Physiology Lab #2 Flashcards

1
Q

CNS vs PNS

A

CNS - Brain + Spinal Cord

PNS - After nerves/cranial nerves exit (exit out of brain/spinal cord)

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2
Q

Split of PNS

A

Splits inot the somatic and autonomic

Somatic - Sensory and msucles

Autonomic - Includes sympathetic + parasypathetic (Heart and sweat gland muscles)

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3
Q

Spinal Cord (Sagital view)

A

Can see the vertabral bodies + can see the split into the cranial/Thoracs/Lmbar nerves

Spinal cord ends at L1/L2

L5 ends at T12 thoracic vertabre
C7 or T12 = spinal level (not exiting vertabral body)

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4
Q

Whats surrounds the spinal cord

A

Spinal cord is surrounded by mengies (Dura + Archnoid + Piamoter)
- Drua = tough + where the spinal cord exits

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5
Q

Ventral roots in Spinal Cord

A

Ventral roots = come out of Ventral element
- Vental element (very thin) - often torn in lab or in autopsy (very hard to sampoke venral roots)

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6
Q

Dorsal Root Ganglia

A

Dorsal root ganglia = sits in intervertibral space
- Sits in the foraman between vertabretes - a little away from the spinal cord NOT right on top

Dorsal root = projects through the dorsal horn and synapse (projects through synapse with snsory or motor nuerons)

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7
Q

Grey matter, White matter, Sulci, Gyri

A

Superficial layer = see grey matter

gyri - high points - outpuchings

Suci - valleys - invaginatiions

Sulci/gyri = differentiates us with mice (mice have smooth brain)

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8
Q

Lisy ensepholphosy

A

Disease where the brain is smooth (lethal)

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9
Q

Dorsal root nerves

A

Dorsal root = sensory nerves –> merges with motor nuerons in the ventral roots

Motor nuerons = in ventral roots

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10
Q

Why have different views of the brain

A

Different views = show you different things

Example - cornal = see deep matter structures (Ex. see basal ganglia)

***Applies to reading scans - need to pay attention to the view of the scan

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11
Q

Reading MRI scans based on angle

A

Coronal section - Looking at person facing foward
- see pons

Sagital section - NOW pons looks dfferent compared to in coronal section

Axial - Looking at feet foward if you were to be by their feet (right side of image is the left side of the persons body)

Answering dfferent question depening on view

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12
Q
A

A - Ventral view - can see brainstem

B - BIG line in middle = central sulcus (seperates the two hemispheres)
- Can also see sinus

C - se the cerebelum

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13
Q

Brainstem + cranial nerves

A

The cranial nerves exit from the brainstem

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14
Q

Sinuses in brain

A

Carry venous blood

Sinuses = within the memgies

Subarchnoid veins = where the venous pools sit

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15
Q

Why remove 50 mL of CSF

A

If you have build up of fluid in the brain –> removing 50 mL provides tension relief
- 50 mL = high volume tap

Vs. 20 mL is used fro diagnostics (sample bacetria + cell count)
- If take 20 mL the fluid is replaced in one hour

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16
Q

Cerebrospinal Fluid (CSF)

A

Functions:
1. Cushions the brain and spinal cord
2. Supplies nurtiesnts to the brain
3. removes wate products that result from brain metabolsim

**Adults have 150 mL of CSF
**
Up to 50 L can be draine dBUT typically drain 20 mL
**Normal raite of CSF production = 20mL/hou r
**
Entir CSF is replaced every 7.5 hours

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17
Q

CSF replacement

A

CSF = associated with arterial and venous

Arterial. = push CSF to CSF space
Venous = Absorb CSF

***Get constant turnover of blood and CSF

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18
Q

What is found in CSF

A

CSF = contains biomarkers for nuerological disease

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19
Q

Glymfatic system

A

Gets waste away form the brain
- Lymphatic system of the brain

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20
Q

Sampleing CSF

A

Use lumbar puncture for sampling CSF

sampling CSF = important in diagnostics

Have an emerging role in development of biomarkers in CSF for disease and therputics
- Ex. Infection or mengitus or multiple sclerosis –> have biomarers of what is happening in the brain BUT can’t take out the brain for biopsy = use CSF

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21
Q

Does Lumbar tap affect spinal cord?

A

When put in needle for lumbar tap - the needle goes to C4 or L5 vertabret (below the spinal cord = won’t injure the spinal cord)
- There are nerve roots = could cause pain

CSF = windo into what is going on in brain or spinal cord

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22
Q

Grey Vs. White matter

A

Grey = where neurons sit
- Grey = split into motor nuerons and intervenous nuerons

White = Myelin (primarily form oligiodendricytes)
- has tracks of nuerons

Grey matter = surounded by white matter

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23
Q

B12 deficneicey

A

Involoves dorsal tracals and cortecus spinal tracks –> clincally develops pathology related to these abnormaloties

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24
Q

Imaging of White and grey matter

A

Can see diference in imaging - grey and white matter are different radiologicaly

Image -
1. White layer around top = fat layer within the skull
2. can see ventrical (has CSF - black part is CSF)
3. Thin grey around the gryi = Dura layer suroudning the brain

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25
Q

Spinal cord englargments

A

Spinal cord = has enlargments

Englargments = in cervical and lumbar areas
- Have englargments because these areas have nerves for arms = have many tracks/nuerons going to arms because hvae lots of motor nuerons and sensory axons in arms (cervical area) = have englargments (Same idea for lumbar areas)

Compared to thoracis - thin because just affecting intercaustal muscles = fewer muscles = less nerves

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26
Q

Sagital Section of spinal cord

A

Image 1
White = CSF
Small bone like on right = spinous process of vertabrete
Big bone on left = Vertabrete

Image 2 - CSF = dark

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27
Q

Axial Section of spinal cord

A

White = spinal cord

Left side = right side of pateint
Top = Ventral
Bottom = Dorsal

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28
Q

Lumbar part of spine

A

Can see the spinal cord end and nerves exit through intervertebral foraman

At end = have a series of nerves come out of spinal cord = caudual quina

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29
Q

Cadua Quina

A

Series of nerves coming out of spinal cord

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30
Q

Ventral root

A

Thing going towards the left

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31
Q

Spinal Reflex

A

Have the dorsal root ganglia –> then goes to dorsal neuron –> synapsse to internueron –> activates quadriceps muscles and inhibits hamstrng muscles = get relex
- hamstring = angtagonist muscle

***Considered afferent response

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32
Q

Major Pathway from CNS to PNS

A
  1. Motor pathways
  2. Sensory pathways
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33
Q

homoculous

A

Shows contromutions (amount of cortext) that inerculing relation region

See leg = medial aspect of hemisphere
Hand = large represnetation + face/tongue is large –> have a lot of cortext for these areas = allows fine motor movement
Legs = less fine movement = less neurons = smaller on humunculous

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34
Q

Motor pathways from CNS to PNS

A

From cortex to spinal motor neurons –> move muscles
- Have lateral corticospinal tract –> goes to synaspse on moto nueros –> goes to skelatal muscles

LOOK AT IMAGE

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35
Q

Sensory Pathways

A
  1. Dorsal Column system
  2. Spinothalamic tract
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36
Q

Dorsal Column system

A

Function
1. Sense fine touch
2. Periopersepction (know where you are in space)

Ex. B12 defeincey - can’t talk because you don’t know where the leg is n soace because B12 affects dorsal sensory oathway (IF pateints look at legs then they can wlak)

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37
Q

Spinothalamic tract

A

Function - pain and temperature

38
Q

Cells types in CNS and PNS

A

CNS:
1. Nuerons - have many types –> different based on region
2. Astrcytes - have many subtypes (push to understand the subtypes)
3. Oligiodendrycytes - have many subtypes (push to understand the subtypes)
4. Microglia - have many subtypes (push to understand the subtypes)
5. Endothelial cells

PNS:
1. Schwann cells - Mylenate cells of PNS
2. Muscle

39
Q

Anatomy of a neuron

A

Parts
1. Dnedrites (branches)
2. Cell Body (aka Soma)
3. Nuceus - contains genetic infomration
4. Axon
5. Mylin sheat (image = yellow part)
6. Axon terminal

40
Q

Dendrite

A

Branched part of the nerve

Function - receives input from synapses (receives signal from other nuerons)

41
Q

Cell body

A

Aka Soma
- Can be bigger depending on the subtype (Image = can see nuclei next to bigger soma - tehse smaller nuclei are the astrocytes and microglia - shows how big soma can be)

Function - contains the nucues + other organelles (Mitocondria + ER etc)
- Buissness end of cell (doing transcription/tranlsation) –> proteins made would then go to dendrites and axons

42
Q

Axon

A

Conducts electrical impuses along nueronal cell

Can be very long (up to one meter in humans) (ex. cell body can be in spinal cord and axon goes to feet)

43
Q

Myeilin sheeth

A

Insulates the axon to protect the nueron and speed up the transmission of electrical impulses
- Leafing wrapped around the axon

CNS = oligiodendrites surround axon
PNS = Schwann cells surround azon

44
Q

Axon terminal

A

Transimitts electrical and chemical signals to other nuerons and effector cells

45
Q

Nueronal Diversity

A

There is a lot of nuronal diveristy

Types of nuerons:
1. Unipolar
2. Bipolar
3. Pseudounipolar
4. Multipolar

46
Q

Purkinie cell

A

Very distict cell type

Good exmaple of a dedritic tree

Axons = single projections into cerebelum

47
Q

Shape of dendrites

A

NOT single branch - is many branches with buds

Image - can see dendritic spines –> area whete dendrute synapse is formed
- Long term potential of dendrites - how we form our memebories –> because dendrite spine changes

On dendrites = have receiptors that sit on dendrites (receive signals)

48
Q

Denderite vs. cell body

A
49
Q

Past vs. present thoughts about axons

A

Past - thought that nuerons synthesize proteins in soma and the proteins travel meters along axon t diffreent places

Now - know proteins are made in the axon themselves

50
Q

Axon regeneration

A

If cut an axon it will heal 1 mm per day –> means that if you have an injury you can calcute how long it will taje to reinervate muscle

Issue - after 18 months miscle loses regernation capacity if the axon cannot heal in that time = then doctors might do surgery

51
Q

Axon Hillock

A

Transistion between the soma and axons

Function - where the electrcal signals are summed –> get Action potential
- Intiator of action potential

52
Q

Structural components of Axons

A
  1. Microtubules
  2. Neuroflilaments
53
Q

Microtubules

A

Long polymers of tubulin dimers
- Larger

Function - Traffics things up/down axon (Things move on microtubules up/down axon)
- Ex. Move mitocondria

54
Q

Nuerofilament

A

Have 3 types:
1. Light
2. Medium
3. Heavy

Woodwork of axon (Building blocks of axon)

Used to measure in CSF and blood – if you cut a nerve then the nuerofilaments are broekn = can see nuerofilaments in CSF = use this as a biomarker for disease
- Ex. ALS – see changes in Nuerfilaments over time (lower neurofilaments = slowing of disease progression)

55
Q

Axoplasm

A

Cytoplasm of Axon

56
Q

Axon Transport

A
  1. Retrograde transport - movement of things from distal to soma
    • Slow (200 mm/day) and backward
    • Uses Dynein (moves endosomes + mittocondira + neutrophic signals + toxins + Viruses)
  2. Anterograde transport - movement of things from soma to distal
    • Foward moving
    • Has slow transort or fast trasnprt (Fast = 400 mm/day ; slow = 0.5-3 mm/day)
    • Fast Uses Kineisin (carries proteins or organelles or vesicles)
    • Slow = uses kinesis to move tubulin + Actin + NF and SOD1 “Go pause Go”

BOTH = occur on microtubules

Proteins used

57
Q

Nodes of Ravier

A

Gaps in mylin sheath

Exposed regions of axons –> allows for rapid transmission down axon

Have Na chanels in node – allows the action potnetial to be transmitted down the axon

58
Q

Important characterstic of neurons

A

Neurons are excitable –> are able to transmit electical signals down axon –> then get the data in the dendrite –> then do things in the soma

59
Q

Action Potential Pumps

A
  1. Na/K pump - let Na out of cell and K into cell –> allows cell to be at resting potential (~ -70 mv)
  2. K pump - K goes out of cell
  3. Na chanel - Na into Cell

At rest - K and Na pumps are cloced ; Na/K are pen and Na is going out of cell and K goes into cell

60
Q

Generating action potential

A

Have something that stimulates the neuron – Na chanels open in resonse –> Na goes into the celll –> Action potnetial travels down –> As AP travels down more Na chanels open = get propogation of AP

NOW - the upstream Na chanels close (only open for a short time) –> K chanels open –> membrane potential is restored to -70 mv

Chart of membrane potential volatge:
1. Na chanels open - Na enters the cell = Na goes in = increase volatge in cell (memebrane potential becomes less negative)
2. As Na open K also opens = K leaves cell
3. Na chanels close - no more Na in cell but K is still open
4. Na still closed
5. K chanels close, Na chanels reset
6. Extra K diffuses away

61
Q

Action potential on mylinated vs. Unmylinated

A

No mylin = need action potential on entire membrane (all the way down)

Mylein = only need Action potential at exposed regions
- Creates Saltator conductions –> Action Potential (depolorization) only needs to occur in gaes = jump from gap to gap = faster conduction down nerve

62
Q

Nerve conduction Study

A

Median speed 49 meters/second

IF take away myline (ex. in gycanber syndrome) – Now speed is 21 meters/s –> becase the mylin is gone = no saltador conduction = slow response

63
Q

Nuerotrasmitters types

A
  1. Classical (Ex. Acytlchorline used at nueromuscular junction)
  2. Amino Acid (Ex. Glutamate - makes up most of the nuerotransmitters in the brain; GABA)
  3. Peptide (Ex. Opiate)
  4. Gaseous (Ex. Nitric Oxide)
64
Q

Stiff person syndrome

A

Person us unable to produce GABA = cells are hyperexcitable = get stiff
- Have Antibodies against things that make GABA

65
Q

Why can we differentiate between different forms of tactile touch

A

Cells receive signal (General EPSB) –> Na chanels open in dendrite –> Cell becomes depolarized (less negative) –> Get Excitatory EPSB –> Activates nueron

AND

Cells receive signal –> activate in motor nueron –> Cl goes into the cell –> cell becomes hypopolarized –> Get INhibitory IBSP –> Silences nueron

CELL - summs the EPSB and the IPSB - Cells gets excitatory and inhibitory inputs at the same times and sums them up anotomically and temperaly

66
Q

Excitatory and inhibitory buerotransmitters

A

Glu - excitatory nuerotransmitter – gets released from presynatptirc membranes –> binds at the post synaptic memebrane —> Na chanels open –> Get Action potential

Gly and GABA –> inhibitory neurotranmitters –> Realased to post synatic memebrane –> Opens Cl chanels –> get hypopolarization

67
Q

Integration

A

The algebraic summation of inhibitory and excitatory synaptic potentials

Occurs in the neuropil (Usually at the initial segments of cell)

68
Q

How can you get an action potential when have multiple things firing using Integration

A

Scenerior 1 - Stimulus is fired from an excitatory input BUT you don’t reach the Action potnetial (Very little excitation input that is not enough for an Action potential) –> No AP

Scenrior 2 - IF a Synpase fires twice = have a temperal summation = get Action Potential

Scenerio 3 - IF 2 excitatory synapses fire together –> Get Action potential (Spatial integration)
- Have input from multiple synapses

Scenrio 4 - IF you have an inhibtory synapse –> get deflation BUT you also have excitatory fireing –> Summation of inhibitory and excitatory is not enough for Action potential –> No AP
- It is possible that this could sum to get AP if excitatory is higher

69
Q

Charactristic of Action potnetial

A

Action potentials are all or nothing

70
Q

Oligio dendrites vs. Schwann cells

A

1 Oligiodendrite envelopes senveral axons AND oligiodentrites only have one layer of mylin around axon
- Oligo = in CNS

Schwann = Can have multiple layers
- Schwann = in PNS

71
Q

Astrocytes

A

Function - supporting cells in brain
1. Envelope the synapse
2. Interact with vasculator
3. Instruct epithelial cells of brain capilaries to defenestrate
4. Astrocytes = active in the synape + modulation + Maitnance of metabolsim in CNS

More Atrocytes in cell compared to nuerons

Issues with astrocytes = affects how the synapse behave

72
Q

What makes the Blood Brain barrier

A

The tight junctions between endothelial cells make up the BBB

73
Q

Tripartide

A

Presynapse + Post synapse + Astrocyte

Astrocyes = absorbs extra neurotransmitters + release nuerotransmitters

74
Q

Microglia

A

Function:
1. Important for development - Involved in synaptic pruning (prune synaotic spines away)
2. Regulates nueronal circuts (Ex. release ATP)
3. CNS maintance
4. Phagocytoces
5. Releases Growth Factors

Affects disease - over activation can lead to cell detah (target in neurodegernative diseases)

75
Q

Schwann cells

A

1 Axon = has 1 schwann cell

Schwann cells = forms lameals –> More Lamals = faster conductions

Disease example - ECM benget Syndrome –> Have stripping of mylin –> conduction velacity slows –> have weak

75
Q

Staining peripheral nerves

A

Staining = done in practice –> cut erves and can see mylination (can see thickness of mylin)

Images:
Left - Axons are stained black
Right - Axoplasm is white ; Can see mylinated axons (Mylin is black)

76
Q

Synaptic Transmission

A

Packaging Neurotransmitters = Takes a lot of energy

Nuerotransmitters = encased in vesicles –> Vesicles are snet to the synapse –> When the cell is depolaorzied Ca goes to the synaspse –> Get fusion of vesicles with memebrane –> Release nuerotransmitters to the cleft –> Neurotrasmitters go to the receptors on post synaptic surface

Overall - Load vesicles with NT - Vsciles fuse with memenbrane - Release contents of the vesicles

77
Q

Synaptic proteins

A

Synaptic transmission = complex (Uses many proteins)

Uses more than 1000 proteins in presynaptic nerve terminal and over 100 proteins function in exocytosis

78
Q

Choligernic synapse

A

Image (Left) - shows steps
Image (right) - vesicles with Achetylcholine fise with presynatptic –> contents go to synaptic cleft

Acytlcholine = important in CNS (implicated in alzheimers)

79
Q

Nueromuscular Junction

A

Acytlcholine is rekeased from motor nuerons –> Acytlcholine binds to the Acytlcholine receptors –> Na chanels open –> Get muscular depolarization –> AP opens the T-Tubulues –> S (Has Ca) opens –> Ca is released –> As Ca binds to troponin complex there is a conformation shift = other binding sites are exposed = Actin is able to bind to myosin = get muscle contraction

80
Q

Types of axons

A

There are different Axon types for different modalities

Example - Different types for priopoception + touch + Mechanical/thermal + Pain

81
Q

Types of receptors

A

Have many different forms

Example - can have a free nerve ending or tarctile areas around hair or ruffini ending or corpsicle –> different endings transmit different sensory responses

82
Q

Refractory neurons

A

Sensory neurons can become refractory (become desensitived)

Example - don’t feel clothes because nuerons bcome desensituzed

83
Q

Models for nervous system

A
  1. Mice (Ex. have ALS model - ind limbs are lagging)
  2. C. Elegans - quick and easy (can model different diseases)
  3. Drosphila - Morpholgy can be derived + easy mutated + fast cycle
  4. Zebrafish - Can see things developmentally
  5. Cell culture - Ex. hiPSC
  6. Yeast - East to grow and screen
84
Q

Things to use for biomarkers

A

There is a BIG effort to find biomarkers

Things to use:
1. Blood
2. Spinal cord and brain tissue biopsy (hard to do + can only do few times)
3. Urine
4. Skin (Punch Biopsy) - Can evaluate nerve fibers or DP43 protein (What is seen i brain can be reflected in skin)
5. Muscle
6. Electrophysiology - use for diagnosis
7. PET imaging - Can see CNS (Use for cancer + Alzheimers)
8. CSF

85
Q

Issue with using blood for biomarkers

A

Can’t always see things - espcially because of Blood Brain Barrier

86
Q

Issue with Biomarkers

A

Lack reproducibilty - people get different results

87
Q

Recent Rise in gene discovery

A

Example ALS

1994 - found 1 ALS gene –> Gene discovery was flat until 2010 –> After have rapid discovery of genes related to ALS

Recent discovery of genes - can use this inofrmation to make models (Can introduce muttaions to fly or mouse and get model of disease)

88
Q

Discovery of iPSCs

A

Discivered by Takahasha

How - Took skin from mice first then humans
- Took skin –> take the fibroblasts out –> add in 4 diferent factors (KLF4, SOX2, c-MYc, Oct3/4) –> get stem cells –> can diferentae cells ro se in the lab OR can reintroduce them to people for treatment

Issue with iPSCs = expsnsive + human iPSCs are slower to grow than mice

89
Q

Versitity of iPSCs

A

Versitle human iPSC platforms allow for study of cell types involoved in nuerological diseases

IPSCs can be used:
1. Record electrophysiology
2. Can mix will cells (Co- culture ALS nueronal cells with normal astrocytes)
3. Induce cell stress
4. Drug screen
5. Study disease

90
Q

Oppertunity to idetify mechanism of disease

A

use iPSCs from ASL pateins

Can Asses for ALS pathology + functional assays (Electrophysioogy) + Vulnerability to cell stress + Modeling non cell autonomous contrbutions to motor cell + drug screening

91
Q

Diseases of nervous system

A

Parkinsons + Alzhemiers + Huntingtons + ALS + epilespy + Ataxia + Multiple sclerosis + Peripheral nueropathy + Neoplasia + Stroke + Infection disease + Prior disease