The Nervous System can be divided in:
Central Nervous System (CNS)Brain and Spinal Cord
Peripheral Nervous System (PNS)Cranial and spinal nerves, ganglia, sensory
receptors
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Division of the Peripheral Nervous System
Sensory or afferentSomaticVisceral
Motor or efferentSomatic - voluntaryVisceral or Autonomic Nervous System
(ANS) - involuntarySympatheticParasympathetic
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Six regions in the adult brainCerebrumDiencephalonMesencephalonPonsCerebellumMedulla oblongata
Brain contains extensive areas of neural cortexLayer of gray matter on the surface of the
cerebellum and cerebrum
Major regions and landmarks
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Surface contains gyri, sulci, fissuresFissures
Longitudinal fissure separates two cerebral hemispheres
Transverse fissure separates cerebellum from cerebrum
The cerebral hemispheres
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The cerebral hemispheres
SulciParieto-occipital sulcus separates parietal
from occipital lobeLateral sulcus separates temporal from
parietal lobeCentral sulcus separates frontal and parietal
lobe
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The cerebral lobes Frontal
Precentral gyrusPrimary motor area – conscious
control of voluntary movements. Premotor cortex – memory bank for
skilled motor activities or of patterned and repetitious nature.
Broca’s areaLocated on the left hemisphere.
Controls speech.
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The cerebral lobesPrefrontal cortex – responsible for
personality, cognition, intellect. Lesion cause mental and personality disorder
ParietalPrimary Somatosensory Area – touch,
pressure, temperature, vibration, and pain from body wall
Somatosensory association area – interprets stimulus sent by the above area. Ex: recognizes objects by touch.
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The cerebral lobesTemporal
Primary Auditory area – temporal lobe. Primary association auditory area – interprets
the sound heard by above areaWernicke’s area – only on left hemisphere,
between parietal and temporal lobes. Area responsible for understanding spoken language
Olfactory area –uncus. Smell area.
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The cerebral lobes
OccipitalPrimary visual area – perception of lightVisual association area – interprets the
images seen on the area aboveInsula
Gustatory cortex
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Cerebral hemispheres - internal structures
Gray matterCell bodies of the neuronsDendrites Small unmyelinated axonsNeuroglias
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Cerebral hemispheres - internal structures
White matterTracts
Association – connects 2 areas of the same hemisphere
Projection – connects upper and lower brain. Ex: internal capsule
Commissure – connects the 2 hemispheres.
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Cerebral hemispheres - internal structures
Corpus callosumConnects the 2 hemispheres
FornixConnects limbic system areas
Septum pellucidumSeparates the 2 lateral ventricles
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Cerebral hemispheres - internal structures
Basal Nuclei – regulation of voluntary motor activities. Allows smooth movements.Caudate NucleusPutamen Globus pallidus
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Diencephalon: external view
Olfactory tractOlfactory bulbOptic nerveChiasma opticPituitary gland or hypophysis Mammilary bodies – relay for olfaction
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The Epithalamus
Roof of the third ventricleContains choroid plexus Contains pineal gland
Regulates sleep-awake cycle
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Relay area for impulses Two large lobes of gray matterInterthalamic adhesion or intermediate mass
The thalamus
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Autonomic center for regulation of body temperature, water balance, etc
Secretes hormonesMammilary bodies – relay station for olfactionPituitary glands – secretes hormonesOptic chiasm
The hypothalamus
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The Brain Stem
MidbrainCerebral Aqueduct – connects third and forth
ventriclesCerebral peduncles – connects pons to
cerebrumCorpora quadrigemina
Superior colliculi – visual reflex centerInferior colliculi – auditory reflex center
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The Brain Stem Pons
Consists of tracts and nucleiConnects brain to lower CNS
• Medulla Oblongata• Tracts• Decussation of the pyramids• Autonomic reflex centers – heart rate, blood
pressure, vomiting, swallowing, respiratory rhythm
• Olives30
Cerebellum
Two hemispheres connected by the vermisArbor vitae – white matterCortex of gray matter
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Dura mater Falx cerebri-formed by dura mater that
dips into the longitudinal fissure and separates the 2 hemispheres
Falx cerebelli – separate the two cerebellar hemispheres
The cranial meninges
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The cranial meninges – dura mater
Superior sagittal Sinus – collects blood from the brain
Tentorium cerebelli – separates the cerebrum from the cerebellum
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The cranial meninges
Arachnoid Subarachnoid space
Filled with CSF Arachnoid villi – projections of the mater
that protrude through the dura For the CSF to drain back to the venous
circulation
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Filled with cerebrospinal fluid (CSF)Lateral ventricles
Septum pellucidumInterventricular foramina or foramen of
Monro
Ventricles of the brain
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CSF cushions delicate neural structuresSupports the brainPathway of CSF
Produced at the Choroid plexusTravels through the apertures on the 4th
ventricle to the subarachnoid space Diffuses across the arachnoid villus
(granulation) into the superior sagittal sinus
Cerebrospinal fluid (CSF)
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12 pairs of cranial nervesTo help to remember“Old Opie Occasionally Tries Trigonometry And
Fells Very Gloomy Vague And Hypoactive”
Cranial Nerves
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Cranial Nerves
Number Name Major FunctionsI Olfactory (sens) SmellII Optic (sens) VisionIII Oculomotor
(mot)Eye movement
IV Trochlear (mot) Eye movement
V Trigeminal (mix) Chewing muscles, head and face sensation
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Cranial nerves
VI Abducens (mot) Eye movement
VII Facial (mix) Face expression, taste
VIII Vestibulocochlear(sen)
Vestibular: posture and balanceCochlear: hearing
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Cranial NervesIX Glossopharingeal
(mix)Swallowing, taste, general sensation for pharynx
X Vagus (mix) Visceral muscle movement and taste sensation
XI Accessory (mot) Swallowing, and head movement
XII Hypoglossal (mot)
Movement of tongue for speaking, swallowing and mixing food
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Brain Dissection
PonsMedulla OblongataCerebellumCranial nerves: I (bulb, tract) II (nerve, chiasma) III
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Brain Dissection
Sagittal CutDiencephalon
EpithalamusThalamusHypothalamus
VentriclesLateral, third, forth
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