sometimes open/closed
potassium ions
pass more readily
through
resting neuron
cells membranes
than sodium & calcium ions
high concentration
sodium ions
on the outside of membrane
high concentration of
potassium on inside
resting potential
large numbers
negatively charged ions
cannot diffuse
through membrane
are inside the cell
resting cell
more positive ions
leave the cell
than enter it
causing
inside of membrane to
develop negative charge
local potenital changes
stimulation of membrane
affects its
resting potential
in local region
membrane is depolarized
if it becomes less negative
it is hyper polarized
if Imore negative
L.P. changes
graded and subject
to summation
reaching threshold potential
triggers action potential
action potentials
at threshold
sodium ion
channels open
sodium ions
diffuse inward
depolarizing membrane
this rapid change=
action potential
at the same time
potassium channels open
potassium ions
diffuse outward
repolarizing membrane
active transport
reestablishes & maintains
OG concentrations
of ions across membrane
propagation of action potential
along nerve fiber
impulse conduction
all-or-none response
action potential
generated if stimulus
of threshold is
applied to axon
all impulses
conducted
on axon
same strength
refractory period
brief time during
passage of impulse
membrane unresponsive
to ordinary stimulus
absolute refractory period
membrane can't
respond to stimulus
relative refractory period
membrane can respond
high-intensity stimulus
impulse conduction
unmyelinated axon
conducts impulses
travel over
its entire surface
myelinated axon
conducts impulses
travel
from node to node
saltatory conduction
more rapid on
myelinated axons
w/ large
diameters
neurons
vary in
size
shape
size & lengths of
axons & dendrites
number of
dendrites
includes
cell body
contains
granular cytoplasm
chromatophilic subsatance
rough ER
inclusions
glycogen
lipids
pigment
mitochondria
lysosomes
golgi apparatus
microtubules
nucleus
cell processes
organelles
axon
one
rises from
axon hillcock
synaptic cleft
myelin
dendrites
highly branched
provides receptive surfaces
many
neurofilaments
support axons
white matter
myelinated axons
gray matter
unmyelinated axons & cell bodies
structurally classified
bipolar
unipolar
multipolar
functionally classified
interneurons
motor neurons
sensory neurons
Central Nervous System
(CNS)
bundle of axons
tracts
brain
neuroglia
outnumber
neurons
assemble in
special, protective way
ex. blood brain barrier
types
oligodendrocytes
microglia
astrocytes
ependyma
abundant
fill spaces
support neurons
hold nervous
tissue together
help metabolize glucose
help regulate potassium
ion concentration
produce myelin
1 more item...
malfunction can
cause diseases
spinal cord
neurons that
conduct impulses
from CNS to
responsive structures
called effectors
carry out motor functions
outside of the NS
include muscles & glands
Peripheral Nervous System
(PNS)
ganglia
clusters of neurons
outside CNS
schwann cells
encase large axons
myelin
neurilemma
nodes of Ranvier
satellite cells
bundles of axons
nerves
nerves
cranial & spinal
connect CNS to other body parts
structures at the
ends of neurons
sensory receptors
provide sensory functions
gather info
detecting changes
in and outside of body
then
transduce their info
into impulses
1 more item...
subdivided into
somatic nervous system
communicates
voluntary
conscious
instructions
originating from the CNS
to skeletal muscles
1 more item...
automatic nervous system
communicates
instructions
from CNS that control other systems
eg. heart and glands
involuntary
subconscious
1 more item...
functions
w/o conscious effort
regulates
visceral activites
that maintain
homeostasis
general characteristics
automic functions
reflexes controlled
from centers
in hypothalamus
brainstem
spinal cord
automatic nerve fibers
associated w/
ganglia where
impulses are intergated
before distribution
of effectors
provides a degree of
independence from CNS
consists of
visceral efferent fibers
associated w/ ganglia
divided into 2
sympathetic
prepares the body
for stressful &
emergency conditions
leave the spinal cord
synapse in ganglia
preganglionic fibers
pass through
white rami
to reach paravertebral
ganglia
fibers synpase w/ paravertebral or collateral ganglia
paravertebral ganglia
& interconnecting fibers
comprise the sympathetic trunks
postganglionic fibers
pass through gray rami
to reach spinal nerves
parasympathetic
most active
under ordinary conditions
includes
parasympatheic fibers
that begin in the brainstem
and sacral region of spinal cord
1 more item...
automatic neurotransmitters
sympathetic and parasympathetic preganglionic fibers secrete acetylcholine
synaptic transmission
neurotransmitter molecules
diffuse across synaptic cleft
react w/ receptors
in postsynaptic
synaptic potentials
some neurotransmitter
depolarize
postsynaptic membrane
can trigger action potential
excitatory postsynaptic
potential (EPSP)
others hyper-polarize
inhibiting action potential
inhibitory postsynaptic
potential (IPSP)
neurotransmitters
produces at least 100
diff. types of neurotransmitters
in brain alone
calcium ions diffuse
into synaptic knobs
in response to action pot.
releasing NT
quickly decompose/remove
from synaptic clefts
neuropeptides
chains of amino acids
enkephalins, endorphins, and substanceP
composed of
neural tissue
neuroglia
functions
nourishing neurons
sending
receiving
chemical messages
neurons
send (axons)
receive (dendrites)
bioelectrical signals
(impulses)
biological messenger
molecules
neurotransmitters
convey neural info
across synaptic clefts
at functional connections
synapses
1 more item...
specialized to
react to
physical
chemical
changes in
surroundings
receives the signals
dendrites
1 more item...
blood vessels
connective tissue
3 general functions
receive info
sensory
decided what to do w/ info
integrative
acting on those decisions
motor
synapse
functional connection
between two cells
cleft
gap between parts
of 2 cells in synapse
transmission
impulse in presynaptic
neuron signals post synaptic cell
impulse processing
neuronal pools
neurons organized
in CNS
each pool
receives input
processes information
may generate output
each neuron
may receive
excitatory
stimulus
inhibitory
neuron facilitated
receives sub-threshold
stimuli & becomes
more excitable
convergence
impulses
2 or more
may coverage on
single postsynaptic neuron
enables neuron
to sum input from
diff. sources
divergence
impulses from
presynaptic neuron
may reach several
postsynaptic neurons
allows a single neuron
reaching threshold
to have potentially
widespread effects
impulse is conducted along the axon to a synapse
axons have synaptic knobs at
their distal ends that release neurotransmitters
neurotransmitter is released when a
n impulse reaches the end of an axon
neurotransmitter diffuses
across the synaptic cleft
neurotransmitter reaching a postsynaptic neuron
or other cell may be excitatory or inhibitory
impulse processing
neuroal pools
nervous system divided into PNS & CNS
most sympatheitc