click below
click below
Normal Size Small Size show me how
Neuro II-p. 14-32
Thomadaki Fall 2010
Question | Answer |
---|---|
What are hypokinetic disorders? Examples | PROBLEMS WITH DIRECT PATHWAY Akinesia (parkinson's...trouble starting & stopping movement) Bradykinesia (slow movements also in parkinson's) |
What are hyperkinetic disorders? Examples | PROBLEMS WITH INDIRECT PATHWAY Dyskinesias (involuntary mvts) - chorea, ballismus, athetosis, dystonia |
What is Chorea? | Side effect of long term L. Dopa use Irregular involuntary twitching of extremeties (quick, jerky, non-repetitive/unpredictable movements) |
What is Athetosis? | Writhing, constant motion |
What is Dystonia? | Ususally genetic, occur with overuse. Severe spasm |
What is parkinson's disease? | Depletion of dopaminergive cells in Substantia Nigra causing breakdown of nigrostriatal circuitry. |
What are two types of Parkinson's D/E? | Typical - injury to dopaminergic cells in substantia nigra Atypical - same symptoms as typical but they don't subside when given L Dopa |
What are the symptoms of Parkinson's D/E? | Akinesia, Bradykinesia, Resting tremor, Cogwheel/lead pipe rigidity, Flexed posture, Mask-like facial expression, shuffling gait & impaired balance |
What is the treatment for Parkinson's? | Admin of L-DOPA (precursor to dopamine since dopamine doesn't cross BBB). Anticholinergic drugs (transplant of human dopamine cells, pallidotomy, GP I pacemaker, thalamectomy) |
What is Huntington's D/E? | Autosoma dominant hereditary d/e w/ an insidious onset in 4th or 5th decade of life, resulting from slow degeneration of neurons in striatum |
What are symptoms of Huntington's D/E? | Chorea - (eventually takes over all voluntary movement), dementia, behavioral or psychiatric disturbances |
Prognosis of Huntington's D/E? | 15-20 year after onset |
What is Sydenham's Chorea? AKA? | St. Vitu's Dance. Transient (reversible) childhood chorea associated with RHEUMATIC FEVER and affecting the striatum |
What is Athetosis? | Degeneration of globus pallidus resulting in constant, slow, sinous, writhing movements of DISTAL extremeties. Weak trunk |
What is Ballsim? | Lesion of subthalamic nucleus (usually caused by a small stroke) or it's connections. Results in contralateral involuntary movements of PROXIMAL extremeties |
What is Wilson's D/E? | Autosomal recessive disorder that results in abnormal metabolism of CU |
Abnormal metabolism of CU in wilson's disease degenerates what? | Liver & Basal Ganglia |
Symptom of Wilson's D/E | Kayser-Fleischer ring in cornea |
What is Dystonia Musculorum Deformans | Rare hereditary condition associated with injury of LENTIFORM NUCLEUS, resulting in co-contraction of antagonist and agonist muscles |
What are focal dystonias? | Include torticolis (repeated spasm of SCM & Trap), blepharospasm (spasm of upper eyelid) dysphonia (vocal cords), writer's cramp (hand) |
Motor function of Basal Ganglia & cortical association area | gather visual, auditory, proprioceptive, etc. information about the relative position of the body, the object and overall intention of movement |
What areas do the basal ganglia & cortical association area include? | Anterior Frontal Lobe Posterior parietal lobe |
Function of Anterior Frontal Lobe | Motor Designing |
Function of Posterior parietal lobe | Utilize space in emotion |
What areas do the cerebellum and motor cortex include? | Primary motor cortex (area 4, precentral gyrus) Premotor and supplementary motor cortices (Area 6) |
What is the motor function of Cerebellum & motor cortex? | Plan the sequence & timing of muscle contraction & relaxation to ensure smooth movement |
Motor funcion of the brainstem & spinal cord | Execute the movement |
What are the two descending tracts? | Lateral Pathway Ventromedial pathway |
Lateral pathway influences what motor neurons? | Motor neurons that innervate DISTAL muscles of the limbs |
What tracts are in the lateral pathway? | Lateral Corticospinal Tract Rubrospinal tract |
Ventromedial pathway influences what motor neurons? | Motor neurons that innervate AXIAL & PROXIMAL LIMB muscles |
What tracts are in the ventromedial pathway? | Ventral Corticospinal Tract Pontine & medullary reticulospinal tract Vestibulospinal tract Tectospinal tract |
The corticobulbar tract is the major input of the __________ neurons in the ________. The input is mostly (uni/bilateral?) | LMN, brainstem, bilateral |
What areas in the brain are associated with the Corticospinal Tract? | motor cortex areas 4&6 & somatosensory cortex |
What is the pathway of the corticospinal tract? | Motor & somatosensory cortex --> corona radiata --> posterio limb of internal capsule --> crus cerebri --> basilar pons --> pyramid/pyramidal decussation X lateral corticospinal tract --> synapses w/ ventral horn cells |
Corticospinal tract innervates what muscles? | distal primarily flexor muscles |
What is the pathway of the rubrospinal tract? | Red nucleus (under control of cortex) X in pons --> terminates in ventral horn cells (especially of cervical spine) |
Rubrospinal tract functions are overtaken by _________ | corticospinal tract |
What are the symptoms of a lateral pathway (UMN) injury? | Paresis or paralysis/plegia but no immediate atrophy of muscles. Spasticity (hypertonia & hyperreflexia/clonus) Clasp knife rigidity Babinski sign (often see before spasticity) Absent superficial reflexes |
What are the superficial reflexes? | Cremasteric/anal wink/abdominal |
Pontine Reticulospinal tract travels where? | From reticular formation in pons to ventral horn cells bilaterally |
Function of the Pontine Reticulospinal tract | Facilitation of antigravity muscles (extensor of lower limb) |
Medullary Reticulospinal tract travels where? | From reticular formation in medulla to ventral horn cells bilaterally |
function of the Medullary Reticulospinal tract | Inhibits antigravity muscles |
Vestibulospinal tract travels where? | From vestibular nuclei to ventral horn cells bilaterally |
Function of the Vestibulospinal tract | Controls head & back muscles based on directional info it receives from vestibular apparatus in inner ear Facilitates upper and lower limb EXTENSORS |
Tectospinal Tract travels where? | From superior colliculus (which receives input from retina) X in medulla --> ventral horn cells |
Function of Tectospinal Tract | Turns head and eyes toward stimulus |
Decorticate | Triple flexion upper limbs + extension of lower extremeties (CST) |
Decerebrate | Tonic flexion of upper and lower limbs (CST& RST) |
Lesion to brainstem above vestibular nuclei leads to what type of rigidity? | Decerebrate |
Lesion to cerebral hemisphere with intact brainstem leads to what type of rigidity | Decorticate |
Define motor unit | 1 alpha motor neuron and all muscle fibers it supplies |
Define motor neuron pool | all alpha motor neurons that innervate a muscle |
What motor neurons innvervate skeletal muscle? | Ventral horn cells (Alpha and Gamma) & motor nuclei of CN |
Alpha motor neurons innervate what type of skeletal muscle fibers? | extrafusal (contractile muscle) |
Gamma motor neurons innervate what type of skeletal muscle fibers? | Intrafusal (muscle spindles) |
What are symptoms of a lower motor neuron lesion? | Paresis/paralysis/plegia; Atrophy; Fasciculations; hypo(a)tonia and hypo(a)reflexia |
Define fasciculation | Visible muscle twitching resulting from involuntary synchronus ctx of all the muscle fibers in a motor unit |
Define fibrilation | Spontaneous activity of one muscle fiber; not visible to eye |
A fasciculation is a characteristic of what type of disease? | slowly progressive |
A fibrilation is a characteristic of what type of disease? | Progressed muscle denervation or myopathy |
What are the motor and sensory neurons in muscle spindle? | Gamma = motor; Ia & II = sensory |
Stretch reflex requires what NT? | AcH |
Ia inhibitory reflex requires what NT? | Glycine |
What are 3 types of intrafusal fibers | (1) Nuclear Chain Fibers - thin fibers w/ nuclei arranged in single file; afferents incl Ia & II (2) Nuclear Bag Fibers - thicker fibers w/ nuclei grouped in central region--> (a) DYNAMIC (b) STATIC |
What are static nuclear bag fibers? | Slowly adapting stretch receptors; afferent include Ia & II |
What are dynamic nuclear bag fibers? | Sensitive to rate of change (rapidly adapting); afferents include Ia ONLY |
Stretch reflex to is agonist/antagonist excitation/inhibition? | agonist excitation |
Ia Inhibitory reflex to is agonist/antagonist excitation/inhibition? | antagonist excitation |
Recurrent (Renshaw cell) inhibition reflex to is agonist/antagonist excitation/inhibition? | Agonist inhibition |
Ib reflex to is agonist/antagonist excitation/inhibition? | agonist inhibition |
What is the purpose of recurrent inhibition? | To avoid overexcitation of agonist motor neuron pool |
To avoid over excitation of agonist motor neuron pool alpha motor neurons synapses with what cell? | Renshaw inhibitory cell |
What is the response of a Renshaw Inhibitory Cell? | withdraws the inhibition of Ia interneurons so that the antagonist is excited + agonist is inhibited |
Where are golgi tendon organs located? | jct between muscles & tendon, in series with extrafusal muscle fibers |
Are golgi tendon organs sensory or motor? | Sensory |
Inhibitory reflex: Ia :: Golgi Tendon Organs: ? | Ib proprioceptors |
What is the difference between Golgi Tendon Organs & Renshaw Cells? | Golgi - stops when injury to TENDON; Renshaw stops when injury to MUSCLE |
Why doesn't golgi tendon need motor innvervation? | Because it lengthens/straightens w/ muscle |
Central axons of Ib fibers from __,__,__ synapse on a __ (inhibits/excites) ___ of ___ muscle in response to what? | Golgi tendon organ, cutaneous receptors, joint receptors; Ib inhibitory interneuron; inhibits; alpha motor neuron pool; agonist; muscle tension |
What occurs in the Flexion & Crossed Extension Reflex? | Central axons of A-alpha nociceptors excite flexors of hurt lower limb (to flex knee) while exciting extensors of contralateral limb for support |
Deep Sensibility pathway... | FG (T6 & down) & FC (T6 & up) info ipsilat in SC -->Nuc. grac. & cuneat. --> IAF X ML --> Ventral post. lateral thalamic nuc. --> internal capsule --> somatosensory cortex |
Somatosensory cortex contains what areas? | Broadman's 3,1,2 |
What sensations comprise deep sensibility? | Proprioception, vibration, 2-pt discrimination, pressure, touch |
Proprioception from lower body runs in what tract? | Spinocerebellar |
How do you test for deep sensibility? | Vibration tuning fork on dermatomes; Position sense of upper extremeties; Romberg's test |
Neuro tests will determine if injury is in __, __ or ___ | PNS, SC or Brainstem & up |
Neur exams tests what 4 things? | (1) CN (if no sx then can't be in brainstem); (2) Muscle (3) Reflex (4) Sensation |
With an injury to Spinal Nerve there will be LO DS &/or P&T to... | Same side as injury |
With an injury to SC there will be LO DS &/or P&T to... | P&T on one side, DS on other side |
With an injury to Brain there will be LO DS &/or P&T to... | Contralateral to injury. Whole body affected |
Anterolateral system is made up of what 3 tracts? | Spinothalamic, Spinoreticular, Spinomesencephalic |
Anterolateral system is involved in perception of what? | Pain & temperature |
P& T fibers enter the ____ & end in the _____ | tract of lissauer, dorsal horn |
What fibers are associated with pain? | C & A-delta (slower fibers) |
Vibration testing assesses what in the periphery and what centrally? | Periphery = A-alpha & A-beta; Central = Dorsal column/med. lemniscus |
Pain testing assesses what in the periphery and what centrally? | Periphery = C + A-delta; Central = LSTT |
P&T fibers cross in the ___ and ends in the ____ then run through the ____ and end in the ____ cortex | Ventral white commissure; ventral posterior lateral thalamic nucleus; interal capsule; somatosensory |
The limbic system includes higher control of what? | (1) autonomic fx (2) homeostasis (3) reproduction (4) emotion (5) motivated behavior (6) learning |
What are the 2 components of the limbic system? | Limbic lobe & Limbic system |
What comprises the limbic lobe? | Septal area, cingulate gyrus, parahippocampal gyrus, hyppocampus & amygdala, uncus |
What comrises the limbic system? | Limbic lobe & all its subcortical & cortical connections (hypothalamus, thalamus, brainstem reticular formation, epithalamus, olfactory cortex, prefrontal cortext) |
Limbic system is AKA? | Papez Circuit |
What are the components of the Hippocampal Formation? | Part of parahippocampal gyrus, hippocampus, dentate gyrus, subiculum |
What are the afferents of hippocampal formation? | Entorhinal area of parahippocampus gyrus --> Contralateral hippocampus via hippocampal commissure, Amygdala, Thalamus, Locus coeruleus Raphe nuclei Ventral tegmental area |
What structure has Norepinephrine? | Locus coeruleus |
What structure(s) has(ve) serotonin? | raphe nuclei, ventral tegmental area |
What is the entorhinal area? | Primary olfactory cortex. It immediately excites hippocampus |
What is the efferent pathway of hippocampal formation? | Fornix --> septal area & mammilary bodies of hypothal. -from mam. bodies-> ant. nuc. of thalamus --> cingulate gyrus |
Function of hippocampal formation? | Holds a map of SPACIAL MEMORY (passage of learning & short term memory into long term memory) |
Symptoms of a lesion to hippocampal formation? | Defects in explicit memory & spacial orientation |
What are the types of memory? | EXPLICIT (declarative...the facts) & IMPLICIT (non-declarative...how you do something) |
What are examples of EXPLICIT MEMORY? | Episodic (events); semantic (facts) |
What part of the brain deals with explicit memory? | Medial temporal lobe |
What are examples of implicit memory and what part of the brain controls it? | Priming [neocortex] Procedural (skills & habits) [striatum] Emotional responses to associative learning [amygdala] Musculoskeletal responses to associative learning [cerebellum] |
What are examples of amnesia? | Retrograde Anterograde Global Modality specific |
Hippocampus is the ___ memory as Cortex is to ___ memory | short term; long term |
What information passes through the amygdala? (afferents) | Autonomic, sensory, auditory & visual information |
Efferent information in the amygdala goes where? | via stria terminalis --> septal nuclei & hypothalamus, brainstem & cortex |
What is the function of the amygdala? | "affective perception of sensory stimuli" (what a sensory stimulus makes you feel like. Gets you ready to react. Gets info before it becomes conscious) |
What are the symptoms of a lesion to the amygdala | Diminished capacity for fear conditioning |
What causes Kluver Bucy Syndrome? and what are the symptoms? | Cutting out both temporal lobes (incl amygdala & hippocampal formation) Symptoms = visual agnosia, hyperorality, hypersexuality, docility, apathy, bulimia, memory deficit |
What causes Korsakoff's psychosis? What are the symptoms? | Thiamine deficiency leading to destruction of 3rd ventricle. Symptoms = anterograde and progressively retrograde amnesia |
What are some conditions that affect the temporal lobe? | Temporal lobe epilepsy, olfactory hallucinations, visual hallucinations (deja vu), gustatory & auditory hallucinations, lip smacking, motor acts, amnesia that can last for several hours, sometimes aggressive behavior; schizophrenia; alzheimers (see notes) |