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123 Cards in this Set
- Front
- Back
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Functions of III oculomotor |
Somatic motor of 4 eye muscles: superior rectus, inferior rectus, inferior oblique, medial rectus - III motor nucleus Visceral motor: Constricting pupil in pupillary reflex - EW Nucleus is found in Rostral midbrain |
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IV Trochlear |
Somatic motor control of superior oblique exits dorsally Caudal medulla |
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V Trigeminal (2) |
SomatoSensory component: Branches: Ophthalmic (forehead, eyelid, nasal cavity), maxillary (upper teeth, hard and soft palate), mandibular( cheek, anterior 2/3 tongue) mesencephalis nucleus in the medulla: proprioception of mastication muscles Pontine nucleus: in the pons. Termination site for tactile Spinal: Pain and touch, nucleus in pons/medulla/SpC Motor component: Branchial motor control of muscles of mastication. Nucleus is in the pons at level of main sensory V |
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VI Abducens (1) |
Lateral rectus - looking right or left Diplopia Found in somatic motor pons (near midline) Remember the rules of 4, motor nuclei in midline 3 4 6 12 (divisible by 12) |
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VII Facial (4) |
Sensory: pain and tactile of ear, tympanic membrane. Terminates in Spinal V pons level Visceral sensory: Taste of 2/3 tongue caudal Pons, rostral medulla. Joins solitary tract and projects to solitary nucleus Motor: Facial and midear muscles - pons super salivatory nucleus (all glands except parotid) pons |
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VIII |
Special sensory
Vestibular: nuclei at floor of 4th ventricle, goes to III, IV, VI for balance pons/medulla |
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IX (4) |
Sensory: Somatic sensory: Posterior 1/3 tongue, tonsil, soft palate, upper layrnx, uvula - terminates in spinal V pons/med/spc Visceral sensory: Chemoreceptors in carotid - inferior solitary nucleus posterior 1/3 taste - superior(upper) solitary nucleus Motor: Branchial motor: stylopharngeal - nucleus ambiguus Medulla Visceral motor: parotid gland + vasodilation - inferior salivary nucleus Medulla
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X (4) |
Somatosensory: meninges, ear, pharynx - terminate in spinal V visceral sensory: larynx, lower pharynx, airway, abs - nucleus of solitary tract Motor: Branchial motor: nucleus abiguus - VF, constrictor muscles , pharynx Visceral motor -airwaym digestive tract, liver, kidney - dorsal motor nucleus in medulla |
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XI (accessory) (1) motor |
Branchial motor: trapezius - raise shoulders sternomascloid - no nucleus in C1-C5 and travels up to brainstem to exit at medulla |
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XII (hypoglossal) M |
somatic motor - all muscles of hte tongue besides palatoglossus (X) |
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CN in nucleus ambiguus |
IX X |
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CN in nucleus of solitary tract |
VII IX X |
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CN in superior salivatory nucleus |
VII visceral motor of glands - e.g. lacrimal for tears |
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CN of inferior salivatory nucleus and purpose |
IX visceral motor of parotid |
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Describe auditory pathway |
f |
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Describe corticobulbar pathway |
f |
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describe spinothalamic pathway |
f |
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describe ML pathway |
f |
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4 medulla CN |
IX, X, Xi, XII |
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4 Pons cranial nerves |
V VI VII VIII |
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4 Midbrain CN |
III IV |
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Lesions to cranial nerves are all |
ipsilateral |
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Contralateral lesions seen in |
corticopsinal, ML, spinothalamic |
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Ipsilateral lesions in tracts |
spinocerebellar sympathetic fibres (descendng) |
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Myopia |
Short sightedness Lens too strong Biconcave glasseses |
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Hyperopia |
Long sightedness lens too weak convex glasses |
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Astigmatism |
Lens has unequal curvatures |
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Presbyopia |
Old eye - decreasing elasticity of lens |
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When objects come closer, 3 things happen |
Convergence: activation of medial rectus accomodation: changing shape of lendes + contraction of cilary muscles to relax lens(make more round) pupil constriction: prevents divergent light entering |
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Vitreous humour |
Fills posterior segment supplies nutrients to ganglion cells |
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Iris role |
gives eye colour, changes shape of the pupil |
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pupil |
focuses light into fovea by changing shape. right in front of lens |
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lens |
focuses light |
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cornea |
most exterior allows light to pass through provides most refractive power +43D |
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suspensory ligaments |
holds lens into place + changes it shape. Taunt = distant, slack = close |
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Blood supply of retina |
choroid: ext 1/3 photoreceps central arter + vein: ganglion + bioloar cells |
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Fovea |
pit of retina, highest density |
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intraocular muscles |
ciliary iris sphincter |
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extraocular muscles |
superior rectus - up superior oblique - down lat medial rectus - towards nose inferior rectus - down inferior oblique - up lat lateral rectus - abducts |
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Describe pathway |
Light hits the fovea --> photoreceptors --> bipolar cell --> ganglion cells --> optic disc --> optic nerve --> chiasm --> superior colliculi --> lateral geniculate nucelus --> V1
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Lesion to optic tract |
Homonymous hemianopia (either left or right)
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lesion to chiasm |
Bitemporal hemianopia
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Lesion to optic radiation |
(same side) L or R homonymous hemianopia with macula sparing |
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lesion to optic nerve |
.Left or right anopia (opposite side) |
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Phototransduction pathway |
happens in outer segments of photoreceptors photorecepts - pigment molecule changes shape - membrane channel blocked - activates bipolar cells - activates ganglion - LGN |
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Visual pigments of rods and cones |
Rhodopsin |
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Rods |
night, B&W absorbs most of the visible spectrum sensitive to light and responds well to dim light high afferent convergence - low VA |
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scotopic |
rods - dim light |
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cones |
colour and day red, green, blue (in terms of wavelength absorption) cones insensiive - photopic each cone synapses with one biploar cells - littel convergence |
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optic disc and blind pot |
optic dic - nasal ret blind spot - temporal VF |
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cones have highest density in |
fovea |
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rods highest desnisty in 10-20 range |
not in fovea, dense elsewhere |
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formula for power of lens units for divergences and converges |
1/focal length converge +D diverge -D |
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when lens bulges |
focal point shorter |
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image is formed |
upside down |
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conjunctivitis |
produces teas and mucous |
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schlera |
protects shape of eyes and attaches it to extraocular muscles |
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Week 3 Neurodevelopment |
Neuralation - nervous system starts to form |
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3 germlayers of NS |
ectoderm - becomes NS and bottom becomes skin mesoderm: somites (muscles) Endoderm: intestines |
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End of week 3 D17 |
neural plate induced by mesoderm. becomes thicker and thicker due to chemicals Neural plate continues to grow - swelling of brain and elongation of SpC Day 18-20 |
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CAT SCAN |
xray for 3d visualisations at different planes bone and blood - white. Abnormal would have many whites because of blood clots advantagesL inexpensive, quick, high resolution disadvantages: lots of radiation, reactions, risk of artifacts e.g. metal plates |
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MRI |
magnetic fields and then radiofrequency applied to disturb - makes molecules flipa nd produces energy advantages: shows soft tissues and all planes. no radiation disadvantages: expensive, 40 mins purposes: diagnoses stroke, MS, infections visualises injuries and torn ligaments evaluates bone tumours and cysts |
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fMRI |
same but measures oxygen in brain looks at func low res |
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DTI - diffusion tensor imaging |
detects water diffusion - looks at white matter |
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PET |
half life tracer detects cancer, demntia, seizures and maps brain func adv: shows diff activity in areas dis: time consuming, low res, radioactive, time constraints |
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summarise formation of the brain. What day does it start |
Starts at day 24 |
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what does prosencephalon make |
telenceph (cortex) and dienceph (thalamus) |
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Malformations to neural tube |
failure to close open: communicates with atmosphere closed: covered with skin causes: folate deficiency |
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Posterior defects (3) |
Spina bifida occulta - missing vertebrae, L5 not closed but no protrusion Meningocele: Sac of cyst of meninges. Some paralysis Myelomeningocele: Protrusion of meninges + spinal nerves. paralysis of limbs and ab muscles |
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Complication of meylomeingocele (3) |
Chiari II - paralysis of cranial nerves and brain damage Hydrocecphalus (water head) obstruction of CSF Synngomyelia fluid cyst in Spc |
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ANterior defects |
Encephalocele - anterior pore didn't close and skull defect |
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Anencephaly |
No presenceph |
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4 stages of CNS development |
cellular prolif migration axon growth synapse formation refinemetn of system |
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Cellular prolif when does it peak |
2-4 months at ventricular layer (most inside) (the layers are ventricular, mantle and then marginal) 1st wave: neuroblasts produced (neurons) 2nd wave: glioblasts made --> glial --> astrocytes and oligodendrocytes completeion: ependymal cells that line lumen + ventricles |
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Migration |
Neurons in ventricular layer have to migrate to final location to ,ature time and location specific 6 layers in cortex, radial cells all it to propel up |
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Other forms of migration |
along existing axon pathway along conc gradient of transcriptional molecules |
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Axon growth |
newly placed neuron has structure at tip of growing axon - the growth cone growth cone has lamellipodium: sheetlike expansions of the axon, and filopodia: receptors responds to cues in teh environment |
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synapse formation |
achieved through molecules released in target cell that attracts growth cone |
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brain growth |
highest peak at 2-4 months, migration in 3-5 months and hten cortex and fissures seen |
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development of ventricles |
13 weeks same ratio as brain but in 2nd and 3rd trimester, ratio smaller |
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abnormalisty of neuronal prolif |
microencep: too mall megaenceph: too large of brain, no separation between grey and white matter - both associated with speech delays |
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disorders with migration |
gray matter heterotopia - wrong regions. Lisseneceph: failure week 12-24 - lack of brain grooves penventricular heterotopia: didnt migrate to cortex, No proper circuits. Agnesis of corpus collosum - no hihger order function |
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refinement: 4 steps |
topograph, cell death, synaptogenesis, myelination |
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forming topographic maps |
2 receps have matching arrangements in cortex due to different preferences for guidance molecules |
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cell death |
peaks at week 24. Down to half cells by 4 weeks after birth starts at w4 - 4m |
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synaptogenesis |
formation of synapses starts week20 and peaks after birth bc stimulus dependent elimination starts at 4 months after birth and peaks at 10 |
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myelination |
reules: peripheral before central sensory before motor LMN before higher projection fibres before association fibres |
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dentritic and axonal arborization |
w16 to adult branching out |
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Motor control in embryo and fetus Week 7.5 8.5 10 12 |
1.7 - head turn reflex 8.5 1st spontaneous movement 10 change position 12 kicking rolling |
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after birth high functioning areas due to myelination and synaptogenesis |
bs pheripheral nervse cerebellum dienceph |
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after birth cortex |
differentiation of cortical regions _ white matter myelination still not many synaptogensis and myelination but high rate at 3 years, 3-16x size of cortex compared to new born |
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otic pit |
makes inner ear at Week 4 as thickening of ectoderm 3-4 days later - makes otic vessivle (membraneous labyrinth of ear and ganglion VIII) |
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external ear |
1st and 2nd arches |
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ossicles form from |
condensed mesynchyme by D28 1st arch |
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late week 5 ear |
CNVIII and ducts |
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9month ear |
structurall func |
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endogenous development of hearing |
W20, regular in W22 spontaneous nerve activity and cochlear nuclei without outside stimulation promotes axon growth |
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exogenous hearing |
W28 - sounds heard tune frequency of each hair ceclls. Starts low |
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fetus can hear |
up to 85dB (mother's peristalsis) simple music help develop circuits uterus is filter. 120-140 dB kill hair cells |
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emotional vocalisation |
W18: resp contractions |
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brain plasticity in infancy |
1st 3 months - makes many synapses (1000 million) but temp synapses made in first 3-4 years permanent |
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pruning |
1st 3 years: more myelination than cell death - increases brain size 3 year olds: 2x synapses than adults but down by 10. Experiences shape these circuits. if not used - pruned |
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cortical developmnet 1st year |
rapid. auditory - myelination and synapto visual: M and S started before birth but still low VA corticospinal tract myelinates top to bottom |
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corticoregion maturation (post concep) |
W36 - posterior internal capsule first to mature, then temp and frontal last at W 120 |
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Language acqu |
Grwoth of synapses in Wernicke's area + understanding of lang 18m - increase in words peak at 3 |
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mimicking |
mirror neurons - neurons activated when seening action smae as neurons when making action |
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final maturation |
gray matter loss primary cortical first, then parietla regions(speech and language) at 11-13 association areas at 18+ |
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Alcohol causes damage to |
All stages |
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methylmercury (fish) |
prolif, differentiation (early stages) + synap |
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lead causes |
diff, myelination, synap, aptosis |
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aptosis |
death of cells |
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critical periods |
heating 3-4 years language - until puberty |
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what is reticular nuclei |
collection of structures at core of brainstem + runs through length . Collates info from all tracs and projects to all parts of CNS allows coordiation of systems |
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Cortical activity levels RN |
RAS: aware of internal and external sitmuli and acts as gage projects to thalamus: (reticulothalamus pathway) modulates level of sensory down by thalamus Cortex: modulates electrical activity to influence -level of arousal - sleep/wake cycle -focus attention on specific stimuli + filter bilateral damage: coma |
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Noradrenalin |
sympathetic fight/flight - influences cog functions, mental state, memory nucleus: locus coeruleus in the pons low: silent in sleep high: highest in REM< decreases attention and memory |
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precerebellar nuclei |
nuclei found in pons tegmentum sends info to cerebellum form brainstem about visual, auditory and vestibular recieves infro from cortex and sPc controls many subconsciour motr activity |
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reticulospinal tract |
pons and med modulate motor movements directly and indirectly. COntrols innate muscle tone, adjeustive mentvemnt, coordinates NS movement, posture controls sensitivity of reflexes - does to ventral horn |
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serotonin |
comes from raphe nucleus (along midline) rostral raphe: to higher CNS structures caudal ralph: BS, SpC projections to hypothalamus + cortex for circadian rhythms + sleep patterns modulates pain pahways (caudal --> dorsal horn of spinothalamic) |
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dopamine |
VTA and substantia nigra. supplies to basal ganglia and cortex working memory, pleasure and reward |
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motor functions of RN |
for complex sequences e.g. swallowing breathing CPG - orders neurons to do jobs at specific timing |
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CPG for swallowing |
NTS DSG (near nucleus of solitary tract - recieves info) VLM VSG (near N A) and sends to V VII X XII C1-C3 |
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autonomic and visceral reflexes RN |
range of nuclei in medulla nad pons recieves info from SPc and CN and sends to visceral motor neurons, cardian and resp muscles rostral medulla: acts as CPG for cardio and resp pons: CPG for lungs and breathing patterns |
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Branchial arches 1st, 2nd, 3rd, 4th/6th |
1st: V muscles of mastication 2nd: facial 3rd: IX (pharynx) 4th and 6th - XI X |
