Exam 2 Flashcards
Most ocular trauma
People <30 yrs
Occurs at home
With blunt or sharp objects
Without eye exam
With trauma induced lid injuries you must rule out
Associated ocular injury (globe rupture, hyphema)
Laceration danger zones
The eyelid margin (tarsus-must realign to avoid nothing, if not done correctly can cause exposure or epiphoria)
The lacrimal outflow system (Lacrimal canaliculus, must stent to avoid excess tearing)
Upper Eyelid retractors (see orbital fat, must get CT orbits)
What do we do for animal bites?
Copious irrigation
Debridement nonviable tissue
Early primary wound closure
Broad spectrum antibiotics
What do we do form chemical/contact injuries?
Irrigate to pH neutrality
Topical anesthetic
Identify acid vs base
Thermal injury
Usually affects eyelid
Must lubricate to preserve tissue viability
Late phase treatment
Abrasions and foreign bodies
Illuminate, anesthetic, fluorescein
Lid eversion
Topical cycloplegia, antibiotic, eye patch
Topical anesthetics should only be used
During exam or procedure
Never prescribed
How do we detect abrasions and foreign bodies
Fluorescein
Suspect a ruptured globe if
Severe blunt trauma
Sharp object
Metal on metal contact
High velocity injury
Warning signs of open globe
Laceration
Pigment
Pupil irregularity
Sub conjunctival hemorrhage
Uveal prolapse
Hyphema
Lens opacity/dislocate
Suspect an open globe if
Bullous sub conjunctival hemorrhage
Uveal prolapse
Peaked or keyhole pupil
Hyphema
Vitreous hemorrhage
Post-traumatic lens opacity
Low IOP
Anterior chamber is collapsed
Seidels sign
Gross inspection/symmetry
What do you do if the globe is ruptured?
Shield eye
No topical meds
Antiemetic narcotics
Tetanus prophylaxis
IMMEDIATELY refer to ophthalmologist
If you see post-traumatic proptosis you should suspect
Hemmhorage or orbital emphysema (air from sinus)
Must get CT orbits
What do you do for orbital hemorrhage?
Systemic corticosteroids
Ocular hypotensive agents
****Canthotomy/cantholysis
Therapeutic orbital floor fracture
Signs of an orbital fracture
Globe dystopia (enophthalmos)
Diplopia
Blepharoptosis
Hypoesthesia
Orbital imaging
CT (assessing for fractures, metallic FB may exist)
Orbit protocol (axial, coronal, sagittal)
Orbital fractures features
Fractures
Orbital heme
Orbital air
Optic neuropathy
Globe injury
Medical treatment for orbital fractures
Antibiotics
Nasal decongestion
Oral steroids
Abstinence from aspirin, NSAIDS, nose-blowing
Indications for surgery for orbital fractures
Enophthalmos
Restrictive diploplia
Defect >50% of orbital wall
Traumatic optic neuropathy is associated with
Closed head injury, mid facial fracture
Common in motor vehicle accidents
Traumatic optic neuropathy features
Loss of vision
Ipsilateral afferent pupillary defect (swinging flashlight test)
Flashing lights and floaters are associated with
Retinal detachment
A peaked iris toward an area of sub conjunctival hemorrhage indicates
Ruptured globe
A laceration medial to the punctum may injure
The lacrimal canaliculus
The uvea includes
Iris
Ciliary body
Choroid
The fundus includes
Retina
Macula
Optic nerve
What is the dividing structure for pre-septal and post-septal infections
Orbital septum
_ is the key for red eye and pink eye
History (onset, progression, other people with eye condition, trauma, contact lenses, recent URI, visual disturbances, discharge, itching, photophobia, PMH, medications, allergies)
Key exam points for red or pink eye
Visual acuity
Pattern of hyperemia
Classify discharge
Detect opacities
Fluorescein
Anterior chamber depth
Pupil irregularities
IOP
proptosis
Red flags for people with red/pink eye
Blurred vision
Sever pain
Photophobia
Colored halos
Reduced visual acuity indicates
Keratitis
Iridocyclitis
Glaucoma
NEVER in simple conjunctivitis
Ciliary flush indicates
Ciliary or iris involvement
Corneal o pacification indicates
KP
Diffuse haze
Corneal ulceration
Other red flags
Pupil abnormalities
elevated IOP
proptosis
Strabismus
Blepharitis
Inflammation along eyelid margin associated with normal skin flora
If angular associated with Moraxella
Burning sensation, mattering
Toothpaste sign
Swollen meibomian gland
Treatment: remove debris with soap
If staph use bacitracin
Hordeolum
Acute bacterial infection of sebaceous glands
External (Zeus, moll)
Internal (meibomian)
Painful pustule formation (tenacious/gritty/purulent secretions)
Treatment: massage and compress
Antibiotics if systemic infection
Chalazion
Hail stone (hard, painless lump)
Chronic lipo-granulomatous inflammation of Meibomian gland(may develop from internal Hordeolum)
Same management as Hordeolum
Dacryocystitis
Inflammation of the lacrimal sac caused by flow obstruction and subsequent bacterial infection
Erythema and edema over the lacrimal sac (mucopurulent drainage expression on massage of punctum)
Treatment: ophthalmology consult, broad spectrum antibiotics
Surgical correction
Dry eye syndrome
Tear defiency, abnormal tear film, Meibomian dysfunction
Burning history, foreign body sensation
Associated with aging
Treatment: artificial tears, lubricating ointment, punctual occlusion
Bacterial Conjunctivitis
Self-limited
**Think purulent discharge
Neonates-gonococcal conjunctivitis
Adults-pseudomonas, proteus, bacillis
Treatment: antibiotics
Conjunctivitis: Chlamydia
Trachomatis- leading cause of blindness in poverty stricken
Adults- chronic, low grade hyperemia with inferior bulbar and palpebral mounds
Elementary bodies on direct fluorescent AB stain
Treatment: antibiotics, treat sexual partners for adults
Neonatal conjunctivitis
chlamydial: from infected cervix, onset >7 days after birth
Gonococcal: <3 days after birth
Viral conjunctivitis
Most common caused of acute red eye- often adenovirus
Watery/mucoid discharge
Allergic conjunctivitis
Itchy eyes with watery discharge
Management:
Vasoconstrictors
H1 receptor antagonists
NSAIDs
Mast cell stabilizer
H1 receptor antagonist and Mast cell stabilizer
Corneal abrasion
Pain, blurred vision, photophobia, tearing, miotic pupil
Fluorescein stain
Treatment: lubrication
Pterygium and pinguecula
Pterygium grows onto cornea, pinguecula does not
Associated with UV exposure
Acute angle closure glaucoma
Ciliary flush, corneal edema, fixed mid dilated pupil, elevated IOP
EMERGENCY: beta blocking agent to lower IOP
Alpha agonists- decrease aqueous production and increase outflow
Laser iridiotomy
Anterior Uveitis
Autoimmune reaction
Inflammation of iris and ciliary muscle
Periocular pain and photophobia
URGENT referral to ophthomologist
Keratitis
Blurred vision, photophobia, periocular plain, FB sensation
Ciliary flush with white cloud, irregular light reflex
Dendritic ulcer on fluorescein stain= Herpes
EMERGENT Referral
Avoid steroids
Risk of corneal perforation and endophthalmitis
Episcleritis and scleritis
Focal inflammation
Ocular pain and hyperemia
Urgent referral
Systemic corticosteroids
Severe ocular pain and and hyperemia
Thinning and meting do sclera
Preseptal cellulitis
Pain, swelling edema
Prevent spread to post-septal issues
Post-septal or orbital cellulitis
Bacterial infection of periocular tissue
Papilledema
Admit and ophthalmology consult
Antibiotics
Thyroid eye disease
Retraction of upper lid
Impaired eye movement and muscle edema (IR most common)
May have systemic signs of hyperthyroidism
Bring thyroid levels to normal range
Orbital tumors
Gradual development of proptosis, diplopia
Red eye conditions that are non-vision threatening
Conjunctivitis
Corneal abrasions
Small foreign body
Pterygium
Red eye conditions that are vision threatening
Orbital cellulitis
Scleritis/uveitis
Chemical injury
Keratitis
Acute angle closure glaucoma
Penetrating trauma/cranial perforation
Corneal ulcerations
Optical coherence tomography
Uses tight to take cross sectional pictures of the retina
In Vivo histology
Takes a series of photos which can be used to create a 3D reconstruction
Central Retinal Artery Occlusion
Proximal to bifurcation at the optic nerve
Severe vision loss, retinal whitening, cherry red spot, vessel attenuation
Risk factors: HTN, coronary artery disease, smoking
Associated with concurrent or future strokes
Branch retinal artery occlusion
Distal branch occlusion
Segmental retinal whitening and vessel attenuation
Emboli may or may not be present
Central rental vein occlusion
Painless vision loss
Diffuse retinal homorrhage, disc edema, cotton wool spots
Risks: HTN, vascular disease, >65
Branch retinal vein occlusion
Retinal hemorrhages, educate, cotton wool spots
Hypertensive retinopathy
Acute: malignant HTN/HTN emergency
Chronic: leads to arteriosclerosis and predisposes to vascular occlusions and macroaneurysms
Rental findings in HTN emergency
Optic disc edema, diffuse retinal hemorrhages, cotton wool spots, macular star
Bilateral
**when patient presents with bilateral, adult, decline in vision must check BP
Admit patient and reduce BP
Chronic HTN
no symptoms
Can predispose to vein occlusions, arterial occlusions, macular edema, macroaneurysms
Flame hemorrhage, AV nicking, cotton wool spots
Control BP
Age related macular degeneration
Leading cause of blindness in developed world in people >50
Dry: non-exudative or non-neuvascular
Wet: exudative or neuvascular
Advanced ages, smoking, family history, Northern European ancestry
Symptoms: blurry vision, decreased reading ability, metamorphopsia, central scotoma
Advanced: Charles Bonnet syndrome
Peripheral vision unaffected
AMD pathophysiology
Inflammation or oxidative stress leading to accumulation of drusen
Deprivation of retinal pigment epithelium oxygen and nutrients leading to retinal atrophy
Dry AMD
Drusen and pigmentory changes
NO hemorrhage
Progressive
Blindness may develop in late AMD
Stages of Dry AMD
Early: Few drusen, Good vision (20/20 to 20/40)
Intermediate: many large drusen, vision still good (20/30 to 20/80)
Late: drusen, pigmentary changes center involving, vision 20/100-20/200
Dry AMD treatment
Stop smoking
AREDS2 vitamins to strop progression to Wet AMD
Amsler grid testing to detect transition to Wet AMD
Wet, Exudative or Neovascular AMD
Damage to outer retinal layers to neovascular growth into the retina
Hemmorage, subretinal fluid, macular edema, presence of retinal pigment epithelial detachments
Wet AMD pathophysiology
Choroidal neuvascularizzation forms due to brakes in Bruch’s membrane caused by drusen
Subrential fluid, hemorrhage, and potentially irreversible scarring
New onset distortion and loss of vision
Complications of Wet AMD
Disciform scar
Wet AMD treatment
Anti-VEGF agents to mediate growth of neovascular vessels (induction therapy: 3 injections at 4-6 week intervals, if dry extend interval between injections)
Normal vitreous structure
Collagen fibrils separated by hyaluronan
Posterior vitreous detachement
Hyaluronan loss with age
Collagen fibrils collapse and vitreous shrinks (remain adherent
Flashes and floaters, blurry vision
Retinal tears
Breaks in retina created through localized traction of vitreous gel
Retinal defect breaks suction that attaches retina
Most occur as a result of posterior vitreous detachment (can be caused by trauma, myopia)
Symptoms are identical to those of posterior vitreous detachment
Treatment: laser retinopexy/cryotherapy
Retinal detachment
Separation of the neurosensory retina from the RPE
3 types:
Rhegmatogenous (break/tear most common)
-need to determine if macular is attached or detached
Tractional (diabetes associated)
Exudative
Symptoms: flashes and floaters + painless black curtain, variable blurred vision
Treatment: surgical retinal specialist (find breaks, plug breaks, seal breaks)
Sclera buckle
External repair
Retinal detachment repair
Pushes eye wall inward to relieve traction and re-apples retina to eyewall
Pars Plana Vitrectomy
Internal repair
Remove vitreous gel and lose areas of adherer to relieve traction
Hold retina in place with gas bubble
Use laser to self the retina and seal breaks
Categories of Systemic Illness related to Eye disease
Infectious
Autoimmune, non-infectious, inflammatory
Neoplastic
Vascular disease
Toxic
Hereditary
Metabolic/nutritional
Diabetic retinopathy is the leading cause of _
blindness in working age
Diabetic Retinopathy pathogenesis
Multi factorial
Hyperglycemia leads to endothelial damage (retinal capillary changes, basement membrane thickening)
Loss of pericytes
Endothelial barrier decompensation leads to leakage and edema
Consequences of proliferative diabetic retinopathy/traction retinal detachment
Preretinal hemorrhage
TRD
Screening guidelines for diabetics
Type 1- annual screening for diabetic retinopathy beginning 5 years after disease onset
Type 2- screening at time of diagnosis and annually thereafter
Diabetic retinopathy treatment:
NPDR: better glycemic and BP control, risk factor modification
PDR: panretinal photocoagulation +/- intravitreal injection
Diabetic macular edema: anti-VEGF
Traction retinal detachment or vitreous hemorrhage: surgical vitrectomy
Anti-VEGF for diabetic macular edema
Injected into vitreous
Decrease vascular permeability leading to resolution of macular edema
What is Uveitis?
Inflammation of uvea (choroid, ciliary body, iris)
Defined by location affected (different causal conditions)
Warning signs of uveitis
Pain
Photophobia
Eye redness
Vision loss
Infectious disease associated with uveitis
TB
Syphilis
Herpes simplex and varicella zoster retinitis
CMV
toxoplasmosis
West Nile
Zika
Ebola virus
Chorodial tubercle
Tuberculosis
Syphilitis-associated uveitis
Can present many ways
Conjunctivitis, scleritis, interstitial keratitis, granulomatous is uveitis, large keratic precipitates, iris nodules
**Chorioretinitis
Vasculitis, vitritis
Manage with IV penicillin
Retinal whiting is associated with
VZV
Endogenous endophalmitis
Infection in the body can hematogenously spread to eye
Decreased vision, red, injected eye
Anterior chamber and vitreous inflammation, pain
Management: find systemic source, IV/intraocular antibiotics, surgery as indicated
Treatment of non-infectious uveitis
Prednisone
If reoccurs/suboptimal response restart steroid taper an and add anti metabolic
Add biologic
HLA-B27 associated anterior uveitis
Ankylosing spondylitis
Pain, redness, photophobia
Visual acuity decline
Slit lamp-posterior synechiae
Macular edema
Sarcoidosis uveitis
Bilateral granulomatous panuveitis
Ocular involvement
work up: CT chest, ACE, lysozyme, iCa
Non-casceating epitheloid granuloma s
PFTs and gallium scan
SLE retinal vasculitis
IV solumedrol, prednisone, IV cyclophosphamide
Secondary complication: retinal neovascularization
Ocular malignancy
Usually uveal metastasis
Men-lung
Women-breast
Most common primary intraocular tumor
Choroidal melanoma
Metastatic lesions are likely to develop in
Choroid
Hydroxychloroquine toxicity causes
Bull’s eye maculopathy
Ring of RPE depigmentation, sparing fovea
Paracentrol scotoma that affects reading and eventually central vision
Screening: Humphrey visual field 10-2, multifocal ERG, spectral domain optical coherence tomography scan, fundus autofluorescence
**flying saucer sign
Checkpoint inhibitor uveitis
Sunset glow fundus
Headache, tinnitus, vitiligo
Space occupying lesions result in_
Proptosis
Thyroid ophthalmopathy
Most common cause of exophthalmos
Immune mediated
Extraocular (recuts muscle) enlargement due to accumulation of extracellular matrix proteins, endomysial edema, fibrosis, fatty infiltration and lymphocytic cell infiltration
*****spares tendons and fat
Idiopathic orbital inflammation
Acute onset pain and proptosis
Immune disorder
May be ini or bi lateral
May affect all of orbit or confined to lacrimal gland or eye muscles
*****Tendons and fats involved
Diagnosis of exclusion
Chalazion
Tensor nodule
Lipid granuloma
Basal cell carcinoma
Most common malignancy of eyelid
Lower lid
Locally invasive
Acute purulent conjunctivitis
Bacterial or viral
Redness, itching, exudate
Neutrophils
Pinguecula/ Pterygium
Yello-white pacification
Actinic damage in sun-exposed areas
Solar elastosis
Must rule out actinic induced tumors
Squamous cell carcinoma
Near limbus
in situ: confined to epithelium
SCC invaded through basement membrane into stroma
Keratitis/ulceration
Due to wide variety of pathogens (bacteria, fungi, viruses-Herpes simplex, parasites- ancanthameoba)
Lots of neutrophils present
Keratoconus
Bilateral degeneration
Progressive thinning and ectasia
Conical shape generating astigmatism
*****central thinning + breaks in Bowman’s layer
Fuchs Endothelial Dystrophy
Most common dystrophy
Inherited disorder with incomplete penetrance
5th or 6th decade
Common transplant indication
Thickened Descemet’s membrane + Guttae
Loss of endothelial cells (stroma and Bullous keratopathy)
Glaucoma
Evelvated IOP
Open angle- increased resistance in open angle
Angle closure- iris adheres to the trabecular meshwork
Cataract
O pacification of crystalline lens
Common cause of vision loss
Age- related results primarily from opacification of the lens nucleus (nuclear sclerosis)
What is the uvea
Highly vascularized, pigmented (melanocytes)
Iris, ciliary body, choroid
Uveal melanoma
Most common primary intraocular malignancy of adults
**not associated with UV light
Due to maturations in GNAQ and GNA11
Deletion in BAP1
Usually incidental finding or present due to visual symptoms related to retinal detachment
Prognosis depends on size, cell type, proliferative index, cytogenetic profiles
Hematogenous spread to liver (80% 5 year survival rate)
Histology of uveal melanoma
Spindle cell
Mixed
Epitheloid (worse prognosis)
Arteriolosclerosis
Thickening of vascular wall
Macular star
Exudate from damages vessels in outer plexiform layer in malignant hypertension
Hypertension histology features
Macular star
Arteriosclerosis
Nerve layer infarct (occlusion of retinal arterioles, cotton-wool spot)
Pathology of nonproliferative diabetic retinopathy
Retinal edema, exudates, hemorrhages, capillary microaneurysms, loss of pericytes
Proliferative diabetic retinopathy
New vessel sprouting on surface of retina
Retinal neuvascularization (when breaching the internal limiting membrane)
Vitreous hemorrhage and scarring
Age related macular degeneration
Leading cause of blindness in elderly
Loss of central (fovea) vision
Can be atrophic or exudative
Atrophic AMD
Dry
Atrophy of RPE
Photoreceptor degeneration
Neuvascular AMD
Wet
Choroidal neovascularization
Hemmhorrhage and scarring
Detached RPE
Retinoblastoma
Most common primary intraocular tumor worldwide
Most common intraocular tumor of children
Leukocoria
Loss of both RB alleles
Retinoblastoma pathology
Microscopic: Encephloid white
Microscopic:
-blue:blue cell tumor, hyper cellular, high nuclear to cytoplasmic ratio, numerous mitoses and karyorrhectic debris
-pink: necrosis
-purple: dystrophic calcifications
Flexner-Wintersteiner rosettes
Anterior ischemic optic neuropathy
Similar to stoke
-ischemia: transient interruption to blood flow, transient loss of vision
-infarct: total interruption in blood flow, permanent loss of vision
Bilateral infarcts have been reported in temporal arteritis
Giant cell arteritis
Chronic granulomatous inflammation of large to small sized arteries in the head
Most common vasculitis in elderly adults
Ophthalmic artery occlusion may lead to supper blindness
Diagnosis based on temporal artery biopsy
Treat with high dose steroids
Pathology of giant cell arteritis
**Transmural chronic inflammation with giant cells
Intimal thickening
Disruption of internal elastic lamina
What is the role of the somatosensory system
Mediates multiple senses with distinct neuroanatomical pathways
The dorsal column and medical lemniscus system, trigeminal lemniscus pathway senses
Fine touch, vibration, conscious proprioception
The anterolateral system, trigeminothalmic tract pathway senses
Crude touch, pain, temperature
Somatosensation for the body starts with the
DRG
Somatosensation for the face starts with the
Trigeminal ganglion
DRG neurons
Carry somatosensory info from body to spinal cord
Pseudounipolar shape
Peripheral processes of a DRG neuron extension into the skin via spinal nerve
Central processes of a DRG neuron extend into the spinal cord
DRG cell bodies
Differ in size
small DRG cell bodies are
Associated with pain and temp
large DRG cell bodies are associated with
Fine touch and proprioception
Pain and temp are associated with which system
Anterolateral system
-free nerve endings
-pain receptors
Mechanoreceptors are associated with which system
Dorsal column, medial lemniscus system
-meissners corpuscles
-Merkel cells
-pacinian corpuscles
Ruffini’s corpuscles
Proprioception is associated with which system
Dorsal column/medial lemniscus (conscious) or system or spinocerebellar tracts (unconscious)
-muscles spindles
-Golgi tendon organ
Pain and temp DRG neurons have peripheral processes with
Free nerve endings
Meissners corpuscles account for _ receptors on finger tips
60%
Merkel cells account for _ of receptors on finger tips
30%
Pacinian corpuscles account for _ of receptors on finger tips
3%
Proprioception is mediated by
Muscle spindles and the Golgi tendon organs
Information is transmitted to cerebral cortex (conscious) and cerebellum (unconscious)
How does primary somatosensory axon diameter and myelination affect conduction
Speed conduction
A Dermatomal loss indicates
Damage to a spinal nerve root
A more restricted pattern of loss will occur
If a specific peripheral nerve is affected
DRG axons project into _ and ascend _
Dorsal column (formed by fasciculis cuneatus and gracious)
Ipsilaterally
Fasciculus cuneatus can be found in
Cervical spinal cord
The gracile column carry’s sensation from
The legs
The cuneate nucleus carries sensation from
The upper body
The dorsal column increase in width from
Sacral to cervical levels
Axons of gracile and cinematic fasciculi terminate
In the medulla in gracile and cuneate nuclei
Crossing axons of the gracile and cuneate nuclei give are known as
Internal accurate fibers
Ascending axons after crossing are known as
Medial lemniscus
Lesions of the medial lemniscus at any level will result in loss of fine touch and conscious proprioception on the _ side
Contralateral
Neurons in the VPL project via _ to _
Posterior limb of the internal capsule to the post-central gyrus of the cerebral cortex
Neurons in the primary somatosensory cortex project to
Other cortical areas
Somatosensory radiations originate from _ and project to _
Originate from VPL of thalamus
Project to primary somatosensory cortex (post central gyrus)
The anteriolateral system conveys
Pain and temp information for the body
DRG neurons have axons that enter the spinal cord through _ and terminate _
Lissauer’s tract
In the substantia gelatinousa of the dorsal horns
Pain information reaches the _ in the medulla and pons as well as the _ in the midbrain
Reticular formation
Periaqueductal gray
Lesions of the spinothalamic tract at any level will result in
Loss of pain and temperature on the opposite side of the body
Neurons in the VPL project via _ to the _
Posterior limb of the internal capsule
Post-central gyrus of the cerebral cortex
_ and _ are activated by painful stimuli which may be related to _
Cingulate gyrus and insula
Suffering
_ receives pain information and projects to the reticular formation which provides feedback to the spinal cord
PAG
The PAG projects to
Reticular formation
What nuclei are part of the reticular formation and project to the dorsal horn?
Nuclei magnus and paragigantocellularis
Neuropathic pain
Described as burning
Common in diabetes
Can also occur after herpes zoster
Irritation of the neurons but no tissue damage
Due to plasticity pain may occur as a result of inappropriate reorganization at higher levels of the nervous system
Phantom limb pain
Trigeminal ganglion neurons have axons which enter_ and terminate in the _
Pons
Main trigeminal nucleus
Neurons in the main trigeminal nucleus have axons which cross the midline and ascend in
The trigeminal lemniscus
Neurons in the VPM project via _ to the _
Posterior limb of the internal capsule
Post-central gyrus of the cerebral cortex
Neurons of the VPM project to
The lateral post central gyrus
Neuronal cell bodies in the trigeminal ganglion have axons that travel from
The PNS as the trigeminal nerve, enter the pons and descend as the spinal trigeminal tract
The spinal trigeminal nucleus nconveys
Pain and temp info
Axons from the spinal trigeminal nucleus ascend to _ via _
VPM
trigeminothalamic tract
Neuronal cell bodies in the spinal nucleus of V have axons that cross and ascent to _ as the _
VPM
Trigeminothalamic tract
Neurons of the VPM project to the
Postcentral gyrus
Mesencephalic nucleus of V
Displaced ganglion cells project to principle sensory nucleus and motor V
Proprioceptive information for the face
The Mesencephalic trigeminal nucleus conveys
Proprioceptive information for the face
Lower motor neurons innervate
Muscles
Lesions in lower motor neurons cause
Flaccid paralysis
Upper motor neurons terminate on
Lower motor neurons
Lesions of upper motor neurons cause
Spastic paralysis
CN motor nuclei and the ventral horn of the spinal cord are
Lower motor nuclei
Pyramidal neurons in the pre central gyrus, red nucleus, superior colliculus, vestibular nuclei, and reticular nuclei are
Upper motor nuclei
Brain stem indirect motor control nuclei are
Upper motor neurons
Final common pathway
Lower motor neurons
The ventral horn in large in the _ and _
Cervical and lumbosacral enlargements
Lower motor neurons in the spinal cord are _ organized
Somatotopically organized
The motor nucleus to axial muscles are located in the ventromedial cell group
The motor nucleus to the limb muscles are in the dorsolateral cell group
Lower motor neurons in the ventral horn have axons that exit in the
Ventral roots
Lower motor neuron axons form _ with the muscle cells
Neuromuscular junctions
Lower motor neurons are found in _
The nuclei of the cranial nerves with motor components (axons terminate in muscles in the head and neck)
Edinger-westphal, superior and inferior salivary and dorsal motor vagal nuclei are part of the _ system
Parasympathetic
Rabies
Affects lower motor neurons
Spreads retrograde
Polio
Affects lower motor neurons
Picornavirus tranmitted via fecal oral route
From gut it spreads to spinal cord and destroys neurons in ventral horn
Can also kill lower motor neurons in brainstem
Spinal muscular atrophy
Neuroregeneration disorder that affects lower motor neurons in the ventral horn
Loss of function mutation in the SMN1 gene (encodes survival motor neuron proteins
Results in muscular atrophy
The primary motor cortex is in the
Precentral gyrus
The primary motor cortex receives info from
Premotor and supplementary motor cortex
The primary motor nucleus contributes to the
Corticospinal and corticobulbar tracts
The secondary motor cortex receives information from
Basal ganglia via the ventral anterior nucleus of the thalamus
The premotor cortex receives information from the cerebellum via
The ventral lateral nucleus of the thalamus
The supplementary and premotor cortex project to _ and contribute to _
The primary motor cortex and contributes to the corticospinal tract
The cell bodies of the corticospinal and corticobulbar tracts originate in the
Pre-central gyrus of the cerebral cortex
The corticobulbar axons terminate in lower neurons of the
Ventral horn of the spinal cord
Most projections of the corticobulbar tract are
Bilateral (except facial and hypoglossal nuclei)
The projection from the corticospinal tract are primarily
Contralateral
The axons from the corticobulbar tract terminate in the brainstem and are not found
In the pyramids of the medulla or the spinal cord
The lateral area of the precentral gyrus controls _ and gives rise to _
Face and head movements
Corticobulbar tract
All of the precentral gyrus except the lateral portion give rise to the
Cortispinal tract
Axons of the corticospinal and corticobulbar tracts are located in _ of the cerebral peduncle
The middle 1/3
Where are the lower motor neurons of the corticospinal tract?
Ventral horn of the spinal cord
Where are the upper motor neurons of the corticospinal tract located?
Precentral gyrus
The upper motor neuron axons of the corticospinal tract form the
Corticospinal tract
The axons of the lower motor neurons of the corticospinal tract form the
Ventral root
Axons from pyramidal neurons in layer 5 of the periphery grove rise to
Corticospinal and corticobulbar tracts
The precentral gyrus contains the
primary motor cortex
Corticospinal and corticobulbar tract axons descend in
The posterior limb and the gene of the internal capsule, respectively
The corticospinal tracts and corticobulbar tracts descend in the _ of the cerebral peduncles
Middle 1/3
Where are the cerebral peduncles are located
On the ventral surface of the midbrain
The corticospinal tract is somewhat dorsal in the _ but ventral in the _ and _
Pons
Midbrain, medulla
The corticospinal tract crosses in the _
Pyramidal decussation of the caudal medulla
Pathway of the corticospinal axons
Descent in corticospinal tract
Decussation in the caudal medulla
Becomes lateral corticospinal tract as it travels to lateral funiculus of spinal cord
The lateral corticospinal tract primary influences
Lateral LMNs
The ventral corticospinal tract primarily influences
Medial LMNs
Most corticobulbar projections are bilateral except
Facial motor nucleus of the pons- partial bilateral input (control forehead) and completely crossed input (neurons controlling lower face)
Hypoglossal nucleus receives contralateral input from the corticobulbar tract
The hypoglossal nucleus of the medulla receives primarily _ input from the corticobulbar axons
Contralateral
Craniobulbar lesion vs CN VII lesion
CN VII lesion- cannot wrinkle forehead
corticobulbar lesion- can wrinkle forehead
Corticobulbar tracts do not extend past
Brainstem
Corticospinal tracts get smaller as it extends _
Causally toward the spinal cord
The frontal eye fields mediate
Lateral gaze and saccades
Frontal eye fields project to contralateral
PPRF
The PPRF projects to ipsilateral
CN nuclei III, IV, VI via MLF
Internuclear neurons in abducens nucleus project to the
contralateral occulomotor nucleus via MLF to the coordinate lateral and medial recuts muscles
Brainstem upper motor neurons receive input from _ and project to _
Cerebral cortex
Lower motor neurons
Brainstem upper motor neurons
Superior colliculus- tectospinal tract
Red nucleus- Rubrospinal tract
Vestibular nuclei-vestibulospinal tracts
Reticular formation- reticulospinal tracts
Propriospinal pathways
Communication between different segments of spinal cord allowing for movement coordination
Neurons in the superior colliculus (UMNs) project to the contralateral spinal cord via _ and influence _
Tectospinal tract (travels in the ventral funiculus)
Medial LMNs
Neurons of the red nucleus of the midbrain project to the contralateral spinal cord via _ and influence _
Rubrospinal tract (travel in lateral funiculus)
Influence lateral LMNs (facilitate flexion of upper extremities)
Vestibular nuclei project to the spinal cord via
Vestibulospinal tracts (travel in the ventral funiculus)
Medial- projects bilateral from medial vestibular nuclei to medial LMNs, end at cervical levels
Lateral- projects ipsilaterally from lateral vestibular nucleus to lateral LMNs, facilitates extensors and postural stability
Neurons in the reticular formation project to the spinal cord via _ and facilitates _
Ventral funiculus
Postural control
Voluntary control of limbs, especially fine movements of the hands
Corticospinal
Voluntary control of facial movement, chewing swallowing and speech
Corticobulbar
Coordination of head and neck with eye movements
Tectospinal
Facilitation of upper limb flexors
Rubrospinal
Facilitation of extensors, postural stability
Lateral vestibulospinal
Pontine reticulospinal
Inhibition of spinal segment reflexes
Medullary reticulospinal
ALS results in
Degeneration of both upper and lower motor neurons (degeneration of corticospinal tracts)
Gain of function mutation in SOD1 gene
A reflex arc consists of
Afferent limb and efferent limb
A sensory neuron either synapses _ or _
Directly on lower motor neuron
Interneuron that synapse on lower motor neuron
A functioning upper motor neuron is not necessary to elicit
A reflex (may result in abnormal reflex)
The neuronal cell body responsible for afferent limb of spinal cord reflex is in
Dorsal root ganglion
The neuronal cell body responsible for efferent limb of spinal cord reflex is in
Anterior (ventral horn
Medial muscles are represented in the _ ventral horn
Lateral muscles are represented in the _ ventral horn
Flexors are represented _ within the ventral horn
Extensors are represented _ within the ventral horn
Medial
Lateral
Dorsally
Ventrally
The afferent limb of the spinal can involve sensory info from
Muscle spindles, golgi tendon organs, or pain receptors
Pain may stimulate a _ reflex
Withdrawal
Flexor withdrawal reflex
Pain info enters dorsal horn
Interneuron process leads to either motor excitation or inhibition
Activation of flexors on same size as pain and extensors on opposite side
Components of stretch reflex
Afferent: DRG peripheral process in contact muscle spindle and central process in contact with inter neurons or lower motor neurons in ventral horn
Efferent: lower motor neurons in the ventral horn with axons that innervate muscles
Sensory receptors of muscles and tendons
Golgi tendons
Muscle tendons
Motor neurons of muscles and tendons
Alpha (extrafusal)- movement
Gamma (intrafusal)- cause contraction allowing muscle spindles to respond to change in extrafusal muscle
Damage to upper motor neurons _ lower motor neurons resulting in _ stretch reflexes
Disinhibits
Increased
Re-emergence if Babinski sign in adults is indicative of
Upper motor damage
Bladder control
Autonomic reflex involving the spinal cord descending input from the brain
Reflex incontinence occurs when
Spinal cord in completely damages from rostral to sacral levels
No way to control reflex because you have no sensory input
_ spinal cord lesions can destroy the spinal micturation reflex
Sacral
Lesions _ causes decorticate posturing
Above the red nuclei
lesions _ cause decerebrate posturing
Below the red nuclei but above the vestibular nuclei
The basal ganglia are involved in
Cognition
Emotion
Movement
The caudate, putmen, and accumbens
Striatum
Putmen and globes pallidus
Lenticular nucleus
The caudate nucleus is found
Within the lateral ventricle
The globus pallidus is divided into
Globus pallidus externa and interna
_ is the part of the limbic system involved in addiction
Nucleus accumbens
What seperates the external and extreme capsules
Claustrum
What supplies the basal ganglia
Lenticulostriate arteries (branch off of middle cerebral arteries)
The subthalamic nucleus is located
in the diencephalon ventral to the thalamus
The substantia Niagara is located in
The mesencephalon
The substantia Niagara produces _ and projects to the _ and _ via the _ pathway
Domaine
Caudate and putmen
Nigrostriatal pathway
Damage to the substantia Niagara results in
Parkinson’s disease
Huntingtons disease
Enlarged lateral ventricles due to degeneration of striatum
Behavior change, cognitive impairment, involuntary movements/neural rigidity (indirect pathway is disrupted)
Autosomal dominant (CAG repeat)= polyglutamine tracts, genetic anticipation
Wilson disease
Copper accumulation in the basal ganglia
Kayser-Feisher Rings
Autosomal recessive, loss of function mutation in ATPB7
What is the effect of a lesion of the subthalmic nucleus in the diencephalon
Hemiballismus (hyperkinetic movement on contralateral side of body
Lesion of substantia nigra causes
Hypokinetic disorders like Parkinson’s
Dopamine is excitatory for _ and inhibitory for _
D1 receptors (direct pathway)
D2 receptors (indirect pathway)
Activation of the direct pathway _ from the cerebral cortex
Increases output
Activation of the indirect pathway _ from the cerebral cortex
Decreases
Parkinson’s pathways
Death to neurons in the substantia nigra leads to decreased inhibition of globus pallidus interna and increased inhibition of globus pallidus externa leading to increase inhibition increased inhibition of the thalamus by globus pallidus interna and less output to the cerebral cortex leading to hypokinetic disorders
Degradation of GABA neurons in the striatum causes
Huntington disease
Inputs to the cerebellum
pons via middle cerebral peduncle
Spinal cord via inferior cerebral peduncle
The cerebellum sends info to the _ via the _
Thalamus
Superior cerebellar peduncle
Damage to the cerebellum causes
Ataxia and other forms of incoordination
The cerebellar peduncles are
Collections of axons
The vermis and paravermis make up the
Spinocerebellum
Lateral cerebellar hemisphere
Cerebrocerebellum
Flocculonodular lobe
Vestibulocerebellum
The cerebellar cortex receives input from
Spinal cord, vestibular nuclei, inferior olive, pons
Layers of the cerebellar cortex
Mossy fibers terminate on
Granule cells
Mossy and climbing fibers project contralaterally to
Deep nuclei
Deep cerebellar nuclei project
Out of the cerebellum
The inferior Olivia ray nucleus projects to the contralateral Purkinje cells via _ as _
The inferior cerebellar peduncle
Climbing fibers
Axons originating from the frontal cerebral cortex travel in the _ of the cerebral peduncle
Medial 1/3
Axons originating from the rest of the temporal lobe cortex travel in the _ of the cerebral peduncle
Lateral 1/3
The superior cerebral peduncle is comprised of axons that leave the cerebellum from _ and decussate in the _
Dentate nucleus
Midbrain
Blood supply of cerebellum:
Superior cerebellar artery- superior Cerebellum, superior cerebellar peduncle, part of middle cerebellar peduncle
Anterior inferior cerebellar artery - Ventral an inferior Cerebellum, middle cerebellar peduncle
Posterior cerebellar artery- inferior and posterior Cerebellum, inferior cerebellar peduncle
Lesion of the vestibulocerebellum
Impaired balance and wide based gait
Nystagmus
Symptoms due to damage to vestibular system
Lesions of the spinocerebellar pathways result in
Stomping gate due to lack of Proprioceptive information which makes patients unaware of where there legs and feet are without visual input
Lesions of the cerebrocerebellum pathway
Intention tremor
Difficulty with skilled movements
Suptle nystagmus
Other symptoms of cerebellar damage
Dysarthria
Abnormal swallowing
Symptoms of lesions of cerebellar pathways will be _ to the side of the cerebellum
Ipsilateral
Lateral Medullary syndrome
Stokes involving branch of vertebral artery or posterior inferior cerebellar artery
Ipsilateral pain and temp loss for the face
Contralateral pain and temp loss for body
Ataxia
_ is a common cause of cerebellar damage
Alcohol
Freidreich ataxia
Autosomal recessive
GAA trinucleutude repeat in intron 1 of MRDA gene
Accumulation of iron in mitochondria kills neurons with long axons
Spasticity loss of fine touch (corticospinal, tract), vibration (dorsal root ganglion loss), ataxia, including stopping gate (dorsal root ganglion and spinocerebellar tract loss)
Ataxia telangiectasia
Loss of function mutation in ATM gene
Purkinje cells degenerate after birth leading to ataxia
Problems with balance, hand coordination, eye movements, and slurred speech
Spinocerebellar ataxias
Autosomal dominant
Abnormal gait, incoordination of limbs, abnormal eye movements, degeneration of cerebellum
The vestibular apparatus is located
Within the labyrinth of the temporal bone
The orientation of the semicircular canals is different to
Allow for representation of the 3 special dimensions
The vestibular apparatus consists of
Urticle, saccule, 3 semicircular ducts
Sensory receptors for the vestibular apparatus are found
In five locations: 3 ampullae associated within the semicircular canals, the urticle, and the saccule
The crisae within the three ampullae detect
Rotational acceleration
The maculae within the urticle and the saccule detect
Linear acceleration and head position
he air cells are the _ of the vestibular system and are found in both _ and _
Sensory receptors
Cristae of the ampullae and the maculae of the urticle and saccule
Hair cells are embedded in the
Cupula of the ampullae
The cristae of the ampullae detect
Rotary movement
The maculae of the utricle and saccule detect
Linear motion and gravity
Utricle- acceleration in the horizontal plane
Saccule- acceleration in the verticals plane
The vestibular nuclei are located
In the dorsal lateral medulla and pons
The vestibular cortex is composed of
Parietal operculum and posterior insula
_ is critical for coordinated movements
Medial longitudinal fasciculus
The abducens nucleus projects to the contralateral occulomotor nucleus via _ so the muscles of the two eyes are in sync
MLF
Which lobe of the cerebellum interacts with the vestibular system to produce coordinated eye movements
Flocculonodular lobe
The lateral vestibulospinal tract facilitates
Extensor muscles
Damage to the vestibulospinal system may cause difficulty with
Balance and motor coordination (ataxia)
Disturbances of the vestibular system can result in
Nausea and vomiting (vomiting center in the medulla)
The taste pathway is _
Ipsilateral
What cranial nerves convey taste information
CN VII, IX, X
All cranial nerves conveying taste information contribute to _ and terminate on _
Solitary tract
Solitary nucleus
Taste buds are in
Papilla
How do taste buds work
Fluids enter taste port
Microvilli contain taste receptors (salty, sweet, bitter, sour, umami)
Receptor cells release transmitters onto afferent nerve fibers
Ageusia
Absence of taste
Hypogeusia
Decreased taste
Dysgeusia
Abnormal taste
The olfactory epithelium lines
The superior nasal concha
Sustentacular cells are
Supporting cells near olfactory receptor cells
Basal cells are
Stem cells that give rise to neurons in adults
Located in olfactory epithelium
The axons of olfactory receptor neurons form the _ which protects to _ in the olfactory bulb
Olfactory nerve
Mitral cells
Is the olfactory nerve myelinated?
No but it is ensheathed by Schwann cells
The olfactory bulb is part of the
Telencephalon
The olfactory stria form the
Olfactory trigone
The amygdala projects to _ and is involved in _
Hypothalamus
Feeding behavior
The piriform cortex is involved in
Fine discrimination of odors
The entorhinal cortex is involved in
Associations between odors and memories
Anosmia
Absence of smell
Hyposmia
Decreased smell
Dysosmia
Abnormal smell
Kallmann’s syndrome
Anosmia (olfactory nerves do not enter brain
Hypogonadal
Uncinate fits
Olfactory hallucinations
Feelings of unreality
Olfactory nerve transection
Loss of smell
Age related loss of olfactory receptor neurons
Diminished smell (hyposmia)
Loss of smell is one of the first signs of
Parkinson’s
Alzheimer’s
Other forms of dementia
Distinguishing sign of COVID
How does COVID affect olfaction
Infection of sustentacular cells where virus replicates
Unilateral deafness implies
Unilateral lesion of cochlear nuclei, CN VIII or the choclea
The cochlear duct contains
Endolymph
Ménière’s disease
Excessive amounts of endolymph
Low frequency ringing, hearing loss and dizziness
Only one ear is affected
Organ of Corti
Contains hair cells which transducer sound waves into neural signals
What type of ganglion cells are in the spiral ganglion
Bipolar type I ganglion cells
What type of cells are in teh superior Olivia ray complex
Unipolar type II ganglion cells in the spiral ganglion
Damage to hair cells can result in
Hearing loss
Intensity
Loudness
Frequency
Tone
High frequencies are represented at the _ of the cochlea while low frequencies are at the _
Base (often loose ability to hear high frequencies with age, also sensitive to toxic drug effects
Apex
What causes bilateral hearing loss
Aging, toxicity, genetic factors
Most frequent mutation in deaf individuals
gap junction protein beta 2 (disruption of hair cell function)
What kills hair cells?
Loud noises
CN VIII enters the brainstem at the _ and terminates
Junction between the medulla and the pons
Cochlear nuclei
The caudate nucleus is separated from the putamen by
Anterior limb of internal capsule
In Huntington disease the _ are among the earlies to degenerate
Caudate and the putamen
Huntington disease
Autosomal dominant
Gain of function mutation in HTT
Symptoms include chorea
The putamen and globus pallidus are seperated from the thalamus by the
Posterior limb of the internal capsule
The claustrum seperates the
External and extreme capsule
Where is the amygdala located
Anterior temporal lobe
The striatum receives inputs from the
Cerebral cortex via corticostriatal pathway
Substantia nigra via nigrostriatal pathway
Degeneration of dopaminergic neurons in the substantia nigra causes
Parkinson’s disease (problems initiating movements and resting tremor)
Unilateral damage of the subthalamic nucleus can result in
Hemiballismus (flinging of the contralateral arm)
Wilson disease
Signs related to damage to basal ganglia
Autosomal recessive
Loss of function in ATP7B
Abnormal accumulation of copper
Kayser-Fleuscher rings
Lesion of the subthalamic nucleus
Hemiballismus (sudden, violent, involuntary movements of limb on contralateral side)
Function of the vestibular system
Sensory and motor components that provide information about the position of the head in three dimensional space to the brain
Coordinates eye movements and maintains balance
Damage to the vestibular system cause
Dizziness, vertigo, imbalance, and nystagmus
Three semicircular canals
Anterior, posterior, lateral
Sensory cells are located
3 crystal ampullarii in each semicircular canal
2 maculae associated with the utricle and saccule
What structures detect movement
Hair cells
Sensory information from the vestibular nuclei travels to the cerebellum via inferior cerebellar peduncle
Four deep nuclei of the cerebellum
Dentate, emboliform, globose, fastigial
Damage to the vermis results in
Truncus ataxia
Damage to the cerebellar hemispheres
Impairs skilled movements especially involving the hands (dysmetria)
The three main cellular layers in the cerebellar cortex are the
Molecular, Purkinje, and granule
Ataxia Telangiectasia
Purkinje cells degenerate in children as a result of a loss of function mutation in ATM gene
Damage from the dentate nucleus to the ventral lateral nucleus of the thalamus results in
Intention tremor
Where is the reticular formation located
Core of midbrain, medulla, and pons
The dendites of the reticular formation
Respond to extreme stimuli
Where are the gaze centers located?
In the reticular formation
Midbrain- INC, riMLF (vertical gaze)
Pons- PPRF (horizontal gaze)
The reticular formation acts as _ and projects to _
UMN
LMN in the spinal cord
The reticular formation coordinates rhythmic movements such as walking via the
Reticulospinal tract
What controls swallowing?
Swallowing centers in the reticular formation
Emesis is controlled by
Vomiting centers in the reticular formation of the medulla
The vomiting center can be activated by
Strong emotion (limbic system)
Vertigo (vestibular system)
Chemicals from the blood (chemoreceptor trigger zone)
Visceral afferents (from the vagus)
The vomiting center coordinates emesis by
Causing closure of pharynx, larynx, glottis (via nucleus ambiguus)
Gastrointestinal chances (via dorsal motor vagus)
Respiratory changes (ventral respiratory group, another reticular formation center)
Micturition is controlled by
A center in the pontine reticular formation
Voluntary control of micturition
Frontal lobe receives sensory information from thalamus about bladder state
The pontine micturition center (reticular formation) receives input from the cerebral cortex and communicates with the spinal cord to trigger emptying of the bladder
Reticular formation role in respiration and cardiac function
Nucleus of the solitary tract receives chemo sensory information relevant to cardiac and resp function
Cardiac info is transferred to rostral ventral lateral medulla (reticular formation) which sends input to the IML to exert sympathetic control
Cardiac info is transferred to nucleus ambiguus (exerts parasympathetic function via vagus)
respiratory info is sent to the rostral ventral respiratory group (reticular formation) which projects to the phrenic nucleus via the spinal cord
Locus coeruleus
Located in pons, lateral to fourth ventricle
Releases noradrenalin (wakefulness, increased attention response, learning)
Serotonin-containing neurons
Found in the raphe nuclei of the midbrain, pons, and medulla
Involved in sleep-wake cycle
Lesion or impairment causes insomnia
Also important for mood
Pedunculopontine and laterodorsal tegmental nuclei
Acetylcholine pathways
Located in the midbrain and project to diencephalon and brainstem
Medial septal nucleus
Acetylcholine pathway
Projects to the hippocampal formation
The nucleus basalis
Acetylcholine pathway
Projects widely within the cerebral cortex
Acetylcholinergic
Acetylcholine pathway
Projections important in mood, sleep, learning
Where is the nucleus basalis located
Ventral to the anterior commissure and ventral pallidum
The ascending reticular activating system projects to
Hypothalamus and thalamus
The reticular formation is important for
Sleep regulation
Orexin is involved in
Wakefulness and appetite
Mutation= narcolepsy
Melatonin regulates
Circadian rhythms
The primary somatosensory cortex corresponds to
Postcentral gyrus
Premotor cortex corresponds to
Caudal portion of middle frontal gyrus
Primary auditory cortex corresponds
Anterior transverse temporal gyrus
Primary visual cortex corresponds to
Cuneate and lingual gyri
Supplementary motor cortex corresponds to
Caudal portion of superior frontal gyrus
3 types of cerebral cortex
Archicortex (3 layers, hippocamplal formation)
Paleocortex (3-4 layers, olfactory cortex)
Neocortex (6 layers, majority of cerebral cortex
Brodmann’s areas
Layers of cerebral cortex
Information is processed by
Columns in the cerebral cortex
3 main types of projections involving cerebral cortex
Projection fiber bundles: connect cortex with sub cortical structures
Commissural bundles: connect two cerebral hemispheres
Association bundles: connect one area of cortex with another area in the same hemisphere
The anterior commisure connects
Olfactory and limbic structures
connects two olfactory bulbs and the two amygdala
Most information is transmitted between left and right cerebral hemispheres via
corpus callosum
Parts of the corpus callosum and their connections
Forceps minor fiber bundle in the genu- connects frontal lobes
Rostrum fibers- orbital regions
Body- connect parietal and temporal lobes
Forceps major fiber bundle in the splenium- connects occipital lobes
The left hemisphere is usually dominant for
Language
The right hemisphere does
Visual special processing
Facial recognition
_ is responsible for expressive speech and is located primary within the inferior frontal gyrus of the dominant hemisphere
Broca’s area
_ is responsible for receptive speech and is located primarily in the superior temporal gyrus close to the parietal lobe of the dominant hemisphere
Wernicke’s area
Planum temporal
Higher order processing center for sound
Wernicke and Broca’s areas are connected by
Arcuate fasciculus
Lesions result in conduction aphasia
Prosody is primarily represented in
Right hemisphere
What connects adjacent gyri
Short association fiber, arcuate fibers, or adjacent gyri
The uncinate fasciculus connects limbic structures in the
Temporal lobe with the frontal lobe
The cingulum connects the _ with _
Cingulate gyrus
Limbic
Reading involves multiple areas of the brain
Inferior frontal gyrus- vocalization, articulation
Parieto-temporal- word analysis
Occipito-temporal- word recognition, automaticity
People with dyslexia have a greater reliance on structures in the _ lobe
Frontal
Some dyslexia has been associated with a neuronal migration disorder called
Periventricular nodular heteropia
Gerstmann Syndrome
Dysgraphia
Dyscalculia
Finger agnosia
Left right confusion
Lesion on angular gyrus of dominant hemisphere
Hemineglect
Lesion in parietal cerebral cortex causes patient to disregard opposite side
Prosopagnosia
Facial blindness
Damage to right fusiform gyrus
Types of dementia resulting from damage to the cerebral cortex
The autonomic nervous system is also known as the
General visceral efferent system
The ANS acts on
Cardiac and smooth muscle as well as organs
ANS divisions
Parasympathetic
Sympathetic
The parasympathetic system has _ preganglionic axons and _ postganglionic axons
Long
Short
The sympathetic system has _ preganglionic axons and _ postganglionic axons
Short
Long
ANS preganglionic neurotransmitter
ACH
Parasympathetic postganglionic neurotransmitter
ACH
ANS sympathetic nervous system postganglionic neurotransmitters
NE- most tissues
Ach- sweat glands
Adrenal medulla- releases epinephrine or norepinephrine
The cell bodies of postganglionic neurons are located in
Autonomic ganglia (multipolar)
What controls the sympathetic and parasympathic nervous systems via projections to preganglionic neurons
Hypothalamospinal tract
Preganglionic neuronal cell bodies of the ANS are located in the _ while postganglionic cell bodies are located in the
CNS
PNS
Preganglionic sympathetic neurons are located in the _
IMLCC at T1-L2
Preganglionic myelinated neuron axons exit in the _ and travel in the _ before terminating in _
Ventral roots
White ramus
Paravertebral or prevertebral ganglia
Postganglionic neurons are located in _ and their unmyelinated axons travel within the _
Paravertebral or prevertebral ganglia
Gray ramus
Sympathetic nervous system
Postganglionic neurons are _
Axons are _ and travel in _
They release _ as their neurotransmitter
Multipolar
Unmyelinated, gray ramus
Noradrenaline
Postganglionic sympathetic neurons that innervate sweat glands release _
Ach
Central horners syndrome
Miosis, ptosis, anhydrous is
The hypothalamus controls the adrenal gland in two ways
Short term- ANS
Long term- endocrine
Preganglionic neurons of the parasympathetic system are located
In the brainstem and sacral spinal cord
The _ is located in the occulomotor complex in the midbrain and is responsible for constricting pupils
Nucleus of Edinger-Westphal (preganglionic parasympathic neurons)
Ciliary ganglion (postganglionic parasympathetic neurons)
Lacrimation and salivation
Superior salivatory nucleus is located in the pons (preganglionic)
Pterygopalatine and submandibular ganglia (postganglionic)
Also under control of hypothalamus
Dorsal motor nucleus of the Vagus
Medulla
Control lung, hearing, gastrointestinal
Parasympathic postganglionic neurons are
Multipolar, unmyelinated
Presynaptic fibers of the sympathetics synapse
Paravertebral ganglia or prevertebral ganglia
Pathways in the sympathetic chain
Ascend then synapse (head, cardiopulmonary, neck, upper limb)
Synapse at level (thoracic cardiopulmonary)
Descend then synapse (spinal nerves to lower trunk and lower limb)
Bypass to synapse in the prevertebral ganglia (innervation for abdominopelvis viscera)
Parasympathetics
Craniosacral system
Presynaptic parasympathetic fibers
Very long
Most synapse with postsynaptic cell bodies in or all wall or target organ
EXCEPTIONS: ciliary, pterygopalatine, optic, submandibular
The suprarenal gland uses _ as a postsynaptic neurotransmitter
Epinephrine
Does the skin have Parasympathetics
No
Skin sympathetics
Gray rami to periphreal nerve
Contracts arrector pili (Ach/NE) , Vascoconstrictiion (Ach/NE), Increases sweating (Ach/Ach)
Eyes sympathetics
Carotid plexus to long and short ciliary nerves
Dilation of pupils (Ach/NE)
Eyes Parasympathetics
CN III to ciliary ganglion to short ciliary nerve
Constricts pupil
Contracts ciliary muscle (accommodation)
(Ach/Ach)
Lacrimal glands sympathetics
Carotid plexus to
-deep petrosal nerve
-nerve of Pterygoid canal
-maxillary nerve
-zygomatic nerve
-lacrimal nerve
Descreases secretion due to vasoconstriction
(Ach/NE)
Lacrimal glands Parasympathetics
CN VII to nerve of pterygoid canal to pterygopalatine ganglion (synapse)
Promotes secretion
(Ach/Ach)
Salivary gland sympathetic
Via carotid plexus
Decreases secretion due to vascoconstriction
Thicker secretions
(Ach/NE)
Salivary glands Parasympathetics
CN IX to optic ganglion
CN VII to submandibular ganglion
Follows branches of mandibular nerve
Makes secretions more abundant and fluid
(Ach/Ach)
Heart Sympathetics
Cervical and upper thoracic sympathetic ganglia to cardiac plexus
Increases heart rate
Increases strength of contraction
Dilates coronary vessels
(Ach/NE)
Heart Parasympathetics
Vagus nerve to the cardiac plexus
Decreases heart rate
Weaker contractions
Constriction of coronary vessels
(Ach/Ach)
Lungs Sympathetics
Upper thoracic sympathetic ganglia to pulmonary plexus
Inhibits parasympathic effects
Constriction of vessels
(Ach/NE)
Lungs parasympathics
Vagus nerve to pulmonary plexus
Constriction of bronchi
Bronchial secretion
(Ach/Ach)
Splanchnic nerves
Carry autonomic supply to and from viscera
Cardiopulmonary- postsynaptic sympathetic to heart and lungs
Abdominopelvic- Presynaptic sympathetic to prevertebral ganglia
-greater- to celiac ganglia
-lesser- to superior mesenteric and aorticorenal ganglia
-least- to renal plexus
-lumbar- to inferior mesenteric ganglia
Sacral- Presynaptic sympathetic to pelvic viscera
Pelvic- Presynaptic parasympathics to lower digestive and pelvic viscera
Suprarenal medulla sympathetics
T10-L1 spinal cord
Through Paravertebral ganglia
Splanchnic nerves
Through prevertebral ganglia
Synapses in suprarenal medulla
Releases epinephrine directly into bloodstream
(Ach/Epi)
Suprarenal medulla Parasympathetics
None
Digestive tract sympathies
Splanchnic nerves to prevertebral ganglia
Decreases peristalsis
Reduces blood supply
Contracts internal anal sphincter
(Ach/NE)
Digestive tract sympathetics
Vagus and pelvic Splanchnic nerves
Promotes peristalsis
Increases digestive juices
Allows for defecation
(Ach/Ach)
Urinary tract Sympathetics
Splanchnic nerves to prevertebral ganglia
Decreases urine formation
Maintains urinary continence
(Ach/NE)
Urinary tract Parasympathetics
Vagus nerve and pelvic Splanchnic nerves
Contracts bladder wall
Relaxes internal sphincter of the bladder
(Ach/Ach)
Liver and gallbladder sympathetics
Splanchnic nerves to prevertebral ganglia
Activates glycogenolysis
(Ach/NE)
Liver and gallbladder Parasympathetics
Vagus nerve
Promotes conservation of glycogen
Increases bile secretion
(Ach/Ach)
Genital system sympathetics
Splanchnic nerves to inferior hypogestric plexus
Causes ejaculation
Decreases erection
(Ach/NE)
Genital system Parasympathetics
Pelvic Splanchnic nerves
Increases erection
(Ach/Ach)
Sympathetic lesions
Oculosympathetic palsy
Ptosis
Miosis
Anhidrosis
Enophthalmos
Parasympathetic lesion
CN III- enlarged pupil
CN VII- dry eyes
CN VII/IX- dry mouth
Hypothalamus function
Control ANS
Control endocrine
Memory formation
Maintain homeostasis
Anterior hypothalamus contains
Paraventricular nucleus
Supraoptic nucleus
Suprachiasmatic nucleus
SON and PVN
Vasopressin/oxytocin containing mango cellular neurons
Project to posterior pituitary which releases vasopressin and oxytocin into general circulation
PVN also has parvocellular neurons which project to the median eminence and release TRH and CRH
SCN
Receives input from the retina
Project to area ventral to PVN
Involved in circadian rhythm
