Transcript of Mr. E Murphy. Strange fact A newborn baby's brain grows almost 3 times during the course of its...
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- Mr. E Murphy
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- Strange fact A newborn baby's brain grows almost 3 times during
the course of its first year.
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- Objectives Identify the importance of the nervous system in
humans Know the difference between the CNS and the PNS Structure of
the neuron
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- The nervous system Nervous system and the endocrine allow
animals to respond to stimuli
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- CNS vs PNS CNS = Central nervous system PNS = Peripheral
nervous system Brain and spinal cord Network of nerves that carry
messages from CNS to the body
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- Response to a stimulus 1. Reception Stimulus is detected 2.
Transmission Message is transferred 3. Integration What does the
message say?? 4. Response The effect of the message
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- Neurons Three types of neurons: 1. Sensory 2. Motor 3.
Interneuron A neuron is a nerve cell
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- Summary Identify the importance of the nervous system in humans
Know the difference between the CNS and the PNS Structure of the
neuron
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- Mr. E Murphy
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- Objectives Explain the role of the different parts of the
neuron Describe the movement of a nerve impulse Illustrate the
transfer of a message at a synapse
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- Keywords Resting Neuron Threshold All or nothing law
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- Neuron Cell body Dendrites Axon Myelin sheath Schwann cell
Neurotransmitter vesicles Copy diagram into your note copy
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- Neuron Structure Cell Body: Nucleus of the neuron is contained
in the cell body Dendrites: Carry messages towards the cell body
(sensory) Axons: Carry messages away from the cell body (motor)
Myelin sheath: acts as an insulator around the axon, speeds up the
transport of messages
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- Neuron structure Schwann cells: Produce the myelin sheath Nodes
of Ranvier: Gaps in the neuron.
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- Nerve impulse Refractory period: 5/1000 of a second delay Speed
of an impulse: With myelin sheath 120 m/sec Without myelin sheath 2
m/sec Synapse
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- + + + + + + + + + + + + + + +- - - - - - - - - - - - - - - - -
- - - - Passage of an impulse along a neuron - - - - - - - + + + +
+ + + + + ++ + + + + - - - - - - - - - - - - - - Cell body Resting
Neuron Stimulus axon Stimulus changes the charge This change
triggers the next section
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- + + + + + - - - - - - - + + + + +- - - - - - - + + + + + - - -
- - - - Charge is restored Charge travels along the axon When the
threshold is reached the axon changes its permeability to ions This
causes a chain reaction Inside +ve, Outside ve Requires energy (
ATP) Once the impulse has passed the area behind returns to resting
state
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- Synapse
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- Functions of synapses 1. Transmit impulses from one neuron to
another or to an effector 2. Control the direction of an impulse 3.
Prevent over stimulation of effectors 4. Impulse can be blocked,
important in controlling pain
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- Summary Explain the role of the different parts of the neuron
Describe the movement of a nerve impulse Illustrate the transfer of
a message at a synapse
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- Mr. E Murphy
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- Objectives Central nervous system: Brain and Spinal cord
Location and function of the different brain parts Illustrate the
cross section of the spinal cord Peripheral Nervous System Reflex
action
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- CNS Brain and the spinal cord
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- Brain parts Cerebrum: Largest part of the brain 75% of the
neurons in the brain Two halves (right and left cerebral
hemispheres) Voluntary movements, interpreting results from the
sense organs, intelligence etc. Left hand side = hand use,
language, maths Right hand side = art, music, emotion Cerebral
cortex (outer part of cerebrum)........4 lobes, control different
functions
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- Brain Parts Cerebellum: Controls muscular coordination and
balance Involuntary Medulla oblongata Connects spinal cord with the
brain Involuntary actions (breathing, coughing)
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- Brain Parts Thalmus Sorting centre for brain, relaying messages
Hypothalmus Regulates the internal environment of the body
(homeostasis) Link between mind (brain) and the body??
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- Brain Parts Pituitary gland Not part of the brain Produces
hormones
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- Mr. E Murphy
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- Objectives Brain structure and function Parkinsons disease
Spinal cord
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- CNS Brain and the spinal cord Cerebrum Meninges gland
Oblongata
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- The brain 12,000 million neurons Cell bodies and synapses form
the grey matter of the brain, with the nerve fibres forming the
white matter Brain and spinal cord are protected by bone and are
covered by three membranes called meninges Meningitis is the
inflammation of the meninges
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- Brain parts Cerebrum: Largest part of the brain 75% of the
neurons in the brain Two halves (right and left cerebral
hemispheres) Voluntary movements, interpreting results from the
sense organs, intelligence etc. Left hand side = hand use,
language, maths Right hand side = art, music, emotion Cerebral
cortex (outer part of cerebrum)........4 lobes, control different
functions
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- Brain Parts Cerebellum: Controls muscular coordination and
balance Involuntary Medulla oblongata Connects spinal cord with the
brain Involuntary actions (breathing, coughing)
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- Brain Parts Thalmus Sorting centre for brain, relaying messages
Hypothalmus Regulates the internal environment of the body
(homeostasis) Link between mind (brain) and the body??
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- Brain Parts Pituitary gland Not part of the brain Produces
hormones
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- Parkinsons disease Nervous system disorder Cause: Failure to
produce a neurotransmitter called dopamine in a part of the brain
Effect: Inability to control muscle contraction Symptoms: Trembling
of the hands and legs Later muscles and body become stiff and
rigid
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- Facial expression can become fixed and has an unblinking stare
Everyday activities become difficult Thought process not affected
until late in the disease Prevention: No way to prevent or cure
Treatment: Initial treatment exercise Home help Drugs can reduce
symptoms, but not stop the degeneration of the brain
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- Mr. E Murphy
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- Objectives Spinal Cord Peripheral Nervous System Reflex
action
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- Parkinsons disease Nervous system disorder Cause: Failure to
produce a neurotransmitter called dopamine in a part of the brain
Effect: Inability to control muscle contraction Symptoms: Trembling
of the hands and legs Later muscles and body become stiff and
rigid
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- Facial expression can become fixed and has an unblinking stare
Everyday activities become difficult Thought process not affected
until late in the disease Prevention: No way to prevent or cure
Treatment: Initial treatment exercise Home help Drugs can reduce
symptoms, but not stop the degeneration of the brain
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- Spinal cord Made up of nerve tissue Protected by bony
vertebrate The spinal cord transmits messages to and from the brain
Location: Neural canal of vertebrate Neural canal is lined by
meninges Dorsal root carries sensory neurons into the spinal cord,
ventral neurons carry motor neurons out Dorsal root swellings
contain ganglia (groups of cell bodies of sensory neurons)
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- Peripheral Nervous System (PNS) Mainly nerve fibres outside the
brain and spinal cord Consists of long dendrites or axons taking
impulses to or from the CNS Nerve fibres do not contain cell
bodies
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- Peripheral Nervous System (PNS) Cell bodies of sensory nerves
are located in ganglia in the PNS (Dorsal root ganglia) Cell bodies
of motor neurons are found in the CNS (Grey matter of the brain and
the spinal cord)
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- Reflex Action Automatic, involuntary, unthinking response to a
stimulus Neurons which make up the pathway taken by nerve impulses
in a reflex action make up a reflex arc The simplest form of
activity in the nervous system is a reflex action
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- Reflex Action E.g. grasp reflex in babies, movement of the iris
in the eye, blinking our eyes for protection, and protecting
ourselves when we fall Fast reaction, allowing us to protect our
body
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- Withdrawal reflex 1. Receptors in the fingers are stimulated by
the hot flame 2. Sensory neurons carry an impulse into the spinal
cord 3. a) An interneuron carries the impulse across the spinal
cord to a motor neuron b) Another neuron takes the impulse up to
the brain 4. Motor neurons take the impulse straight out of the
spine to the effector (i.e. muscle) This causes the hand to pull
back 5. At the same time as the hand is withdrawn, the impulse
reaches the brain. Then we feel pain
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- Activity Complete exam questions 2010 Q 11 a, b 2009 Q 15 c ii
2008 Q 4 2006 Q 14 b 2005 Q 3b, Q 14 c) ii 2004 Q 15 a
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- Solutions 2012 Q 13
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- Solutions 2012 Q 13
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- Solutions 2010 Q 11 a, b
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- Solutions 2009 Q 15 c ii) 2008 Q 4
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- Solutions 2006 Q 14 b)
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- Solutions 2005 Q 3 b), 14 c) ii
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- Solutions 2004 Q 15 a)
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- Solutions 2012 OL Q 15 b)
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- Solutions 2007 OL Q 15 a)