1. CNS Gross Anatomy

2. Spinal Cord Same Meningeal Layers as the Brain About 45cm long
Diameter of 1 cm.
Pia mater
Root filaments
Dorsal
Ventral
Arachnoid mater
Mixed spinal
nerve
Dura mater

3. Spinal Nerve Components
Dorsal Division: sensory part of nerve, sensory information enters spinal cord through dorsal root fibers
Ganglion: cell bodies of these nerves come together to create the dorsal root ganglion
Dorsal Horn or Column: information enters the spinal column at the dorsal horn

4. Spinal Nerve Components
Ventral Division: motor commands, leave the ventral root and go to muscles
Ventral Horn or Column: information passed from brain to spinal cord then from the ventral root to the extremities

5. Transverse view of spinal cord
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6. Segmental Spinal Reflex Arc
A stimulus/response system that maintains a constant state of muscular tone
Works by:
muscles spindles sense stretching and send information through gamma nerves to dorsal root of spinal cord
a signal is sent back from the ventral root for the muscle to contract

7. Spinal Cord Dorsal root fibers form ganglion
Connect to ventral fibers to form peripheral spinal nerves.
Attached by Filum Terminale

8. Internal Spinal Cord Gray Matter Two Dorsal Horns (Sensory Info)
Two Ventral Horns (Motor Info)
White Matter
Three Myelinated Fasciculi
Dorsal, Lateral and Ventral

9. Spinal Cord Segments & Nerves
31 Spinal Segments and Nerves
Cervical 8
Lumbar 5
Coccygeal 1
Thoracic 12
Sacral 5

10. Ventricles Lateral Ventricles Connected by interventricular foramen
Collateral trigone area
Posterior and inferior horns
Connects to Third Ventricle through Monro’s foramen

11. Ventricles
Birds Eye View
Usually symmetrical in healthy people

12. Other ventricles… Third Ventricle Ventral to the corpora quadrigemina
Surrounded by central gray area
Connects to fourth ventricle through Cerebral Aqueduct
Fourth ventricle
Near Pons / Medulla

13. Ventricles

14. Ventricles in clinical setting
Hydrocephalus
E.G. cyst

15. White matter fibers from the cortex

16. Medullary Centers Interhemispheric (between) Connections
Intrahemispheric (within) Connections
Three types of fibers
Projection: Project through internal capsule
Association: Within a hemisphere i.e. Arcuate fasciculus
Commissural: Between hemispheres i.e. Corpus callosum

17. Meninges Three Basic Levels Extensions of Dura mater
Falx Cerebri: Vertical partition dipping into cranial space (Refection)
Tentorium Cerebri: Houses the cerebellum
Falx Cerebelli: Separates two cerebellar hemispheres

18. Meninges Arachnoid Trabeculae Arachnoid Villi
Connects Pia and Arachnoid
Inside subarachnoid space
Arachnoid Villi
Specialized protrusions through which Cerebrospinal Fluid (CSF) leaves the brain

19. Peripheral Nervous System (PNS)
12 pairs of cranial nerves-
Sensory, motor, or mixed
“On Old Olympus Towering Top A Famous Vocal German Viewed Some Hops.”
31 pairs of spinal nerves

20. Cranial Nerves (12 pair) Olfactory: sensory for smell
Optic: sensory for vision
Oculomotor: motor for vision
Trochlear: motor for vision
Trigeminal: sensory to eyes, nose, face and meningies; motor to muscles of mastication and tongue
There are 12 pair but only 7 pair relate to speech and hearing (5, 7-12)

21. Cranial Nerves Abducen: motor to lateral eye muscles
Facial: sensory to tongue and soft palate, motor to muscles of the face and stapes
Vestibulocochlear: sensory for hearing and balance (aka Acoustic)
Glossopharyngeal: sensory to tongue, pharynx, and soft palate; motor to muscles of the the pharynx and stylopharyngeus
Facial:sensory: taste in front 2/3rd tongue; motor: facial expression, tear and salivary glands
Glossopharyngeal: sensory: posterior 1/3rd taste

22. Cranial Nerves
Vagus Nerve: sensory to ear, pharynx, larynx, and viscera; motor to pharynx, larynx, tongue, and smooth muscles of the viscera, 2 parts: superior laryngeal branch and recurrent laryngeal branch
Spinal Accessory Nerve: motor to pharynx, larynx, soft palate and neck
Hypoglossal Nerve: motor to strap muscles of the neck, intrinsic and extrinsic muscles of the tongue
Viscera: soft organs in the body cavities: lungs,kidney, heart
SLN has external (innervates cricothyroid) and internal branches: detects foreign obj. to initiates cough
Vagus: Sensory info pain, touch, temp
RLN: laryngeal muscles except cricothyroid
Accessory: motor: recall motor maintains muscle tone and posture
Hypoglossal: damage to this could cause artic and swallowing probs