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NERVOUS SYSTEM
DRAW YOUR OWN CONCEPT MAP OF THE
NERVOUS SYSTEM
COMPONENTS OF NERVOUS SYSTEM
NEURONS _________-collection of nerve cell bodies
 NERVES-bundled neurons
 SPINAL CORD-connection between ______ and
periphery
 BRAIN
Draw picture of a neuron below
NEURONS
Basic units of
communication in
nearly all nervous
systems
 Send
___________ to
and from the
_____ and
_____ and the
effectors
(muscles/glands)

Monitor information in and around the body and
issue commands for responsive actions
 Contain dendrites, cell bodies and axons

STRUCTURE

 Fine hair-like extensions on the end
of a neuron.


Function: __________ incoming stimuli from
environment or other neurons; conduct nerve impulse
toward the __________
 The control center of the
neuron; contains the nucleus


OF A NEURON
Function:
Nucleus 

Function: Tells the soma what to do
STRUCTURE

Axon 


Function: Conducts nerve impulses away form the
cell body to other neurons or to effectors
 A fatty protein that coats
most axons; made of non-conducting cells known
as Schwann cells


OF A NEURON
Function: Insulates neurons; prevents from losing
charged ions from the nerve cell
Nodes of Ranvier  Gaps between sections of
myelin sheath
Function:
 Situation where ________ of an impulse is greatly
____________ by the message ‘jumping’ the gaps in
the axon.

STRUCTURE

OF A NEURON
Neurilemma
A thin outer
membrane surrounding
the axon on all nerve
fibres in the PNS
 formed by Schwann
cells


Not all cells that have a
myelin sheath have
neurilemma
_______________
 No neurilemma





Nerves in the brain that
contain myelinated fibres
(myelinated axons look white)
_______________
No neurilemma

Do not contain myelin sheath
3 CLASSES OF NEURONS


Detect and relay information from __________ to
the brain and ____________


Communicates with other neurons. Often links
_________ and ____________. Involved in
memory and other complex brain functions.


Delivers information from other _________to
muscles and _________
DRAW TYPES
OF NEURONS
3 TYPES

Function:
 Neurons located near effectors
(muscles and glands)


NEURONS
Sensory Neurons Neurons located near receptor
organs (skin, ears, eyes)


OF
Function: Delivers information from other neurons to
muscles and glands
Interneurons  Neurons that relay messages
between other neurons such as sensory and motor
neurons. (Found most often in brain and spinal cord)

Nerves-
Responsible for transferring impulses from
receptors to CNS and back to effectors
 Draw nerve bundle

PRACTICING
SCIENTIFIC LITERACY
Paolo Zamboni
 CBC


Your task:
Find a research
article on the topic of
new treatment for MS
 Complete the
attached worksheet


Central Nervous
System (CNS)


Brain and spinal cord,
coordinates
_________ and
__________
information
Peripheral Nervous
System (PNS)

Nerves that ______
information between
the _____ and other
parts of the body
CENTRAL NERVOUS SYSTEM
Consists of brain and
spinal cord
 Brain

acts as coordinating
centre
 Enclosed within the
skull
 Surrounded by 3-layer
protective membrane
(___________)

Outer Middle-arachnoid mater
 Inner
CENTRAL NERVOUS SYSYTEM
 Cerebral

spinal fluid
___________
the meninges and
spinal cord


Transports
nutrients to brain
cells and relays
waste from cells
to blood

What procedure is
used to identify
meningitis
PERIPHERAL NERVOUS SYSTEM




Responds to external
stimuli


Contains special motor
nerves that control
the internal organs of
the body
SOMATIC SYSTEM
Brings information about the external
environment to the CNS and sends information
back to the skeletal muscles
 Under voluntary control


Ie.

What do the 12 pairs of cranial nerves control

What do the 31 pairs of spinal nerves control
AUTONOMIC SYSTEM
Brings information about the body’s _________
_____________to the CNS and carries signals
back to regulate the internal environment
 Controls:


Involuntary
Ie.

Uses 2 groups of motor neurons
______________ neurons-run from CNS to ganglion
where they connect to second group
 ______________ neurons-run to the target organ,
muscle or gland

AUTONOMIC SYSTEM
Sumpathetic nervous
system

Prepares the body for
stress





Nerves-______
preganglionic nerve,
________ postganglionic
nerve
Preganglionic nerve
releases ___________
Postganglionic nerve
releases ____________
Nerves come from the ribs
and small of the back
Parasympathetic nervous
system






__________ fight or flight and
restores the body to normal
Nerves-_______ preganglionic
nerve; _________
postganglionic nerve
Preganglionic nerve releases
_____________
Postganglionic nerve release
acetylcholine and
_______________
Nerves come from brain/cervical
area or caudal sections of spinal
cord
Vagus nerve lead to heart,
lungs, liver, pancreas and
digestive tract
REFLEX ARC

It is the simplest of nerve pathways
 Usually __________ involve the brain
 Contains 5 essential components

DRAW REFLEX ARC
REFLEX ARC

Patellar reflex

How to stimulate it:

What is detected by sensory receptors

Where does impulse travel to

What does CNS do with message

How does your body react
3 STAGES
OF A NEURON


State where no nerve impulse is being conducted
although the nerve is capable of doing so



State during which the neuron is actively involved in
conducting a nerve impulse
Recovery/Refractory Potential

The state during which the neuron is _________ to
conduct a nerve impulse since the neuron must
‘__________’ following the last impulse
1. RESTING
POTENTIAL






During resting potential there is an ion displacement between
the inside and outside of the neuron (either side of the cell
membrane) as follows:
More ______ ions on the _________ than the _______
There are more _____ ions on the _______ than on the
_______
There are many large anion (- ions) locked inside since they
are too big to pass through the membrane
Neuron has a voltage difference of ______ mV
1. RESTING



POTENTIAL
Due to the difference in ion displacement there
is a _____________ difference across the cell
membrane = _______________
This membrane potential when the neuron is at
rest is called the resting potential = 70mV
This difference in ion displacement and thus the
resting potential is largely maintained by a
protein channel called the ______________
HOW IS

RESTING POTENTIAL MAINTAINED?
Draw example of ion distribution
NA+ / K+ PUMP




Powered by _____ this pump ‘actively’ pumps Na+
ions _____ of the cell and K+ ions ___ the cell
As a result of this active transport, the cytoplasm of
the neuron contains more ___ ions and fewer ____
ions than the surrounding medium
The cell membrane also has 2 other separate protein
channels, one that ‘leaks’ K+ ions and one that ‘leaks’
Na+ ions down their ________________________
There are more K+ channels than Na+ channels which
means more K+ ions leak out of the cell as opposed to
Na+ leaking into the cell
NA+ / K+ PUMP
As a result, K+ ions leak out of the cell to
produce a ___________ charge on the inside of
the membrane
 This charge difference is known as the
___________________ of the neuron.

2. ACTION POTENTIAL



The mechanism by which neurons send impulses, also
known as a ___________
They are comprised of electrical signals generated at the
______ and moving along the axon toward the end
opposite the soma (______________)
In order for an action potential to occur, the neuron must
receive _____________ stimulation to open enough Na
gates to reach the ___________ level


If sufficient Na gates are opened to reach the
threshold level, other Na and K gates will be
stimulated to open
This creates a self propogating _______ of
action potentials and Na and K gates opening
along the entire length of a neuron and an action
potential and nerve impulse occur
2. ACTION POTENTIAL


Since an action potential will only occur if the
membrane threshold level is reached, an action
potential can also be described as an
______________________
Action potential can be divided into two phases:
_______________ and _________________
DEPOLARIZATION

If a neuron received sufficient stimulation to
reach the membrane threshold, successive Na
gates along the entire neuron will open


The movement of Na ions into the neuron causes
the membrane potential to change from -70 mV
to +40 mV


As the membrane potential becomes more
__________, Na gates begin to ________
At the end of depolarization, the Na gates are
all closed
REPOLARIZATION
At the end of the depolarization phase, K gates
begin to open, allowing K to _________ the
neuron
 These K gates are activated at the __________
membrane potential value of _____mV


The excessive diffusion of K ions out of the
neuron produces a change in membrane potential
such that the potential becomes more negative
than the resting membrane, this is referred to
as ________________


Following
repolarization, the K
gates close slowly
During the
conduction of a
nerve impulse, each
successive section
of a neuron’s
membrane will
undergo an
_______________
__________
consisting of
depolarization
followed by
_______________

Draw graph below

In each picture,
identify the following



Which area is
depolarized?
Which area is
polarized resting?
Which area is
repolarized?
3. RECOVERY/REFRACTORY



PERIOD
Immediately following an action potential, a neuron is
________ to conduct a nerve impulse because the Na
gates won’t _______
A neuron which is undergoing recovery is said to be
_____________ since it cannot conduct a nerve
impulse
During the recovery phase the following events are
occuring:


The Na/K pump is returning the _____ ions to the ________
and ____ ions to the ________ of the neuron

The membrane potential is returning to its resting value of
_____mV

Once the recovery phase is complete, the neuron
is no longer in its refractory period and is ready
to conduct another nerve impulse
SALTATORY CONDUCTION
Neurons ________________ coating are
unmyelinated
 Unmyelinated neurons


an impulse must pass through _______________
along the neuron cell membrane which makes the
conduction of nerve impulses relatively _______
SALTATORY CONDUCTION

Myelinated neurons

An impulse does _____ occur along sections of the
neuron which are __________ in myelin

Gaps in myelin are called _______________

Nodes are site of _______________

ALL OR

NONE RESPONSE
If an axon is stimulated ________ its threshold
it will trigger an impulse down its length.


An axon cannot send a mild or strong response.
It either responds or does not!!!
SYNAPTIC TRANSMISSION

___________ are the small spaces between
neurons
Vessicles located in the end plates of axons
release chemical messengers called
_________________
 Neurotransmitters are released from the
__________ neuron and __________ across
the synapse
 Neurotransmitters bind to receptors, creating a
depolarization of the dendrites of the
postynaptic neuron


Draw diagram