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Astrocyte

Schwann cell

Oligodendrocyte

Microglia

Ependymal cells

Nissl bodies

Satellite cells
Astrocyte: BBB, transport for nutrients and metabolites, specialized contacts between neuronal surfaces and blood vessels, work with neurons in processing information and memory storage

Schwann cell: myelin outside of CNS

Oligodendrocyte
: myelin in CNS

Microglia: clearing cellular debris (phagocytic properties)

Ependymal cells: serve as lining for ventricles and choroids plexuses involved in production of CSF.

Nissl bodies: staining granular body.

Satellite cells: a type of schwann cell, they support neurons in the PNS
NTs

ACh

Norepinephrine

Serotonin

Dopamine

Histamine

GABA

Glycine

Glutamate and aspartate

Endorphins/enkephalins

Substance P
ACh: I or E; involved with memory

NorEpi: I or E; regulates sympathetic effectors, emotion related when acting in brain

5-HT: mostly I; moods, emotions, sleep

Dopamine: mostly I; emotions/moods; regulating motor control

Histamine: mostly E; emotions and regulation of body temp and water balance

GABA: I; most common inhibitory in brain

Glycine: I; most common inhibitory in SC

Glutamate: E; most common excitatory in CNS

Endorphins/enkephalins: mostly I; act like opiates to block pain

Substance P: mostly E; transmits pain information
Basal Ganglia

location
function
NTs found here
wrapped around thalamus. ganglia are cell bodies and nuclei.

- regulating control on motor integration.

- Dopamine and GABA are found here and responsible for inhibition of tone

- extrapyramidal. Control body tone and gross movemente
Midbrain and Medulla

cranial nerves?
Midbrain: Cranial nerves III and IV

Medulla: CN 8,9,10,11 & 12
RAS fxn
allows consciousness and ability to be aroused
arachnoid villi
absorb CSF back into blood. Can become blocked (hydrocephalus)
Meninges of brain
Dura mater, arachnoid mater, pia mater

vessels pass in subarachnoid space

Spinothalamic
- Crude, survival based.

- crude touch, pain and temp.

-myelinated and non.

- fibers synapse quickly upon entering the SC and synapse to the other side
Posterior column
- "fine touch"

- position, localization and vibration

- travels up the same side of the SC and synapses with second order neuron that goes to the thalamus (after crossing at medulla)
Pyramidal

vs.

Extra-pyramidal
Pyramidal:
  • Corticospinal
  • Unmyelinated neurons pass through cell bodies of Betz cells in motor cortex, down SC on opp. side to anterior horn cells.
  • fine, discrete movements
  • excitatory in nature

Extra-pyramidal:
  • coordination - cerebellar
  • Tone - midbrain
Brachial plexus

Lumbar plexus

Sacral plexus
Mixed spinal nerves with both sensory and motor neurons

C5-8, T1: innervates hands, arms and wrist

L2-4: anterior and posterior portions of the lower body

L5 - S5: same as above
Sympathetic nervous system

vs.

Parasympathetic
Thoracocolumnar
Preganglionic ACh; post-ganglionic: Epi
Short preganglionic, long post-ganglionic (with exceptions)

Craniosacral
ACh throughout
Long preganglionic, short post-
Partial vs. generalized seizures
Generalized seizures always cause a loss of consciousness.

They're often preceded by aura and a postictal state results afterward.

Can be absence, tonic-clonic or atonic

Partial can be simple or complex
  • simple: with or without jacksonian march
  • complex: non-motor; temporal lobe, emotional, sensory
dementia

vs.

delerium
Dementia: progressive failure (without return) of cognitive fxns. From: trauma, vascular diseases, Alzheimer's, infections. Lewy bodies and lacunar infarcts are shown. Decrease in ACh production and abnormal amyloid production.

Delerium: temporary loss of cognitive fxns. Due to nervous tissue injury, exposure to toxins, drug intoxication, metabolic disorders.
Alzheimers
loss of NT stimulation by choline acetyltransferase

B-amyloid produced that we can't get rid of- related to apoE4

Ca2+ and it's rapid influx is involved.

Tau proteins form neufibrillary tangles
Cerebral hemodynamics

what influences it

CPP
20% of CO

10% of body's blood

influenced by CO2 and O2 levels in the blood

CPP = MAP - ICP (normally 5 - 15 mmHg)

ICP stages
I: decrease the blood
II: arteries constrict
III: autoregulation goes and arteries dilate. bad news.
IV: shifting contents. coma, death
Cerebral edema

Vasogenic

Cytotoxic

Ischemic

Interstitial
Cerebral edema is an increase of fluid (H2O) inside the brain tissue. The four most common types are: Vasogenic edema: This edema is the most important clinically. An increased permeability of the capillary endothelium of the brain after injury to the vascular structure results in a disruption of the blood-brain barrier. Proteins leaking out into the extracellular spaces taking water with them. It spreads rapidly and is self sustaining. Cytotoxic (meatabolic) edema: Failure in a cell's active transport systems resulting from cytotoxic substances leads to cell swelling. Ischemic edema: Following cerebral infarction, edema is confined to the intracellular compartment. In the following hours and days brain cells undergo necrosis and die releasing lysosomes. The autodigestive process leads to a more permeable blood-brain barrier. Interstitial edema: This edema is caused by leakage of the neuroglia ependymal cells. CSF leaks leaks from the ventricles into the interstitial spaces through the ependymal cells (transependymal movement). Hydrostatic pressure within the white matter increases repidly and that matter is reduced with the rapid disappearance of myelin lipids. It's most often seen with noncommunicative hydrocephalus (see below).
Hydrocephalus

communicating
non-communicating

acute
normal-pressure
communicating: impaired absorption of CSF caused by high venous pressure or congenital abnormalities in the subarachnoid space (or meningitis, subarachnoid hemorrhage or subarachnoid mass)

non-communicating: obstruction within the ventricular system caused by congenital abnormality in the ventricular system or mass lesions
Focal brain injury

Epidural
Subdural
Intracerebral
Epidural: arterial bleeding between dura mater and skull. Lateral shift and uncal herniation. Middle meningeal artery most commonly torn.

Subdural: venous bleeding into subdural space. Acute or chronic, increase in ICP either way.

Intracerebral: injury to smaller vessels within the brain. Increasing mass with increasing ICP.
Diffuse brain injury

mild concussion

Classic cerebral contusion

Mild DAI

Moderate DAI

Severe DAI
Diffuse brain injury: most common in frontal and temporal axonal tracts

Mild concussion: temporary interruption in axonal fxn.

Classic cerebral contusion: LOC up to 6 hours. results from neurological dysfunction without anatomical disruption.

Mild DAI (diffuse axonal injury): post-traumatic coma 6-24 hours long with resulting problems

Moderate DAI: coma lasts >24 hours without full recovery.

Severe DAI:
major brainstem and axonal damage assoc. with prolonged coma if pt survives
CVAs

risk factors
Types
  • Thrombotic
  • Embolic
  • Hemorrhagic
Risk factors:
- Arterial hypertension
• Smoking
• Diabetes Mellitus
• Insulin resistance
• Polycythemia
• Hyperlipidemia
• Hyperhomocysteinemia
• Atrial fibrillation

Thrombotic: thrombus in blood supply of or to brain. Can have Transient Ischemic Attacks (TIAs) that progress over time.

Embolic: Something comes from elsewhere and blocks the blood supply (e.g. thrombus from carotid, endocarditis, fat emboli 2o long bone breakage)

Hemorrhagic: Happens in hypertension, malformation of vasculature, bleeding into a tumor, anti-coagulation. Also a lacunar stroke is of this type: microinfarcts that are assoc. with DM or HTN
Intra-cranial aneurysms

Risks
Types (2)
Forms
Risks:
– Congenital malformation
– Arteriosclerosis
– Trauma\Infection
– Cocaine use

Types:
Saccular: gradual growth over time of sac in the vessel
walls
Fusiform: greater than 25 mm and result from diffuse
arteriosclerosis. Commonly found in the basilar arteries or
terminal internal carotids

Forms:

Berry: usually in circle of willis
Broab based
Fusiform
Cavernous angiomas

Capillary telangiectasis
Cavernous Angiomas: sinusoidal collections of blood vessels without brain tissue interspersed. Rarely bleed

Capillary telangiectasis: dilated capillaries with interspersed normal brain tissue. Bleed only rarely and are associated with Rendu-Oster-Weber disease
Headaches

Cluster
Tension
Migrane

Cluster: usually men, happen at night, lacrimation, red eyes, nasal stuffyness, ptosis, N&V, pain referred to midface and teeth. Happen in clusters. No warning, unilateral tearing, burning, periorbital and retrobulbar or temporal lasting 30 min to 2 hours

Tension: trigeminal nerve involved (clenching jaw). Occurs in tandem with migranes.

Migranes: has trigger; aura; release of vasoactive neuropeptides, ionic alterations, platelet release of serotonin, degranulation of mast cells; activation of locus ceruleus and exitation of trigeminal nuclei resulting in dilation of dural arteries phases.
Meningitis

causes
Causes: Bacterial, fungal or viral.
  • Bacterial: streptococcus pneumoniae or Neisseria meningitdis
  • Fungal: more in immunocompromised (coccidiodes, TB, histoplasmosis, cryptococcosis)
  • Viral: best outcomes. can be caused by all common URI viruses.
Parkinsons

what it involves.

types
Involves dopiminergic neurons of the basal ganglia and nigrostriatal pathway. Lewy bodies and intracytoplasmic eosinophia inclusion bodies are found

Primary is idiopathic and Secondary is d/t impact of drugs, toxins, infections

MS

what it involves

types by classification
  • Relapsing remitting
  • Primary progressive
  • Secondary progressive
  • Progressive relapsing
CM
Viral insult to genetically susceptible individuals. Immune cells respond and excrete glutamate at myelin sheath.

– Types by classifications
:
• Relapsing Remitting: characterized by distinct periods of Improvement and acute attacks
• Primary Progressive: steady worsening of symptoms
from the beginning
• Secondary Progressive: begins with periods of remission and relapses but becomes steadily more progressive
• Progressive Relapsing: steadily progressive but has periods of acute attacks as well

Clinical Manifestations (Syndromes)
• Spinal type: spastic ataxia, deep sensory changes in the extremities, and bowel and bladder symptoms, weakness and numbness
• Cerebellar: motor ataxia, hypotonia, asthenia, nystagmus
• Mixed: optic neuritis, diplopia, vertigo, cerebellar signs, visual field defects,


Amyotrophic Lateral Sclerosis
First involves lower motor neurons

Can target just one muscle group

Flaccid paralysis until upper motor neurons are involved.
CNS tumors

– Astrocytomas
– Oligodendrogliomas
– Ependymomas
– Astrocytomas
• most common tumor that grows by expansion and infiltration,
located within the cerebellum
– Most common lobes: frontal, temporal, and parietal
– Gradual growth and increase in ICP
– Often found initially with the onset of a new seizure
– Oligodendrogliomas
• less common tumor that is slow growing and found in the
frontal lobe
– Ependymomas
• arise from the fourth ventricle
Increased incidence in children
Myasthenia Gravis

pathophysiologh

CM
Disease of the Neuromuscular junction

Autoimmune disease mediated by anti-ACh receptor antibodies that mess up the motor endplate.

Clinical Manifestations
• Insidious onset
• Fatigue and weakness with increased symptoms after exercise
• Diplopia, ptosis, ocular palsies
• facial droop, difficulty swallowing, weight loss
• Respiratory depression, increasing weakness of the legs and arm muscles (proximal)
Stages of concussion
Grade I: Confusion and disorientation accompanied by momentary amnesia Grade II: Momentary confusion and retrograde amnesia that develops after 5 to 10 minutes and only incorporates events occurring several minutes before the injury. Grade III: Confusion and retrograde amnesia present from impact. Anterograde amnesia (forgetting events after the event) involved persisting for several minutes. Grade IV: Immediate loss of consciousness lasting less than 6 hours. Retrograde (before event) and anterograde amnesia present. Associated with focal signs (e.g. loss of reflexes, transient cessation of respiration, brief bradycardia, hypotension lasting 30 seconds to a few minutes).
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