Week 1 Flashcards
What is hemiparesis?
weakness of the entire left or right side of the body.
What is hemiplegia?
Paralysis of one side of the body.`
Where does the brainstem begin
at FORAMEN MAGNUM
Mostly INFRATENTORIAL
What are the Crainial Nerves associated with,Midbrain,PonsMedulla?
Md-3&4, Pons 5-8, and Medulla 9-12
Cranial nerve func. ->sensory (Afferent)?
Pseudounipolar = GENERAL Sensory
Bipolar = SPECIAL Sensory
What are the nerve funct. of motor (efferent) fibers?
Multipolar:
- Skeletal Muscle
- >Somites
- >Branchial Arches - Smooth Muscle
- >PREganglionic
- >Parasympathetics
What are the functions of the nuclei of Cranial Nerves?
Sensory =2nd Order
Motor= Alpha Motor or Pregang. Parasymp.
What are the ganglia in the the neurons of Cranial Nerves?
SENSORY-Pseudounipol. Bipolar
OR,Multipolar Parasymp. Gang
What is the order of the alar & basal plate org. @ medulla level?
Somatic Sensory,-> Visceral Sensory,->Visceral motor-pregang Para,-> Somatic motor- Alpha Motor
What sypmathetic muscle opens the eye?
Mueller’s Muscle
What Somatic muscle opens the eye?
Levator palpebrae
What is the trajectory of the upper motor neurons of the corticospinal tract?
It begins in the cerebral peduncle pierces the pons and goes inside the pons to go through the pyramid of the medulla
What are the somatic motor CNs in the head?Branchial?
Somatic: EYE = 3, 4, 6 TONGUE = 12 Branchial Arch Muscle: Mastication = 5 Facial Expression = 7 Pharynx & Larynx = IX, X, XI (Nucleus Ambiguus)
What are the cranial nerves of the Medulla?
Hypoglossal (XII)
Accessory (XI, ambiguus)
Vagus (X)
Glossopharyngeal (IX)
Function of the Hypoglossal Nucleus?
TO Intrinsic and Extrinsic Muscles of the Tongue Somatic Motor (GSE)
What nerves innervate the Spinal Accessory Nucleus and what muscles does that affect?
Spinal Accessory Nucleus (Cervical 1-5,6)
TO Sternocleidomastoid & Trapezius muscles
What is the function of the dorsal motor nucleus of the vagus?
CN X; innervates the visceral motor to thorax and abdomen
What are the symptoms of a Lower Motor Neuron Lesion? Where can it be?
LOWER MOTOR NEURON = Atrophy, Fasciculations
Lesion could be in Medulla or Nerve
What are the symptoms of a Upper Motor Neuron Lesion? Where can it be?
UPPER MOTOR NEURON = Spasticity
Lesion in Cerebral Cortex or Corticobulbar Tract
What are the clinical signs and lesion location in the body of a alternating hemiplegia?
IPSILATERAL TONGUE LMN SIGNS; CONTRALATERAL BODY UMN SIGNS
CN XII lost
What are the ways YOU can GET AN UMN
LESION INVOLVING
TONGUE???
- Corticobulbar Tract=Contralateral to hypoglossal nuc. (weak but no fasciculations)
- If at the nucleus, ipsilateral
What it the path for the hypoglossal nerve from the cortex?
From cortex->into corticobulbar tract-> decusates to hypoglosal nucleus
What nerve would cause atrophy of trapezius?
Acessory Nerve (comes from medulla and cervical canal)
Vocal paralysis comes from what nerve? What nucleus caused it?
10, Nuc. Ambig.
What senses can be found at the Spinal Trigeminal Nuc.?
Somatic Sensory for skin of Outer Ear
What are the nuclei for the vestibulocochlear N. (VIII)
Somatic Sensory (SSA):
1) (Hearing) Organ of Corti Spiral Ganglion Cochlear Nuclei
2) (Balance) Cristae Amp. & Macula Vestibular Ganglion Vestibular Nuclei
What Are the nuclei of the Pons?
Vestibulocochlear (VIII)
Facial (VII)
Abducens (VI)
Trigeminal (V)
What are the nuclei and sensory responsibilities for the AFF for Facial N?
AFF:
1) Somatic Sensory:
GSA: FROM Skin of Outer Ear (gen. gang.) Spinal trigeminal Nuc.
2) Visceral Sensory:
SVA: FROM Taste Buds on Ant. 2/3 Tongue (chorda tympani - gen. gang. - nervus intermedius) Nuc. of Solitary Tract
What are the nuclei and sensory responsibilities for the EFF for Facial N?
EFF:
1) Visceral Motor:
GVE: Superior Salv. Nuc. = Parasympathetic TO
A) Pterygopalatine ganglion (via nervus intermedius then gr. Superficial petrosal n.) to Lacrimal Gland
B) Submandibular ganglion (via nervus intermedius then chorda tympani) to Submand. & Subling. Glands
2) Branchial Motor:
SVE: Facial Motor Nuc. = Branchial Motor TO Musc. Facial Expression, platysma, stapedius, stylohyoid, & post. belly digastric
Why would the a patient not be able to move his forhead?
Corticobulbar Tract synpses on 2 facial nerves so damage spares the forehead; LMN lesion to VII would cause paralysis to entire 1/2 of face (Bell’s Palsy)
What Nerve/Nucleus is responsible for Medial Strabismus?
Abducens!
LESIONS:
VI NERVE->NO Lateral Gaze Eye Same Side
VI NUCLEUS->NO Lateral Gaze Eye Same Side
NO Conjugate Contralateral Medial Gaze
Explain Internuclear Ophthalmoplegia
destruction of the medial longitudinal fasiculus inhibits Abducens->Oculomotor comm. Contralateral eye movement inhib.
What nerves does the Medial Longitudinal Fasciculus connect?
Connects the vestibular nucl. to 3,4,6
What are the functions of CN V AFF?
Somatic Sensory:
GSA:
FROM Skin of Face & ant. scalp, mouth & nasal Mucous Membrane, Dura (trigem. ganglion, V1,V2, V3)
Main Sensory Nuc. & Spinal Trigeminal Nuc.
FROM Stretch Receptors of Muscles of Mastication (JAW JERK)-> Mesencephalic Nucleus Motor Nucleus of V
What are the functions of CN V EFF?
Branchial Motor:
SVE: Motor Nucleus of V (Mandibular Nerve) TO Muscles of Mastication, tensor tympani, tensor veli palatini, mylohyoid, ant. belly digastric
What produces Aqueous humor and where does filter into?
Aqueous humor, continuously produced by the ciliary body, passes from the posterior chamber to the anterior chamber, then enters the Canal of Schlemm
Blockage of the aqueous flow can what disease?
Blockage of the aqueous flow can damage the optic nerve and cause glaucoma.
What is accommodation?
Changing the curvature of lens can help to bring an image to focus on the retina
Explain Presbyopia.
the lens looses its elasticity when it gets old and has trouble bringing a near image to focus
What are Cataracts?
problem of the lens, which occurs when the lens loses it opacity.
What is hyperopia? What lense fixes it?
The eyeball is too short, and light rays come to a focus behind the retina. Biconvex Lens
What is Myopia?
The eyeball is too long and light rays focus in front of the retina. Biconcave lens
What is Astigmatism?
curvature problems of the cornea or the lens
What are 4 major cell types in the internal nuclear layer?
Muller Supporting cell - is the major glia in the retina this extends the whole thickness of the retina.
Horizontal Cell - modulate signals sent out by photoreceptors
Bi-polar neuron - relay signals between cell layers.
Amacrine cell - modulate functions of ganglion cells.
What are the 3 layers in the retina?
External Nuclear, Internal Nuclear, and Ganglion Cells
What axon cells are collected into a bundle and to become the optic nerve?
Ganglion cells
What is the name of the area where sensory axons exit the eyeball? What is another name for it and where is it in the eye?
Papilla (optic disc) Blind Spot; medial to the macula densa
Why is the macula an area with high visual acuity? How is it related to the fovea?
Avascular so it has high visual acuity because light is not blocked by blood vessels and it has a high density of photoreceptors. The fovea has many cone photoreceptors!
What is the leading cause of blindness in the elderly population?
Macular Degeneration; looses central vision-external nuc. layer
What are the layers of meninges that wrap around the eyeball?
Choroid->Sclera->Retina
Possible cause(s) of high intracranial pressure
adsf
Why it can cause problems if you do lumbar puncture on a patient with papilledema?
adsf
What are the Biochemical events that happen in the photoreceptors?
light->rhodopsin conf. chg->transducin binds GTP->PDE activity incr->cGMP levels decreased->close Na+ ch.->hyperpolarization->Reduce Glu release
What causes retinitis pigmentosa?
mutations->severe degeneration of rod photoreceptors and patient has Impaired night vision
Impaired peripheral vision
Purposes of the visual info sent to LGN, Pretectal Nuc, and the suprachiasm?
LGN-Pattern, Pretectal Nuc.-Light reflex, Suprachiasmatic Nuc. of hypoth.->ciracadian rhythm
What areas of the brain cortex are responsible for visual info?
Areas 18-19 Visual Assoc., Sent here 1st->Area 17:Principal visual cortex, Areas 18-19 Visual associtation areas
What part of the brain initiates the pupillary reflex?
Information processing in the visual cortex
can initiate pupillary dilation reflex
What are the Nerves of the midbrain?
Trochlear (CN IV) & Oculomotor (CN VIII)
Where can CN 4 be found in the midbrain?
Somatic Motor (GSE, MYOTOME)
Where does CN4 decussate?
Superior Medullary Velum
Common place for LESIONS of TROCHLEAR?
NUCLEUS (Rare): 1) Contralateral SO 2) Possibly with Horner’s syn. NERVE: 1) Before Decussation (Rare) = Contralat. SO 2) At Decussation = Bilateral SO’s 3) After Decussation = Ipsilateral SO
Signs of lesions in the trochlear?
1) Extorsion (Can’t Look Down & In)
2) Vertical Diplopia (Double Vision) when Reading or Walking Down Stairs
3) Head Tilt + Chin Down Contralat. to Affected SO
Oculomotor Nucleus myotome and function?
Somatic Motor (GSE, MYOTOME), Motor TO Levator Palpebrae Superioris & Extrinsic Eye Muscles
MM and Func. Visceral Motor (GVE)?
Nuc. of Edinger-Westphal->Parasymp. TO Ciliary Ganglion To Pupillary Constrictor & Ciliary Body
Common clinical causes of Oculomotor Palsy?
Posterior Cerebral Artery Stroke JUST OCCULOMOTOR NERVE: Posterior Communicating Aneurysm Increased Intracranial Pressure Diabetes (spares pupil)
Horner’s Syndrome vs. Lesion CN III
Horner’s Syndrome Sympathetics Lost: Partial Ptosis (Muller’s m.), Miosis (Pin Point Pupil), Anhydrosis Lesion CN III Somatic Motor Lost: Full Ptosis (Levator m.) Down and Out Parasympathetics Lost: Mydriasis (Dilated Pupil)
What are the parasymp. of the midbrain
3,7,9
Path of Optic nerve in Diencephalon? how are they myelinated?
Retinal Ganglion Cells TO Lateral Geniculate Body. Oligodendroglia
Why do both eyes blink w/ pupillary light reflex?
Optic Nerve Innervates both E-W and Pretectal Nucleus so both eyes are in conj.
What is th SVA fund. of the olfactory N
Bipolar Neurons Olfactory Epithelium to Olfactory Bulb
What is the SENSORY Component of “MOTOR” Cranial Nerves?
Proprioceptive Fibers (GSA) To Mesencephalic Nuc. of V (not in ganlia, scattered)
What supplies blood for the CN I & II?
Ant. Cerebral
What areas does PCA supply?
III Oculomotor Nucleus, Edinger-westphal, and Trochlear Nucleus
What Areas does AICA supply?
V Motor nuc. ,VI Abducens, VIII Facial Nucl., Sup Salvatory nuc, Facial n.
What Area does PICA supply?
VIII Cochlear nuclei Vestibular Nuclei, IX All components, X Nuc. amb.
What supplie blood to XI and XII?
ANT. SPINAL A. ->Accessory nuc. and Hypoglossal nuc.
Effects of Lesions of the Ventral Pons?
Raymond’s Syndrome LCST & CN VI=Contralateral Hemiparesis, Ipsilateral Medial Strabismus
Effects of lessions in the middle pons?
(Millard-Gubler Syndrome) LSCT & CN VII = Contralat., Hemiparesis, Ipsilat. Facial Paralysis
Effects of lessions in the Dorsal Pons?
LOCKED IN SYNDROME
Foville’s Syndrome
Nuc. VI (MLF) & VII and CN VII = Ipsilat. Medial Strabismus & Facial Paralysis,
Loss of Conjugate Movement of Contralat. Med. Rectus
What is Weber’s syndrome?
Lesion in LCST and CN II -> Contralat. Hemiparesis, Ipsilat. Ocular Paresis
What is Parinaud’s Syndrome?
Superior Colliculi-cant look up: Paralysis of Upward Gaze
What is the RF function? (PAPA D)
1) Pain Suppression System (Nuc. Raphe Magnus in Pons)
2) Autonomic Reflexes – Pattern Generators (Physiology)
RESPIRATORY CENTERS (Medulla, Pons)
CARDIOVASCULAR CENTERS (Medulla)
3) Descending Sympathetics (from Hypothalamus)
Lesion = ipsilat. HORNER’S SYNDROME
4) Arousal & Consciousness
-Ascending Reticular Activating System (ARAS)
5) Posture (Reticulospinal Tracts)
What are the 3 Longitudinal Zones?
Median Zone: Raphe Nuclei (5-HT) -Medial Zone: Ascending & Descending Projections -POSTURE TRACTS: Medullary & Pontine Reticulospinal Tracts (Motor Sys. Lectures) -Lateral Zone: CN Reflexes & Visceral Functions
Location and function of the NE Sys in the midbrain?
Located in the locus ceruleus,Solitary Nucleus, Lateral Area of Medullary Reticular Formation
has wide spread projections and is secreted for attention
Location and function of the DA Sys int the midbrain?
Initiation of Movement, Motivation, Cognition axons to striatum located in Substantia Nigra and axons to limbic system located in VTA where DA is made