Nerves Flashcards
1
Q
what are the sub divisions of the nervous system
A
CNS - brain, spinal chord
PNS
autonomic
somatic - conscious
enteric - Gut
2
Q
numer of nerves in each spinal area including crainaium
A
12 -cranial 8 - cervical 12 - thoracic 5 - lumbar 5 - sacral 1 - coccygeal
3
Q
number of nerves in each spinal area including cranium
A
12 -cranial 8 - cervical 12 - thoracic 5 - lumbar 5 - sacral 1 - coccygeal
4
Q
what dose the cell body contain
A
nucleus - makes/ transcribes proteins
5
Q
what are the dendrites
A
receiving information
leading to the cell body
6
Q
what’s the initial segment of the axon called
A
the action hillock
7
Q
what dose the action hillock do
A
the location at where an action potential is fired
8
Q
what are the axon terminals
A
release neuro transmitter across synapse to the dendrites
9
Q
what are afferent neurons
A
sensory receptor to CNS
10
Q
what are efferent neurones
A
CNS to muscle, gland or other neurone (EXIT)
11
Q
what are interneurons
A
neurones in between afferent and efferent neurones
12
Q
what are interneurons
A
neurones in between afferent and efferent neurones
13
Q
what are the glia
A
the connective tissue of the nervous system
14
Q
what are the 4 types of glia
A
astrocytes
oligodendrocytes
microglia
ependymal cells
15
Q
what do the astrocytes do
A
LOOKS LIKE A STAR
maintain the correct environment for neurones - by insulating the capillaries to stop ion transfer creating the BLOOD BRAIN BARRIER
16
Q
what are oligodendrocytes
A
in charge of myelination of the CNS
don’t wrap themselves around instead just wrap their feet around nerves
17
Q
what do microglia do
A
part of the immune system
waiting to be activated by pathogen - destroy by phagocytosis
18
Q
what do the ependymal cells do
A
form the barrier between the spinal chord and the CSF
produce the CSF
19
Q
what dose the dorsal route ganglion contain
A
the afferent cell bodies
20
Q
what are meninges
A
the dura mater, arachnoid mater, and pia mater
21
Q
what is a sulcus
A
a grove on the brain
22
Q
what is the cerebrum
what are the 4 lobes
A
frontal lobes
parietal lobes
temporal lobes
occipital lobes
23
Q
what is the cerebellum
A
the part of the brain at the back of the skull in vertebrates, which coordinates and regulates muscular activity.
24
Q
what is a gyrus
A
a ridge on the brain
25
what dose the thalamus do
it is the last relay of sensory info
26
what dose he hypothalamus do
hormones
appetite
sexual behaviour
27
what is the diencephalon contain
thalamus
| hypothalamus
28
what dose the brain stem do
maintain basic human life functions
29
what dose the brain stem do
maintain basic human life functions
30
what do action potentials do
transmit signals over long distances
31
what do graded potential do
decide when an action potential should be fired
32
what is the resting membrane potential
the battery that keeps the cell ready to respond
33
how much more negative is the inside of a cell to extracellular (neurones )
- 70mV difference from outside to in
34
how is a resting membrane potential created
leaky potassium
35
what is the equilibrium potential for potassium
-90mV
36
why do neurons have a RMP of -70mV
3 reasons
there is a few leaky Na+, Cl-
some proteins traped inside the cell are negative
Na/K pump
37
where are post synaptic potentials
at synapses
38
where are end plate potentials
at the neuromuscular junction
39
where are pacemaker potentials
in pace maker tissue
40
what are graded potentials good for
short distances
| being 'graded' (ie press hard get bigger response than pressing soft)
41
graded potentials can change the voltage in a cell by
hyperpolarising
| depolarising
42
what is the threshold for firing an action potential and opening voltage gated sodium channels
-55mV
43
a EPSP dose what
depolarises the neurone
44
a IPSP dose what
hyperpolarise the neurone
45
what do EPSP and IPSP stand for
EPSP - excitatory pre synaptic potential
IPSP - inhibitory pre synaptic potential
46
what is GABBA
a major inhibitory neurotransmitter
47
what are the two types of IPSP that you can get
FAST
and
SLOW
48
what are the two types of EPSP that you can get
FAST
and
SLOW
49
how are post synaptic potentials produced
by a neurotransmitter opening or closing LIGAND-GATED ION CHANNELS
50
how are action potentials produced
by depolarisation of the membrane potential causing the opening of VOLTAGE-GATED ION CHANNELS
51
what is summation
the addition of graded potential (synaptic integration) leading to a breach of threshold - action potential
52
why dose the location of a synapse matter
as the closer to a action hillock the less ''signal'' will be lost
53
what is temporal summation
| synaptic integration
the repeat stimulation by one nerve leading to 2 quick EPSPs
54
what is spatial
| synaptic integration
the stimulation of two responses from two different neurones
55
where are IPSP located
| 2
often closer to the action hillock meaning they shut down the cell
axoaxonic synapse between the axons of a IPSP onto a EPSP leading to the shut down of the EPSP signal `
56
what causes the quick depolarisation of a action potential
the opening of the sodium channels
57
how is a nerve cell repolarised
the opening of potassium channels
58
action potentials are...
...all or none
59
how is the size of a stimuls transferred to an action potential
stimulis measured in size (amplitude) and conveys to the FREQUENCY OF ACTION POTENTIALS
60
how is the speed of a singal sped up along an axon
by increasing the size of an axon or by myelination of the axon
61
how dose a large axon increase the speed of a action potential
makes it easier for a current to flow down the axon meaning the voltage gated Na can be spread out further
62
what are the Gaps between myelination called
nodes of Ranvier
63
what myelinates the nerves in the CNS
| the PNS
```
CNS = oligodendrocytes
PNS = schwann cells
```
64
what dose myelination do
insulate the axon
| which makes it easier for current to pass through
65
where on myelinated nerves are the voltage gated channels
in the nodes of Ranvier
66
what dose multiple sclerosis do
damage the myelin sheath meaning the action potential cant reach the voltage gated Na channels
67
what is a nerve trunk made of
lots of different nerve fibres
68
what is a compound action potential
its the measuring of the difference in times that action potentials arrive due to the difference of size and myelination
69
what is the fastest nerve fibre
large and myelinated
70
what is the slowest neurone
thin and un myelinated
71
what are A-alpha
motoneurons 70-120m/s
72
what are A-beta
touch and pressure
73
what are A-gamma
motoneurons of MUSCLE SPINDLES
74
what are A-deltas
touch, cold and FAST pain
12-30m/s
75
B
preganglionic autonomic fibres
76
C
heat, SLOW pain 0.5-2m/s
77
what are the most and what are the least sensitive nerve fibres to local anaesthetics
least sensitive are A-alpha
most sensitive are C
78
what is the Sarcolemma
the muscle membrane on the opposite side on the synapse to the axon terminal
79
what are the junctional folds important for
separating the acetylcholine receptors to the crests and the sodium channels to the troughs to enhance the effect of depolarisation
80
how the acetylcholine vesicles realised into the NMJ
via calcium dependent exocytosis
81
what are the receptors on the NMJ
| what do the open
nicotinic acetylcholine receptors
| ligan gated Na/k channels
82
what is the ligand gated channels evoke
what dose it do
the voltage gated (Na) non specific monovalent cation channel
let SHIT TONNES of Na in and not let K out
83
what is the job of these peripheral NMJ channels
to generate a Graded potential and get the muscle cell to threshold to fire action potential
84
every time acetylcholine binds to these receptors there is..
...ALWAYS A ACTION POTENTIAL
85
how is ACh removed
by acetylcholinesterase
it is broken down to acetate
and choline
86
what dose choline do after being broken down
head back in to the axon terminal to make new ACh
87
what dose tetrodotoxin do
block Na gated voltage channels
88
what dose joro spider toxin do
block voltage gated calcium channels
89
botulinum toxin
breaks the cork screw like proteins that pull the vesicles towards the membrane
90
curare
binds to the nicotinic acetylcholine receptors
| competitive antagonistic
91
novichok
is a anticholinesterases
92
what are the neurotransmitters used in the PNS
only ACh
| this is the NMJ
93
what are the neurotransmitters used in the CNS
ALL HAVE SEVERAL RECEPTORS
```
ACh
noradrenaline
dopamine
serotonin
histamine
glutamate
GABA
glycine
```
94
what is different between ACh and all other neurotransmitters
ACh is the only one that is broken down the rest are taken back up into the axon terminal
95
what are the two most important neurotransmitters in the CNS
glutamate - dose almost all fast excitatory activity in brain
GABA - dose all the fast inhibitory activity in the brain (opening the chlorine channels)
glycine - dose what GABA dose but just in the spina chord
96
what do ionotropic postsynaptic potentials lead to
Fast EPSPs
97
what do metabotropic postsynaptic potentials do
release slow EPSPs
98
what is the effect of axo-somatic attached neurones
have a big effect on the post synaptic neurone
99
what are the 3 types of synaptic connectivity
convergence
1111111111
1
divergence
1
1111111111111
feed back inhibition caused
by a inhibitory interneurone that was attached to the axon collateral
meaning that it has inhibited its self
monosynaptic pathway
polysynaptic pathway
100
what is monosynaptic pathways
have only one synapse involved between sensory input and motor output
101
what is polysynaptic pathway
have multiple synapses in between sensory input and motor out put
meaning the out put can be changed by putting an inhibitor inter neurone in and leading to hyperpolarisation
102
why is lots of synaptic integration needed for the CNS
due to the really small graded potentials
