Anatomy Nervous System Lab

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Anatomy Nervous System Lab
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Divisions of the Nervous System

• Central nervous system brain spinal cord
• Peripheral nervous system cranial nerves
  spinal nerves

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The Brain

• Brain stem
• medulla oblongata (M.O.)
• pons
• midbrain
• Diencephalon
• thalamus
• hypothalamus
• mamillary bodies
• epithalamus (pineal gland)
• Cerebrum
• Cerebellum

Cerebrum
T
P
P
H
midbrain
M
Cerebellum
pons
m.o.
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The Brainstem

• medulla oblongata (M.O.)
• pons
• midbrain
• cerebral peduncle
• cerebral aqueduct of midbrain
• corpora quadrigemina
• superior colliculi
• inferior colliculi

pons
Cerebral peduncle
m.o.
Cerebral aqueduct of midbrain
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The Diencephalon

• thalamus
• hypothalamus
• mamillary bodies
• connects to pituitary gland via infundibulum
• epithalamus (pineal gland)

T
P
H
M
infundibulum
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The Diencephalon
Intermediate mass of Thalamus
Pineal gland
Hypothalamus
Infundibulum
Pituitary gland
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Cerebrum
convolutions
gyrus
sulcus
(separated from cerebrum by transverse fissure)
4 lobes per hemisphere- frontal, parietal,
temporal, occipital
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The Cerebrum
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The Cerebellum

• gray matter folia
• white matter arbor vitae
• separated from cerebrum by transverse fissure
• 2 hemispheres connected by vermis

Transverse fissure
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The Spinal Cord

• Begins at foramen magnum ends at L2 vertebral
  level by forming conus medularis

• Has 2 thickened areas-
• cervical enlargement - supplies nerves to upper
  extremity
• lumbar enlargement - supplies nerves to lower
  extremity

• Made up of 31 spinal cord segments

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Cross Sectional Anatomy of the Spinal cord
segments
Dorsal root
Dorsal root ganglion
Gray commissure
Spinal nerve
Ventral root
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The Spinal Cord Spinal Nerves

• Each spinal cord segment gives off a pair of
  spinal nerves
• each spinal nerve forms from union of
  dorsal/ventral root of spinal cord segment
  exits between vertebra at IVF
• 8 pair cervical spinal nerves 1st cervical
  nerve exits between occipital bone C1, 8th
  cervical nerve exits the IVF between C7-T1
• 12 pair thoracic spinal nerves
• 5 pair lumbar nerves
• 5 pair sacral nerves
• 1 pair coccygeal nerves

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Below the conus medularis, spinal nerves must
angle downward (in the subarachnoid space) before
exiting their IVF. These spinal nerves make up
the cauda equina
Cauda equina
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The Central Nervous System
CNS well protected by bones (cranial
vertebrae), CT meninges, cerebrospinal fluid
(CSF)
Meninges Connective tissues that surround and
protect the brain and spinal cord (CNS)

• 3 layers
• Dura Mater
• Arachnoid
• Pia Mater

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Meninges
Dura Mater tough, fibrous outer layer

• 2 layers thick around brain with creation of
  dural sinuses between layers dural folds into
  fissures of brain

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Dural folds and dural sinuses
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Dural folds and dural sinuses
Superior sagittal sinus
Inferior sagittal sinus
Falx cerebri
Straight sinus
Confluence of sinuses
Transverse sinus
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Meninges- Dura mater

• 1 layer around spinal cord with epidural space
  external

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Meninges
Arachnoid spidery web-like middle layer
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• Pia Mater delicate, thin inner layer
• filum terminale - extension of pia mater extends
  from tip of cord to coccyx to anchor cord in
  place
• denticulate ligaments anchor cord laterally

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Meninges
Subarachnoid space between arachnoid pia
mater contains cerebral spinal fluid (CSF)
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Subarachnoid space (blue space)
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Cerebrospinal Fluid (CSF)

• clear, colorless fluid formed by filtration of
  blood plasma by choroid plexuses within
  ventricles of the brain.

• functions in protection of CNS, support,
  nutrient supply, waste removal

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CSF Circulation
Lateral ventricles (in cerebral hemispheres) ?
interventricular foramen ? third ventricle (in
diencephalon around thalamus) ? cerebral aqueduct
of midbrain ? fourth ventricle (between
pons/cerebellum) ? subarachnoid space central
canal of SC
Lateral ventricle (behind septum pellucidum)
Third ventricle
Aqueduct of midbrain
Fourth ventricle
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Reabsorption of CSF through arachnoid
granulations (arachnoid villi) of dural sinuses
(superior sagittal sinus) ? into cerebral veins
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(space around within thalamus hypothalamus)
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Cranial Nerves

• 12 pairs of nerves that connect to the brain
  provide motor, sensory /or autonomic
  (parasympathetic) function

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Spinal nerves Plexuses
(Intercostal nerves)
(Common peroneal nerve)
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