Neuroanat

Descending tracts Lateral corticospinal Rubrospinal Lateral reticulospinal Medial reticulospinal Vestibulospinal Tectospinal Anterior corticospinal Pyramidal system Provides voluntary control of skeletal muscles Owes name to pyramidal cells of primary moter cortex Consists of: Descending pathways (UMN) Motor cells in the ant gray horn of SC and motor nuclei of CN are final common pathway for the control of skeletal muscle activity, referred to as LMN Lesions of Corticospinal tract Above level of decussation, manifest contralaterally Ex: stroke involving right motor cerebrum – left-sided paralysis Below level of decussation, manisfest ipsi Ex: spinal cord lesion on right side – right-sided paralysis Char of LMN lesion except: (+) Babinski sign Flaccid paralysis Severe atrophy Muscle fasciculations Paralysis Atrophy Fasciculations Clonus Pathologic reflexes Muscle tone

UMNL Spastic + + Increased

Geniculate ganglion is the sensory neuron of what CN? Trigeminal Facial Vagus Glossopharyngeal Pure sensory: 1,2,8 Pure motor: 3,4,6,11,12 Mixed: 5,7,9,10 Midbrain: 3,4 Pons: 5,6,7,8 Medulla: 9,10,11,12 C Sensory neuron N

LMNL Flaccid + + Decreased

1 2 5

Olfactory cell Rods and cones Semilunar/gasserian/trigeminal ganglion

7 8 9

Geniculate ganglion Spiral ganglion Petrosal ganglion

1 0

Ganglion nodosum

Olfaction/smell Vision Mucous memb of ant 2/3 of tongue; skin of face Taste buds of ant 2/3 of tongue Hearing and equil Mucous memb and taste buds of post 1/3 of tongue Larynx, heart, lungs, GIT

CN 3

Motor neuron Main oculomotor nucleus Edinger Westphal nucleus

4 6 5

Trochlear nucleus Abducens nucleus Motor nucleus of trigeminal Superior salivatory nucleus Nucleus ambigous Inferior salivatory nucleus Nucleus ambiguus Dorsal motor nucleus Spinal accessory nucleus Hypoglossal nucleus

9 10 11 12

Effector EOM Ciliary and sphincter papillae musc Superior oblique Lateral nucleus Muscles of facial expression Lacrimal, submandibular and sublingual gland Musc of deglutition Parotid gland Muscle of phonation Visceral organs and glands SCM, traps Muscles of tongue

General sensation receptors Touch: Meissner’s corpuscle, Merkel’s disc Hair follicle endings, Golgi Mazzoni Pressure: Pacinian corpuscle Pain: free nerve endings Temperature: Krause end bulb (cold), Ruffini’s corpuscle Proprioception: tendon and muscle spindles Organ of Corti is the receptor for: Vision Hearing Equilibrium Olfaction Special sensation receptors Vision: rods (night vision), cones (daylight and color) Gustation: taste buds Olfaction: olfactory cells Hearing: Hair cells of Organ of Corti Equilibrium: utricle and saccule Concerned with regulation of muscle tone is the function of what lobe of cerebellum

Anterior Posterior Floculonodular None Anterior: paleo or spinocerebellum-limbs via spinal connections Maintain coordination of limb movements while movements are being executed; regulation of muscle tone Posterior: neo or cerebrocerebellum-cerebral cortex Flocculonodular: archi or vestibulocerebellum-vestibular apparatus Responsible for coordination of paraxial muscles associated with equilibrium Inability to stop a movement at the proper place is called: Dysmetria Ataxia Dysdiadochokinesia Asynergia Posterior lobe syndrome Ataxia: (loss of coordination of voluntary movements); rate, range and force of movements are abnormal resulting to intentional tremor Dysmetria: __________ when attempting to touch a target Dysdiadochokinesia: inability to perform RAM Flocculonodular lobe syndrome: Truncal ataxia: disturbance of balance manifested chiefly by a lack of coordination of paraxial musc; no control over the axial musckes; attempts to walk on a wide base with the trunk constantly reeling and swaying The 3rd and 4th ventricles communicate through Foramen of Monroe Foramen of Luschka Aqueduct of Sylvius Foramen of Magendie CSF Flow: Lateral vent  intervent foramen or foramen of Monroe  3rd vent  aqueduct of sylvius or iter  4th vent  foramen of Magendie and Luschka  subarach space  arachnoid villi  superior saggital sinus  transverse sinus  sigmoid sinus  int jugular vein CSF is located in what space? Epidural Subdural Subarachnoid Extradural Regulatory center for temp and hormonal balance Epithalamus Thalamus Hypothalamus Subthalamus Diencephalon

Contains functional centers for integration of all information passing from brainstem and SC to the cerebral hemispheres Subdivided into 4: Thalamus, hypo, sub and epi Thalamus Largest division 2 egg-shaped masses bordering 3rd ventr Receives precortical sensory input from all sensory systems except olfactory Plays an important role in sensory and motor system integration Heschl’s gyrus is asso w/: Visual area Auditory area Speech area Sensory area Cerebrum Frontal lobe Motor area; seat of mental activities Parietal lobe Somesthetic area Occipital lobe Visual center Temporal lobe Hearing center Primary somesthetic area: BA 3,1,2 BA 4 BA 41, 42 BA 17 Primary Primary Primary Primary

motor area – precentral gyrus BA 4 somesthetic area – post-central gyrus BA 3,1,2 visual area – BA 17 auditory area – BA 41,42

Failure to carry out learned movements in the absence of sensory loss or motor strength: Ataxia Apraxia Alexia Agnosia Disorders of higher cerebral function: AGNOSIA: failure to recognize stimuli perceived by the senses Visual: failure to recognize objects visually in the absence of defect in VA “receptice disability” Tactile: inability to recognize objects by touch when tactile proprioceptive senses are intact; lesions in Supramarginal gyrus Auditory: failure to recognize what one hears with intact hearing; lesion in BA 22 Apraxia: “motor disability” inability to carry out learned/purposeful movements in response to stimuli that normally elicit them

Artery that supplies visual area: Ant cerebral Mid cerebral Post cerebral Post comm. Ext carotid: Sup thyroid Asc pharyngeal Lingual Facial Occipital Post auricular Superficial temporal Maxillary Int carotid: Subclavian Divide into 3 parts by sc____ant 1st: vertebral, thyrocervical, int thoracic 2nd: costocervical 3rd Ipsilateral arm and leg paralysis: Hemiplegia Monoplegia Paraplegia Quadriplegia A px who shows unsteadiness with eyes closed may show the ff except: Romberg’s Loss of position sense Loss of pain and temp Loss of 2-pt discrimination Charact of Sympa div of ANS: Emerges from thoracolumbar div of CNS Pregangl fibers are longer than postgang fibers Limited branching of pregang fibers (1:1) ALL True re Bells palsy: Absence of lacrimation Inability to open eyelid Loss of sommon sensation ant 2/3 of tongue ALL Musc of facial exp: Zygomaticus: smile Risorius: grin Buccinator: blowing, sucking Mentalis: chin Supplied by facial nerve

Bells palsy: paralysis of musc of facial exp, no sensation on ant 2/3 of tongue, dry mouth, no tears, hyperacussis III: diplopia: eyes turned down and out; dilated and fixed pupil V: facial hemianesthesia, paralysis of musc of mastication; deviation of jaw to weak side; loss of gen sens of ant 2/3 of tongue VII: facial paralysis; loss of corneal/blink reflex; hyperacussis; dry mouth, loss of lacrimation Loss of taste ant 2/3 of tongue IX: dysphagia, loss of taste and common sensation of post tongue X: dysphonia, dyspnea, dysarthria, dysphagia, loss of gag reflex, sagging of palatal arch deviation of uvula XI: meakness in turning head toward opposite side and shrugging shoulder XII: hemiparalysis of tongue; deviation to weak side A tumor in foramen ovale will paralyze: Maxillary of trigeminal Vagus Mandibular of trigeminal Facial Cranial Fossa Anterior Foramina in cribriform plate: 1 Middle Optic canal: 2, ophthalmic art Sup orbital fissure: 3,4,6, opth nerve (5) Foramen rotundum: maxillary n (5) Foramen ovale: mandibular n (5) Posterior Jugular foramen: 9,10,11 Hypoglossal canal: 12 Int acoustic meatus: 7,8 Foramen magnum: medlla, meninges, vertebral art, 11, spinal roots Wernicke’s area BA 22 BA 44,45 BA 41, 42 BA 18,19 Patient knows what he wants to say but speech is slow, deleting many words: Motor aphasia Sensory aphasia Agnosia Agraphia Exxagerated DTR and bilat babinski are indicative of lesion in: AST Dorsal column Corticispinal tract Ant horn of SC