85. types of neurones 86. dendrites and axon Flashcards

1
Q

What is a neuron

A

an electrically excitable cell that responds to stimuli and processes and transmits info through ELECTRICAL AND CHEMICAL signals

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2
Q

What are the three main parts of a neuron

A

cell body (soma/perikaryon)- contains nucleus and organelles

dentrites- elongated processes from the cell body receives stimuli from synapses

axon- single long process ending at synapses specialized to generate and conduct nerve impulses to other cells

NEURONES ONLY HV 1NUCLEUS

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3
Q

What are the three main type of neurons

A

Sensory- afferent meaning they receive stimuli

Motor- efferent meaning sends impulses to effector organs

interneurons- connect different neurons together

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4
Q

neirones can be classfied by the number of processes coming from their body. What are the types

A

Multipolar- one axon, 2 or more dendrites

bipolar- one axon, one dendrite

pseudounipolar/unipolar-single process that bifurcates, one branch peripheral, one CNS

axaxonic- no true axon, many dentrites. doesn’t produce action potential

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5
Q

what are the granulations you can view with microscope in the cytoplasm of perikaryon

A

Nissl granulations

because of highly developed RER

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6
Q

What are dendrites

A

short processes that carry info back towards the soma

action potential propagates down dendrite

they occur on dendritic spines- depends on actin filaments (key in neural plasticity

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7
Q

what is axon

A

fine cable like projection

carries signals to and from soma

plasma membrane= axolemma contents-axoplasm

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8
Q

where does the neuron have the greatest density of voltage dependent sodium channels

A

where the axon emerges from soma : axon hilock

making it the most excitable part of neuron

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9
Q

axons are surrounded by myelin sheath. How does this help the neuron

A

increases speed of info transmission because of the gaps this sheath makes called nodes of ranvier

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