the structure of neurones aims 1.to describe the structure of sensory and motor neurones 2.to relate...

The Structure of Neurones The Structure of Neurones

Aims 1. To describe the structure of sensory

and motor neurones2. To relate the structure of sensory and

motor neurones to their function

NeuronesNeurones

Click button to reveal type of neurone and Click button to reveal type of neurone and direction of impulse.direction of impulse.

Neurone 1Neurone 1

Click any label to reveal name of Click any label to reveal name of structure.structure.

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ImpulseImpulseSensory NeuroneSensory Neurone

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Click button to reveal further information.Click button to reveal further information.

SchwanSchwann Celln Cell BB CC

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AA

Found in mammals. Cell wraps itself around Found in mammals. Cell wraps itself around axon, enclosing it in many layers of plasma axon, enclosing it in many layers of plasma membrane. This creates a membrane. This creates a myelin sheathmyelin sheath (largely lipids with some proteins) which speeds (largely lipids with some proteins) which speeds up conduction by offering electrical insulation. up conduction by offering electrical insulation. They can carry out phagocytosis to remove cell They can carry out phagocytosis to remove cell debris.debris.

SchwanSchwann Celln Cell BB CC

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Cell Cell BodyBody


Cell body contains neurone’s nucleus and Cell body contains neurone’s nucleus and cytoplasm with many mitochondria and cytoplasm with many mitochondria and ER. Groups of ribosomes are often visible ER. Groups of ribosomes are often visible as dark specs. Neurotransmitter (e.g. as dark specs. Neurotransmitter (e.g. Serotonin) are produced here.Serotonin) are produced here.

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Cell Cell BodyBody



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ReceptorReceptor


Receptor cells are transducers – convert Receptor cells are transducers – convert one form of energy e.g. light or heat into one form of energy e.g. light or heat into electrical energy. Often found in sense electrical energy. Often found in sense organs. Initiate the action potential in the organs. Initiate the action potential in the sensory neurone in response to a stimuli.sensory neurone in response to a stimuli.

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ReceptorReceptor


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Synaptic Synaptic knobknob

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Axon terminates in a junction with next Axon terminates in a junction with next neurone. A gap of 20nm between them. neurone. A gap of 20nm between them. The knob is packed with mitochondria and The knob is packed with mitochondria and vesicles with neurotransmitter. This will vesicles with neurotransmitter. This will diffuse across gap and excite/inhibit diffuse across gap and excite/inhibit signal in next neurone.signal in next neurone.

Synaptic Synaptic knobknob

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AxonAxon

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Extension of cytoplasm from the cell Extension of cytoplasm from the cell body. Carries electrical signal (action body. Carries electrical signal (action potential) from the cell body to the potential) from the cell body to the synaptic knobs in the central nervous synaptic knobs in the central nervous system (CNS).system (CNS).

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DD EE FF GGAxonAxon



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DD EE FF GGNode of Node of RanvierRanvier


2-32-3μμm gaps in the myelination of the m gaps in the myelination of the axon. Occur between Schwann cells every axon. Occur between Schwann cells every 2-3mm.2-3mm.Help speed of transmission by enabling Help speed of transmission by enabling action potential to jump from one node to action potential to jump from one node to next.next.

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DD EE FF GGNode of Node of RanvierRanvier



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DD EE FF GGDendriteDendritess


Many thin extensions of cytoplasm from Many thin extensions of cytoplasm from the cell body. Carry the electrical signal the cell body. Carry the electrical signal (action potential) from the receptor to the (action potential) from the receptor to the cell body.cell body.

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DD EE FF GGDendriteDendritess


Click button to reveal type of neurone and Click button to reveal type of neurone and direction of impulse.direction of impulse.

Neurone 2Neurone 2

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Many thin extensions of cytoplasm from Many thin extensions of cytoplasm from the cell body. Carry the electrical signal the cell body. Carry the electrical signal (action potential) from synapse with (action potential) from synapse with previous neurone to the cell body.previous neurone to the cell body.

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ImpulseImpulseMotor NeuroneMotor Neurone

DendriteDendritess

AACC

Click any label to reveal name of Click any label to reveal name of structure.structure.

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DD EE FF


GGFF


DendriteDendritess

AACC

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DD EE FF



Node of Node of RanvierRanvier

AACC

BB

DD EE FF

2-32-3μμm gaps in the myelination of the m gaps in the myelination of the axon. Occur between Schwann cells every axon. Occur between Schwann cells every 2-3mm.2-3mm.Help speed of transmission by enabling Help speed of transmission by enabling action potential to jump from one node to action potential to jump from one node to next.next.


Node of Node of RanvierRanvier

AACC

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DD EE FF


DD


AxonAxon

AACC

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DD EE FF

Extension of cytoplasm from the cell Extension of cytoplasm from the cell body. Carries electrical signal (action body. Carries electrical signal (action potential) from the cell body in the CNS to potential) from the cell body in the CNS to the synaptic knobs at neuromuscular the synaptic knobs at neuromuscular junctions. An axon in a motor neurone can junctions. An axon in a motor neurone can be over a metre long!be over a metre long!

DD


AxonAxon

AACC

BB CC

DD EE FF


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Cell Cell bodybody

AA

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DD EE FF

Cell body contains neurone’s nucleus and Cell body contains neurone’s nucleus and cytoplasm with many mitochondria and cytoplasm with many mitochondria and ER. Groups of ribosomes are often visible ER. Groups of ribosomes are often visible as dark specs.as dark specs.

CC


Cell Cell bodybody

AA

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DD EE FF


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Schwann Schwann cellcell

AACC

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DD EE FF

Found in mammals. Cell wraps itself Found in mammals. Cell wraps itself around axon, enclosing it in many layers around axon, enclosing it in many layers of plasma membrane. This creates a of plasma membrane. This creates a myelin sheath (largely lipids with some myelin sheath (largely lipids with some proteins) which speeds up conduction.proteins) which speeds up conduction.

BB


Schwann Schwann cellcell

AACC

BBAA

DD EE FF


AAImpulseImpulseMotor NeuroneMotor Neurone

Synaptic Synaptic knobknob CC

BBAA

DD EE FF

Axon terminates with a neuromuscular Axon terminates with a neuromuscular junction. The knob is packed with junction. The knob is packed with mitochondria and vesicles with mitochondria and vesicles with neurotransmitter. This will diffuse across neurotransmitter. This will diffuse across junction and lead to contraction of junction and lead to contraction of muscle.muscle.

AAImpulseImpulseMotor NeuroneMotor Neurone

Synaptic Synaptic knobknob CC

the structure of neurones aims 1.to describe the structure of sensory and motor neurones 2.to relate...

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