Musculoskeletal - 521 - (1-3) Dr. Fernandez Test Flashcards
(173 cards)
1
Q
What are the two sensory divisions of the Nervous System?
A
Visceral and Somatic
2
Q
The autonomic nervous system is ALWAYS
A
Motor
3
Q
The somatic motor division of the PNS innervates…
A
Skeletal Muscle
4
Q
What percentage of interneurons comprise the human nervous system?
A
90%
5
Q
How long can a neuron live?
A
Whole life
6
Q
What are some exceptions to neurons being amitotic?
A
Olfactory neurons - some areas of the brain.
7
Q
What are Nissl bodies?
A
They are dark areas associated with Ribosomes and thus a lot of protein production
8
Q
Is a Schwann cell a glial cell?
A
Yes - specialized type
9
Q
What histologically indicated an axon hillock?
A
No Nissl bodies.
10
Q
What is another name for Nissl Bodies?
A
Chromatophilic substance
11
Q
Are dendrites myelinated?
A
No
12
Q
Can an axon be branched?
A
Yes
13
Q
What is another name for the axon hillock?
A
Initial Segment
14
Q
Which is smoother, the axon or the dendrites?
A
Axon
15
Q
What is the most common type of neuron morphology?
A
Multipolar
16
Q
Where are Bipolar neurons found?
A
Olfactory and Retina
17
Q
Where are unipolar neurons found?
A
Dorsal root ganglia
18
Q
What are the two main processes that form off a unipolar neuron?
A
Central process (goes to spinal cord) and peripheral process
19
Q
A neuron that has only dendrites, in which the soma acts as an axon, is called…
A
Anaxonic
20
Q
What percentage do glial cells make up in the CNS?
A
90% (50% by volume)
21
Q
Name 4 kinds of CNS glia and 1 PNS glia.
A
Astrocyte, oligodendrocyte, microglia, ependymal
Schwann Cells
22
Q
What is the apparatus that separates neurons from capillaries and what cell does it come from?
A
Perivascular feet.
Astrocyte (remember - a glial cell)
23
Q
What cell covers axons in the CNS?
A
Oligodendrocytes
24
Q
What cells are simple columnar ciliated?
A
Ependymal cells
25
Which glial cell is responsible for CNS immune activity?
Microglia
26
Do oligodendrocytes myelinate axons?
Negative ghost rider. They cover axons in the CNS
27
How many nerve fibers can an oligodendrocyte wrap?
| How many can a Schwann cell wrap?
Many
| One
28
Can an oligodendrocyte form a myelin sheath?
Yes - they can wrap multiple times
29
When developmentally does myelination stop?
adulthood
30
What is the lipid makeup of myelin?
80%
31
Are all axons myelinated?
No. But all are wrapped
32
What is the gap between Schwann cells called?
Node of Ranvier
33
If an axon is wrapped once it is...
| If an axon is wrapped many times it is...
Unmyelinated
| myelinated
34
Can myelination occur in the adult brain?
You better freakin hope so.
The brain does this continually to form new skills (especially motor) and acquire new memories
New myelination is KEY for learning and pathway reinforcement
35
Explain the difference between electrical potential and current.
potential - difference in charge
| current - movement of said charge
36
What is the Na/K pump ratio?
3 Na OUT for 2 K IN
37
Why does nerve tissue have such a high use of ATP?
Na/K pumps run continuously and require one ATP per cycle
38
K leak channels accomplish what?
More negative charge outside cell
39
Na leak channel accomplish what?
Prevent hyperpolarization - not many of these
40
Why does the Axon Hillock have such high density of voltage gated channels?
Trigger zone for initiating action potential
| 500 per square micron
41
What additional voltage gated channel is present at the terminal bouton?
Ca++
42
What can initiate a local potential?
ligands (hormones or neurotransmitters)
| light, temperature, mechanical disturbance
43
Local potentials are (3 things)...
Graded, Decremental, and Reversible
44
What are 2 types of postsynaptic potentials?
Excitatory (Na+ flows into cell)
| Inhibitory (K+ leaves cell - hyperpolarization)
45
Do neurotransmitters have to be exclusively excitatory or inhibitory?
No. Depends on receptors.
| ACh excitatory in muscle cells and inhibitory in Cardiac tissue.
46
Excitatory postsynaptic potentials make the membrane more...
positive
47
Inhibitory postsynaptic potentials make the membrane more...
negative (hyperpolarized)
48
What two things can directly cause hyperpolarization in an IPSP
Either Cl- flows in or K+ flows out
49
What is the difference between temporal and spatial summation?
Temporal - signal comes from single source (many times)
| Spatial - many sources of local potentials cause action potential
50
A rapid spreading wave of depolarization and repolarization is called a....
Action Potential
51
EPSP's take the membrane______ to threshold
| IPSP's take the membrane ______ to threshold
Closer to
| Further From
52
Where is an important site of depolarization in the cell (after dendritic stimulis)?
Axon Hillock
53
What is the peak charge of depolariztion?
+35 mV
54
What ion depolarizes?
| What ion repolarizes?
Na in
| K out
55
What does the slow action of K+ channels cause?
Hyperpolarization
56
Is a nerve signal decrimental?
No - it's like a fuse.
57
What is the Refractory Period?
Short time after action potential fires when it is resistant to stimulation
58
What is the Absolute refractory period
firing of potential
59
What is the Relative refractory period
Hyperpolarized stage
60
What two processes in the membrane are always on?
```
Na/K pump
leakage channels (Na in / K out)
```
61
All healthy axons are covered by...
glial cells
62
The larger the diameter of the axon...
The faster the signal
63
What type of conduction occurs in myelinated axons?
Saltatory
64
How fast do signals travel in unmyelinated axons?
1-4 mph
65
How fast do signals travel in myelinated axons?
268 mph
66
What causes saltatory action in myelinated axons?
Current flow pushes Na to next node, which opens channels, etc.
67
The current flow along the inside of an axon in the area of a Schwann cell is...
Decremental
68
What is the disease in which myelin sheaths deteriorate, thought to be an immune disorder triggered by a virus?
Multiple Sclerosis
69
How many neurotransmitters are there?
Over 100 known
70
name 3 types of synapses:
axodendritic, axosomatic, axoaxonic
71
How many synapses are on a Purkinje cell?
100,000
72
Describe neurotransmitter direct/indirect effects.
Neurotransmitter can either bind directly to ion channel and change its shape (Direct)
or, indirect via second messengers
73
Terminal boutons have what additional voltage gated channels in their membrane?
Ca++
74
What does Ca++ generally do in the terminal bouton?
Activates protein kinases > phosphorylates proteins > exocytose vesicles
i.e. Ca > Calmodulin > kinase activated > phosphorylates synapsin (which triggers exocytosis of neurotransmitter)
75
How can repetitive firing change a synapse?
Increase number of receptors, increase membrane surface.
76
What are the 4 major categories of neurotransmitter?
ACh
Amino Acids
Biogenic Amines (AA's with COOH removed)
Neuropeptides
77
What are two types of Biogenic Amines?
Catecholamines (epinepherine, dopamine)
| Indolamines (serotonin, histamine)
78
Chains of 2-40 AA's that have long lasting effects are called what?
Neuropoptides
79
What are some examples of neuropeptides?
opioids, somatostatin, substance P
80
What is a typical second messenger?
cAMP
81
Norepinepherine acts through what second messenger and is considered what type of synapse?
cAMP
| Excitatory Adrenergic
82
What happens to most neurotransmitter after release?
Reuptake by the presynaptic neuron ending (bulb/bouton)
83
Describe an Inhibitory synapse?
GABA binds post-synapse and triggers Cl- channels.
| This hyperpolarizes the cell
84
Which wast product induces sleepiness in the brain and is temporarily counteracted by caffeine?
Adenosine
| caffeine binds but does not activate adenosine receptors
85
Where does the spinal cord begin and end?
Foramen Magnum to L1
86
Why does the spinal cord only go to L1?
Vertebral column grows faster than spinal cord.
87
What begins inferior to L1
Medullary cone
88
What is the structure from L2 to S5 called?
Cauda Equina
89
How many spinal nerves are there?
31 pairs
90
Where are spinal taps (and spinal anasthesia) usually done and why?
L3- L4. There is more leeway in the cauda equina, and the nerve fibers here are less likely to be pierced
91
What are spinal nerves that branch and merge called?
Plexus
92
What are the 3 Mater (Meninges) of the Spinal cord and brain?
Dura
Arachnoid
Pia
93
Where is an epidural given?
right outside the dura mater in fat/vasculature and anethetic diffuses from there
94
What is between the dura mater and the csf?
Arachnoid.
| simple squamous w/ loose CT mesh
95
Where is the pia mater found?
On the surface of the spinal cord
96
Are the meninges sensitive to pain?
Extremely
| while brain is not
97
CSF is found in the...
Subarachnoid space
98
What does the fat in the epidural space resemble?
Hypodermis
99
From superficial to deep, what are the layers of the meninges?
Dura - outside
Arachnoid - middle
then the CSF
Pia - layer around the spinal cord
100
What layer of the meninges is stretched/can be seen in spina bifida?
Dura mater
101
What matter is interior in the spinal cord and exterior in the brain?
Gray matter
102
Name the 3 horns of gray matter in the spinal cord?
Dorsal, ventral, lateral
103
The Dorsal Root is completely
Afferent/Sensory
104
The Ventral Root is completely
Efferent/Motor
105
Where do autonomic motor neurons arise from?
Lateral horn
106
How many pairs of Spinal nerves are there and what is the regional breakdown?
```
31 pairs
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
```
107
What is the basal lamina and loose CT around Schwann cells called?
Endoneurium
108
What surrounds spinal nerve "fascicles"
Perineurium
109
What surrounds the entire spinal nerve?
Epineurium
110
Where are unipolar neurons found?
Dorsal Root ganglion
111
Where are PNS motor nerve cell bodies found?
Ventral or lateral horns of the spinal cord.
112
Where are the only places where there is one way traffic?
Roots
113
What 2 main branches do each spinal nerve have?
Dorsal ramus
| Ventral ramus
114
What are the 3 classifications of nerve fibers and which one is unmyelinated?
A, B, and
| C (unmyelinated)
115
What are the 4 divisions of A fibers and what do they do?
A- alpha (skeletal, proprioception)
A - beta (skin sensory)
A - gamma (motor efferent)
A - delta (sensory, dentin/pulp, fast pain, temp)
116
What fibers are autonomic preganglionic sympathetic?
B fibers
117
What fibers elicit dull slow pain?
C fibers
118
What general pattern does anesthetic follow in blocking of nerve fibers?
Thin ones blocked first
| so A-alpha is the last one blocked
119
Why would a patient still feel pressure?
That sense is in the large A-alpha type fibers.
120
What is the sensation of pain called?
Nociception
121
What substances stimulate nociception upon injury?
serotonin, protaglandins, histamine, K+, and ATP, and bradykinin
122
Are there any nociceptors in the brain?
No
123
From whence comes visceral pain?
organs
124
What defines an analgesic?
Maintain consciousness
125
What is a general term for dysfunction in the PNS?
Neuropathy
126
How do local anasthetics work?
They inhibit the influx of Na+ ions across a membrane
127
What are the 3 components to a local anesthetic?
aromatic ring
ester or amide
amine
128
Ester based anesthetic example:
cocaine, chloroprocaine
129
Amide based anesthetic example:
lidocaine
130
Describe the general mechanism for a local anesthetic.
Base forms a salt to pass through epineurium and recombines in the cytoplasm to block Na+ channels
131
What is the fewest number of synapses a reflex can have?
one
132
Example of a monosynaptic reflex:
stretch receptor
133
Example of polysynaptic reflex:
withdraw reflex
134
When you almost fall asleep and jerk your head, what type of reflex is that?
monosynaptic
135
What type of receptor initiates the stretch reflex?
Muscle spindles inervated with type a-alpha sensory neurons
136
What type of inhibition is part of the stretch reflex?
reciprocal (so one signal comes in - two go out)
137
What intermediate step is present in the patellar reflex arc?
Interneuron initiates inhibitory response (relaxing opposing muscle)
138
What prevents muscles from contracting excessively?
The Golgi tendon reflex
139
What additional feature is there to a crossed extensor reflex?
Interneuron needs to cross spinal cord to initiate additional contraction contralateral to balance
140
What two muscle fibers (type/location) are in the flexor withdrawal/crossed extensor reflex?
Type A-delta ipsilateral
| Type A-delta contralateral
141
The autonomic nervous system is entirely...
Motor
142
Where is the cell body in a presynaptic neuron of the autonomic nervous system?
CNS
143
Where is the cell body in a postsnynaptic neuron of the autonomic nervous system?
Ganglion
144
Are postganglionic nerve fibers myelinated?
no
145
What characteristics to post-ganglionic axons have in the sympathetic division of the ANS?
Long, unmyelinated, branched
146
Where do preganglionic neurons of the Sympathetic division of the ANS originate in the spinal cord?
T1-L2
147
Where do preganglionic neurons of the Parasympathetic division of the ANS originate in the spinal cord?
Either brainstem or S2-S4
148
Parasympathetic preganglionic axons are:
Long and myelinated
149
Parasympathetic postganglionic axons are:
Short and unmyelinated
150
What are the four cranial nerves involved in parasympathetic division?
III, VII, IX, and X
151
The somas of preganglionic sympathetic neurons are in the:
Lateral Horn of the gray matter in T1-L2
152
How to remember Sympathetic pre and post ganglionic fiber lengths?
Think chain ganglia. Right next to spinal cord so unmyelinated post fiber is long
153
What are ganglia outside the Chain ganglia for Sympathetic division?
Collateral (aka prevertebral)
154
What two Rami connect the spinal nerve to the sympathetic chain ganglia?
White and Gray Rami
155
Where do Splanchnic nerves go?
Carry preganglionic sympathetic fibers to collateral (prevertebral) ganglia.
156
What fiber type are postgangionic?
C fibers (unmyelinated)
157
Where are 3 places sympathetic collateral ganglia innervate?
celiac, superior/inferior mesenteric)
158
Adrenal Medulla cells can be considered...
postganglionic sympathetic neurons
159
What class of molecule is epinepherine/norepinepherine?
catecholamines
160
T/F
| The ganglionic fiber innervating the adrenal medulla has no synapse prior.
True
161
Where are parasympathetic ganglia generally located?
Close to or within the target organ.
162
What nervous system controls the digestive tract?
Enteric.
163
What neurotransmitter does the parasympathetic nervous system use?
ACh - the entire system is cholinergic - both pre and post ganglionic neurons
164
What neurotransmitters does the sympathetic nervous system use?
Both cholinergic and andrenergic
165
What do most post sympathetic neurons release as neurotransmitter?
norepinepherine (andrenergic)
166
What sympathetic postganglionic neurons are cholinergic?
Sweat glands, blood vessels,
167
The sympathetic adrenal innervation releases what transmitter at the medullary synapse?
ACh
168
What two cholinergic receptors are there in the ANS?
Nicotinc - always stimulatory
| Muscarinic - stimulatory/inhibitory
169
What two andrenergic receptors are there in the ANS?
Alpha - mostly stimulatory
| Beta - excitatory / inhibitory (depends on subtype)
170
Beta-1 adrenergic receptor does what to the heart?
Stimulates
| hence beta blockers
171
Beta-2 andrenergic receptor does what?
Relaxes bronchial smooth muscle
172
What are some examples of singular (sympathetic) innervation?
Erector pili, adrenal medulla, some sweat glands
173
What is sympathetic tone?
firing frequency results in single-innervated sympathetic system.
