Glossary of USMLE Step1 Neuro Anatomy Kaplan
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- Neural Crest Derivatives?
- 1) Adrenal Meduall
2) Ganglia (Sensory + Autonomic)
3) Pigment Cells (Melanin)
4) Schwann Cells
5) Meninges (Pia + Arachnoid)
6) Pharyngeal Arches
8) Parafollicular (C) Cells
9) Aorticopulmonar Septum
10) Endocardial Cushions
- Asymptomatic defect in vertebtral arches
- Spina Bifida Occulta
- Meninges project through the vertebral defect
- Spina Bifida w/ Meningocele
- What Labx do you ask for in Spina Bifida?
- Alfa-feto protein (increased)
- What happens in meningmyelocele?
- Meninges and spinal cord project through vertebral defect
- What are the FOUR sympathetic ganglions?
- 1) Superior Cervical Ganglion
2) Middle Cervcial
- What level does the Lateral Horn of the Sympathetic system comprises?
- What are the Four cranial ganglia of the Parasympathetic System?
- 1) Ciliary ganglion
- What cranial nerves are Parasympathic?
- 1) III
3) IX 3,7,9
- What controls the foregut and midgut in the parasympathetic?
- Vagus X, at terminal ganglia
- What Parasympathetic controls the Hindgut?
- Pelvic Splachnic Nerves S2-S4
- Ciliary Ganglion controls what CN and muscle?
- Parasymp. CN III
- Submandibular galgion controlled by?
- Parasymp. CN VI
Submandibular and sublingual glands
- Pterygopalatine ganglion is in control of?
- Otic Ganglion controls what?
- Parasymp. CV IX
- Decrease in Alfa-feto Protein in Pregnancy equals?
- Down Syndrome
- Forebrain TEL
- Telecephalon? CNS Structure + what ventricle is formed?
- Cerebral Hemis. Lat. Ventri
- Diecephalo? makes what structure in CNS and what Ventricles?
- Thalamus, Pineal Third Vent
- Mesencephalon? CNS/Ventricle
- Midbrain Cerebral Acued.
- PONS Cerebellum 4th Ventri
- Medulla 4th Ventri
- Who makes the PONS Bridge?
- What makes Craniopharyngiomas?
- Remannts of Rathke's Pouch that compress optich chiasm
- Anterograde movement by?
- Retograde movement in CNS?
- These viruses affect retrograde movement?
- Oligodendrocyte vs Schwan?
- Oligo can myelinate more than 1 cell, sometimes up to 50 cells!
- Hair cells are derived from what layer?
- Substantia Nigra derives from with plate? Alar or Basal?
- Polyhydramnios caused by?
- Potter's Syndrome (Bilateral Renal Agenesis), Oligohydramnios causes limb deformities and pulmonary hipoplasia
- What connects the lateral ventricles?
- Foramen of Monroe (Mon Roe)
- What connects the 3rd ventricle with the 4th?
- Acueduct of Sylvius
- What connects the ventricles and the subarachnoid space? And where is this located?
- Located in the 4th ventricle
1) Two Lateral formaina of Luschka
2) Median foramina of Magendie
- Normal pH of CSF?
- CSF has higher concentrations of ____ than blood?
- Cl-, Ca2+, HCO3- and glucose
- How are protein levels in CSF compared to blood?
- How are Sodium levesl in CSF compared to blood?
- Same about 138 mEq/L
- Are PMN normal in CSF?
- No!!! Bacterial Meningitis
- What does it mean when there is an increase in protein in CSF?
- Possibly a CNS tumor
- Define Hydrocephalus?
- Increase in volume (excess) or pressure of CSF producing ventricular dilation
- Communicating Hydrocephalus
What are the underlying causes?
- It is due to oversecretion of CSF by:
1) Choroid Plexus Papilloma
2) Tumor in Subarachnoid space
3) Meningitis (limits absorption into superior saggital sinus)
- Noncommunicating Hydrocephalus
- undersecretion/ obstruction of CSF flow
1)tumor blocking foramen Monro, cerebral aqueduct, 4th ventricle or Fomanina Magendie or Lushka.
- Mechanism of Normal Pressure hydrocephalus?
- - CSF not absorbed by arachnoid villi
- ventricles enlarged
- ventricles press agains cortex and skull
- Symptoms of NPH (normal pressure hydrocephalus)?
- 1) confusion
2) gait apraxia
3) urinary incontinence
stiff legs, dementia
confused with Alzheimer
like magnetic feet stuck to the ground
- Blood-brain barrier regulated by what type of cells? What type of junctions?
- - Tight Junctions in the capillary endothelium
- Where is CSF produced?
- Choroid Plexus
- What part of hypothalamus is controlled by sympathetic?
- Posterior Hypothalamus...
remember to use your posterior to be sympathetic w/ someone
- Sympathetic Response? Think of the tiger chasing you
- - Eyes open wide + pupil dilation (to see better)
- Perspire (to slip from it)
- Hair Sticks up (to look ferocious)
- Sphincters close (don't wanna go to the bathroom in the middle of the chase)
- Increase HR
- Epinephrine increase adrenalin
- liver increase degradation of glycogen to glucose
- Stress causes diabetes!
- Horner Sx is an attack to sympathetic. What are the symptoms?
- - Miosis enophthalmos
- Anhydrosis (can't sweat)
- lack of piloerection
- What kind of neurons does the ventral horn contains?
- What kind of neurons does the dorsal horn control?
- Sensory neurons
- What 2 motorneurons does the ventral horn have?
- Alpha and Gamma
- What do alpha motorneurons control?
- skeletal muscle (extrafusal fibers)
- What do gamma motorneurons control?
- muscle spindle contractile intrafusal fibers
- Neural Systems
- 3 Major Neural Systems
- Motor Systems composed of?
- 1) Upper Motorneuron
2) Lower Motorneuron
- Where are the bodies of the upper motor neurons found?
- 1) Red nucleus
2) Reticular Formation
3) Lateral Vestibular Nuclei of the brain stem.
4) Cerebral Cortex (Most Important)
- What tract are the upper motor neurons run in?
- Corticospinal Tract
- Where is the motor cortex located in the brain? What lobe of the brain?
- 1) Precentral Gyrus of the Frontal Lobe
2) Premotor Area both 60%
3) 1ry + 2ry somatosensory cortical areas of parietal lobe 40% of fibers
- Where do corticospinal tract fibers exit the cerebral cortex?
- In the Internal Capsule
- Dorsal Horns transmit what type of stimulus?
- Ventral Horns transmit which type of stimulus?
- Motor (Remember S&M)
- What happens to the corticospianl tract at the lower medulla?
- They cross the decussation of the pyramids continue contralaterally
- Decorticate rigiditiy is caused by?
- Lesions above the midbrain
- A lesion below the midbrain causes what type of rigidity?
- Decerebrate Rigidity
- What reflexes are lost in an Upper Motorneuron Lesion?
Reversal of Reflexes
- 1) Babinski Reflex (extension instead of flexion)
2) Abdominal Reflex Lost
3) Cremasteric Reflex Lost
- What are the two sensory systems?
- 1) Dorsal Column-Medial Meniscal System
2) Anterolateral (Spinothalamic) System
- Where is the 1st order neuron for the Sensory Systems?
- Dorsal Root Ganglion (Pseudounipolar neuron)
- Where is the 2nd order neuron?
- Brain stem or Spinal Cord before crossing
- Where is the 3rd order neuron?
- Thalamus (T for Third)
It already has crossed to the other side
- What does the Dorsal Column-medial leminiscal system convey? (DC-ML)
- Propioception and Stereoception
- sensory info. for discriminatory touch
- joint position
- pressure sensation from trunk and limbs
- What type/class of fibers does the Dorsal Column (DC-ML) system have?
- Class II or A-beta
- Which part of the Dorsal Column is located medially? (Which Fasciculus)
- Fasciculus Gracilis
- What does the fasciculus gracilis control? (Closest to the midline)
- Lower Extremities
- Remember that you are graceful when you walk
- Also, gracilis muscle is on the medial aspect of the leg/thigh
- What part of the brainstem is the 2nd order neuron located?
- Does the second order neuron for sensory pathway cross the midline?
- NO! It crosses at the 3rd order neuron in the Thalamus
- Where do 2nd order Dorsal Column cells synapse?
- Where do 3rd order of the Dorsal Column-Medial Leminiscus System (DC-MLS) cells synapse?
- Medial Leminiscus like its name
Part of the Thalamus
in the Ventroposterolateral Nucleus (VPL)
- Where can you find 2nd order neuron in the Dorsal Column pathway? What Nuclei?
- What pathway crosses the midline in the sensory pathways?
- The 2nd order neuron always crosses... need two lines to make a cross
- Where is the 3rd order neuron located in the Dorsal Column Medial Leminiscus (DC-MLS) Pathway? Which nucleus?
- At the medial lemniscus like its name
- It is found in the Ventroposterolateral Nucleus
- Where do the 3rd order Neurons project in the Dorsal Column Pathway?
- To the ANTERIOR portion of the PARIETAL Lobe
- Primary somethetic (somatosensory) area
- located in the Postcentral gyrus
- How do you determine a lesion to the Dorsal Column?
- Loss of Joint sensation
- pressure sensation
- two-point discrimination
- loss of the ability to identify characteristics of an object
- What is asterognosis?
of an object using the sense of TOUCH
- How do you diagnose Dorsal Column Pathway lesion?
- ask patient to close his eyes and place feet together
- positive if patient sways
- if patient sways with eyes open then the lesion/damage is at the cerebellum and not dorsal column
- What is another name for the Anterolateral System?
- Spinothalamic Tract System
- What does the Anterolateral System sense?
- - pain
- crude touch sensations
- Via what fibers do the dorsal root ganglia enter the spinal cord?
- Dorsal Root Fibers
- via A-Delta
- Class III
- Class IV
- What is the backup of the Corticospinal Tract Lesions?
- The backup is that 20% of the fibers do not cross
- the conscious crosses
unconscious doesn't cross
- What do direct fibers that do NOT cross controll?
- They control proximal pathways giving function to the proximal extremities
- What is a picture of a Monkey's Bottom w/ flowers?
- Medulla Oblongata IX, X, XII
- What is the function of a bipolar neuron?
- They are responsible for special senses
- Function of a pseudounipolar neuron?
- It is a scanning neuron
- Where are 3ry (Tertiary) neurons of the Dorsal Column Systems located?
- Thalamus (Remember T is for Third/Tertiary and Thalamus)
- What happens to all the lesions that are unilateral in the Spinal Cord or the Brain Stem?
- They result in a contralateral loss of pain and temperature
- Where is the 2nd Neuron located for the Anterolateral (Spinothalamic) System?
- Dorsal HORN Gray Matter
- What order neuron crosses in the Anterolateral AL-SpT tract?
- 2nd order neuron
- Where do the axons of the 2nd order neuron enter?
- Ventral White Commissure
- Where does the analgesia begin after a lesion of the anterolateral/spinothalamic tract?
- 1 or 2 segments below the contralateral side of the lesion.
- What information does the spinocerebellar pathways carry?
- Unconscious propioceptive input from muscle spindles and GTOs to cerebellum
- What two major spinocerebellar pathways are there?
- Dorsal and Cuneocerebellar
(Dorsal and Ventral)
- Where are the 2nd order neuron from the Dorsal Spinocerebellar tract found?
At what level?
- - Clarke Nucleus
- Spinal Cord level (T1-L2)
- Where are the bodies of the cuneocerebellar tact found? (What nucleus)
At what level?
- - External Cuneate Nucleus
- What information is gathered from the dorsal spinocerebellar pathway?
- Input from lower extremities and lower trunk
- What information is gathered by the Cuneocerebellar tracts?
- Propioceptive input to the cerebellum from upper extremities and upper trunk
- What disease atacks the Spinocerebellar tract?
- Friederich's Ataxia
- What form of inheritance is Friederich's Ataxia?
- Autosomal Recessive
- What are the symptoms in a hemisection of the spinal cord?
- 1) ipsilateral spastic paresis below injury
2) ipsilateral loss of joint position sense, tactile discrimination and vibratory sensations below lesion
3) contralateral loss of pain and temperature starting 1 or 2 segments below lesion
- What is another name for hemisection of the spinal cord?
- Brown-Sequard Sx
- What pathways are interrupted by a hemisection?
- 1) corticospinal
2) dorsal columns
3) spinothalamic (anterolateral)
- What spinal cord lesion is caused by Vitamin B12 Deficiency?
- Subacute Combined Degeneration
- What other Diseases cause Subacute Combined Degeneration (SCD)?
- - Vitamin B12
- Pernicious Anemia
- What pathway is damaged in Polio?
- What pathway is damaged in Tabes Dorsalis?
- Dorsal Column
- What Pathway is damaged in Amyotrophic Lateral Sclerosis?
- - Corticospinal Tract
- What pathways are damaged in Anterior Spinal Artery occulsion (ASA)?
- - LMN
- Spinothalamic tract (SpTh)
- Corticospinal tract (CST)
Except Dorsal Column (DC) is spared
- What pathways are damaged in Subacute combined degeneration?
- - Corticospinal Tract (CT)
- Dorsal Column
- Spinocerebellar Tract
- What sign do we find on Dorsal Column lesion?
- Romberg's Sign (+)
- What tract is damaged in Syringomyelia?
- - Spinothalamic (SpTh)
- What is a late complication of Syringomyelia?
- Horner Syndrome (ptosis, miosis, anhydrosis)
- What tracts are damaged in Hemisection: Brown-Sequard Sx?
- - DC
All of them!
If lesion is above T1 then Horner Sx. (Ipsilateral)
- Which side is affected in Horner Sx lesion at T1-T4?
- Contralateral side
Above T1 is ipsilateral side
- What happens in Vitamin B12 Def?
- Demyelination of Spinal Cord Tracts
- What tracts are affected by Vitamin B12 deficiency?
- - Dorsal Columns (DC)
- Spinocerebellar Tracts
- Corticospinal Tracts (CTS)
- Patient with paresthesias, bilateral spastic weakness, Babinksi sign and antibodies to intrinsic factor? Diagnosis Dx:?
- Dx: Subacute combined degeneration
Intrinsic Factor is deficient and wont let the ileum absorb Vitamin B12
- How are Multiple Sclerosis, Vitamin B 12 deficiency and Subacute Combined Degeneration similar?
- They are all conditions where CNS is demyelinated
- What cells are within the white matter of spinal cord?
- they create the myelin for all axons inside the CNS and tracts of white matter
- What tract is injured in a patients with signs of UMN and LMN?
- Amyotrophic Lateral Sclerosis (ALS)
- Which cells regenerate in the PNS? Why?
- Cells in the Ventral Root
- they contain myelin from Schwann Cells which promote regeneration of cut axons.
- What are the three Ps of Tabes Dorsalis?
- 1) Pain
Argyll Robertson Pupils
Last P is Pupil Defect!
- What structures degenerates in MS?
- Myelin containing nerves
i.e. Optic Nerves, formed by oligodendrocytes not schwann(PNS)
- What test do you find positive in MS?
- Heterogeneous Immunoglobulin G Staining w/ oligoclonal banding
- Charactestic of Syringomyelia?
- Bilateral loss of pain and temperature
- What level does the fasciculus cuneatus begins?
- T5 segment
- What cells are affected in LMN lesions?
- Alpha motor neurons in the ventral horns
- What cells manage the reflex contraction of muscle and extension of oposite muscles?
- Muscle Spindles
- What are does the anterior spinal artery supply?
- Ventrolateral 2/3's of the spinal cord
- DC are spared
- NO problems in pain and temp.
- What is affected if the spinothalamic tract on the left side is affected?
- Pain and temperature sensations on the right leg
- Where do axons of fasciculus cuneatus have their bodies in?
- Dorsal Root Ganglia
- The Brain Stem
- pg. 363
- What three parts make the Brainstem?
- 1) midbrain
- What cranial nerves arise from the midbrain?
- 1) oculomotor III
2) trochlear IV
3 and 4
- What cranial nerves enter or exit the pons?
- V, VI, VII, VIII
- What three cranial nerves enter or exit from the medulla?
- IX, X, XII
- Are Motor Nuclei located medially or lateral?
- Medial M=Medial M=Motor
- What are some of the symptoms for a pineal tumor?
- Parinaud Sx:
1) paralisis of upward gaze
2) noncummunicating hydrocephalus
- What cranial nerve is affected in Neurofibromatosis II?
- VIII, associated with Schwannomas
- What happens to a lesion of the nucleus ambiguus?
- Ipsilateral paralysis of the soft palate
- uvula deviates away from the lesion
- nasal regurgitation of liquids
- difficulty swallowing
- What does the solitary nucleus control?
- solitary sounds like salivary and taste.
- it controls the taste and visceral sensory neurons
- What cranial nerve does the spinal nucleus control?
- Trigeminal nerve V
- What is the major parasympathetic nucleus in the brain stem? Where is it located?
- Dorsal motor nucleus in the 4th ventricle
- What cranial nerves does the nucleus solitarius control?
- VII, IX, X
- What nerve is NOT affected when there is an intramedullary lesion?
- Spinal Accesory Nerve (XI)
- What muscles does the spinal accesory nerve innervate?
- 1) sternocleidomastoid
- Where is the abducens nucleus found?
- Floor of the 4th ventricle
- lateral to the MLF
- What happens when the abducens nucleus has a lesion?
- - ipsilateral facial paralisis of the VII nerve
- inability to look to the side of the lesion
- Where does the facil nerve exit the brain?
- pontomedullary junction
- What is the superior olivary nucleus responsible for?
- It receives auditory impulses from both ears by cochclear nuclei.
- cochclear nuclei at pontomedullary junction
- Where are vestibular nuclei found?
- posterior surface of pons
- What three structures are found in the pontomedullary junction?
- - Facial motor nucleus exits fibers
- cochlear nuclei
- What four nerves emerge from the pons?
at the pontomedullary junction
- What is another name for midbrain?
- What structures pass through the midbrain?
- - cerebral acueduct
- superior colliculi
- inferior colliculi
- What is the function of the inferior colliculi?
- processes auditory information received bilaterally from cochlear nuclei
- What is the function of superior colliculi?
- help direct movement of both eyes in gaze
- What two nerve emerge from midbrain?
- oculomotor III
- What do the cerebral peduncles contain?
- Corticospinal fibers
- How do oculomotor nucleus exists the midbrain?
- ventrally in the interpenducular fossa
- How do trochlear nerves exit?
- posterior midline inferior to the inferior colliculi
- How does the ear protect itself against damage to the inner ear from loud sounds?
- It contracts the stapedius and tensor tympani muscles
- What happens to the Upper Face and Lower Face in a corticobulbar lesion?
- The Upper Face has normal function since it has a bilateral innervation.
The Lower Face is affected contralaterally since there is only one set of fibers going there.
- What are the components of the ear?
- 1) external ear
2) middle ear
3) inner ear
- What structures make up the external ear?
External Auditory Meatus
- What makes up the middle ear?
- - Temporal Bone
- tympanic membrane
- connecting it to the oval window
- What bones are included in the middle ear?
- What makes up the inner ear?
- - labyrinth
- channels (semicircular ducts and cochlear duct)
- What is the characteristic of endolymph?
- It contains the same characteristics as intracellular fluid
- What is the characteristic of perilymph?
- It is ionically extracellular fluid
- How does sound travel from the ear to the brain?
- hair cells in the organ of Corti are conected to the spiral ganglion.
- to cochlear part of CN VIII
- ventral cochlear nuclei --> Superior Olivary N. --> Inferior Colliculus --> Midbrain
- What is stimulated in low-frequency sounds?
- Apex of of the cochlea
- What is stimulated in high-frequency sounds?
- Base of the cochlea
- Does perilymph move towards or away the direction of movement?
- How does endolymph move?
- Against the direction of movement
- Static Laberynth is made up of?
- How can you tell if there is excitation from the kinocillium?
- They are pointing toward the striola
- What are the components of the dynamic laberynth?
- Ampulla, endolymph, hair cells, crystals
- What consists in a Pinealoma Sydrome?
- Insomnia, headache and can't look up
- What is the mechanism of damage in a pinealoma?
- - Damage to the superior colliculus center for upward gaze
- pupillary constriction for accomodation
- decrease in melatonin
- decrease in sleep patterns
- headache from tumor compression
- - Can't follow Upward gaze
- Pupils Accomodate but not react
- Pinnealoma/Parinaud Sx
- What nerve is intact when you have good convergence?
- III adducts well
- Patient difficulty swallowing and palata droopped, what center is affected?
- Nucleus Ambiguus
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