Brain

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Brain

• Prosencephalon embryonic forebrain
• Telencephalon
• Rhinencephalon
• Olfactory bulbs
• Olfactory tract
• Olfactory lobe

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Key Points

• Identify the meaning of rhin- and olfactory.

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Brain - Prosencephalon

• Telencephalon
• Cerebral hemispheres
• Paleostriatum primary region in fish, primarily
  involved with olfactory reflexes
• Neostriatum beginning with reptiles, more
  complex and paleostriatum becomes buried
• Hyperstriatum primarily in birds responsible
  for stereotypical behavior such as migration,
  courting, nesting

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Brain - Prosencephalon

• Telencephalon
• Cerebral hemispheres Cerebrum
• Corpus striatum Basal nuclei remnants of
  paleostriatum buried in mammalian brain,
  responsible for stereotyped repetitive
  movements
• Cortex starting with reptiles, billions of
  neurons that must be folded to fit in skull in
  mammals

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Cerebral Cortex

• Voluntary movement (motor)
• Conscious sensations (sensory)
• Memory
• Integration (decisions)
• 4 lobes according to skull bones

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Brain - Prosencephalon

• Telencephalon
• Lateral Ventricles
• Cavities in brain that contain
• Cerebrospinal fluid (CSF)
• Formed from blood vessels called choroid plexus
• Circulates around CNS providing cushion,
  protection, nutrients

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Cerebrum Comparisons
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Brain - Prosencephalon

• Diencephalon
• Epithalamus - Pineal body is light receptor in
  agnathans endocrine in gnathostomes
• Thalamus intermediate mass/adhesion sensory
  relay
• Hypothalamus optic chiasma, infundubular stalk
  for pituitary gland functions as endocrine,
  regulates ANS, emotions, water balance,
  thermostat, hunger, satiety

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Diencephalon

• Third Ventricle carries CSF
• Enters from Lateral ventricle via the
  interventricular foramen
• Exits to Fourth ventricle via the cerebral
  aqueduct

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Brain

• Mesencephalon embryonic midbrain, but term used
  in adult too
• Optic lobes especially well developed in birds
• Auditory lobes auditory reflexes
• Corpora Quadrigemina
• Cerebral Peduncles motor tracts
• Cerebral Aqueduct for CSF gtamphibians

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Key Points

• What does the term corpora quadrigemina mean?
• What structures are included in the corpora
  quadrigemina that you learned in lab?

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Brain

• Rhombencephalon Embryonic hindbrain
• Myelencephalon
• Medulla oblongata
• Pyramids crossing of sensory motor tracts
• Vital reflexes such as breathing, connection
  between brain spinal cord for ascending
  descending pathways

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Brain - Rhombencephalon

• Metencephalon
• Cerebellum Coordination balance, quite large
  in birds mammals
• Pons bridge between parts of brain
• Fourth Ventricle carries CSF

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Key Points

• What is the root enceph?
• Pro? Tel? Di? Mes? Met? Myel? Rhomb?

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Cranial Nerves See Cr. N. Page

• I. Olfactory Nerve Sensory only for smell
• II. Optic Nerve Sensory only for vision
• III. Oculomotor Nerve Motor to intrinsic
  extrinsic eye muscles

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Cranial Nerves

• IV. Trochlear Nerve motor to extrinsic eye
  muscles
• V. Trigeminal nerve mixed nerve, motor to
  mastication pharyngeal arch muscles, sensory to
  nose mouth
• VI. Abducens nerve motor to extrinsic eye
  muscles

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Cranial Nerves

• VII. Facial Nerve motor to facial muscles,
  salivation, lacrimation, taste
• VIII. Acoustic Vestibulocochlear Nerve
  sensory only for hearing equilibrium
• IX. Glossopharangeal Nerve Motor for
  swallowing, taste

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Cranial Nerves

• X. Vagus Nerve Sensory for taste, motor to
  visceral of thorax abdomen for the
  Parasympathetic Nervous System
• XI. Accessory Nerve amniotes only Motor for
  swallowing, head movement
• XII. Hypoglossal Nerve Amniotes only, motor
  for tongue

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Key Points

• Which cranial nerves are sensory only?
• Which cranial nerve is the most important for
  internal homeostasis?
• Which cranial nerves are missing in the shark?

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Key Points

• Name the three parts of the embryonic brain.
• Match these terms with the three parts listed
  above
• Hypothalamus
• Pons
• Cerebral peduncle
• Cerebellum
• Cerebrum

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Key Points

• Name the 12 cranial nerves in order.