The nervous systemThe nervous system

Content by Megan McDonald

CNSCentral Nervous System

Brain Spinal Cord

PNSPeripheral Nervous System

Spinal Nerves

Cranial Nerves

CNS

PNS

Afferent(Sensor

y)

Efferent(Motor)

Sense organ

Somatic(voluntar

y)

Autonomic(involunta

ry)

Parasympathetic

Sympathetic

ActivityActivityMarieb colouring bookChapter 7, Qu.2, Page 132

Nervous system functionNervous system functionSensory – afferentIntegrative – information

processedMotor - efferent

Nervous tissueNervous tissueNeurons – Afferent, interneurons,

efferentNeuroglia – supporting cells

NeuronsNeuronsNerve cellInitiates, propagates and

transmits electrical signals.

NeuronNeuron

NeurogliaNeurogliaSupporting cell of nervous systemAstrocytes – metabolic, physical

support; brainOligodendrocytes – myelin forming;

CNSEpendymal cells – produces CSFMicroglia – repair damaged neurons;

CNSSchwann cells – myelin forming; PNS

Activity 14.3Activity 14.3Marieb colouring bookChapter 7, Qu.7, Page 135Chapter 7, Qu.6, Page 131

Activity 14.4Activity 14.4Purple book

Neuron functionNeuron functionStimulus ExcitabilitySynapseAction potential

Action PotentialAction PotentialResting state – inside cell

membrane is more –ve than outside

Depolarisation – inside membrane becomes +ve

Repolarisation – inside membrane returns to –ve.

SynapseSynapseNeurons not connected physicallyGaps between neuronsImpulses pass over synapses via

neurotransmitters

Reflex ArcReflex ArcRapid action without conscious

controlOccurs at spinal cord level

Reflex ArcReflex Arc

Stimulus

Afferent neuron

Spinal cord

Efferent neuron

Muscle Contracts

Activity 14.5Activity 14.5Marieb colouring bookChapter 7, Qu.11, Page 137

Central Nervous SystemCentral Nervous SystemBrainSpinal Cord

CerebrumCerebrumLeft and right hemispheresHemispheres joined by corpus

callosumGyri – ridgesSulci – groovesFissures – deep groovesLobes – regions of cerebrumCerebral cortex – grey matter

CerebrumCerebrum

Frontal Lobe

•Personality•Decision making•Co-ordination of complex movements•Speech (L) motor

CerebrumCerebrum

Parietal Lobe

•Sensation•Proprioception•Understanding of sensation•Speech comprehension

CerebrumCerebrum

Occipital Lobe

•Vision•Interpreting vision

CerebrumCerebrum

Temporal Lobe

•Motivation•Emotion•Memory•Hearing

CerebrumCerebrum

DiencephalonDiencephalonEnclosed by cerebral

hemispheresThalamusHypothalamusEpithalamusPineal bodyChoroid plexus

BrainstemBrainstemConnects cerebrum and

cerebellum to spinal cordMidbrainPonsMedulla oblongata

CerebellumCerebellum“Little brain”Posterior and inferior to

cerebrumPosture and balance

Basal NucleiBasal NucleiAKA Basal gangliaMasses of neuron cell bodiesLentiform nucleusCaudate nucleusSubstantia nigra

Activity 14.6Activity 14.6Marieb colouring bookChapter 7, Qu.13, Page 138Chapter 7, Qu.15, Page 138Chapter 7, Qu.16, Page 139Chapter 7, Qu.17, Page 140Chapter 7, Qu.18, Page 141

CNS ProtectionCNS ProtectionBonyMembranous (meninges)Cerebral Spinal FluidBlood brain barrier

MeningesMeningesThree layers of tissue form

meningesDura materArachnoid materPia mater

CSFCSFCerebrospinal FluidContained between Arachnoid

and Pia matersIn subarachnoid spaceFormed by choroid plexusContained in ventriclesNourishment

Activity 14.7Activity 14.7Purple book

Spinal CordSpinal CordContinuation of medulla

oblongata31 pairs of spinal nervesConducts afferent and efferent

signalsReflex arc

PNSPNSPeripheral Nervous SystemCranial NervesSpinal Nerves

Cranial NervesCranial Nerves12 PairsOriginate in brainPge 149

Cranial NervesCranial NervesII Olfactory

II Optic

III Oculomotor

IV Trochlear

V Trigeminal

VI Abducens

VII Facial

VIII Vestibulocochlear

I Olfactory

Cranial NervesCranial NervesII Olfactory

IX Glossopharyngeal

X Vagus

XI Accessory

XII Hypoglossal

Spinal NervesSpinal Nerves

31 Pairs8 cervical12 thoracic5 sacral1 coccygeal

Spinal PlexusSpinal Plexus

CervicalLumbosacralBrachialPreserves (some) function in case

of injury

Somatic Nervous SystemSomatic Nervous System

Conscious controlEfferent impulses – to musclesAfferent impulses – from skin etc

Autonomic Nervous Autonomic Nervous SystemSystem

Unconscious controlSympatheticParasympathetic

Activity 14.11Activity 14.11Purple book

Homework!Homework!Muscle chartAnat family

Thank you