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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)