neuro anatomy high yield - fmge

High yield FMGE - Neuroanatomy

Global Institute Of Medical Sciences – www.gims-org.com

NEURO ANATOMY

Schwann cells - Myelin production in cns

Oligodendrocytes - Myelin production in cns

The fastest conduncting fibres are TYPE-A fibres

TYPE-A:-

α – Muscle spindle { Extra fusal muscle fibres }

γ – Intra fusal muscle fibres

δ – Collaterls to Aα

Type-B:-

Supplies preganglionic autonomic fibres and receives information

from skin,viscera,connective tissue .

TYPE-C:-

These are unmyelinated

Sends efferents to post ganglionic autonomic fibres

Jumping of AP from one node to other is Saltatory condunction

Fibrous Astrocytes – Blood Brain Barrier {BBB}

Spinal cord ends at L2 Verterbra

Laminae I – Marginal cell

Laminae II – Substantia gelatinosa of Rolando

Laminae III – Chief – sensory cells

Laminae IV – Clrake’s cells

Laminae IX –Substantia gelatinosa centralis

The occulomotor nerve emergsfrom medial aspect of crus cerebri

The Trochlear nerve emergs from lateral aspect of crus cerebri

A pair of superior and inferior colliculi forms corpora quadrigemina

Telencephalon – Cerebral cortex , Basal ganglia

Diencephalon – Thalamus , Hypothalamus

Mesencephalon – Midbrain , cerebral penduncles

Rhombcephalon – Pons , cerebellum , Medulla

Spinal cord develops from the downward Continuation of Neural Tube

Anterior Spinothalamic Tract – Crude touch sensations , Chief-Sensory cell



Lateral Spincothalamic Tract – Substantia geltinosa , Pain and

Temperature

Renshaw cell –Laminae VII

Laminae -IX – α OR γ Motor neurons

Medulla oblongata –3cm length , 2cm width

Anterior surface of pons is marked in the midline by shallow groove which

contains Basilar Artery

Cerebello pontine angle has Facial Nerve , Vestibulo cochlear Nerve and

Glossopharyngeal Nerve emergs from Medial To Lateral

Spinal nucleus of trigeminus presents on the Lateral aspect of medulla ,

More medially nucleus gracilis and nucleus cuneatus

Medial lemniscus is formed by fibres arising from nucleus gracilis and

nucleus cuneatus

Cerebrum and cerebellum are separated by Tentrioum cerebella

Cerebellar nuclei – Dentate , Emboli form , Globose ,Fastigeal

Dentate is the largest form of cerebellar nuclei

Anterior spinal artery – Anterior 2/3 of spinal cord

Posterior spinal artery – Posterior 1/3 of spinal cord

Greater Anterior segmental medullary artery – Adam Kiewilz

Directly arising from aorta

Major source of blood to lower third of spinal cord

Spinal shock is more common in Lower Third Of Spinal cord

Anterior Longitudinal artery and Intra medullary arteries are end arteries

of spinal cord

Spinal shock is seen Most common in Thoracic and Lumbar Area

Lumbar spinal shock - Most common Abdominal Aortic Aneurysm

Synaptic cleft - 20 - 40 nm Wide

Subconscious Kinesthetic sensations from upperlimb – Cuneocerebellar

Tract

Toxin induced neuronal degeneratiob – Injury to dorsal columns

Lateral spinothalamic and anterior spinothalamic ascends in the form

Of spinal Lemniscus

Dorsal spino cerebellar tract – Clarke’s column



Ventral spino cerebellat tract – Marginal cell

Spino cerebellar tract carries Subconscious kinesthetic sensations

Syringomyeliea – Dorsal Column Injury – Sensory Loss

ARAS – Conscious And Awarness

Upper motor neuron { UMN } – Spastic Paralysis

Lower motor neuron { LMN } - Flaccid Paralysis

Babinski sign positive – UMN Lesions

CSF – 150 Ml

Globus Pallidus + putamen = Lentiform Nucleus

Lentiform Nucleus + Caudate Nucleus = Corpus Striatum

Corpus striatum is important for Intelligence and Longterm Memory

and Development of IQ

Flow of CSF from Lateral 2/3 rd ventricle – Foramen of Monro

CSF from 3rd – 4th ventricle – Aqueduct of sylvius

Area 4 – Primary Motor Area

Area 6 – Pre Motor Area { Association Area }

Area 8– Frontal eye field { Conjugate Movements of eye ball }

Area 9,10,11 – Controls personality and intellect

Area 3,2,1 – Primary sensory area

Damage to somato sensory area causes deficit in fine touch ,position

and vibration sense ( Dorsal columns are more commonly involved )

Area 17,18,19 – Visual Cortex

Area 17 – Primary Visual Area

Area 18 – Visual Association Area

Area 19 – Identification and Analyzing

Area 41 – Primary Auditory Area

Area 42 – Auditory Association Area

Area 22 – Wernicke’s Area

Area 44,45 – Broca’s Area

The posterior limb of internal capsule contains Cortico spinal tract

Blood supply of internal capsule – Middle cerebral artery

Specific Gravity of CSF – 1.005

Concentration of Nacl is high in CSF when compared to plasma



Production of CSF – 0.3 ml / min

Thalamus is supplied by Posterior cerebral Artery (75%) , Middle

Cerebral Artery (25%)

Thalamus - Striate Vein - Venous Drianage of thalamus

Lateral Hypothalamic Area considered as feeding ccentre

Hypoglossal nucleus – Innervates Styloglossus and Genioglossus

Arterial Supply Of Medulla

Anterior spinal artery – Branch of veretebral artery

Posterior spinal artery – Branch of veretebral artery

Posterior inferior cerebellar artery –Branch of verterbral artery

Substantia Nigra :-

Dorsal part – Pars Compacta

Ventral part –Pars Reticularis

Pars Compacta contains Dopaminergic and Cholinergic Neurons

Pars Reticularis contains Dopaminergic Neurons

Trochlear Nerve is the only cranial nerve arises from Dorsal aspect of

brain { Posteriorly }

Lesion in red nucleus causes Benedict’s syndrome

Paranaud’s syndrome – Tumor at superior collicular which

compresses pineal body

Blood supply of pons – Superior Cerebellar Artery , Posterior –

Inferior Cerebellar Artery

Archicerebellum – Lingula + Floculla

Function : Equilibrium – Tone and Posture of trunk muscles

Paleo cerebellum – Tone and Posture of Anti gravity muscles

Neopallial cortex – Skilled Movements

Climbing Fibers , Mossy Fibers , Granular Fibers – { Excitatory

Neurotransmitters are Aspartate , Glutamate }

Purkinjie cell – Neurotransmitter – GABA

BBB is absent in Posterior Pituitary , Median Eminence , Pineal

Gland

Putamen – Anterior Cerebral Artery

Anterior Chorodial Artery – Optic Tract , Optic Chiasma



Globus pallidus – Straite Arteries – Branch of middle cerebral artery

Tail of caudate nucleus and amygdaloid body are perforating

branches of middle cerebral artery

Lesions in corpus striatum – Parkinsonism

The cranial nerve which does not have parasympathetic component

–Abducens Nerve

neuro anatomy high yield - fmge

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