The Brain

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The Brain Cranial Nerves
Ch 14
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Development of the neural tube from embryonic
ectoderm
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Embryonic Development
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Brain Development
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Coverings of the Brain- Meninges
skin
skull
dura mater
arachnoid layer
pia mater
cerebral cortex
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• Menenges
• Covers and protects CNS
• Protects blood vessels and encloses venus sinuses
• Contains CSF
• Forms partition within the skull

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Cerebruspinal Fluid
Brain
Ventricles
CSF
Spinal Cord
Rt. Ventricle
Lf. Ventricle
Saggital View
Anterior View
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Ventricles
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• CSF
• 150 ml in adult
• contains glucose, proteins,lactic acid, urea,
  cations, anions, WBC
• Functions
• Reduces wt. of brain by 97
• Prevents head injury
• Supplies brain with nutrition
• Transports hormones along ventricular channels

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The Brain
Parietal Lobe
Frontal Lobe
Temporal Lobe
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Pineal gland
cerebellum
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Cerebrum

• Involved with higher brain functions.
• Processes sensory information.
• Initiates motor functions.
• Integrates information.

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Cerebrum Cross-Section
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Motor, Sensory Association Cortex
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Primary Sensory Cortex
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Primary Motor Cortex
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Right-Left Specialization of the Cerebrum

• left side
• language development
• mathematical learning capabilities
• sequential thought processes
• right side
• visual spatial skills
• musical and artistic activities
• intuitive abilities

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Diencephalon
hypothalamus
thalamus
pituitary
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Diencephalon
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Thalamus

• Relay center for sensory tracts from the spinal
  cord to the cerebrum.
• Contains centers for sensation of pain,
  temperature, and touch.
• Involved with emotions and alerting or arousal
  mechanisms.

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The Reticular Formation
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Hypothalamus
Regulates

• autonomic control center- blood pressure, rate
  and force of heart contraction, center for
  emotional response and behavior
• body temperature
• water balance and thirst
• sleep/wake cycles
• appetite
• sexual arousal
• control of endocrine functioning
• Acts on the pituitary gland through the release
  of neurosecretions.

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Hypothalamus
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The Limbic System
The Limbic System
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Midbrain

• Contains ascending and descending tracts to the
  cerebrum and thalamus.
• Reflex center for eye muscles.
• Also involved with processing visual and auditory
  information (connects head movements with visual
  and auditory stimuli).

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Pons

• Connects the two halves of the cerebellum.
• Regulates breathing.

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Medulla Oblongata

• Composed of nerve tracts to and from the brain
  (these tracts cross over left to right and right
  to left)
• May be regarded as an extension of the spinal
  cord
• Almost all of the cranial nerves arise from this
  region

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Medulla Oblongata

• Contains control centers for many subconscious
  activities
• Respiratory rate
• Heart rate
• Arteriole constriction
• Swallowing
• Hiccupping
• Coughing
• Sneezing

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Cerebellum

• Controls and coordinates muscular activity.
• Important in equilibrium, posture and movement.

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Cranial Nerves

• On Old Olympus Towering Tops A Fat Voracious
  German Viewed A Hop
• Olfactory- smell
• Optic- vision
• Oculomotor- 4 of the 6 extrinsic eye muscles
• Trochlear- extrinsic eye muscles
• Trigeminal- sensory fibers to the face and motor
  fibers to the chewing muscles
• Abducens- controls eye muscles that turn the eye
  laterally
• Facial- facial expression
• Vestibulocochlear- hearing and balance
• Glosopharyngeal- tongue and pharynx
• Vagus- from medulla- acetylcholine slows heart
  breathing
• Accessory- accessory part of vagus nerve
• Hypoglossal- moves muscles under tongue

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Cranial Nerves
Olfactory
Optic
Oculomotor
Trochlear
Trigeminal
Abducens
Facial
Vestibulocochlear
Glossopharyngeal
Vagus
Accessory
Hypoglossal
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Olfactory Nerves I
Olfactory bulb
Olfactory tract
Filaments of olfactory nerve
Olfactory receptor cell
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Optic Nerves II
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Oculomotor Nerves III
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Trochlear Nerves IV
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Trigeminal Nerves V
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Abducens Nerves VI
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Facial Nerves VII
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Vestibulochoclear Nerves VIII
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Glosopharyngeal Nerves IX
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Vagus Nerves X
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Accessory Nerves XI
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Hypoglossal Nerves XII
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Traumatic Brain Injuries

• Concussion
• Contusion
• Subdural or subarachnoid hemorrhage
• Contrecoup injury

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Cerebrovascular Accidents (CVAs)

• Ischemia
• Thrombus
• Embolism
• Arteriosclerosis
• Stroke

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Degenerative brain diseases

• Alzheimers
• Downs
• Parkinsons
• Huntingtons Chorea
• MS
• Epilepsy
• Schizophrenia

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PET Scans
F-Dopa deficiency