Neuro Flashcards
(128 cards)
1
Q
Draw action potential graph?
A
2
Q
What is resting membrane potential value?
A
-70mV
3
Q
What is ion movement at rest?
A
K+ higher conc inside
Na+ higher conc outside
4
Q
What is value of threshold?
A
-55mV
5
Q
What is value of repolarisation?
A
+30mV
6
Q
What occurs in AP?
A
1) Resting membrane potential is -70mV
Na-K ATPase 3Na+ out 2K+ in
2) Threshold exceeded -55mV
Na+ channels open, leads influx Na+
Depolarisation
3) Repolarisation +30mV
Na+ shut
K+ voltage gated channels open
4) K+ voltage gated channels open too long
hyperpolarisation
5) Back normal
7
Q
Define two types refractory periods?
A
Absolute refractory period- Na+ close
- No further Action Potentials
Relative refractory period- Can have Action Potential
- Need bigger stimulus
8
Q
What refractory period can action potentials occur?
A
Relative refractory period
9
Q
What function refractory periods?
A
Impulses travel unidirectionally
Not overlapped
10
Q
What stains myelin?
A
Osmium stains myelin
White to black
11
Q
What is quickest form of conduction?
A
Myelination
Saltatory conduction
12
Q
What cells form myelin in CNS?
A
Oligodendrocytes
13
Q
Where are oligodendrocytes found?
A
CNS
14
Q
Where are schwann cells found?
A
PNS
15
Q
What cells form myelin in PNS?
A
Schwann cells
16
Q
What diseases caused by damage to myelin sheath?
A
Multiple sclerosis
Guillain Barre syndrome
17
Q
What two types of synaptic transmission? What most common?
A
Chemical (common)
Electrical
18
Q
Where does electrical transmission occur?
A
Brainstem
19
Q
What is quicker electrical or chemical?
A
Electrical
20
Q
What joins pre and post synaptic cells in electrical transmission?
A
Gap junctions
21
Q
What 5 things occur in chemical transmission?
A
1) Manufacture
2) Storage
3) Release
4) Activation
5) Reuptake/breakdown
22
Q
Are NMJ excitatory or inhibitory?
A
Excitatory
23
Q
What 2 things occur when neurotransmitter binds to postsynaptic receptor on CSM?
A
Depolarisation- propogate AP- inhib- EPSP
Hyperpolarisation- prevent AP- inhib- IPSP
24
Q
What process called for neurotransmitters have effect?
A
Summation
25
What are two types of summation?
Spatial- multiple presynaptic neurons together release enough neurotransmitter stimulate AP
Temporal- one presynaptic neuron releases neurotransmitter many times over period time
26
Give 3 examples of fast neurotransmitters?
ACh
Glut
GABA
27
Name slow neuromudulators?
Dopaminergic
Serotonin
Noradrenergic
28
What is main excitatory neurotransmitter?
Glut
29
What is main inhibitory neurotransmitter?
GABA
30
Is ACh excitatory or inhibitory?
Ach- excitatory at skeletal muscle
- inhibitory at heart
31
What are 2 main Ach receptors? What do act on?
Nicotinegic- brain
Muscarinic- peripheral organs/glands
32
What neurotransmitter is used an NMJ?
Ach
33
What breaks Ach down?
Acetylcholinesterase (AChE)
Cholinergic receptor
34
Where is Noradrenergic work?
Function?
Affected by?
Heart and CNS
Fight and flight
Stimulants, antidepressant
35
Where is dopaminergic?
Affected by?
Basal ganglia (substantia nigra)
Stimulant increase
Antipsycotic decrease
36
Treatment parkinsons?
Parkinsons- lack dopamine
L- Dopa- use NAD enyme make more dopamine
37
Serotonin excite or inhib?
Effected by?
Excitatory
Antidepressant- prozac
Ecstasy
38
Give example of antidepressant?
Proza
39
Name 2 main conscious tracts?
DCML and spinothalamic
40
Name main ascending unconscious tract?
Spinocerebellar
41
Name main descending tract?
Corticospinal
42
What does DCML fibres carry?
Fine touch
Vibration
2 pt discrimination
Proprioception
43
What tract is responsible for fine touch?
DCML
44
How does DCML tract work?
1st order- lower limb- gracilis (below T6)
- upper limb- cuneatus (T6 and above)
- reach dorsal root gangli- ascend ipsi
2nd order- decussate medulla to contralateral thalamus
3rd order- to contralateral SSC
45
What neurons lower limbs in DCML?
What neurons upper limbs in DCML?
Gracilis- Lower limb (below T6)
Canaetus- Upper limb (T6 above)
Grass
46
Where does decussation occur in DCML?
Medulla
47
Function 3rd order neuron in DCML?
Contralateral thalamus to contralateral somatosensory cortex
48
Draw DCML tract?
Function?
Fine touch
Vibration
2 pt discrimination
Proprioception
49
State function of spinothalamic tract?
Carry pain and crude touch
50
What tract carries pain and crude touch?
Spinothalamic
51
Explain spinothalamic tract?
1st degree neurons- receptors in periphery
- reach dorsal root ganglia
2nd degree neurons- decussation @lvl spinal cord
3rd degree neurons- ascend to contralateral thalamus
- contralateral somatosensory
52
Draw spinothalamic tract?
Function?
Pain and crude touch
53
Draw dcml tract?
Function
Fine touch
Ppt
Vibration
2 pnt discrim
54
What tract is responsible for:
Crude touch
Fine touch
Crude- spinothalamic
Fine- DCML
55
What is function of spinocerebellar?
Neurons travel?
Unconscious proprioception
Body to cerebellum
56
How many order neurons do ascending tracts have?
3
57
How many order neurons do descending tracts have?
2
Name- UMN, LMN
58
Where do pyramidal descending tracts decussate?
Example?
Medulla
Corticospinal
59
Explain process corticospinal descending tract?
1st order- motor cortex through corona radiate- internal
capsule
- pass through brainstem until medulla
- decussate @medulla- 85% contralateral- lateral
- 15% remain ipsilateral- anterior
2nd order- terminate @ventrolateral horn spinal cord
- synapse into 2nd order
60
Draw corticospinal tract?
61
What neurons effected by bells palsy?
LMN's
62
What neurons effected by stroke
UMN's
63
Label ventral and lateral corticospinal
ventral and lateral spinothalamic
DCML
64
What is PNS divided into?
65
Define afferent?
Receptors to CNS
66
Define efferent?
CNS to receptors
67
What efferent system is voluntary?
Example
Somatic
Skeletal
68
What is autonomic ns?
Examples?
Involuntary
Part efferent
Smooth muscle, cardiac, glands
69
What is autonomic division split into?
Symp and para
70
State differences between somatic and autonomic efferent ns?
Somatic- single mylinated axon CNS- muscle
- no synapse
- Ach only EXCITATORY
Autonomic- 2 acons- pre and post ganglionic
- pre- Ach (excite)
post- Ach (excite)
- NAd (inhibt)
71
What neurotransmitters in somatic efferent ns?
Ach
72
How many axons in somatic efferent ns?
One myelinated axon
CNS-muscle
73
How many axons in autonomic efferent ns?
2- preganglionic and post
- pre- always Ach
- post- Ach (excite)
- NAd (inhibt)
74
What neurotransmitter in autonomic efferent?
Pre ganglionic - Ach (excite)
Post ganglionic- Ach (excite)
- NAd (inhibt)
75
What is autonomic ns split into?
Sympathetic
Parasympathetic
76
What is sympathetic ns function? Effect?
Fight or flight
Amplify
Apart GI tract, lungs (dilate), pupils (dilate)
77
What receptors paired with Ach?
Nicotinic
78
What receptors paired with NAd
Adrenergic
79
Function parasympathetic?
Rest and digest
80
What nerves parasypathetic?
10, 9, 7, 3
81
What is nervous system of GI tract?
Enteric ns
Act independently
82
Define motor unit?
Alpha motor neuron and all extrafusal fibres it innervates
83
How are motor neurons arrange in spinal cord?
Somatotopic
Mn medial controlled proximal
Mn laterally controlled distally
84
Where do motor neurons start and finish?
UMN
LMN
UPM- motor cortex to spinal cord
LMN- spinal cord to muscle
85
Damage- symptoms?
UMN- hypertonia, spasticity, hyperreflexia
LMN- hyporeflexia, muscle atrophy, hypotonia
86
Define end plate potential?
Why is it diff?
NMJ of EPSP but stronger depolarisation
AP propogated to all adj fibres in alpha motor unit
87
Define muscle spindle?
Intrafusal and stretch receptor
88
With reference to picture state efferent and afferent supply to muscle spindle?
Efferent- Y neurons at 1 and 3
Afferent- 1a fibres at 1 and 3, type 2 fibres at 2
89
Function Y neurons?
Efferent supply- Y neurons prevent IF becoming slack
90
What is fast type 1a or type 2?
1a- fast
2- slow
91
Function of Y, 1a and type 2 fibres?
Detect stretch
92
Function golgi tendons?
Tension receptors
93
What nerves involved in patellar reflex?
L3/4
94
Explain patellar reflex?
1) Patellar knocked
2a) Activate stretch receptors
- 1a from intrafusal fibres to CNS
- Monosynaptic excitatory stimulation of quadraceps
Knee jerk extension (1a)
2b) Polysynaptic
Inhibition of flexors of knee (1a)
Excitation synergestic muscles at knee (1a)
3) 1b
Polysynaptic (CNS) inhibition knee jerk when excess
- stretch detected
- prevent overextension and injury
- inverse myotactic reflex
95
What is inverse myotactic reflex?
Polysynaptic (CNS) inhibition knee jerk when excess
- stretch detected
- prevent overextension and injury
- inverse myotactic reflex
1b
96
In knee jerk reaction what muscle stimulated/inhibt?
Quadraceps- stim
Flexors knee- inhib
Monosynaptic- don't enter CNS
97
What are two branches of spinothalamic tract?
Anterior
Lateral
98
What information carried anterior spinothalamic?
Crude touch
Pressure
99
What information carried lateral spinothalamic?
Pain
Temperature
100
What type of fibres carry crude touch and pressure?
Which tract- which side?
C fibres
Spinothalamic- anterior
101
What type of fibres carry pain and temperature?
Which tract- which side?
Alpha fibres
Spinothalamic- lateral
102
Function nociceptors?
Sense pain
103
What senses pain?
Nociceptors
104
Explain response pain?
1) Nociceptors sense pain
2) Transmit impulse to dorsal root ganglia via:
alpha myelinated C unmyelinated
3) Decussated 1-2 spinal lvls above
4) Lateral- alpha (fast pain)
Anterior- C (slow pain)
5) To thalamus
6) To SSC
105
Are alpha or C fibres myelinated?
Alpha- myelinated
C- unmyelinated
106
What neurotransmitters used alpha fibres?
Glutamate- fast
107
What neurotransmitters used C fibres?
Glut
Substance P- bind longer
108
What is pain gate?
C fibres
Small descending pathways- inhibit pain spinothalamic
Transmission nociceptor to DRG occurs
Inhibit impulse reach SSC
109
Define analgesia?
Selective pain suppression
Consciousness not effected
110
Define anaesthetic?
Total pain suppression
Consciousness can effected
111
What is parkinsons caused by?
Loss substantia nigra- lack dopamine
Can't inhibit movement
112
What is berry aneurysm caused by?
Common location
Intracranial aneurysm- outpouching
Circle willis- anterior circulation
113
What is duchenne muscular dystrophy?
Recessive or dom?
X linked muscle degradation
Recessive
114
What is multiple sclerosis caused by?
Myelin scarring
115
What causes huntingtons?
Type disease?
Codon?
Low lvls GABA
High lvls dopamine
Too much movement
Autosomal dominant
Anticipation CAG
116
How many repeats needed huntingtons?
Anticipation
CAG
36+
117
Define anticipation in disease?
Extended mutated triplet repeats
Earlier and severe symptoms
118
Explain brown sequard?
Hemisection of spinal cord compressed
Lesion below and above spinothalamic decussationq
119
What are common signs of BSq syndrome?
Ipsilateral- paralysis side of the lesion- compromise to
lateral corticospinal tracts
loss of proprioception and vibration- DCML Contralateral- loss pain and temperature sensation-
spinothalamic tract.
120
When does gastrulation (formation trilaminar disc) occur?
After wk 3
121
State how brain formed?
1) Ectoderm differentiate by mitosis
2) Neural groove
3) Neural tube
4) Neural crest cells
lateral neural tube
5) Crest cells differentiate into brain and CNS
122
What do the brain and CNS develop from?
Crest cells
123
What are 3 bases that brain divides from?
Prosencephalon
Mesencephalon
Rhombencephalon
124
Draw flow chart to show where diff structures brain form?
125
Where does cerebral cortex form from?
Telencephalon
Prosencephalon
126
Where does thalamus form from?
Diencephalon
Prosencephalon
127
Where does midbrain form from?
Mesencephalon
128
Where does pons and cerebellum form from?
Metencephalon
Rhombencephalon
