B17 ns03part2

Nervous SystemNervous SystemPart 2Part 2

Chapter 17

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Limbic SystemLimbic System

• tracts & nuclei

• parts of cerebrum ( prefrontal lobe), basal nuclei, thalamus, hypothalamus, amygdala, hippocampus

• the emotional/visceral brain

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Limbic SystemLimbic System

• links basic emotions and higher functions

e.g. stress causing high BP, gut irritability

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Limbic SystemLimbic System

• prefrontal lobes (highest mental functions)

modify behaviour in response to emotions

amygdala/hippocampus important in memory

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Memory & LearningMemory & Learning

• Memory

storing thoughts, events, facts

• Learning

using memories to change behaviour

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MemoryMemory

short termshort term - as in remembering a phone number you have just looked up

long termlong term - as in remembering your own name

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MemoryMemory

improved byimproved by

• repetition - - - - -

• linking with known facts

• strong

emotions

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MemoryMemory

• stored throughout the cortexstored throughout the cortex

• found in association areasfound in association areas

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MemoryMemory

• hippocampus links association hippocampus links association areas with prefrontal lobes areas with prefrontal lobes where memories are usedwhere memories are used

• amygdala links amygdala links pain/pleasure/fear with pain/pleasure/fear with memoriesmemories

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Long Term PotentiationLong Term Potentiation

• neurons at well used synapses change physically

• they transmit information from one neuron to another more easily

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Peripheral Nervous SystemPeripheral Nervous System

• everything outside the CNS:everything outside the CNS:

• sensory nerves

• motor nerves

• ganglia

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Peripheral Nervous SystemPeripheral Nervous System

• sensory nerves (afferent)sensory nerves (afferent) carry information from receptors…

• TO the CNS

• motor nerves (efferent)motor nerves (efferent) carry information

• FROM the CNS to muscles & glands

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Peripheral Nervous SystemPeripheral Nervous System

• sensory nerves (afferent)sensory nerves (afferent) special and general senses

• motor nerves (efferent)motor nerves (efferent) somatic (skeletal muscle) & autonomic (smooth &

cardiac muscle) and glands

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Peripheral Nervous System Peripheral Nervous System Definitions Definitions

• ganglia ganglia - collections of neuron cell collections of neuron cell bodies in the PNSbodies in the PNS

• nervesnerves - bundles of axons and/or bundles of axons and/or dendrites in the PNSdendrites in the PNS

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Peripheral Nervous System Peripheral Nervous System DefinitionsDefinitions

• sensory nervesensory nerve - bundle of sensory bundle of sensory neuron dendritesneuron dendrites

• motor nervemotor nerve - bundle of motor neuron bundle of motor neuron axonsaxons

• mixed nervemixed nerve - bundle of both sensory bundle of both sensory dendrites & motor axonsdendrites & motor axons

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NerveNerve

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Peripheral Nervous System Peripheral Nervous System

includes sensory & motorincludes sensory & motor

• sensory:sensory: special & general senses

• motor:motor: somatic (skeletal muscles) and autonomic (cardiac & smooth muscles and glands)

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Cranial NervesCranial Nerves

• 12 pairs12 pairs

• come out of the brain

• sensory, motor & mixedsensory, motor & mixed

• control/sense head & neckhead & neck except X, the vagusX, the vagus, which runs to organs of thorax & abdomenthorax & abdomen

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Cranial NervesCranial Nerves

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Spinal NervesSpinal Nerves

• 31 pairs all mixed31 pairs all mixed

• come out of the spinal cord

• each has 2 roots2 roots - ventral rootventral root (motor) &

• dorsal rootdorsal root (sensory) and dorsal dorsal root ganglionroot ganglion (sensory neuron cell bodies)

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Spinal NervesSpinal Nerves

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ReflexesReflexes

• there are a number of reflexesreflexes in the body - they are

• automatic, rapid and involuntaryautomatic, rapid and involuntary

e.g. sneezing, knee jerk, eye blink (often protective)

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ReflexesReflexesDorsal root

Ventral root

Synapse

(Brain or Spinal cord)

(Interneuron)

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Spinal Reflex ArcSpinal Reflex Arc• 5 components5 components (somatic)

1) sensory receptor1) sensory receptor

2) sensory neuron2) sensory neuron

3) Interneuron (association)3) Interneuron (association)

in brain or spinal cordin brain or spinal cord

4) motor neuron4) motor neuron

5) effector organ5) effector organ

(muscle or gland)(muscle or gland)

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Spinal Reflex ArcSpinal Reflex ArcDorsal root ganglion

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Somatic Nervous SystemSomatic Nervous System

• controls skeletal musclesskeletal muscles

• under voluntaryvoluntary conscious control e.g. jumping

• one neuron motorone neuron motor

pathwaypathway from spinal cord

(efferent pathwayefferent pathway)

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Autonomic Nervous SystemAutonomic Nervous System

• controls cardiac & cardiac & smooth muscle and smooth muscle and glandsglands

• automatic, involuntaryinvoluntary & unconscious e.g.digestion

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ANS Reflex ArcANS Reflex Arc6 components:

1) sensory receptor

2) sensory (afferent neuron)

3) interneuron

4) motor neuron (preganglionic)

5) motor neuron (postganglionic)

6) effector organ (cardiac & smooth muscle. glands

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ANS ANS Motor NeuronsMotor Neurons

ganglia

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Autonomic Nervous System Autonomic Nervous System StructureStructure

• a motor or efferentmotor or efferent system

• 2 neuron2 neuron motor pathway

• neurons synapse in

• ganglia - near the spinal cord ganglia - near the spinal cord (sympathetic) or in the organ (sympathetic) or in the organ (parasympathetic)(parasympathetic)

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Autonomic Nervous System Autonomic Nervous System StructureStructure

ganglia

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Autonomic Nervous System Autonomic Nervous System StructureStructure

2 divisions:2 divisions:

• sympathetic(stress) sympathetic(stress)

(fight/flight)(fight/flight)

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Autonomic Nervous System Autonomic Nervous System StructureStructure

2 divisions:2 divisions:

• parasympathetic(peace)parasympathetic(peace)

(feed/breed or rest /digest)(feed/breed or rest /digest)

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Sympathetic Sympathetic

• acts during stressstress

• activates the adrenal medulla - adrenal medulla - epinephrineepinephrine

• arises from the thoracolumbar thoracolumbar cordcord

• paravertebral gangliaparavertebral ganglia (near spinal cord)

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SympatheticSympathetic

• short preganglionicsshort preganglionics secrete ACh in ACh in gangliaganglia

• long postganglionicslong postganglionics secrete noradrenaline (norepinephrine) noradrenaline (norepinephrine) in organ in organ

• mass activationmass activation

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ParasympatheticParasympathetic

• acts during

• arises from cranio cranio sacralsacral CNSCNS

• terminal ganglia terminal ganglia near organ

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ParasympatheticParasympathetic

• long preganglionics long preganglionics secrete ACh in gangliaACh in ganglia

• short postganglionics short postganglionics secrete ACh in organ ACh in organ

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Actions Of ANSActions Of ANS

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Drug AbuseDrug Abuse

mood altering drugs can affect the N.S. 2 ways:

• affecting the limbic system

• increasing or decreasing neurotransmitter action

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Drug AbuseDrug Abuse

• stimulants excite neuronal activity e.g caffeine

• depressants suppress neuronal activity e.g. alcohol

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Drug AbuseDrug Abuse

• the neurotransmitter dopamine affects mood

• some mood altering drugs prolong dopamine activity

e.g. cocaine

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Drug AbuseDrug Abuse

• psychological/physical dependencies can be developed which

• cause addictions

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Drug AbuseDrug Abuse

addictions cause

• the person to require more and more of the drug to get the same effect and

• the person to suffer from withdrawal symptoms if the drug is not available

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Drug AbuseDrug Abuse

Commonly abused drugs:

• alcohol

• nicotine

• cocaine

• heroin

• marijuana

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Drug AbuseDrug Abuse

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Drug AbuseDrug Abuse

Indicate which are stimulants (s) and which are depressants (d)

• alcohol

• nicotine

• cocaine

• heroin

• marijuana

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Chapter 17: Part 2 Chapter 17: Part 2 Internet ResourcesInternet Resources::

• http://www.hon.ch/HONselect/Selection/A08.html

• http://courses.ncsu.edu/VMA913/• http://

www.webref.org/psychology/l/limbic_system.htm

• http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/PNS.html

• http://www.ndrf.org/ans.htm• http://www.nida.nih.gov/