Neuroanatomy 1

Neuroanatomy 1

1. Learning Objectives:

   • Major brain regions and spinal cord - clinically important points highlighted
   • Meninges, CSF production, drainage sites and collection, ANS, basic spinal cord and spinal nerves - dorsal and ventral roots, root ganglia and rami - NEED TO REMEMEBER
   • Understand fundamental concepts of neuroanatomy
   • Appreciate three brain regions and embryological origins
   • Appreciate structure and function of major brain features

2. Fundamental Concepts

   • The neurone
   • Basic organisation of nervous connections
   • Divisions of nervous system - functional terms
   • White and grey matter - fasiculi (tracts) and nuclei, ganglia

3. The Neurone

   • neurones born with till you die!
   • CR: hypomyeliation, demylination - some breeds of dog
     • signs - whole body tremor

4. Classification of Nerves

   • General: widely distributed
     • General somatic afferent (touch, temp, pain from non-visceral structures)
     • General somatic efferent (motor to skeletal muscle)
     • General visceral afferent (distension, temp, pain from viscera)
     • General visceral efferent (motor to viscera, smooth muscles and glands)
   • Special : tissues are restricted in location
     • Special somatic afferent - vision, hearing, balance
     • Special visceral afferent: taste and olfaction
     • Special visceral efferent: muscles of branchial arches (gills)

5. Grey vs White matter

   • Grey matter - NEURONE CELL BODIES
     • Nuclei: aggregations of neurone cell bodies in brain
     • Ganglia: aggregations of nerve cell bodies in PNS
   • White matter - MYELINATED NEURONE AXONS
     • Funiculi/colummns: white matter in the spinal columns, consiting of fasciculi
     • Fasciculi/tracts: axons of the same origin, destination and function

6. 3 brain regions and their embryological origin

   • overview of CNS development
     • CNS DEVELOPED FROM ECTODERM
   • Brain vesicles and adult derivatives of these
     • Neural Tube - 3 vesicles, Prosencephalon, Mesencephalon, Rhombencephalon
       • Forebrain, Midbrain, Hindbrain respectively, caudal end becomes spinal cord..
   • CR: Failure of the neural tube to close. Rostrally = ANENCEPHALY. Caudally = SPINA BIFIDA (Dermoid Sinus) - Rhodesian Ridgebacks

7. Subdivisions and adult derivatives

   • FOREBRAIN/PROSENCEPHALON
     • Telencephalon
       • cerebral hemisphere and basal nuclei; lumen: lateral ventricle
         • cerebral cortex, hippocampus, lateral ventricle, basal nuclei - caudate nucleus and more
     • Diencephalon
       • Thalamus and hypothalamus; lumen: third ventricle
         • Thalamus, third ventricle, interthalamic adhesion, hypothalamus
   • MESENCEPHALON/MIDBRAIN
     • Tectum (roof)
     • Tegmentum (floor)
     • Lumen: midbrain/cerebral aqueduct
     • Midbrain tumours can block the flow of CSF leading to hydrocephalus
   • HINDBRAIN/RHOMBENCEPHALON
     • Metencephalon
       • pons, cerebellum
     • Myelencephalon
       • medulla oblongata
     • Lumen
       • Fourth ventricle

8. CEREBELLUM

   • Latin - little brain
   • Ratio of cereberum to cerebellum smaller in animals with complicated gait cycle
     • Dog - 8:1 Horse - 7:1 Man - 9:1
   • Regulates movement
   • Cerebellar disorders result in ataxia (incoordination) motor, sensory and vestibular signs