Nbde Part 1 Nerve

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Nasopalatine nerve is parasympathetic nerve raise in pterygopalatine ganglion Communication between pterygopalatine fossa and painnasal cavity through sphenopalatine foramen. Pterygopalatine ganglionic recive preganlionic parasympathetic fibers from facial nerve by greater petrosal nerve send postganglionic parasympathtic fiber to glands in lacrimal and palate and the nose Medial pterygoid nerve CN V3 innervate the tensor

The pharyngeal plexus supplies the uvular area and all soft palat muscles except for tensor veli paltini by v3 Diaphagram contracts=inhaling Diaphagram relaxed =exhaling .abdominal muscles contract. Phreneix nerve travels through thorax between pericardium and pleura. Trigemina nerve

Menscephalic neuleus:mediate proprioception (msucle splind) Chief or pontine nucleus:mediate discriminative sensation(light touch) Subnucleus caudaliss:mediate pain and temprature from head and neck. The pain fiber actually synaps in subncleais caudalis. Spinal cord runs from base of skull to two thirds of the back,ends in adult as a constrictor called conus medullaris around L1(L1-L2)

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Dura and archenoid continu to level S2 where archnoid fuses with the filum terminale. Spinal cord has H shaped mass consist of neuronal cell bodies and intermediate zone. Upper motor neurons(UMNs) lies in spinal cord. Lateral ventricle communicate with third ventricule through interaverticular foramen ( foramen of monro) Third ventricule communicate with fourth via cerberal aqueduct(aquaduct of sylvius) Fourth ventricule located dorsal to medulla and pons and ventral to cerberbellum. Single Median aperture(foramen of Magendie) and lateral apertures (foramen of Luschka) provide communication between fourth ventricule and subarachnoid space. CSF produced by choroid plexus and epndymal cell (lining membrane) in the lateral third and fourth ventricles. Absorbation of CSF into bloodstream take place in superior sagittal sinus via archenoid villi. Archenoid vili act as one way valves from CSF to venous not from venous to CSF. Substantia nigra is in the. Midbrain lesion of it cause parkinson disease Cn3 and 4 arise from midbrain Pons houses one of the brain’s respiratory centers, CN V exit from the pons medulla oblongota responsible for coughing ,gagging,swallowing ,vomiting , junction between posn and medulla site of cranial neve VI,VII,VIII,IX,X,XI,XII(6,7,8,9,10,11,12) medulla has also core of gray matter called Reticular formation involved in regulating sleep and arousal and in pain perception and include vital centers regulate breating and heart activity spinal cord ends at about second lumbar vertebra L2 sensory fibers have thier cell body in the dorsal root the white matter suround the gray matter in the spinal cord the oppoiste in the brain spinal nerve (8 cervical ,12 thoracic ,5 lumbar , 5 sacral , and 1 coccygal nerve ) c1 arise between cranium and atlas, C8 arise between 7th cervical and 1st thoracic all other nerves arise below the respective vertebra , sacrum neve arise forme verterbra upper motor neuron forms two major system (the pyramidal and extrapyramidal ) oligodendrocytes =shwann cells in the CNS , there are no shwann cell in CNS neural crest develop into (dorsal root ganglion ,autonomic ganglion ,chromaffin of adrenal medulla , neurolemma cell(shcwann cell) intergumentary pigment cell (melanocytes) and meningeal covering the brain and spina cord) microglial cells=macrophage of CNS neuroglial cells are non ducting supporting cells of nervous tissue example are --( astrocytes attched to the outside of blood vessls in the brain ),ependymal cells that form as sheath that usually lines fluid cavities in the brain . mandibular lingual gingiva is innervated by lingua nerve . chorda tympani join the lingual neve in the infratemporal fossa the hypoglossal nerve after it exit from hypoglossal canal joined by C1 and C2 fibers from cervical plexus . there are 21 or 23 paravertaberal ganglia (3 cervical , 12 thoracic,4 lumbar , 4 sacral and single unpaired lying in front of coccyx called ganglion of impar.

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superior cervical ganglion :largest liest between internal caroitid artery and internal jugular vein middle cervical ganglion : small located at the level of the cricoid cartilage inferior cervical ganglion :occurs at C7 form Stellate gangilion cell bodies of efferent fibers located in intermediolateral cell column cell bodies of afferent fibers located in the dorsal root ganglia occlomotor nerve supplies: medial ,superior,and iferior recti , inferior oblique and levator palpebrae superioris trochlear nerve supplies the superior oblique muscle (move eyball inferiorly and laterally) abducens supplies lateral rectus of the eye. trochlear never is the smalles nerve and the only nerve that exist from the dorsal of the brainstem. Sciatic largest nerve in the body. Glossopharyngeal has branches(lingual branches two in number one to vallate papillae and mucous covering base of the tongue posterior third, and the other supplies follicular gland of posterior third caries secretomotor fibers to this glands) pharyngeal sensory limb of gag reflex,carotid sinus nerve (carotid sinus baroreceptor) carotid body(chemoreceptor). Glossopharyngeal gives secretmotor branch to parotid gland from otic ganglion via auriculotemporal nerve before entring in the ganglion nerve called lesser petrosal nerve. The skin of lower eyelid is suplied by branches of infratrochlear at medial angle ,the rest supplied by infraorbital branch of V2. Sinus attack painful sensation from ethmoid cells caried by nasociliary nerve. Opthalmaic v1 branches are( lacrimal,frontal,nasociliary,supraorbital,supratrochlear,infratrochlear,external nasal nerves) V2 braches(infraorbital,zygomaticofacial,zygomaticotemporsl) V3 branches(mental,buccal,auriculotemporal) Trigrminal nerve has no parasympathetic component but its usded by Cn3 ,cn9,cn7.

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Abdunce nerve lesion cause medial strabismus(cross eyed) and diplopia(double vision),lateral rectus musle responsible for lateral gaze when contracts it abduct the eye(move to lateral not midal like in adduct) $$$$$$ Pulp has C fibers smallest responsible of mechaniy chemical therma stimulation know mediate second pain signal ,A delta fibers medium zize and A beta biggest ,A delta responsible for first pain signal sharp pain, A beta responsible for pressure and touch. Nervr to stapidus muscle is from facial nerve . Trigrminal nerve exits from inferolateral of the pons Motor devsion of cn5 doent entre the ganglion but passes under it to join v3 Nerves innervate branchial arch dervatives are 5,7,9 CnV1 its considred branchimeric it innervates structures derived from paraxial mesoderm found in the frontonasal process of the developing embryo. Phrenic nerve (c3-c5) is the motor nerve to skelatel muscles of the diaphrgam. Cervical pluxes:c1-c4 Brachial plexus:c5-c8 and T1, formed in the posterior triangle of the neck extand to the axia supplying nerve to upper limb had three cords:

Posterior :axillary and radial nerve are main branch Lateral :musculocutaneous is main branch Medial:ulnar is main branch Lumbar plexus:L1-L4 formed in the psoas muscle supplies part of lower limb mais branches are femoral and obturator Sacral plexus:L4-L5 and S1-S4 supplies lower back ,pelvis,thigh,leg and foot mais branhe is SCIATIC largest nerve in the body. Neurotransmitters in somatic always acetylcholine Neurotransmitters in autonomic are either ach or epinephron norepinephrine. Somatic effect on target cells always excitable ,autonomic is either excitable or inhibitory. Vagus nerve branches: Right and leftrecurrent laryngeal innervates all muscles of larynx except cricothyroid which is supplied by external laryngesl branch of superior laryngeal nerve ,mucous membrane below vocal folds , mucous of upper part of the trachea this nerve comes in contect woth thyroid gland and close to inferior thyroid artery vagus gives parasympathetic to heart.

● Vagus has two ganglia :superior lies withing jugular foramen and inferior below jugular foramen ● Superior ganglia branches ● Menengeal supplies dura mater ● Auricular supplies auricle and external auditory meatus.

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● Superior laryngeal has two branches internal laryngeal supplies mucous membranee of larynx above vocal folds and it pierces the thyrhyoid mebrane ● External laryngeal supplies cricothyroid muscle. ● Thoracic ganglia T5-T12 they are all pass through diaphrgam. ● Greater T5-T9 end in celiac ganglion . ● Lesser T10-T11 end in aorticorenal ganglion ● Least end in renal plexus. ● Thoracic nerve specially greater splanchnic nerve is preganlionic viceral efferent . ● Ciliac plexus distribute to smooth muscle and glands in the viscera. ● Tympanic nerve ,cartoid sinus nerve ,pharyngeal ,tonsillar , are branches of glossopharyngeal nerve.

● ● C1 doesnt play any role on dermatomes .deck 186 Nrv S

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From big to small A-alpha,Beta,Delta ,C fibers. All neuroglia drived from ectoderm except microglia from mesoderm . Microglia smallest cell amoung neuroglia. Ependymal cell is columnar no ciliated. Choroidal cell :modifiedd ependymal cells secret CSF neurotransimitter in sympathetic to paravertebra gangli is norepinephrin except on adrenal medulla where it is acetylcholine in sypmathetic preganglioni fibers are short and postganglionic are long in parasympathetic preganglinoic fibers are long and postganlionic are short. parasympathtic is predominant only sympthetic fiber are in medulla and sweat gland ,pilorecetor muscle of skin , and many blood vessels . sympatheic is widespread action , para is more specific. optic disc is the small blind spot on the surface of the retina , contains no photoreceptors ,consist of unmyelinated axons becore myelinated poster to the optic disc acompnied by artery and vien of the retina . the right visual field is interpreted in the left hemispher and vice versa . the optic tract fibers synaps in the lateral geniculate nuclei with geniclocalcarine fibers (optic radiation) that terminate on the banks of the calcarine sulcus in the primary visual cortex(Broadmann’s area 17) of the occipita lobe . central nervous system begins to develp in the latter part of the third week , cells from ectoderm called neuroectoderm localized in th neural plate , neural tube is formed during the fourth week

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● neural crest also develop from neuroectoderm in the third week these cells immegrate and disperse in the mesenchyme they are essential in developing the face ,neck and oral tissues. ● falx cerebri: longitudinal fissure separates the cerberal hemosphers ,contain inferior and superior sagital sinuses. ● tentorium cerbelli: separates cerebrum and cerbellum, contains straight ,transeverse,superior petrosal sinuses. ● falx cerebelli: separates the lobes of the cereberllum, contains occipital sinus. ● drains of sinuses via internal jugular vein ● diaphragma sellae is ring shaped fold of dura mater covering the sella turcica and containing an aperture for passage of the infundibulum of the pituitary gland ● archenoid memebrane is fragil network of collagen and elastin fibers with coweb like appearance, has moderate vascularity. ● pia mater is extremly thin made up of collagen and elastin fibers contains many blood vessels its adheres closly to the brain and spinal cord. ● meningitis can develop to encephaliti(inflammation of the brain ) ● subarchenoid between archenoid and pia mater ● epidural space over the dura mater become real space in presence of pathlogy such accumulation of blood (epidural hematoma) ● subdural closed space with no egress between dura mater and archenoid membrane often the site of hemorrhage after head trauma. ● pia mater and ependymal contribute to the formation of choroid plexuses .

● Nerve physilogy ● Some mechanical stimuli activate mechanically gated sodium channels (stretching,sound waves) ● Inward current is the movement of positive charge into the cell. ● Spinal cord motor lesion is ipsilateral ,sensory lesion is contralateral. ● Cns fibers are not enclosed with neurolemma. ● Some axon of certain unmyelinated nerve fibers are enrwapping by neurilemma. ● Nondepolarizing nerve block is nerve block produced by local anesthetic. ● Action of local anesthetic is at lipoprotein sheath of the nerve. ● Local anesthetic are clinically effective in both axon and nervr ending. ● Small myelinated nerve fibers for pain and temprature affected first followed by touch ,proprioception and skeletal muscle tone.

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● Myelin sheath decreases membrane capacitance and increase memebrane resistance preventing movment of soduim and postassium . ● Distance between nodes of ranvier is 0.2-2mm ● The larger the diameter the faster conduction. ● Spatial summation :two excitatory inputs arrive at postsynaptic neuron simultaneously produce greater depolarization. ● Temporal summation: two excitatory inputs arrive at a postsynaptic neuron in rapid succession there is increase in the frequencey of nerve impulses in single presynaptic fiber. ● Hyperploaryzation prevent action potential by increasing cl flow (GABAa) or increasing K flow out(GABAb).

● ● Striatum refered to only putamen and caudate nucleus. ● Putamen and globus pallidus called lentiform nucleus. ● Dpoamin is inhibitory in the indirect pathway and excitatory in inderect pathway. ● Basal ganglia is located deep in the cerberal cortex. ● The output of cerbellum is excitatory while the basal ganglia is inhibitory. ● Major part of extrapyramidal system are subcortical nuclei (basal ganglia). ● All preganlionic are nicotinic and muscrinic also medulla nicotinic. ● All postganlionic of parasympathetic are muscrinic and some sympathetic ● Heart smooth muscles ,glands are muscrinic. ● All preganlionic are cholinergic ,all postganglionic of parasympathtic are cholinergic.

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● Most of postsynaptic sympathetic neurons are adrenergic(act on adrenergic receptors) except sweat gland and ,piloerector muscles of hairs ,and to a very few blood vessels. ● Interneurons in the ganglia release catecholamines. ● Enteric nervous system includes myenteric plexus for regulates motility and submucosal plexus regulates ion and water transport and secretion. ● Absolute refractory period the memebrane wil not respond to any stimulus ● Relative refractory period a very strong stimulus may elicit a response in the memebrane. ● Electrical synaps are rare in CNS and common in cardiac and smooth muscles using gab junction. ● Beta 1 receptors responsible for heart rate and strength of heartbeat ● Beta 2 responsible for function of smooth muscles. ● Selective beta receptors block beta1 more than beta2. ● Alpha 1 receptors in postynaptic sympathetic:increase smooth muscle contraction. ● Alpha 2 in presynaptic sympathetic: inhibite NE relase and inhibite insuline release. ● Beta 1 : located in the heart ● Beta2: located in the liver,smooth muscles,bronchioles,uterus,increase hepatic glucose output,decrease blood vessel contraction ,bronchioles and uterus. ● Norepinephrine stimulate mainly alpha receptors. ● Epinephrine both alpha and beta. ● Resting potential range (-)40 and (-)80 ● Visceral smooth muscles and cardiac pacemaker cells lack a stable resting memebrane potential. ● PNS includes primary afferent neurons ,sensory receptors,somatic motor neurons ,autonomic neurons. ● In sympathetic Postganlionic neurons are more that preganlionic neurons opposite in parasympathetic ● Sympathetic start from T1-L2 in the lateral horn of spinal cors. ● Horners syndrome: lack of sympathetic tone cause miosis ptosis anhydrosis on affected side ● Excessive PNS activity caried bu vagus nerve can cause vasovagal episode :hypotension, and possible syncope .

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● Acetylcholine is broken down into acetate and choline by acetylcholinestrase(AChE) on the motor plate. ● If AChE inhibited there will be tetanus. ● Ach synthesized in neuron from acetylCoA and choline bymcholin acetyltransferase. ● Connexon hemichannels in gap junction connexon formed by proteins called connexins. ● The pons: CN5,cn7,cn3 ,respirstory/urinary contole ,controle of eye movment,facial sensation/motor control ● Junction of pons and medulla: cn6 ,8. ● Medulla:cardiovascular,respirstory,auditory and vestibular input,cn9,10,11,12 ● Neurons controlling breathing have mu receptors the one heroin bind(opiates) ● Limbic system is deep withing temporal lobe.

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