Transcript Nervous system - Yr-9-Health

Term 3 Science 2013
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Chapter 7 Body Coordination
There are three sections
 7.1 Nervous control
 7.2 Chemical Control
 7.3 Coordinated Body Systems
Assessment
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A short exam (about 30 minutes) at the
end of each section
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A research activity
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All four pieces will count towards your
term 3 result.
Time table for this term
Week
Topic
Assessment
22-26 July
7.1 Nervous Control
Exam
5-9 August
7.2 Chemical Control
Exam
12-16 August
Research Activity
Report
2-6 Sept
7.3 Coordinated Body
Systems
Exam
Workbook

You will be given a workbook for
the term

You are to use this workbook for writing up your
science practicals and homework

The workbook will be handed up for regular marking
during the term

It is your responsibility not to lose this workbook – it is part
of the assessment for the term
Neural (nerve) Control
http://yr-9-health.wikispaces.com/Unit+Outline
Chapter 7.1 page 225
Nervous System
By the end of the unit you should be able to
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Describe the transmission of impulses from
senses to central nervous system and back to
muscles.
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Describe the reflex action and the pathway of
the reflex arc.
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Describe the function of reflex response.
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Describe the role of the central nervous system.
Let us watch a…..Movie
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http://www.bbc.co.uk/schools/gcsebitesize
/science/aqa/nervesandhormones/thenerv
oussystemact.shtml
nervous system
Human Nervous System
Consists of 2 main parts
 The Central Nervous System (spinal cord
and brain) and,
 The Peripheral Nervous System (all of the
other nerves in your body and limbs.
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Organization of the Nervous
System
Figure 7.2
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Basic Tasks of the Nervous System
Sensory Input:
Monitor both
external and internal
environments.
( Changes= stimuli)
Integration: Process
the information and
often integrate it with
stored information.
Motor output: If
necessary, signal
effector organs to
make an appropriate
response.
Did you know…..You have a nerve along
your whole arm.
The “funny bone” is the only place on
the arm where the nerve is not
protected.
The “funny bone” is on the elbow.
Histology of neural tissue
Two types of neural cells in the nervous system:
 Neurons - For processing, transfer, and storage
of information
 Neuroglia – For support, regulation & protection
of neurons
Nerve diagrams
Basic nerve cell structure
•Many vertebrate peripheral neurons have an insulating sheath around the axon
called myelin which is formed by Schwann cells.
•Myelin sheathing allows these neurons to conduct nerve impulses faster than
in non-myelinated neurons.
•Myelin sheathing has bare patches of axon called nodes of Ranvier
Action potentials jump from node to node
Nerve Cells - Neurons
Nerve cells conduct neural (electric) impulses.
Neurons consist of
 Cell body
 Dendrites (branches that receive information) and,
 Axons (that conduct messages away from the cell) – one
direction only.
 Synaptic knob of the axon
 Myelin – an insulating lining that covers the nerves and increases
neural transmission speeds. Multiple Sclerosis is a disease of the
myelin sheath that may cause many different symptoms.
3 main types of nerve cells
sensory
neurone
relay
neurone
motor
neurone
Classification of neurons
Functional classification based on type of information &
direction of information transmission:
• Sensory (afferent) neurons –
• transmit sensory information from receptors of PNS towards the CNS
• most sensory neurons are unipolar( have only one process from the cell body)
, a few are bipolar( have two processes- one axon and one dendrite)
• Motor (efferent) neurons –
• transmit motor information from the CNS to effectors (muscles/glands/adipose
tissue) in the periphery of the body
• all are multipolar ( have multi processes that extend from the cell body i.e. lots
of dendrites plus a single axon)
• Association (interneurons) –
• transmit information between neurons within the CNS; analyze inputs,
coordinate outputs
• are the most common type of neuron (20 billion)
• are all multipolar
Sensory neurons
Carries impulses from receptors e.g pain
receptors in skin to the CNS( brain or spinal
cord)
Relay neuron
Carries impulses from sensory nerves to
motor nerves.
Motor neuron
Carries impulses from CNS to effector e.g.
muscle to bring about movement or gland to
bring about secretion of hormone e.g ADH
Myelin sheath on nerves
http://people.eku.edu/ritchisong/301notes2.htm
Neuro-transmitters
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In order for neural control to occur, “information” must not only
be conducted along nerve cells, but must also be transferred from
one nerve cell to another across a synapse
Most synapses within the nervous system are chemical synapses, &
involve the release of a neurotransmitter
At the junction of each nerve connection (synapse) there is a small
gap where chemicals are released to transfer the impulse from an
axon to the dendrite of the next nerve.
Many drugs such as opium and heroin (opiates) are chemically very
similar to these neuro-transmitters and this can lead to addiction
to the drug. They produce a similar effect on the brain as do
naturally occurring Endorphins – that act to kill pain, cause
sensations of pleasure (addiction to running), and cause sleepiness.
Transmission of signals
• A synape divides 2 neurons
• The action potential will not move across the synape
• Neuro transmitters-Released by the signal cell to the receiver cell
-Move by diffusion
How Neurons Communicate at
Synapses
Figure 7.10
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.22
The Synapse
Neural Tissue Organization
Today’s activities

Open up your textbook and go to page 225

Create a power point/pressi/word doc to
provide a diagram and succinct definition for
the following important terms:
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CNS, PNS, neurones, dendrites, axons, effectors,
sensory neurones, sheath, cerebrum, cerebellum,
brain stem, medulla, primative (old) brain, new brain
* The Central Nervous System controls
all of the body’s activities.
* The Central Nervous System is
made of two main organs.
1. The brain
2. The spinal cord
* The spinal cord sends messages to the
brain.
* The spinal cord is the part of the
nervous system that connects the brain
to the rest of the nervous system.
* The brain controls everything in the
body.
* The brain is made of more than 10
billion nerves!
* The brain is divided into three
parts and is protected by the skull.
* The Brain has three main parts…
1. The Cerebrum
2. The Cerebellum
3. The Brain Stem
* The Cerebrum is the largest part of
the brain.
1. The cerebrum controls your thinking.
2. The cerebrum controls your memory.
3. The cerebrum controls your speaking.
4. The cerebrum controls your movement and identifies
the information gathered by your sense organs.
5. Cerebrum’s made of two parts- right and left cerebral
hemispheres. Right part controls the left side of body and vice
versa
* The cerebellum is below and to the
back of the cerebrum.
1. The cerebellum controls you balance.
2. The cerebellum controls your posture.
* The Brain Stem connects the brain to
the spinal cord.
* The nerves in the brain stem control
your heartbeat, breathing, and blood
pressure.
* The vertebrae are the many
bones that protect the nerves in
the spinal cord.
* The outer nervous system carries
messages between the central nervous
system and the rest of the body.
* The Outer Nervous System’s job
is to connect the Central Nervous
System to the rest of the body.
* The outer nervous system is made of
the nerves and the sense organs.
Ear
Skin
Eye
Nerves
Tongue
* The outer nervous system
controls the body’s activities
that you don’t think about.
* The outer nervous system controls
activities in your small intestine, your
breathing, and your heartbeat.
controls
Sense organs
carry messages
about the
environment to
the central
nervous
system.
The eyes, ears, nose, tongue, and
skin are examples of sense organs.
The sense organs gather
information (light, sound, heat,
and pressure) from the
environment.
The environment is everything
outside the body.
The sense organs gather
information from outside the
body, then send the messages to
the brain.
Vision is your ability to see.
Vision involves the eye and the brain.
When a sound is made, the air
around the sound vibrates.
Hearing starts when some of the
sound waves go into the ear.
There are nine main parts of the ear.
1. Pinna
5. Anvil
2. Ear canal
6. Stirrup
3. Ear drum
7. Cochlea
4. Hammer
8. Eustachian tube
9. Auditory nerve
The pinna is the part of the ear
that you can see.
The ear canal is the tube between the
outside of the ear and the ear drum.
The ear drum is in the middle ear. It
vibrates when sound waves hit it.
The three smallest bones in the body, the
hammer, the anvil, and the stirrup,
are in the middle ear.
The hammer gets the vibrations from the
eardrum, then sends them to the anvil.
The anvil passes the vibrations to the stirrup.
The stirrup passes the vibrations
to the inner ear.
The Eustachian tube controls the amount
of pressure in the ear.
The inner ear is made of
the cochlea and liquid.
The cochlea is in the inner ear. The
cochlea looks like a shell.
The auditory nerve carries the
hearing information to the brain and
the brain tells us what we heard.
The ear works with the brain to
control your balance.
All of your movements are controlled
by balance and muscles.
The liquid in your inner ear is responsible
for your balance.
The liquid in your ear moves when we move.
The liquid movement sends information to the
brain to tell it how we are moving.
The sense of touch is located in the skin.
The nerves in the skin allow us
to feel texture, pressure,
heat, cold, and pain.
Texture is how something feels.
The nose controls your sense of smell.
The nose is able to smell 80
different kinds of smells.
Your sense of taste comes from the
taste buds in the tongue.
Taste buds are the parts on the tongue
that allow us to taste.
The four kinds of taste buds are
sweet, sour, bitter, and salty.
Tastes and smells work
together to make flavors.
Flavors are the tastes
of food and drinks.
* An automatic reaction that
happens without thinking about it.
* A reflex happens quickly in
less than a second.
The Reflex Arc
 Reflex – rapid, predictable, and
involuntary responses to stimuli
 Reflex arc – direct route from a sensory
neuron, to an interneuron, to an effector
Figure 7.11a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.23
Simple Reflex Arc
Figure 7.11b, c
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.24
Types of Reflexes and Regulation
 Autonomic reflexes
Smooth muscle regulation
Heart and blood pressure regulation
Regulation of glands
Digestive system regulation
 Somatic reflexes
Activation of skeletal muscles
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.25