NBSS (neuroscience) Cellular Structure of the Nervous System Flashcards

1
Q

how can neurons be described?

A

polarised (morphologically and functionally)

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2
Q

what are neurons made up of?

A

axon terminal, dendrites, soma

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3
Q

what does polarised mean?

A

information carried via electrical charges as sodium ions are pushed out of cell and potassium ions in

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4
Q

what is the resting potential?

A

-70mv

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5
Q

how much of the brains energy is consumed to maintain resting potential?

A

60%

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6
Q

over how many mm does the dendritic signal decay?

A

1-2mm

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7
Q

where is voltage gated sodium channel activated at

A

-50mV

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8
Q

what 4 things describes how information is carried in axon hillock?

A

unidirectional

all-or-nothing principle

non-decaying

carried at same amplitude

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9
Q

what type of neurones have two firing modes?

A

thalamocortical

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10
Q

what is an electrical synapse?

A

formed by gap junctions where current carried by ion transfer directly through channels - ‘coupled’

minimal delay

bidirectional

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11
Q

what is a chemical synapse?

A

Physical gap between two junctions, presynaptic neurotransmitters diffuse across to postsynaptic receptors

unidirectional

delay of 0.3-0.5mSec

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12
Q

what are 3 neurotransmitter types?

A
  • biogenic amines
  • amino acids
  • peptides
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13
Q

what are examples of biogenic amines neurotransmitters?

A
  • acetylcholine
  • noradrenaline
  • adrenaline
  • dopamine
  • serotonin
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13
Q

what are examples of amino acid neutransmitters?

A
  • glutamate
  • aspartate
  • g-aminobutyric acid
  • glycine INHIBITIORS VIA HYPERPOLARISATION
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13
Q

what are example of peptide neurotransmitters?

A
  • somatostatin
  • endorphins
  • dynorphins
  • bradykinin
  • enkephalins
  • substance P
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14
Q

what are other examples of neurotransmitters?

A
  • ATP
  • nitric oxide
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15
Q

what does axosomatic mean

A

cell body

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16
Q

what does axodendritic mean

A

dendrite

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17
Q

what is axoaxonic

A

single axon terminal

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18
Q

where are motor neurones found

A

motor neurons are in ventral
(anterior) “horn”

19
Q

motor neurons control what? and what are they described as being

A

motor control our muscles and are
efferent

20
Q

sensory cells project into what?

A

Sensory cells project into dorsal (posterior) ”horn” from ganglia

21
Q

how are sensroy neurons described as

22
Q

how many layers of cortex are there?

23
which layer has the largest cell bodies?
5
24
how do motor axons exit the CNS?
efferently - moves away from
25
how do peripheral sensory neurons exit the CNS?
afferently - moves towards
26
pre ganglionic neurones control what?
post-ganglionic neurons
27
what do autonomic ganglion do?
efferently transmit sensory signals in both the parasympathetic and sympathetic nervous system controlling acitivty of smooth muscle contractions and secretions
28
what speeds up neurone communication?
myelination
29
how does myelination speed up communication?
myelin layers wrapped around axons acting as layer of insulation for action potential transmission across nodes of ranvier with voltage gated sodium ion channels = saltatory conduction
30
what does damage to myelination do? what is this called?
conduction speed slows down or is prevented demyelinating disease: multiple sclerosis, extreme = paralysis
31
what are white matter filled with?
myelinated axons
32
what are grey matter filled with?
cell bodies, dendrites, axons
33
what is the difference in grey and white matter in brain and spinal cord?
- brain: grey matter external, white matter internal - spinal cord: white matter external, grey matter internal
34
what are the 5 glial cell types
oligodendrocytes (CNS) Schwann cells (PNS) microglia astrocytes radial glia
35
whats the function of: oligodendrocytes (CNS) Schwann cells (PNS)
Deposit myelin
36
what are microglia described as being
phagocytic
37
what is the function of astrocytes
- homeostatic function: blood vessel/brain interface linking metabolism to function - refine signalling: remove excess K+ at mylein gaps, remove synaptic neurotransmitter and insulate synapse
38
what is the function of radial glia
they are long and thin, stretching from brain surface to inner luminal surface - structural support of adult nervous system and development of NS
39
where are cells born?
inner ventricular suface
40
where do CNS cell types migrate to?
overlying mantle
41
where are motor neurons formed?
ventral
42
where are sensory neurons formed?
dorsal
43
what is the nerual tube formed by?
dorsal closure
44
what does cell type made depend on?
where in the neural tube they are positioned: dorsoventral position gives types
45
what is the origin of peripheral nervous system (PNS) neurons?
nerual crest populates PNS
46
what is an example of a neuronal defect
Neurulation defects range from spinabifida to a complete loss of head (anencephaly)