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263 Cards in this Set

  • Front
  • Back
What does golgi stain stain for?
neurons; dendrites and axons
Why does the nucleus have pores?
communication between cytoplasm and nucleus
What makes up the cytoskeleton of the cell?
microtubules
What does the ER do?
protein folding, trafficking, packaging
What do chaperone proteins do?
help fold and traffic newly formed proteins
If proteins don't fold correctly, what do the chaperone proteins do?
put it into an aggragate = mis-folded protein

Additional chaperones will try re-folding the protein

If they can't fold it correctly, they'll add a ubiquitin to it = marks protein as ready for degredation = protein escorted into proteosome and ground up into AAs that can be re-used.
What happens if you don't get rid of proteins?
they can build up and form inclusion bodies = can end up killing the cell. Ex. = Alzheimer's Disease
What are depositional diseases?
What happens when we have a build up of disfunctional protein
Whats an example of a demyelinating disease?
Charcot-Marie-Tooth Syndrome = peripheral nerve disease
Whats an example of a Degeneration disease?
Alzheimer's = Central Neuron Disease = central neuron degenerates
What elements make up the cytoskeleton?
Microfilaments (small in diameter)
Intermediate Filaments (med. in diameter)
Microtubules (large in diameter)
Where are microfilaments found?
dendritic spines, dendrite tips

involved in movement
Where are Intermediate filaments found?
cell body (SOMA), cytoplasm, and axons
Where are Microtubules found?
axons, dendrites, cell SOMA

Organize spindle apparatus in normal cells but in neurons, which don't divide, they organize cyto of cell and help with active transport
What do microtubules do and what are they made of?
DO: active transport

MADE OF: Tubulins
What are MAPs?
Microtubule Associated Proteins, for ex. Tau = help hold proteins together.

Heavier MAPs proteins create hooks on microtubule so they can associate with other cellular structures
What are MMP - Kinesin and Dynein?
Mediate Active Transport = Axonal Transport = either retrograde (Dynein) or anterograde (Kinesin)
In what direction does Dynein, an MMP, help mediate active transport?
Retrograde
In what direction does Kinesin, an MMP, help mediate active transport?
Anterograde
Define Retrograde transport
Synaptic Terminal --> Cell Body
(Dynein)
Define Anterograde transport
Cell Body --> Synaptic Terminal

Kinesin mediated
What are the characteristics of slow transport?
Structural proteins
Anterograde only
What are the characteristics of fast transport?
Synaptic related proteins

Anterograde and Retrograde in nature
What is the cause of Alzheimer's disease?
Build up of Amyloid proteins which can't be processed by the cell = neurites die

Over-production and phosphorylation of TAU proteins = interact with neurofilaments to create neurofilament tangles

Tangles + Plaques characteristic of Alheimer's = tie up cyto = kill cell
What are two causes of protein deposition diseases?
1.) can't adequately process mal-formed proteins

2.) Cytoskeleton disorders = abnormally phosphorylated protein can tie together cytoskeleton that is toxic to cortical neurons
T/F: In Alzheimer's, the brain shrinks
TRUE
What are the ways we obtain energy to sustain the high level of activity in the cerebral cortex?
Ox. Phos. (=ample glucose = generates ATP = we need mitochondria

Decomposition of glucose to CO2 and H2O

Energy is used to form NADH and ATP
What activity generates ATP in the mitochondria
Protons enter hole in mito and go into mito matrix
Where are mitochondria distributed?
"SAD"

SOMA
Axon (synaptic endings)
Dendrites
What are some Pathological conditions related to Mitochondria?
"CAGEO"

Calcium Buffering
Apoptosis
Generation of Free Radicals
Excitotoxicity
Oxidative Stress
What is a Mitochondrial Permeability Transition Pore (MPT Pore)?
Inc. Ca2+ = Formation of Pore = Inc. Rapid Ca2+ Release
Can neurons be regenerated?
No, neurons we're born with are all we have, however there is some adult neurogenesis occuring in olefactory bulb
Neuronal Regeneration in Hippocampus is involved in what?
Memory Formation
What are the two ways the MTP Pore is opened?
Transiently Opened = Cell Signaling
Permanently Opened = Apoptosis
Whats the cascade of events that occur when the MPT Pores are Permanently Opened?
If Ca2+ levels high enough, pore wedged open = Ca2+ pores into cell from mito = other stuff flows into mito = mito swells and ruptures = releases triggers for apoptosis = death
ALS, or Lou Gherig's Disease, is due to what?
Excitotoxicity = Permanent Pore Opening = death of motor neurons in spinal cord. B-Amyloid = trigger for pore opening = neuron death
What are the two places neurogenesis occurs in the adult?
Olefactory bulb

Hippocampal Formation
What feature of the dendrites determines the way the neuron works?
Each cell has a dendrite domain and the shape of the domain can determine the way the cell works
Dendrites determine what in terms of neurons?
What type of info the neuron is picking up. Shape of dendritic tree has a lot to do with the way the dendrite will behave
What is the purpose of myelination?
Insulate, Protect

Sequester Na+ channels so they're primarily at an inter-node = in between two nodes
The thicker the myelin, the ____ the axon, the ______ the conduction
Bigger

Faster
Increasing Axon Size does what to conduction velocity?
Increases conduction velocity
Whats the difference between Axon and Dendrite?
Axon can carry a signal a long way w/o losing it while dendrites have tectonic spread = degradation of signal as it moves away from point of stimulus on dendrite
Myelination allows the signal to jump from where to where?
internodal region to internodal region
What do interneurons do?
surround neurons = can shape type of info, and be excitatory or inhibitory. For ex. one interneuron could excite another, which could inhibit yet another.
Define Nucleus as it is used to describe neurons
Nucleus = a tight cluster of neurons in the brain
Define Functional Localization
Being able to look at deficits and localize where it has occured in the brain.
How does the brain project neurons from one nucleus to another?
Neurons tend to project from one nucleus to another via a topographic function (A1 projects to B1, etc)
How does the brain keep track of nerves on body?
Via topographic mapping, whether it be a somatotopic map, cochleotopic map, retinotopic map etc.
What are the 5 ways cells communicate?
"APEES"

Autocrine (= cell activates self)
Paracrine (=cell releases stuff and activates other cells)
Endocrine (=cell releases stuf into blood, affecting cells at a distance)
Ephatic (conduction of nerve impulse without neurotransmitter)
Synaptic (Uses Neurotransmitter across cleft)
Biogenic amines, proteins and pepides are produced where in a neuron?
cell body (NOT in the bouton)
What adaptation does the pre-synaptic bouton have that allows it to align up in the correct spot?
Presynaptic dense projection

On the post-synaptic side, we have post-synaptic density
What are the processes involved in Biogenesis of neurotransmitters?
1. vesicle and neurotransmitter precursors and enzymes synthesized in cell, released from golgi

2. vesicles travel through axon on microtubule tracts via fast axonal transport. Peptide neurotransmitters are already in some vesicles.

3. Nonpeptide neurotransmitters are synthesized and transported into vesicles in the nerve terminal
What are the steps involved in Neurotransmitter formation and release?
1. Neurotransmitter synthesized and packaged in vesicles
2. Action Potential arrives at pre-synaptic terminal
3. Rise in Ca2+ triggers fusion of synaptic vessicles with the presynaptic membrane
4. transmitter molecules diffuse across cleft and bind receptors on post synaptic cell
5. bound receptors activate post-synaptic cell
6. Neurotransmitter is broken down and taken up by the presynaptic terminal or diffuses away
What are the stages of neurotransmitter release?
Docking
Priming
Fusion/Exocytosis
Endocytosis
Recycling
Detail the steps required for neurotransmitter release
1. vesicle with synaptogamin and synaptobrevin (a v-SNARE) go to nerve terminal membrane which has syntaxin and Snap25 (t-SNARES)

2. n-sec-1 dissociates from syntaxin, allowing syntaxin and Snap-25 to form a complex. Distal synaptobrevin winds around this complex, forming a ternary complex

3. the SNAREs, synaptrobrevin, syntaxin and SNAP-25 form alpha helices, drawing vesicle and pre-synaptic membranes into close apposition

4. Entry of Ca2+ = binds synaptotagmin = triggers fusion

5. alpha-SNAP and ATPase NSF bind SNARE complex, using energy from ATP hydrolysis to disassemble SNARE

6. endocytosis of vesicle = synaptobrevin recycled. Syntaxin and SNAP25 free for another cycle
When is ATP added when a neurotransmitter is being released by a vessicle in a neuron?
Prior to the release of the vessicle = priming
What happens when ATP is hydrolyzed after being added to a vessicle-releasing neurotransmitter? What riggers the ATP hydrolyzation?
ATP hydrolysis causes fusion and exocytosis

Ca2+ rushing in triggers ATP hydrolysis = vessicle fused to membrane = open up membrane = endocytosis
What are the two categories of interactions that can occur across a synaptic cleft?
Ionotropic and Metabotropic
Define Ionotropic interactions that occur across a synaptic cleft using Nicotinic Ach receptor
Influx of ions
Occurs in milliseconds


Receptor located on ion channel

Receptor opens and allows Na+ to rush in

Na+ rushes in = cell depolarized.

Can result in formation of AP in adjacent neuron
Define Metabotropic interactions that occur across a synaptic cleft using Muscarininc Ach
Called metabotropic because they can affect metabolism.

occurs more slowly than Ionotropic (seconds or minutes)

More powerful than Ionotropic

transmitter sits down on receptor associated with peptide subunits

Subunit breaks up, and it can go other places in cell to affect how cell is working. ex. = ion channel open or something related to metabolism
Contrast the events of ionotropic receptor vs. metabotropic receptor interactions
Ionotropic: Nicotinic Ach receptor activation --> Membrane Depolarization --> AP Excitation --> Muscle Contraction

Metabotropic: Muscarinic Ach receptor activation --> Release of alpha-GTP and BetaGamma from G protein --> Activation of inward rectifier K+ channel by betagamma --> Membrane Hyperpolarization --> Dec. in Heart Rate (for example...)
T/F: The effect of serotonin on a neuron depends on what receptor we have
TRUE. Serotonin may excite or inhibit based on the receptor present
Outline the steps involved in serotonin release from a neuron
1. Serotonin released and neg. feedback occurs b/c serotonin binds, inhibiting more serotonin release

2. Serotonin re-uptake into pre-synaptic neuron to be recycled.

3. Enzymes in synaptic cleft metabolize un-used, un-uptaken serotonin
Dopamine binds the D1 Receptor causing what?
D1 receptor stimulates cyclic AMP = stimulates activity of cell = inc. our feeling of satiety (fullness)
Dopamine binds the D2 Receptor causing what?
D2 receptor inhibits cyclic AMP = supress their activity = dimishes craving feeling.
How does cocaine work?
blocks the re-uptake of dopamine = good feeling preserved = craving suppressed = very addictive
How do anti-cocaine antibodies work?
They block cocaine, preventing it from attaching to the re-uptake transporters
What is the glial cell's role in the glutaminergic synapse?
Glial cells surround synaptic ending and take up neurotransmitter quickly.

Defect in glial cell = more neurotransmitter in cleft
What is the affect of glutamate in the glutaminergic cleft? How does this lead to ALS or Lou Gherig's Disease?
glutamate released into cleft and binds glutamate receptor, allowing Ca2+ to enter cell = Excitotoxicity = Neuronal Death = Lou Gherigs Disease (ALS)
What is a possible treatment for ALS or Lou Gherig's disease?
Enhance glial cell vacuuming of terminal = less excitatory neurotransmitter present = cells not driven as hard and less neuronal death
What are the three things that make neurons special over other cells?
1. Dendrites studded with spines that concentrate Ca2+
2. Organization of axons
3. Axon delivers info to another place.
What is the purpose of the spines on dendrites?
specialized regions that can concentrate Ca2+.

Usually see synaptic connections on ends of spines.
90% of the cells in the CNS are what kind of cells?
glial
What are the 3 types of neuroglial (glial) cells?
Astrocytes (protoplasmic and fibrous)

Oligodendrocytes

Microglial Cells
Astrocytes Comprise what percentage of the glial cells in the CNS?
50%
What are the three functions of Astrocytes?
1. Metabolic Compartmentalization (set up boundary around neuron)

2. Synaptogenesis (development of nervous system)

3. Tissue Repair - Gliosis (ex. = a scar forms to protect whatever is left)
T/F: Gliosis, the natural process of tissue repair, sometimes via a scar formation, cannot hurt neurons
FALSE. if they proliferate, they CAN hurt neurons and be destructive
T/F: Parts of the neurons and blood vessels of the brain will not contain astrocytes
FALSE - astrocytes will cover all surfaces of the blood vessels and neurons in the brain - BLOOD BRAIN BARRIER
Under what conditions do astrocytes proliferate?
Brain damage due to stroke, traumatic injury, toxin, poison, inflammatory response, etc.

= Astrocyte Proliferation
= Potential Scar Formation
= Fibrous Gliosis = Proliferation of Astrocytes
What occurs in the brain when a patient has a stroke?
Stroke = blood flow to part of brain stops = portion of brain goes without oxygen and dies.

= glial proliferation and fibrotic tissue take over
What occurs in patients with diseases that disallow astrocytes from working?
We don't get rid of waste products = can become toxic to neurons.
Oligodendrocytes do the same thing as what other cell in the PNS?
Schwann cells
What do Oligodendrocytes do?
Provide wrapping of myelin around axon in CNS
Why are Oligodendrocyte processes shorter than Astrocytes?
because oligodendrocyte processes wrap around the axon
Whats the difference between Schwann cells (PNS) and Oligodendrocytes (CNS)?
Schwann cells wrap around only one axon while oligodendrocytes have multiple processes each ending in a wrap = any given oligo can wrap around multiple axons
What is the basis for autoimmune diseases?
Myelination. Myelin consists of many dif. types of proteins = if we're infected with a virus it will stimulate immune system. If virus has protein structure like myelin sheath, body will attack its own myelin = A De-Myelinating Disease
De-Myelinating diease of the PNS is called what?
Guillain-Barre` Syndrome
De-Myelinating diease of the CNS is called what?
Multiple Sclerosis
Where are the majority of the Na+ and K+ channels located on a neuron?
Nodes of Ranvier
Astrocytes are derived from what?
ectoderm (=nervous system)
Oligodendrocytes are derived from what?
ectoderm (=nervous system)
Microglial cells are derived from what?
Monocytes and Macrophages inside brain
What are ramified microglial cells?
Microglial cells with processes all spread out.

Sits quietly, sends processes out exploring brain to explore
Damage in brain (including BBB break or junk gets into brain) means what in terms of microglial cells?
damage in brain = inc. microglial cell proliferation
If a monocyte migrates into the tissue it becomes what?
macrophage
If a monocyte migrates into the brain it becomes what?
microglial cell
Name the cytokines of the CNS
"IITT"

Interleukin-1
Interleukin-6
Tumor Necrosis Factor
Transforming Growth Factor
The cytokines of the CNS (IITT = Interleukin-1, Interleukin-6, Tumor Necrosis Factor, and Transforming Growth Factor) are beneficial in what respect?
Beneficial in inflammation but devastating if over-produced bc they are destructive to surrounding neurons
Name the Lining Cells of the nervous system/ventricles
PEC

Pial Cells
Ependymal Cells (line ventricles)
Choroid Plexus Cells
What cells form the choriod plexus' that filter CSF?
ependymal cells

Cuboidal. Filter CSF formed in ventricles
Define Choroid Plexus
Mass of capillaries surrounded by cuboidal cell lining that filters CSF
The central canal of the spinal cord is lined with what type of cells?
ependymal
T/F: Transfer of substances from CSF around spinal cord to neurons in brain can occur via ependymal cells
TRUE
Choroid Plexus is located where in ventricles?
Lateral Ventricles
Third ventricle
Fourth Ventricle
Where is CSF found in brain?
Ventricles and Subarachnoid Spaces
How much CSF is found in centricles and subarachnoid space?
150 mLs total
How much CSF formed per day?
500-600 mLs

= 0.35 mls per minute = we will also DRAIN it at 0.35 mls per minute
How does drainage of CSF occur?
Subarachnoid granules of superior sagittal sinus

Spinal granulation of spinal nerve
Define Hydrocephalus
Imbalance between CSF production and drainage = Inc. CSF in cranial cavity. Highly Destructive
What is the cause of Hydrocephalus?
Hydrocephalus is secondary to non-communication of the various parts of the ventricular system
Hydrocephalus ex vacuo (demolished brain material=ventricle expands to fill empty space) is common after what?
any kind of trauma or stroke
Define Decorticate Posturing
Arms flexed and held in towards body because cerebral cortex isn't functioning
List the Meninges from Outside to Inside
Dura - Arachnoid - Pia Mater
Define Periosteal Dura
When dura is up against bone
T/F: epidural hematoma = outside dura
TRUE
How do Arachnoid Granulations work?
Arachnoid Granulations extend into sinus

Pressure in sinus must be lower than pressure in granulations

One-way valve opens
What happens when pressure increases in the veins of the brain?
No CSF drainage = Hydrocephalus
What forms the falx and tentorium?
Inner Dura
Veins and Sinuses of the brain are lined with what?
endothelium
Whats the difference between the membranous arachnoid and trabecular arachnoid?
trabecular arachnoid = Connective tissue that connects arachnoid to pia mater
Moving from inferior to superior up the pre-central and post-central gyri on the brain, what do each region of these control?
Face, Hand, Torso, Lower Expremities
The pre-central gyrus does what?
motor to Face, Hand, Torso, Lower Extremities
The post-central gyrus does what?
somatic sensory to Face, Hand, Torso, Lower Extremities
What is the function of the orbital gyrus?
emotional behavior
What is the function of the superior frontal, middle frontal, and inferior frontal gyrus?
Cognitive, Executive Function (attention, memory , language)
The Supramarginal gyrus is important in what in adults?
language function
What is the uncus?
A protrusion off medial aspect of temporal lobe. If we have swelling or bleeding in the area, the uncus can be pushed into 3rd nerve = pupillary dilation and eye becomes unresponsive/immobilized in down and out position
T/F: The Optic Chiasm and Optic tract are part of the cranial nerves
FALSE. They are extensions of the forebrain = above tentorium. CN's start BELOW tentorium
What is the oldest part of the cerebrum?
Limbic Lobe (AKA Pape's Circuit) = Lesions here result in changes in personality
What are the parts of the lateral ventricles?
Anterior horn, body, posterior horn, inferior horn
What does the trigone of the brain demarcate?
where the body, post. horn and inf. horn all come together (AKA confluence of ventricles)
The foramen of magendy and foramen of luschka drain from where to where?
Magendy (Medial) and Luschka (Lateral) drain from 4th ventricle into subarachnoid cistern where CSF is trapped between arachnoid mater and pia of brain = subarachnoid space = CSF creates a water jacket
Detail the path of CSF
40% CSF comes from extracellular fluid from brain

60% CSF produced in mid brain.


Accumulates in ventricular system
Drains down Foramen of Monroe, 3rd ventricle, cerebral aquaduct, 4th ventricle, Out Luschka or Megendy's to subarachnoid cisterns
Define Hydrocephalus
Increased volume of CSF in the ventricular system

Imbalance between CSF production and drainage

Highly destructive
What are the classifications of hydrocephalus?
Communicating = when ventricular system open

Non-Communicating = for ex. Occlusion in cerebral aquaduct

Hydrocephalus ex vacuo = If we lose a significant portion of the brain
A T1 MRI is good for viewing what?
Anatomy
A T2 MRI is good for viewing what?
Where the water is = use for infection and inflammation
What do the ventricles do when a person experiences Hydrocephalus ex vacuo?
They expand to take up the now empty space
Define Dandy-Walker Syndrome
Cerebellum never developed in the back = failure of cerebellar hemispheres to fuse = subsequent lack of growth

Associated with:
Movement Disorders
Mental Retardation
What symptoms will you see in a pt. who cuts their spinal cord around C7? If you see a pt. who transects their spinal cord (=cuts all the way through) at C7?
Paralysis in lower extremities
bladder/bowel symptoms
upper extremity weakness

Transects at C7; Total lower extremity loss of function
bladder/bowel symptoms
Arms still functioning OK
What are the Afferent systems of the spinal cord?
Spinal nerve
Dorsal Root
Dorsal Root Entry Zone (DREZ)
Medial Division of the DREZ (large caliber fibers)
Lateral Division of the DREZ (small caliber fibers)
Group 1a and Group 1b (or A-alpha fibers = Large Fibers) tells us what?
very small stimuli, proprioception, whats touching us.

For ex., two-point discrimination tests large fibers
Group II (or A-beta) tells us what?
Irritating things on our skin ex. = nociceptors
What are some characteristics of The Large Fiber system (A-alpha fibers or 1a and 1b and A-beta fibers or Group II)
Heavily Myelinated

Low Threshold = doesn't take a lot of energy to activate them

1a and 1b are our fastest axons...largest in terms of size and myelination
1a are what?
muscle spindle fibers
1b are what?
golgi tendons
The recurrent meningeal branch of the afferent spinal cord system innervates what?
PLL - posterior longitudinal ligament and dura on ant. side of spinal cord
Where do large fibers enter the spinal cord?
Medial side of dorsal horn...then it sends branches into ventral horn to initiate reflexs
What does the pacinian corpuscle do and whats its path?
Pacinian corpuscle = touch.

sends branch into dorsal portion, then into brainstem to cortex so we're aware of touch
Where are the cell bodies of the naked nerve endings?
DRG. Innervates dorsal horn, which is the pathway we use to feel pain
A-beta fibers or group II do what?
cutaneous touch
A-delta and C fibers end where?
They end naked in tissue and have fairly high thresholds for activation
Which innervate the dorsal horn? Small fibers or Large fibers?
small.

Neurons in dorsal horn then take info through medulla, through pons, to midbrain and into thalamus
Nociceptive activity can be found in what portion of the "H" of the spinal cord?
lateral and medial portion of body
alpha motor neurons project where and control what?
project to skeletal muscle and control skeletal m. movement
Laminae 1 in dorsal horn does what?
receives small fibers and projects to thalamus then to cortex
T/F: Laminae 4 in dorsal horn is a proper nucleus in spinal cord
TRUE. also called nucleus proprius
The medial motor nuclei portion of the ventral horn innervates what?
Axial Muscles
The lateral motor nuclei portion of the ventral horn innervates what?
Appendicular muscles
Flexors are innervated by which portion of the ventral horn?
dorsal. Clusters of alpha-motor neurons. each cluster might represent a dif. muscle
Extensors are innervated by which portion of the ventral horn?
ventral
How do you check flacid weakness or lower motor neuron weakness?
passively move limb. If there's no resistance, there is a lower motor neuron lesion = alpha-motor neuron damage or damage to actual connection to muscle.
What are some of the things we see in flacid weakness?
weakness
hypotonia
hyporeflexia
fasciculations (=skin over muscle ripples = muscles underneath contracting w/o end points)
atrophy and wasting
Spasticity is a sign of what?
upper motor neuron lesion
Without cortical control, what happens when we tap on a tendon?
big response from muscle = Antagonistic Muscle stretched = signal sent to spinal cord = Agonist muscle stretched = we get a bouncing back and forth effect = pt. paralyzed b/c they can't control it. Muscle HAS tone (driven by ventral horn cells) and muscle has reflexes = over-stated
What happens if we break or kill the alpha motor neuron connection to muscle = a lower motor neuron type?
Hyporeflexia
Hypotonia
Fasciculations
Atrophy
Where does the Lateral corticospinal tract originate, decussate, and whats it target?
Arises in motor cortex, decussates (=crosses midline) at caudal medulla and targets lateral ventral horn (alpha motor neruons) and interneurons (golgi type II) at all levels of spinal cord

Gives us fine motor control
List the path of a neuron innervating our hand
Cortical neuron leaves cerebral cortex with axon coming down brainstem

crosses midline at cervical medullary junction

Descends to lateral side of spinal cord

As it goes through cervical region it innervates alpha-motor neurons - it may innervate interneurons which innervate alpha motor neurons, OR it may innervate alpha motor neurons directly.
What signs and symptoms are seen if there is a transection of the spinal cord around the medulla? (ie AT the point of decussation)
upper motor neuron signs and symptoms on the ipsilateral side = side OF the transection
What are the signs and symtoms seen if a pt. suffers and infarct in the cerebrum (ie ABOVE the point of decussation?)
Cortical neruons and axons destroyed = contralateral symptoms; if lesion is on Right, damage will show up on Left
Whats the significance of the decussation point?
If damage occurs ABOVE it, we'll see contralateral (oppsite) side symptoms

If damage occurs BELOW it, we'll see Ipsilateral (SAME side) symptoms.
What are the two spinal cord Ascending Systems we should know?
1. Dorsal Column System

Fasciculus Gracilis ("graceful)

Fasciculus Cuneatus (cube-shaped)

2. Anterolateral System

Spinothalamic tracts (spinal cord to thalamus)
Spinoreticular tracts (spinal cord to reticular formation of brainstem)
What is the overall function of the Dorsal Column System (=fasiculus gracilis and fasiculus cuneatus)?
Carries info from cutaneous receptors = high speed, encapsulated cutaneous receptors
What is the overall function of the Anterolateral System?
Warning or Homeostatic type info = body can adjust autonomic nervous system = can give us the perception of pain.
What is the input, primary cell body, secondary cell body, decussation, and target of the dorsal column system?
Input = Group II A-beta primary afferent fibers

Primary Cell Body = DRG (ipsilateral)

Secondary Cell Body = Nucleus gracilis or cuneatus (ipsilateral)

Decussation = internal arcuate fibers of caudal medulla

Target = thalamus = where it synapses (ventroposterior lateral nucleus of thalamus)
Detail the path of a signal when our hand is touched
hand touched - info sent to dorsal horn of spinal cord - enters dorsal column system - enters laterally compared to input from lower extremity - climbs up to nucleus cuneatus where it synapses - goes up to cortex
Whats the path of a signal from the lower extremity to the brain?
Heavily myelinated fiber enters dorsal portion of spinal cord - gets into fasiculus gracilis - nucleus gracilus in medullary portion of brainstem
In what spinal segments is fasiculus gracilis present?
sacral segements - lumbar segments
In what spinal segments is fasiculus cuneatus present?
T6 to C3
What are the differences in the path of signals from lower extremity and upper extremity?
Upper Extremity: fasiculus cuneatus - nucleus cuneatus - projected from cuneatus across midline - thalamus (twists)

Lower Extremity: fasiculus gracilis - nucleus gracilis- synapses/crosses midline - synapses in thalamus - projected into cortex
What is the input, primary cell body, secondary cell body, decussation, and target of the Anterolateral System?
Input = Group III (A-delta) and IV (C) primary afferent fibers (SMALL FIBERS)

Primary cell body = DRG

Secondary Cell Body = Dorsal Horn

Decussation = Anterior White Commissure

Target = Ventroposterior and posterior nuclei of thalamus
Compare and Contrast the Dorsal Column System with the Anterolateral System
DORSAL COLUMN vs. ANTEROLATERAL

Input: Group II (A-beta) primary afferents (LARGE FIBERS) vs. Group III (A-delta) and IV (C) primary afferents (SMALL FIBERS)

Cell Body: DRG for both

Secondary Cell Body: nucleus gracilus or cuneatus vs. Dorsal Horn

Decussation: Internal Arcuate Fibers of caudal medulla vs. Anterior white commissure

Target: Centroposterior Lateral nucleus of thalamus vs. Ventroposterior and posterior nucleus of thalamus
T/F: Any lesion of the Dorsal Column in the spinal cord will present symptoms on the contralateral side
FALSE. The Dorsal Column doesn't cross over until the medulla, so any lesion of the spinal cord will present with ipsilateral symptoms
If one whole side of the spinal cord is damaged, what symptoms would be seen?
If Dorsal Column System is damaged (DCS), we'd see Ipsilateral effects

If Anterolateral System (ALS) damaged, we'd see contralateral effects
Define Analgesia
When you can't feel noxious stimuli or pain, like a pin prick
What does ALS (Anterolateral System) carry and how do you test it?
Carries small fiber warning-type info.

Damage to it would mean Analgesia on the contralateral side.

Test it with pin prick or thermal sensation
How would you test the Dorsal Column System?
Test with inhibitory sense and two-point discrimination OR test by having pt. close eyes and ask them if they know which way finger or toe is pointing when you move it.
What symptoms would we see if a lesion occurs right in the center of the "H" of the spinal cord?
This is where pain and temp. fibers cross = Bilateral loss of pain/temp. over the segments that are cut. Ex. = Syrinx = a cyst
What is a Syrinx?
A fluid-filled cyst of CSF that forms in the spinal cord, brain stem, or on nerves.

Known to occur post-traumatically.
If the anterior spinal artery is infarcted, what signs/symtoms will we see?
Bilateral bands of analgesia (=can't feel pain)

Loss of motor control

BUT... Because the AREA is fed by a different artery, some parts of the area would be OK, and the patient could still feel vibration and proprioception (i.e. Dorsal Column still intact)
What are the signs and symptoms of Spinal Shock?
Usually seen right after injury

Loss of Descending Control
Hyperpolarization of ventral horn cells
Flaccid weakness break-through clonus (clonus = index that we have spasticity in limb)
Lasts 2 weeks to several months
What are the three longitudinal ligaments?
Ligamentum Flavum (stretches in flexion)
Posterior Longitudinal Ligament
Ant. Longitudinal Ligament (stretches in extension)
When does Ligamentum Flavum stretch?
"F=Flexion"
When does the Ant. Longitudinal Ligament stretch?
Extension
Why is the spinal cord enlarged in the cervical and lumbar regions, but not the thoracic?
Enlarged regions contain neurons for extremities
What spinal nerves come off the conus medularis instead of the spinal cord?
S2, S3, S4 = innervate pelvic basin, pelvic floor and pelvic sphincters around GI
Whats a good marker for the anterior side of the spinal cord? the posterior?
Anterior = Anterior Spinal Artery

Dorsal = Dorsal Column
Why do rootlets in the upper region of the spinal cord exit relatively near where they originate instead of traveling downward and then out, like in the lower region of the spinal cord?
Because the spinal cord grows slower than the spinal canal = rootlets must travel further downward to exit the further down the spinal cord we go.
T/F: After the conus, there's no more spinal cord, only rootlets.
TRUE
Around what vertebral level does the conus stop?
T12/L1
Why are spinal taps performed around L1-L2?
There is no spinal cord to knick there and the rootlets move out of the way when needle is inserted.
Around what spinal level are S2, S3, and S4, all on the conus medularis, located?
T12
T/F: The Filum Terminale fuses to the coccyx
FALSE. It fuses to the sacrum
C1-C7 nerves pass out above or below the associated vertebral transverse process? C8? T1-S5?
C1-C7 = ABOVE
C8 = Transition Level (passes out below C7)
T1-S5 = BELOW
C5, C6, C7 and C8 spinal nerves go through which plexus?
Brachial
T/F: Wherever we have an extremity in the body, we have a plexus?
TRUE
The Dorsal Ramus provides innervation of the dermatomes until roughly what vertical line down the back?
Edge of Scapula

Then the ventral ramus takes over
The ventral ramus provides innervation around roughly what vertical line down the back
From edge of scapula around front of body.

Dorsal Ramus provides the rest.
Dermatomes are created by what two nerves?
Dorsal Ramus and Ventral Ramus
What dermatome are you displaying to someone when you give them the middle finger?
C7
Why are the dermatomes not as uniform (i.e. in bands) in the limbs as in the torso of the body?
Because the nerves go through plexus' to get to the extremities and get shuffled around
What does the transverse sinus mark in cranial anatomy?
Boundary of attachment of tentorium to dural lining of cranium
What structures provide support for the spinal cord?
"SAD-F"

Spinal Dura
Arachnoid
Denticulate Ligaments
Filum Terminale
Spinal Accessory nerve innervates what?
Trapezius and Sternocleidomastoid
Between what two layers do epidural hemorrhages occur?
bone of calvarium (skull) and periosteal layer = outer dura
Between what two layers do subdural hemorrhages occur?
Arachnoid detaches from dura creating sub dural space (=where it normally attaches = space between arachnoid+dura DOES NOT exist normally)
Between what two layers do subarachnoid hemorrhages occur?
Arachnoid and Pia
Define Intraparenchymal hemorrhage
Hemorrhage within tissues of brain
Intraparechymal hemorrhages lead to what other type of hemorrhage?
Intraventricular hemorrhage
When an epidural hemorrhage occurs, what two places can the brain catch on, causing bruising, contusions etc?
At the top, brain can catch on falx cerebri, and at lateral sides it can catch on tentorium cerebelli
Whats one indication on an image (CT, MRI, etc.) that you are seeing a brain hemorrhage?
Flattened Gyruses
Describe generally what a subdural hemorrhage looks like
Subdural will be less "rounded out" as compared to epidural hemorrhages
Describe generally what an epidural hemorrhage looks like
Epidural hemorrhages are usually more round and occur more frequently in the temporal region than do subdural hemorrhages
Describe what a subarachnoid hemorrhage looks like
We will see the "star sign" in the image = pentangular cistern
If a bridging vein gets cut, where will blood pool?
Arachnoid and inner dura
T/F: Straight lines are never normal in imaging of the body
TRUE
T/F: Subdural hemorrhages can be acute or chronic
TRUE

Chronic = usually in elderly individuals or alcoholics
The pentangular cistern is located in what region of the brain?
Subarachnoid
T/F: The circle of willis is contained within the pentangular cistern
TRUE
In what 3 arteries of the brain are aneurysms most common
Anterior Communicating
Posterior Communicating
Middle Cerebral
T/F: Aneurysms are more common in males than females?
FALSE. They are more common in FEMALES by 50%
At what age do anurysms typically show up?
50s and 60s
15% of strokes are due to what?
Ruptured aneurysms

Mortality high
What are some risk factors for aneurysms?
smoking, hypertension
What are the three types of aneurysms?
Saccular

Fusiform

Giant
What is the underlying cause of a cerebral aneurysm?
Weakening of the tunica media in artery
T/F: If an aneurysm bursts into the subarachnoid space, it will show focal signs and symptoms
FALSE, it WON'T show focal signs or symptoms, it will just hurt. like a motha.
45% of people with Aneurysms die.
true story.
Will you see focal signs and symptoms with an intraparenchymal hemorrhage (=ruptured artery bleeds into brain)?
YES

Sulci will be efaced = flattened and not a lot of space for them
Define Duret Hemorrhage
One that occurs WITHIN brainstem = hernia or hemorrhage of brainstem into foramen magnum
What are two places you may see calcification in elderly patients upon imaging?
Coroid plexus and Pineal gland
At what age do anurysms typically show up?
50s and 60s
15% of strokes are due to what?
Ruptured aneurysms

Mortality high
What are some risk factors for aneurysms?
smoking, hypertension
What are the three types of aneurysms?
Saccular

Fusiform

Giant
What is the underlying cause of a cerebral aneurysm?
Weakening of the tunica media in artery
T/F: If an aneurysm bursts into the subarachnoid space, it will show focal signs and symptoms
FALSE, it WON'T show focal signs or symptoms, it will just hurt
45% of people with Aneurysms die.
true story.
Will you see focal signs and symptoms with an intraparenchymal hemorrhage (=ruptured artery bleeds into brain)?
YES

Sulci will be efaced = flattened and not a lot of space for them
Define Duret Hemorrhage
One that occurs WITHIN brainstem = hernia or hemorrhage of brainstem into foramen magnum
What are two places you may see calcification in elderly patients upon imaging?
Coroid plexus and Pineal gland
What does burst lobe syndrome indicate?
A lobe of the brain has burst, duh. = bleeding in center of brain
What does burst lobe syndrome look like on images?
One side of the brian will look swollen. May see fractures in the skull. Swelling outside of skull may be seen
Describe the events that lead to ischemia in the brain
1. Usually an occlusion occurs in a branch (for ex. off the middle cerebral artery)
2. The Ischemic Core fails to obtain blood
3. The Ischemic Penumbra (superficial to the ischemic core) fails to get blood
4. Tissue death occurs
What are the three types of Cerebrovascular Disease?
Infarctive Stroke (Embolic or Thrombotic)
Hemorrhagic Stroke
Diffuse Ischemia
What are the 2 different types of Diffuse Ischemia?
Watershed Infarctions
Global Infarctions
What are the 3 different types of Hemorrhagic Stroke?
Intraparenchymal Hemorrhage
Intraventricular Hemorrhage
Subarachnoid Hemorrhage
What are the 2 different subtypes of Infarctive Stroke
Ebolic (Artery to Artery or Heart to Artery)
Thrombotic (Atherosclerotic or Hypertensive)

ALSO: There are other forms of occlusive disease
Describe patient positioning when looking at a CT
Patient's legs are coming out TOWARDS you, so the left side of the CT is actually the patient's RIGHT
What are some of the signs to look for when determining if there is increased intracranial pressure?
1. Are dark spaces symmetrical?
2. Are ventricles on the mid line?
3. Gyral Efacement
What are the three places nerves carrying vibration, proprioception and fine touch (=Dorsal Column) synapse?
1. DRG
2. Dorsal Column (either cuneatus = upper limbs or gracilis = lower limbs)
3. Ventral Posterior Lateral Thalamus (VPL Thalamus)
What are the three places nerves carrying pain and temp. (=Anterolateral System = spinothalamic tract) synapse?
1. DRG
2. Lamina 1 and Lamina 2
3. VPL Thalamus