1. Central Nervous System Review

2. Dendrites Axon Body/Soma Synapse
NEURON
Neuron Parts 
1. Which structure receives messages?
2. Which structure sends messages?
3. Which structure contains the nucleus?
4. What location of the neuron will contain the released neurotransmitters?
Dendrites
Axon
Body/Soma
Synapse
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4. The Central Nervous System
The brain and spinal cord
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5. The Spinal Cord Conus medullaris Filum terminale Cauda equina 8 12 A B
The inferior end of the spinal cord
Filum terminale
Long filament of connective tissue
Attaches to the coccyx inferiorly
Cervical and lumbar enlargements
Where nerves for upper and lower limbs arise
Cauda equina
Collection of spinal nerve roots 8 12 A B 5 C 5
Coccyx =1
Figure 13.2a
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6. The Spinal Cord Two deep grooves run the length of the cord
Protected by vertebrae, meninges, and CSF
Meninges
Dura mater – a single layer surrounding spinal cord
Arachnoid mater – lies deep to the dura mater
Pia mater – innermost layer
Denticulate ligaments – lateral extensions of pia mater
Two deep grooves run the length of the cord
Posterior median sulcus
Anterior median fissure A B C
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7. Gray and White Matter of the Spinal Cord
Gray matter
Shaped like the letter “H”
Gray commissure – contains the central canal
Dorsal horns
Consist of interneurons
Ventral and lateral horns
Contain cell bodies of motor neurons
White matter
- Outer region of the spinal cord
- Composed of myelinated and unmyelinated axons
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8. Anatomy of the Spinal Cord
Gray matter
Gray commissure
Ventral horn
Lateral horn
Dorsal horn A B C D
Figure 13.4b
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9. Gray Matter of the Spinal Cord and Spinal Roots
Divided according to somatic and visceral regions
SS – somatic sensory
VS – visceral sensory
VM – visceral motor
SM – somatic motor
Figure 13.5
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10. Embryonic Development of the Brain
Primary brain vesicles (4-week old embryo)
Prosencephalon – forebrain
Mesencephalon – midbrain
Rhombencephalon – hindbrain
Secondary brain vesicles
Prosencephalon
telencephalon and diencephalon
Mesencephalon – remains undivided
Rhombencephalon
Divides into metencephalon and myelencephalon
Adult
Telencephalon cerebral hemispheres
Diencephalon thalamus, hypothalamus, and epithalamus
Mesencephalon midbrain
Metencephalon pons and cerebellum
Myelencephalon medulla oblongata
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11. Embryonic Development of the Brain
Divided into four regions
Cerebral hemispheres
Diencephalon
Brain stem
Midbrain, pons, and medulla
Cerebellum
Figure 13.7a–e
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12. Basic Parts and Organization of the Brain
Figure 13.9
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13. Basic Parts and Organization of the Brain
Centrally located gray matter
Externally located white matter
Additional layer of gray matter external to white matter
Due to groups of neurons migrating externally
Cortex – outer layer of gray matter
Located in cerebrum and cerebellum
Figure 13.10
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14. Ventricles of the Brain
Lateral ventricles – located in cerebral hemispheres
Horseshoe-shaped from bending of the cerebral hemispheres
Third ventricle – lies in diencephalon
Connected with lateral ventricles by interventricular foramen
Cerebral aqueduct – connects 3rd and 4th ventricles
Fourth ventricle – lies in hindbrain
Connects to the central canal of the spinal cord A A D D C C B B
Figure 13.11a, b
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15. The Brain Stem Includes the Midbrain Pons Medulla oblongata
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16. Several general functions
The Brain Stem
Several general functions
Produces automatic behaviors necessary for survival
Passageway for all fiber tracts running between the cerebrum and spinal cord
Heavily involved with the innervation of the face and head
10 of the 12 pairs of cranial nerves attach to it
Which CN do NOT attach to brain stem?
CN I – Olfactory
CN II - Optic
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17. Ventral View of the Brain
IDENTIFY:
Olfactory bulb
Optic nerve
Optic tract
Optic chiasma
Mamillary body
Midbrain
Pons
Medulla oblongata
Spinal cord G F E D C B A
Figure 13.12
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18. The Brain Stem – Medulla Oblongata
Is continuous with the spinal cord
1)Choroid plexus lies in the roof of the fourth ventricle
2)External landmarks of medulla
=Pyramids of the medulla (Lie on its ventral surface)
=Decussation of the pyramids (Crossing over of motor tracts)
Figure 13.13a
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19. The Brain Stem – Medulla Oblongata
2)External landmarks of medulla
=Inferior cerebellar peduncles (Fiber tracts connecting medulla and cerebellum)
=Olive (olive of the medulla; Contains inferior olivary nucleus)
=Cranial nerves VIII–XII attach to the medulla
*VIII – Vestibulocochlear
*IX – Glossopharyngeal nerve
*X – Vagus nerve
*XI – Accessory (Spinal Accessory – a branch of the vagus nerve)
*XII – Hypoglossal nerve
Where is CN III – VII located?
CN V, VI, VII at the PONS
CN III, IV at the MIDBRAIN
Figure 13.13b
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20. Several general functions
The Brain Stem
Several general functions
Produces automatic behaviors necessary for survival
Mid-brain & Pons
CN III, IV, VI – Eye movement and pupillary reflex
CN V, VII – Innervation of the face and head
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21. The Brain Stem – The Medulla Oblongata
The core of the medulla contains
Much of the reticular formation (influence autonomic functions)
Visceral centers of the reticular formation include
Cardiac center
Vasomotor center
The medullary respiratory center
Centers for hiccupping, sneezing, swallowing, and coughing
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22. The Brain Stem – The Pons
A “bridge” between the midbrain and medulla oblongata
Pons contains the nuclei of cranial nerves
V – Trigeminal nerve
VI – Abducens nerve
VII – Facial nerve
The pons contains
Motor tracts coming from the cerebral cortex
Pontine nuclei
Connect portions of the cerebral cortex and cerebellum
Send axons to cerebellum through the middle cerebellar peduncles
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23. The Brain Stem – The Midbrain
Lies between the diencephalon and the pons
Cerebral peduncles located on the ventral surface of the brain
Figure 13.13a
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24. The Brain Stem – The Midbrain
Superior cerebellar peduncles
Connect midbrain to the cerebellum
Figure 13.13b
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25. The Brain Stem – The Midbrain
Periaqueductal gray matter surrounds the cerebral aqueduct
Involved in two related functions
Fright-and-flight reaction
Mediates response to visceral pain
Cerebral aqueduct
The central cavity of the midbrain
Figure 13.21
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26. The Brain Stem – The Midbrain (Dorsal View)
Corpora quadrigemina
The largest nuclei
Divided into the superior and inferior colliculi
Superior colliculi – nuclei that act in visual reflexes
Inferior colliculi – nuclei that act in reflexive response to sound
Figure 13.13c
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27. The Brain Stem – The Midbrain
Imbedded in the white matter of the midbrain
Two pigmented nuclei
Substantia nigra – neuronal cell bodies contain melanin
Red nucleus – lies deep to the substantia nigra
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28. The Diencephalon Composed of:
1) Thalamus – process and relay information to the cerebral cortex
2) Hypothalamus – visceral control system
3) Epithalamus (pineal gland) – secretes melatonin (induces sleep)
Figure 13.13c
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29. The Cerebellum C B A Located dorsal to the pons and medulla
Smoothes and coordinates body movements
Helps maintain equilibrium C B A
Consists of two cerebellar hemispheres
Surface folded into ridges called folia
Separated by fissures
Hemispheres each subdivided into
Anterior lobe
Posterior lobe
Flocculonodular lobe (tiny)
Figure 13.15a
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30. The Cerebellum Composed of three regions
Cerebellar Cortex – gray matter
Arbor vitae
Internal white matter
Deep cerebellar nuclei – deeply situated gray matter
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31. Cerebral Hemispheres HEMISPHERES • Left side: words and logic
• Right side: art, music, intuition
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32. BASIC ORGANIZATION OF THE BRAIN
The Cerebral Hemisphere
Sulci- or grooves. Some sulci are used to divide
Gyri- twisted ridges between the sulci in the brain tissue
Fissures- deep sulci
a) Median Longitudinal Fissure- separate the right and left cerebral hemisphere
b) Transverse cerebral fissure- separates the cerebrum from the cerebellum
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33. Frontal lobe Parietal lobe Occipital lobe Temporal lobe
LOBES OF THE BRAIN
5 MAJOR LOBES:
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
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34. Cerebral Lobes
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35. SULCUS LANDMARK
Some sulci are used to divide each cerebral hemisphere into 5 major lobes:
Central sulcus- separates F from P
a) Precentral gyrus
b) Postcentral gyrus
2. Parieto-occipital sulcus- separates the P from O
3. Lateral sulcus- separates the T from F&P
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36. White matter- composed of myelinated axons
Gray matter- composed of neuronal cell bodies, dendrites and short unmyelinated axons.
White matter- composed of myelinated axons
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37. Protection of the brain: 1) Dura Mater 2) Arachnoid 3) Pia
MENINGES
Protection of the brain:
1) Dura Mater
2) Arachnoid
3) Pia A B C
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38. END
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