Disorders

Hematoma Epidural Hematoma Subdural Hematoma Subarachnoid Hematoma Cause Laceration of the middle meningeal artery Laceration of superior cerebral veins Ruptured berry aneurysm Suratentorial Tumor Meningeoma Astrocytoma Germinoma Brain Abscesses Colloid Cysts of 3rd Ventricle Oligodendrogliomas Glioblastoma Multiforme Cause Slow growing tumor of the meninges (15% of gliomas) Typically benign tumor of astrocytes (20% of gliomas) Tumor of germinal cells (generally near the pineal/tectal regions) Strep., Staph., or Pneumococci enter via sinusitis, mastoiditis, etc. Ependymal tumor (2% of gliomas) Slow benign tumor of oligodendrocytes (5% of gliomas) Malignant, rapidly forming astrocytic tumor (55% of gliomas) Histo: contains perivascular pseudorosettes and pseudopalisades Infratentorial Tumor Pituitary Adenoma Craniopharyngioma Choriod Plexus Papilloma Cerebellar Astrocytoma Medulloblastoma Hemangioblastoma Ependymoma Schwannoma Brain Stem Glioma Intraspinal Tumors Foster Kennedy Syndrome Cause Remnants of Rathke's pouch (adenohypophysis precursor) present Remnants of Rathke's pouch (adenohypophysis precursor) present Benign tumor of choroid plexus; can cause hydrocephal. (2% of glio) Benign tumor of cerebellar astrocytes Primitive neuroectodermal tumor (PNET) Tumor of blood vessels typically in the cerebellum (or retina) Tumor of ependymal cells (5% of gliomas) Tumor of Schwann cells from vestibular division of CN VIII Tumor of glial cells in brainstem (usually benign astrocytoma) Schwannoma > Meningioma > Glioma > Sarcoma … Anterior Fossa Meningioma Meningitis Bacterial Meningitis Viral Meningitis Cause Newborns: Streptococci, E. Coli, and Listeria; Infants: S. Pneumonia Young Adults: N. Meningitidis; Adults: S. Pneumonia Mumps, echovirus, coxackie virus, EBV, and herpes simplex type 2 Hydrocephalus Communicating Hydrocephalus Noncomm. Hydrocephalus Normal Pressure Hydrocephalus Hydrocephalus Ex Vacuo Pseudotumor Cerebri Cause Impaired CSF reabsorption (Usually due to arachnoid gran. defects) Blockage within the normal ventricular / aqueductal pathway CSF not absorbed by arachnoid villi Loss of cells in the caudate nucleus Increased resistance to CSF outflow at arachnoid villi Herniation Uncal Herniation Tonsillar Herniation Subfalcine Herniation Cause Protrusion of the brain through the tentorial incisura Protrusion of the brainstem/cerebellum through foramen magnum Protrusion of one hemisphere of the brain below the falx cerebri Congenital Malformation Spina Bifida Occulta Meningocele Meningomyelocele Cranium Bifidum Cause Failure of the posterior neuropore to form Same as spina bifida but more severe Same as meningocele except more severe Defect in occipital bone Colobma Iridis Anencephaly Arnold-Chiari Malformation Dandy-Walker Malformation Fetal Alcohol Syndrome Holoprosencephaly Hydranecephaly Failure of the choroidal fissure (optic nerve fibers) to close Failure of the anterior neuropore to close Congenital Congential failure of Foramen of Luschka and Magendie to open Prenatal exposure to alcohol Failure of midline cleavage of embryonic forebrain Bilateral hemispheric infarction due to occluion of carotid arteries Spinal Cord Injuries Poliomyelitis Tabes Dorsalis Brown Sequard Anterior Spinal A. Occlusion Vitamin B12 Neuropathy Syringomyelia Multiple Sclerosis Friedrich's Ataxia Guillan-Barre' Syndrome Intervertebral Disc Herniation Cauda Equina Syndrome Conus Medullaris Syndrome Effected Area Ventral Horns Dorsal Columns (especially Fasiculus Gracilis) Hemisection of left or right spinal cord Ventral 2/3 of Spinal Cord Dorsal Columns and Lateral Ventral White Matter Ventral White Commissure and Ventral Horns Random but primarily involving white matter of cervical levels Same as Vitamin B12 Neuropathy (aka Subacute Combined Degen.) Motor fibers of ventral roots and peripheral nerves Generally occurs in L-4/L-5 regions or L-5/S-1 regions Sensory loss in a saddle-shaped area (Gradual and Unilateral) Sensory loss in a saddle-shaped area (Sudden and Bilateral) Deafness Conduction Deafness Sensorineural Deafness Cause Interruption of passage of sound waves thru external or middle ear Disease of the cochlea, cochlear nerve (acoustic neuroma), or central auditory connections Brainstem Syndromes Medial Medullary Syndrome Lateral Medullary Syndrome Medial Inferior Pontine Syndro. Lateral Inferior Pontine Syndro. MLF Syndrome Facial Colliculus Syndrome Dorsal Midbrain Syndrome Paramedian Midbrain Syndro. Medial Midbrain Syndrome Jugular Foramen Syndrome Locked In Syndrome Central Pontine Myelinosis Top of the Basilar Syndrome Subclavian Steal Syndrome Affected tracts and nuclei Corticospinal tract, medial lemniscus, hypoglossal nucleus CN VIII Nu., ICP, Nu. Ambiguus, CN 9 & 10, STT, Spinal Nu. Of V Corticospinal tract, medial lemniscus, CN 6 CN 7, 8 (V/C) Nu., Spinal Nu. Of V, MCP, ICP, STT MLF ipsilateral to CN III and contralateral to CN VI CN VII and/or CN VI Nu. Superior Colliculus, Pretectal Region, Cerebral Aqueduct CN III, Medial Lemniscus CN III, Corticospinal tract, Corticobulbar tract CN IX, CN X, CN XI Corticospinal and Corticobulbar tract bilaterally Corticospinal and Corticobulbar tract Visual Defects One-and-a-half Syndrome Argyll Robertson Pupil Horner's Syndrome Papilledema Cause Bilateral lesions of the MLF and a unilateral lesion of CN 6 Syphilis and Diabetes Lesion of oculosympathetic pathway Increased ICP as a result of tumors, hematoma, or hydrocephalus ANS Disorders Hirschprung's Disease Riley-Day Syndrome Peptic Ulcer Disease Shy-Drager Syndrome Botulism Cause Neural crest cells do not migrate to part of colon; peristalsis stops Autosomal recessive; Loss of neurons in ANS/sensory ganglia Excessive production of HCl b/c of increased parasymp. Stimulation Damage to preganglionic neurons of intermediolateral cell column Toxin from the Clostridium Botulinum blocks release of Acetylcholine Limbic Disorders Kluver-Bucy Syndrome Amnestic Syndrome Wernicke's Encephalopathy Strachan's Syndrome Cause Bilateral ablation of anterior temporal lobes, including amygdala Bilateral infarction of the hippocampal formation Vitamin B1 deficiency damaging the mamillary nucleus, DM N. of the Thalamus, periaqueductal gray, and pontine tegmentum Vitamin B1 excess Basal Ganglia Disorders Parkinson's Disease Huntington's Disease Hemiballism Wilson's Disease Tardive Dyskinesia Cause Degeneration of dopaminergic cells of the substantia nigra Inherited autosomal dominant movement disorder of chromosome 4 Causes degeneration of cholinergic and GABAergic striatal neurons Vascular lesion of subthalamic nucleus Autosomal recessive disorder caused by defect in metabolism of Cu Patients are on antipsychotic medications Language Disorders Broca's Aphasia Wernicke's Aphasia Conduction Aphasia Transcortical Motor Aphasia Transcortical Sensory Aphasia Global Aphasia Expressive Dysprosody Receptive Dysprosody Cause Damage to Broca's Area (BA 44,45) Damage to Wernicke's Area (BA 22) Damage to Arcuate Fasiculus (Connects Wernicke's to Broca's) Damage to afferent fibers to Semantics Damage to efferent fibers to Semantics Lesion of Perisylvian Area thus damaging Broca's and Wernicke's Lesion to BA 44, 45 in non-dominant hemisphere Lesion to BA 22 in non-dominant hemisphere Other Disorders Korsakov's Syndrome Diabetes Inspidus SIADH Bell's Palsy Trigeminal Neuralgia Anterior Vermis Syndrome Myasthenia Gravis Alzheimer's Disease Lambert-Eaton Syndrome Cause Insufficient B1 (Thiamine) absorption damages Mammillary Bodies Secondary to damage to posterior pituitary (lack of ADH) Lung tumors produce excessive ADH (opposite of D. Insipidus) Damage to peripheral nerve produces LMN symptoms on Face Damage to a branch of the trigeminal nerve Atrophy of rostral vermis due to excess chronic EtOH consumption Autoimmune disorder directed at Acetylcholine Receptors Degeneration of cortical and cholinergic neurons in N. Basalis of M. Presynaptic defect of acetylcholine release Gerstmann's Syndrome Damage to the inferior parietal lobe of the dominant hemisphere Characteristics "Worst headache of my life", CSF will have RBCs in it Characteristics Benign, and more common in women (3:2) Characteristically found in hemispheric white matter in posterior fossa of children Cause noncomm. hydrocephalus b/c of aqueductal stenosis; causes Parinaud's syndr. Frontal, temporal lobes and cerebellum; Results in cerebral edema and herniation Found at F. of Monro thus causing increased ICP, positional headaches, sudden attack Calcification and frontal lobe involvement; Cells look like fried eggs (perinuclear halo) Most common primary brain tumor, this is commonly found in the frontal and temporal lobes as well as basal ganglia; crosses midline via corpus callosum Characteristics Prolactinoma most common; May cause hypopituitarism, visual field defects Congenital cystic tumor Occurance: 4th V > LV > 3rd V; Most common tumor of children under 2 years Contain pilocytic astrocytes and rosenthal fibers; most common pediatric brain tumor Radiosensitive; common in posterior fossa of children; cause posterior vermis syndrome Characterized by abundant capillary blood vessels and foamy cells Benign, with ependymal tubulus and perivascular pseudorosettes aka Acoustic Neuroma; Antoni A and B tissue and Verocay bodies Causes CN palsies, and may cause the "locked-in" syndrome Ependymoma represents 60% of intramedullary gliomas Ipsilateral anosmia (loss of smell), optic atrophy, and contralateral papilledema Characteristics Fever, headache, nuchal rigidity (tightness in back of neck), Kernig's sign (pain while extending knee), and CSF has decreased glucose but increased neutrophils and protein Same as for bacterial meningitis except CSF has normal glucose levels Characteristics Malabsorption leads to accumulation of CSF in ventricles or subarachnoid space Blockage leads to to accumulation of CSF in ventricles or subarachnoid space Progressive dementia, ataxic gait, urinary incontinence (Wacky, Wobbly, and Wet) Compensatory enlargement of ventricles due to loss of brain parenchyma Found in obese young women; Papilledema without mass, deteriorating vision Characteristics Increased cranial pressure in both hemispheres Increased pressure in the brainstem/cerebellum Increased cranial pressure in one hemisphere Characteristics Usually occuring in sacrolumbar region, hair tuft associated with site of failed closure Subarachnoid space herniates outward from the spinal column Subarachnoid space and spinal cord herniate outward from the spinal column Herniation of meninges, cerebellar tissue, and fourthe ventricle Brain does not develop Tectal plate is broken, cerebral aqueduct is thus occluded, and herniation of both the cerebellar vermis and medulla into the vertebral canal Enormous dilation of fourth ventricle, occipital meningocele, and agenesis of cerebellar vermis and spelnium of corpus callosum Microcephaly and congenital heart defects; most common cause of mental retardation Most severe form of fetal alcohol syndrome, only one lateral ventricle and no corpus cal. Hemispheres are replaced by hugely dilated ventricles Characteristics Same as Lower Motor Neuron lesions (areflexia, flaccid paralysis, fasiculations, etc.) Syphilis; Irritative involvement of dorsal roots results in pain and paresthesias Romberg sign (pt. stands w/ feet together and loses balance when eyes close) Ipsilateral loss of touch below injury and loss of pain and temperature up two levels; Contralateral loss of pain and temperature sensation below the lesion Damages LCST, STT, Ventral Horns; Bilateral Horner's Syndrome, loss of bladder/bowel Caused by megaloblastic anemia; Damages DSCT, LCST, and DC-ML tracts Loss of pain and temperature on outer arms and falccid paralysis of hands Plaques present damaging at random LMN symptoms; upper cervical root (C4) involvement and respiratory paralysis common Spinal root symptoms affecting a specific dermatome Caused by a tumor of the terminal cord; Continence and sexual functioning intact Caused by an intramedullary tumor; sexual and urinary incontinence severe Characteristics Caused by obstruction such as wax, otosclerosis(temporal bone degen.), or otitis media aka Perceptive Deafness, this is caused by presbycusis (degenerative loss of the initial segments of the organ of corti thus causing loss of high frequeny sounds) Characteristics Anterior Spinal A. occlusion; Injured tongue deviates toward injury (lick your wounds) Posterior Inferior Cerebellar A. occlusion; Dissociated sensory loss Paramedian branches of Basilar A. occlusion Anterior Inferior Cerebellar A. occlusion Internuclear Ophtalmoplegia often caused by Multiple Sclerosis Caused by pontine glioma or vascular accident Parinaud's Syndrome; Often the result of a pinealoma or geminoma and results in noncommunicating hydrocephalus, paralysis of upward/downward gaze, pupil deficits Benedikt Syndrome; Ipsilateral eye paralysis, contralateral loss of T/P/V sensation Weber Syndrome; Ipsilateral eye paralysis, contralateral face weakness and spastic Caused by poserior fossa tumor and results in loss of gag reflex, loss of P/T and taste in tongue, and paralysis of palate, larynx, SCM, trapezius Caused by lesion of the base of pons; Pt. Conscious and can move eyes only vertically May become locked in syndrome; Spastic quadriparesis, bulbar palsy, mental changes Rostral Basilar A. occlusion; optic ataxia, psychic paralysis, fixation of gaze (Balint's syndrome), w/ or w/o vsisual anosognosia (Anton's syndrome) Thrombosis of L Subclavian A. proximal to vertebral a.; transient weakness, vertigo Characteristics On attempted lateral gaze the only muscle that functions is the intact lateral rectus Absence of miotic rxn to light (direct/consentual) but preservation of miotic rxn in near r. Miosis (constricted pupil), ptosis (droopy eyelid), apparent enophthalmos (the impression that the eye is sunk in), hemianhidrosis (no sweating on half of face) Enlarged optic disk producing bilateral enlarged eye spots Characteristics Extreme dilation and hypertrophy of colon, fecal retention, absence of myenteric plexus Jewish; Excessive sweating, unstable blood pressure, difficulty feeding, sensory loss Stomach pain Orthostatic hypertensio, anhidrosis, impotence, bladder atonicity Paralysis of striated muscles, dry eyes, dry mouth, bowel obstruction Characteristics Visual agnosia, hyperphagia, docility, and hypersexuality Anterograde Amnesia (inability to learn and retain new memories) Ocular disturbances, ataxia, mental dysfunction Spinal ataxia, optic atrophy, and nerve deafness Characteristics Bradykinesia, stooped posture; Presence of Lewy Bodies; Treated with L-Dopa Glutamate Excitotoxicity: Glu is bound to NMDA receptors resulting in influx of Ca and cell death; chorea, hypotonia, progressive dementia Ballistic movements of one or both extremities Chorea, rigidity, pyschosis, dementia; Copper deposition noted in the cornea Repetitive choreic movement that affects the face and trunk Characteristics Patient understands speech but is unable to fluently speak or repeat phrases Patient cannot understand speech but is able to fluently speak nonsensically; cant repeat Patient understands speech and speaks fluently but cannot follow commands or repeat Patient cannot understand speech or speak fluently but can repeat statements Patient understands speech and can repeat statements but cannot speak fluently Patient cannot understand speech, speak fluently, or repeat phrases Patients can speak normally but can't express emotions or inflection in their speech Patients can speak normally but can't understand the emotional content of heard speech Chracteristics Alcoholics; Ataxia, Mental Status Changes, and Opthalmoplegia Excessive thirst and urination, increased plasma sodium and decreased urinary sodium Decreased thirst and urination, decreased plasma sodium and increased urinary sodium Hemiparesis of upper and lower face Sharp shooting pain in a dermatomal pattern precipitated by cold weather or face touch Ataxia of legs and trunk Fatiguable Weakness of Skeletal Muscle, Dysarthria, Ptosis, and Respiratory Failure Neurofibrillary tangles, senile plaques, amyloid substance, granulovascular degeneration, and Hirano bodies; Associated with memory loss Weakness in limb muscles that improves with use (unlike M. Gravis) Right and left confusion, finger agnosia, dysgraphia, dyslexia, dyscalculia, and either contralateral hemianopia or lower quadrantanopia Structure Choroid Plexus Free Nerve Endings Meissner's Corpuscles Merkel Discs Pacinian Corpuscles Function Secretion of CSF; Forms Blood-CSF barrier Mediate pain and temperature sensation in the epidermis Touch receptor found abutting the epidermis in the dermis Unencapsulated light touch receptor Pressure and vibration receptors found in the dermis Vessel Anterior Spinal Artery Opthalmic Artery Central Retinal Artery P Comm. Anterior Choroidal Artery ACA A Comm. Medial Striate Arteries MCA Lateral Striate Arteries PICA Pontine Arteries AICA SCA PCA Great Vein of Galen Superior Sagittal Sinus Middle Meningeal Artery Supplies Anterior 2/3 of spinal cord and medulla Eye Retina Hypothalamus and ventral Thalamus LGN, Globus Pallidus, and Posterior Limb of Internal Capsule Medial surface of the cerebral hemispheres Connects the ACAs in the Circle of Wilis Anterior putamen, caudate, and internal capsule Lateral surfaces of the cerebral hemispheres Internal capsule, caudate, putamen, and globus pal. Medulla and inferior cerebellum Base of pons Pons and lateral cerebellum Midbrain and superior cerebellum Midbrain, thalamus, LGN, MGN, and occipital lobe Drains the deep cerebral veins into the straight sinus Drains the bridging veins and CSF (via arachnoid villi) Most of the dura, including its calvarial portion Developmental Region Alar Plate Basal Plate Sulcus Limitans Rhombencephalon Prosencephalon Myencephalon Metencephalon Mesencephalon Diencephalon Telencephalon Anterior Neuropore Posterior Neuropore Adenohypophysis Function Gives rise to sensory neurons Gives rise to motor neurons Separates the alar and basal plates Develops into the Metencephalon and Myencephalon Develops into the Telencephalon and Diencephalon Develops into the Medulla and Lower Fourth Ventricle Develops into the Pons, Cerebellum, and Upper Fourth Ventricle Develops into the Midbrain and Cerebral Aqueduct Develops into the Thalamus and Third Ventricle Develops into the Cerebral Hemispheres and Lateral Ventricles Closure gives rise to the lamina terminalis Closure point of the caudal neural tube Derived from mouth ectodermal region called Rathke's Pouch Aggregates Lipofuscin Granules Melanin Lewy Bodies Negri Bodies Hirano Bodies Neurofibrillary Tangles Cowdry Inclusion Bodies Characteristics Accumulation of residual bodies derived from lysosomes Black pigment found in substantia nigra and locus coeruleus; disappears with Parkinson's Neuronal inclusions characteristic of Parkinson's intraneuronal, eosinophilic, rodlike inclusions found in the hippocampus of patients with Alzheimer's Intracytoplasmic degenerated neurofilaments characteristic of Alzheimer's Intranuclear inclusions found in neurons and glian in herpes simplex encephalitis Intracytoplasmic inclusions characteristic of Rabies found in pyamidal cells of hippocampus and Purkinje cells of the Hypothalamic Nuclei Medial Preoptic Nucleus Suprachiasmatic Nucleus Anterior Nucleus Paraventricular Nucleus Supraoptic Nucleus Dorsomedial Nucleus Ventromedial Nucleus Arcuate Nucleus Mammillary Nucleus Posterior Nucleus Lateral Nucleus Secrete Gonadotropic releasing hormones ADH (vasopressin), Oxytocin, Corticotropin Releasing Hormone ADH (vasopressin) and Oxytocin Factors to control hypothalamus Limbic Components Orbitofrontal Cortex DM N. of Thalamus Anterior N. of Thalamus Septal Area Limbic Lobe Hippocampal Formation Dentate Gyrus Hippocampus Subiculum Amygdaloid Complex Function Major link in the Papez Circuit; connects with the mamillary nucleus and cingulate gyrus Consists of the subcallosal area, parahippocampal gyrus, cingulate gyrus, hippocampus, and amygdala Part of Hippocampal Formation; Recieves hippocampal input and projects to hippocampus and subiculum Part of Hippocampal Formation; Recieves input from hippocampus and projects through the fornix to the mamillary Mediates conscious perception of smell; connects with DM Nucleus of Thalamus, Septal Area, and Hypothalamic N Plays a role in affective behavior and memory; connects with Orbitofrontal cortex, Prefrontal Cortex, and Hypothalam Connects with the hippocampal formation via the fornix as well as with the hypothalamus via the medial forebrain bu Functions in learning, memory, and recognition of novelty; Recieves input from entorhinal cortex as well and consist Part of Hippocampal Formation; Contains pyramidal cells that project through the fornix to the septal area and hypo Stimulation produces fear and sympathetic overacitivty; Lesions produce placidity and hypersexual behavior; Reciev septal area and to the DM nucleus of the thalamus corticies, olfactory bulb and cortex, hypothalamus/septal area, and hippocampal formation; Output is through the str Chemical Alpha Fetoprotein (AFP) Kinesin Dynein Function Found in amniotic fluid and maternal serum it is indicative of neural tube defects Mediates fast anterograde axonal transport along neural microtubules Mediates fast retrograde axonal trasport along neural microtubules Cell Neural Crest Microglia Oligodendrocytes Schwann Cells Astrocytes Ependymal cells Tanycytes Origin Monocytes (Mesoderm) Neuroectoderm Neural Crest Cells Neuroectoderm Neuroectoderm Neuroectoderm Characteristics Infoldings of blood vessels of the pia mater, covered with ependymal cells Connected via C fibers Connected via A-beta fibers Surrounded by adipose, connected via A-beta fibers Characteristics Branches off of the vertebral arteries Infratentorial branch of the ICA that runs with the optic nerve Courses though the optic disk to enter the retinal side of the choroid Aneurysm results in third nerve palsy Injury associated with leg/foot defects Most common site of aneurysm in COW; aneurysm causes bitempral lower quadrantanopia Penetrating arteries of the anterior cerebral artery Injury causes deficits in language (Broca, Wernicke), motor (face, arms), and vision (FEF) Penetrating arteries of the middle cerebral artery; Main blood supply of the internal capsule Injury can affect nucleus ambiguus; Branches from the Vertebral Artery Injury affects corticospinal fibers and CN IV root Injury affects CN VII, spinal trigeminal tract of CN V Supplies the SCP, deep cerebellar nuclei, and cochlear nucleus Occlusion results in contralateral hemianopia with macular sparing Formed from the confluence of the inferior sagittal and internal cerebral veins Branch of the maxillary artery that enters the brain via the foramen spinosum Characteristics Failure to close results in ancephaly (failure of brain to develop) Failure to close results in spina bifida oeruleus; disappears with Parkinson's ound in pyamidal cells of hippocampus and Purkinje cells of the cerebellum n the hippocampus of patients with Alzheimer's teristic of Alzheimer's herpes simplex encephalitis Other Contains the sexually dimorphic nucleus which requires testosterone for functioning Controls circadian rhythms and recieves input from retina Controls temperature regulation via parasympathetic stimulation Regulates water balance; Destruction results in diabetes insipidus Savage behavior results when this nucleus is stimulated in animals Stimulation of this nucleus inhibits the urge to eat; Damage results in obesity, savage behav. For example, neurons here produce dopamine, which inhibits prolactin Portion of the memory/emotional Papez branch of the Limbic System Plays a role in thermal regulation Stimulation of this nucleus induces urge to eat; Damage results in anorexia th DM Nucleus of Thalamus, Septal Area, and Hypothalamic Nuclei ects with Orbitofrontal cortex, Prefrontal Cortex, and Hypothalamic Nuclei millary nucleus and cingulate gyrus nix as well as with the hypothalamus via the medial forebrain bundle yrus, cingulate gyrus, hippocampus, and amygdala velty; Recieves input from entorhinal cortex as well and consists of the following three major parts: pal input and projects to hippocampus and subiculum hippocampus and projects through the fornix to the mamillary nuclei and anterior nuclei of thalamus cells that project through the fornix to the septal area and hypothalamus vty; Lesions produce placidity and hypersexual behavior; Recieves input from the sensory association ptal area, and hippocampal formation; Output is through the stria terminalisto the hypothalamus and Associated with Spina Bifida (increased amts.) Down Syndrome (decreased amts.) ural microtubules Nerve trophic factors, neurorophic viruses (Herpes, Rabies, Polio, Tetanus) Function / Characteristics Gives rise to ganglion cells, schwann cells, chromaffin cells, melanocytes, odontoblasts, AP septum of heart, and parafollicular cells Immune response in CNS Myelination of CNS Myelination of PNS Feet form glia limitans and envelope basement membrane of capillaries, forms glial scars, buffers K conc., helps in reuptake of neurotransmitters Cilliated cells that produce CSF Modified ependymal cells that mediate cell transport btw. Ventricels and neuropil, regulate the release of gonadotropic hormones from adenohy.