Neurophys- all together Flashcards
(143 cards)
1
Q
What is the definition of LMNs?
A
Neurons that connect the CNS with effector organs, including muscles and glands.
2
Q
What is the definition of UMNs?
A
Neurons that participate in initiation/regulation of voluntary movement and are located ENTIRELY within the CNS.
3
Q
What are the functions of LMNs?
A
- They are the final pathway for all motor activity of the NS, responsible for reflexes and carrying info.
4
Q
What are the functions of UMNs?
A
REGULATION
- Initiation of voluntary activity of motor system
- Maintenance of muscle tone in postural muscles
- Control of muscular activity associated with visceral functions, such as respiration, urination and cardiovascular functions.
5
Q
Are ascending pathways sensory or motor?
A
Sensory
6
Q
Are descending pathways sensory or motor?
A
Motor
7
Q
Where are the cell bodies of LMNs?
A
Either in the grey matter of the ventral horn or the brainstem for cranial nerve nuclei
8
Q
Where are the cell bodies of UMNs?
A
In the CNS!
9
Q
What are the 6 major regions of the CNS?
A
SC, medulla, pons, midbrain, diencephalon and telencephalon.
10
Q
What is sometimes named as the seventh brain region?
A
The cerebellum
11
Q
What brain regions make up the brainstem?
A
Medulla, pons and midbrain
12
Q
What brains regions make up the forebrain?
A
Diencephalon and telecephalon
13
Q
What is the normal function of the cerebral cortex?
A
Conscious thought
14
Q
What occurs with cerebral cortes dysfunction?
A
Unconsciousness, depression and seizures
15
Q
What is the normal function of the motor cortex?
A
Planning and initiation of movement
16
Q
What occurs with dysfunction of motor cortex?
A
Paralysis
17
Q
What is the normal function of thalamus?
A
Integration of neural pathways
18
Q
What occurs with dysfunction of thalamus?
A
Behavioural changes, satiety/eating disorders, damage to motor/sensory tracts
19
Q
What is the normal function of the hypothalamus?
A
Homeostasis, integration
20
Q
What occurs with dysfunction of the hypothalamus?
A
Narcolepsy, endocrine/limbic dysfunction
21
Q
What is the normal function of the limbic system?
A
Behaviour, emotions
22
Q
What occurs with limbic system dysfunction?
A
Psychosis, addictive/repetitive behaviours, stress/anxiety
23
Q
What is the normal function of the brainstem?
A
CN nuclei, ANS nuclei, reticular formation, axon tracts
24
Q
What occurs with dysfunction of the brainstem?
A
Abnormal CN function, autonomic dysfunction, depression, abnormal motor function
25
What is the normal function of the cerebellum?
Coordination/correction of movements
26
What occurs with cerebellar dysfunction?
Hypermetria/dysmetria and ataxia
27
What is a myotome?
The muscle or muscle group innervated by one spinal nerve
28
What is a dermatome?
The area of skin innervated by one spinal nerve
29
Sensory neurons are located in ---- along the spinal cord.
Dorsal root ganglia
30
The sensory portion of the PNS is classified on the basis of what?
The location of dendritic zones in the body, the origin of the impulse.
31
Where is the dentritic zone from somatic afferent system?
On or near the surface of the body- receive stimulation from the environment
32
Where is the dendritic zone for the visceral afferent system?
In the viscera of the body, stimulated by changes in the internal environment
33
Where is the dendritic zone for the proprioception afferent system?
Dendritic zones in this system respond to changes in position information from the limbs, body, head and neck.
34
The motor or efferent portion of the PNS is classified on the basis of what?
Where the LMN terminates
35
What nerves are included in the GSA system?
CNV and all spinal nerves
36
What nerves are included in the SSA system?
Vision: CNII
Hearing: CNVIII
37
What nerves are included in the GVA system?
CNVII, IX X--> head
CNX and splanchnic branches of spinal nerves --> body
38
What nerves are included in the SVA system?
Taste: CNVII, IX, X
Olfaction: CNI
39
What nerves are included in the GPA system?
All spinal nerves and CNV
40
What nerves are included in the SPA system?
Vestibular system: CNVIII
41
What nerves are included in the GSE system?
All nerves except CNI, II and VIII
42
What nerves are included in the GVE system?
All spinal nerves, CNIII (symp and parasymp innervation of the eye), CNVII, IX and X.
43
Somatic afferent system detects changes in external environment. (T/F?)
TRUE
44
Visceral afferent system detects changes in external environment. (T/F?)
FALSE- it detects changes in internal environment
45
Proprioception afferent system detects:
Changes in position info of the limbs, trunk and head and neck
46
The somatic efferent system innervates -----?
Skeletal muscle- coordinates voluntary movement
47
The visceral efferent system innervates---------?
Cardiac and smooth muscles, blood vessels and glandular tissues- coordinates involuntary movement/regulation--> ANS.
48
Define a NT (4 points)
- Must be present in the presynaptic neuron
- Must be released in response to presynaptic depolarisation
- Release is usually Ca 2+ dependent
- Specific receptors must be present on post-synaptic cell
49
Mechanisms of post-synaptic excitation (cell is becoming more positive)
- Opening of Na channels
- Suppression of Cl and K channels
- EPS receptors increase in number and localisation
- Suppression of inhibitory receptors
50
Mechanisms of post-synaptic inhibition
- Increased Cl conductance
- Increased K conductance
- IPS receptors increase in number and localisation
- Inhibition of cellular metabolism (< metabotropic response)
51
What effect do Cl and K channels have on the potential of the cell?
Cl channels let Cl INTO the cell to keep it -ve, and K channels let K OUT to keep it -ve. The more of these channels are open the harder it will be for Na to create an AP. The more of these are closed the bigger the effect of Na
52
What is the NT ACh's post-synaptic effect?
Excitatory
53
What are the precursors for ACh?
Choline and acetyl CoA
54
What is the removal mechanism for ACh?
AChEase (acetylcholinesterase)
55
Glutamate has an inhibitory post-synaptic effect. (T/F?)
FALSE- it is excitatory
56
What is the prescursor for glutamate?
Glutamine
57
What is the removal mechanism for glutamate?
Transporters
58
What is the most important excitatory NT in the brain?
Glutamate
59
What are the most important inhibitory NTs in the brain?
Gamma-aminobutyric acid (cerebrum) and glycine (spinal cord)
60
Gamma-amino butyric acid has an excitatory post-synaptic effect. (T/F?)
FALSE- it is inhibitory
61
What is the precursor for GABA?
Glutamate
62
What is the removal mechanism for GABA?
Transporters
63
What is the post-synaptic effect of glycine?
It is inhibitory
64
Serine is the precursor for glycine (T/F?)
TRUE
65
What is the removal mechanism for glycine?
Transporters
66
What chemicals does the term "catecholamines" include?
Ad, NAd and dopamine
67
What post-synaptic effect do catecholamines have?
Excitatory
68
Tyrosine is the precursor for catecholamines (T/F?)
TRUE
69
What are the removal mechanisms for catecholamines?
Transporters, MAO, COMT
70
What are MAO and COMT?
Enzymes involved in metabolising catecholamine neurotransmitters.
71
What is the systematic name of serotonin? (Abbr. 5-HT)
5- hydroxytryptamine
72
Serotonin has an excitatory post-synaptic effect (T/F?)
TRUE
73
What is the precursor for serotonin?
Tryptophan
74
What are the removal mechanisms for serotonin?
Transporters, MAO
75
What does MAO stand for?
Monoamine oxidase
76
The post-synaptic effect of histamine is inhibitory (T/F?)
FALSE- it is excitatory
77
What is the pre-cursor for histamine?
Histidine
78
What is the removal mechanism for histamine?
Transporters
79
What is the post-synaptic effect of ATP?
Excitatory
80
What is the precursor for ATP?
ADP
81
What is the removal mechanism for ATP?
Hydrolysis to AMP and adenosine
82
What type of neurotransmitter includes ACh, glutamate, GABA, glycine, catecholamines, serotonin, histamine and ATP?
Small molecular weight NTs
83
What are the post-synaptic effects of neuropeptides?
Excitatory and inhibitory
84
What are the precursors for neuropeptides?
AAs
85
What is the removal mechanism for neuropeptides?
Proteases
86
What is the post-synaptic effects of endocannabinoids?
Inhibits inhibition
87
What are the precursors for endocannabinoids?
Membrane lipids
88
What is the removal mechanism for endocannabinoids?
Hydrolysis
89
What are the post-synaptic effects of NO?
Excitatory and inhibitory
90
What is the precursor for NO?
Arginine
91
What is the removal mechanism for NO?
Spontaneous oxidation
92
Where are small molecule NTs synthesised?
In the nerve terminal
93
Small molecule NTs mediate very slow synaptic action (T/F?)
FALSE- they mediate rapid synaptic action
94
Where are neuropeptides synthesised?
In the cell body
95
What is the speed of synaptic action of neuropeptides compared to the small molecule NTs?
Neuropeptides have slower ongoing synaptic function
96
What is different about the degradation of small molecule NTs and neuropeptides once they a re released from the pre-synaptic membrane?
Small molecule NTs are broken down into their precursors which then diffuse back into the cell. Neuropeptides diffuse away from the terminal and are broken down by proteolytic enzymes.
97
What happens when there is a low frequency of stimulation of the nerve?
There is a localised increase in Ca concentration, which results in the preferential release of small molecule NTs.
98
What happens when there is a high frequency of stimulation of the nerve?
There is a more diffuse increase in Ca concentration, which results in the release of both types of NTs; small molecule NTs in small clear-core vesicles and neuropeptides in large dense core vesicles.
99
What effect does histamine have on the body?
Histamine results in a strong vasodilation, which results in a decrease in BP.
100
What is the difference between ionotropic and metabotropic receptors?
Ionotropic receptors are ligand-gated ion channels, and work very rapidly, about 0.1ms.
Metabotropic channels are G protein-coupled receptors, and are slower, taking about 400ms (in the heart).
101
All skeletal muscles are cholinergic in response and have direct cholinergic neurons innervating them. (T/F?)
TRUE
102
Dopamine is capable of activating both G-protein coupled (metabotropic) and ionotropic receptors. (T/F?)
FALSE- Dopamine acts EXCLUSIVELY by activating G-protein coupled (metabotropic) receptors.
103
What happens to excess dopamine?
It is deaminated by MAO in both the PRE and POST-synaptic membrane
104
What type of receptor are ALL of the histamine receptors?
G-protein linked
105
Of the three receptor types that are recognised for ATP, how many are G-protein linked?
Two- one is ionotropic
106
Only one neuropeptide can be released from a single vesicle. (T/F?)
FALSE- more than one NP may be released from a single vesicle
107
What makes a prepropeptide turn into a propeptide?
A prepropeptide has a signal sequence on the end, and once this is cleaved it becomes a propeptide.
108
Propeptides can give rise to more than one peptide NT. (T/F?)
TRUE
109
Nicotinic receptors are ionotropic ACh receptors (T/F?)
TRUE
110
How many subtypes of muscarinic receptors (mAChR) are there?
5
111
Where are the mAChR expressed?
the striatum and other forebrain regions.
These inhibit dopamine mediated motor effects
112
Glutamate can cross the B/B barrier. (T/F?)
FALSE- it must synthesised locally from mitochondrial conversion alpha-ketoglutarate (which comes from the CAC)
113
What does EAATs stand for?
Excitatory Amino Acid Transporters
114
What is the function of EAATs and where are they located?
They are located on the membranes on both neurons and glial cells. They mediate delivery and uptake of glutamine from glial cells to neurons
115
What is VGLUT and what is its function?
VGLUT is a vesicular glutamate transporter- which loads glutamate into neuronal vesicles
116
The NMDA (N-methyl-D-aspartate) is an ionotropic receptor at which glutamate is excitatory. (T/F?)
TRUE
117
Where is GABA most common?
Local circuit interneurons and cerebellum
118
GABA is removed from the synaptic cleft by specific transporters known as.........?
GAT- GABA transporter
119
GABA is loaded into neuronal vesicles by which transporter?
VIATT- Vesicular Inhibitory Amino Acid Transporter
120
There are three types of GABA receptors, GABAa, GABAb and GABAc. Which two are ionotropic?
A and C
121
Which G protein links the GABAb receptor?
GI/O
122
The beta gamma subunit of the GABAb receptor blocks two Ca channels, and activates KIR3.1, which does what?
The opening of the KIR3.1 means K rushes in and brings the potential further away from the threshold. It causes hyperpolarisation of the post-synaptic membrane.
123
The glycine receptor is a gated channel, gated by which ion?
Cl-
124
NO is made by what enzyme?
NOS- NO synthase
125
NO had a rapid offset. What happens to it?
It is quickly oxidised or bound to Hb
126
How is NO modulated?
By regulating NOS function
127
NOS has different isoforms. (T/F?)
TRUE
128
NO is not limited to synapses, as it can diffuse between cells. (T/F?)
TRUE
129
Where are ependymal cells located?
These coat choroid plexus and ventricles of the brain
130
Schwann cells are capable of phagocytic activity. (T/F?)
TRUE
131
What is the [glucose] and [protein] in CSF compared to plasma?
CSF has lower concentrations of both glucose and proteins. The protein concentration is generally very low, so if there are proteins present this generally indicates a problem.
132
What are the [Na] and [Cl] in CSF compared to plasma?
CSF has higher concentrations of both Na and Cl.
133
What are the [Ca] and [K] in CSF compared to plasma?
CSF has lower concentrations of both K and Ca compared to plasma.
134
The spinal cord is shorter than the spinal canal. (T/F?)
TRUE- this means that the nerves have to travel a bit to find their foramina to exit.
135
How are LMNs distributed to muscles?
Via peripheral (spinal) nerve
136
Where are the cell bodies of LMNs located?
Grey matter of ventral horn
137
The LMNs are thick and heavily myelinated. (T/F?)
TRUE
138
Where are the cell bodies of neurons innervating axial musculature, such as postural trunk muscles, located compared to those innervating appendicular (limb) musculature?
Those innervating axial musculature are located medially within the ventral horn, whereas those innervating appendicular musculature are located progressively more laterally.
139
What is the definition of pain?
An unpleasant sensory or emotional experience associated with actual or potential tissue damage (or described in terms of such damage)
140
What is the signal transduction pathway for sour taste?
Presence of H+ ions (acid)--> Modulates K+ channels--> modifies IC [K+]--> depolarisation--> influx of Ca2+--> NT release
141
What is the signal transduction pathway for salty taste?
Presence of Na+ ions (salt)--> opening of Na+ channels --> influx of Na+--> depolarisation--> NT release
142
What is the signal transduction pathway for sweet taste?
Binding of organic sugars to receptor (dimer of T1R1 and T1R3)--> activation of G-protein gustducin--> stimulates production of cGMP and cAMP--> phosphorylation of K+ channels-->K+ channels CLOSE--> < IC [K+] --> depolarisation --> Ca2+ influx --> NT release. OR the phospholipase Cbeta2 pathway --> Ca2+ release from ER
143
