Musculoskeletal - 521 - (1-3) Dr. Fernandez Test Flashcards Preview

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Flashcards in Musculoskeletal - 521 - (1-3) Dr. Fernandez Test Deck (173):
1

What are the two sensory divisions of the Nervous System?

Visceral and Somatic

2

The autonomic nervous system is ALWAYS

Motor

3

The somatic motor division of the PNS innervates...

Skeletal Muscle

4

What percentage of interneurons comprise the human nervous system?

90%

5

How long can a neuron live?

Whole life

6

What are some exceptions to neurons being amitotic?

Olfactory neurons - some areas of the brain.

7

What are Nissl bodies?

They are dark areas associated with Ribosomes and thus a lot of protein production

8

Is a Schwann cell a glial cell?

Yes - specialized type

9

What histologically indicated an axon hillock?

No Nissl bodies.

10

What is another name for Nissl Bodies?

Chromatophilic substance

11

Are dendrites myelinated?

No

12

Can an axon be branched?

Yes

13

What is another name for the axon hillock?

Initial Segment

14

Which is smoother, the axon or the dendrites?

Axon

15

What is the most common type of neuron morphology?

Multipolar

16

Where are Bipolar neurons found?

Olfactory and Retina

17

Where are unipolar neurons found?

Dorsal root ganglia

18

What are the two main processes that form off a unipolar neuron?

Central process (goes to spinal cord) and
peripheral process

19

A neuron that has only dendrites, in which the soma acts as an axon, is called...

Anaxonic

20

What percentage do glial cells make up in the CNS?

90% (50% by volume)

21

Name 4 kinds of CNS glia and 1 PNS glia.

Astrocyte, oligodendrocyte, microglia, ependymal
Schwann Cells

22

What is the apparatus that separates neurons from capillaries and what cell does it come from?

Perivascular feet.
Astrocyte (remember - a glial cell)

23

What cell covers axons in the CNS?

Oligodendrocytes

24

What cells are simple columnar ciliated?

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.

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