Brain and Cranial Nerves

• Brainstem
• Cerebrum
• Cerebellum
• Diencephalon

• The forebrain
• Develops into telencephalon and diencephalon

• The midbrain
• ONLY primary vesicle that does not form a new secondary vesicle

• The Hindbrain
• Develops into metencephalon and Myelencephalon

• Secondary vesicle arises from prosencephalon 
• Forms into cerebrum and lateral ventricles

• Secondary vesicle 
• Turns into pons, cerebellum and 4th ventricle

• Secondary vesicle 
• Turns into medulla and 4th ventricle

• Arises from prosencephalon 
• Extends from brainstem to cerebrum 
• Surrounds third ventricle
• Forms thalamus, hypothalamus, and epithalamus

• Brain and spinal cord 
• Gray matter - Un-myelinated axons
• White matter - Myelinated axons

• Houses: motor neuron and interneuron cell bodies
• Dendrites 
• Telodendria 
• Un-myelinated axons

• Contains myelinated axons arranged in tracts 
• (Association, commissural, projection)

• Cluster of internal gray matter; deep
• Collectively termed Basal ganglia
• Help initiate and terminate body movements
• Suppresses unwanted movements & regulate muscle tone 
• Oval shaped clusters of neuron cell bodies

Cluster of neuron cell bodies within PNS

• Cranium 
• Cranial meninges- C.T. membranes 
• CSF- Cushioning, nutritive fluid
• Blood-brain barrier- Protections against blood borne harmful substances

• Connective tissue layers that seperate soft tissue of brain from bones of cranium
• Pia mater
• Arachnoid Mater
• Dura Mater

• Most external Cranial Meninge
• Two layers: Periosteal(outer); Meningeal (deep)
• Fused, except at dural sinuses - Drain venous blood away from brain
• Forms folds at fissures (dura septa)

• Three extensions of dura separate parts of the brain
• Flax Cerebri
• Flax Cerebelli
• Tentorium Cerebelli

• Type of dura septa 
• Between cerebral hemispheres

• Type of dura septa 
• Between cerebellar hemispheres

• Type of dura septa 
• Between Cerebrum and cerebellum

• Middle meninx
• Deep to subdural space
• Separated from pia mater with arachnoid space
• Fibers called arachnoid trabeculae 
• (Collagen and elastic fibers; attach to pia mater )
• Deep to the trabeculae is the Subarachnoid space 
•  

• A potential space between arachnoid mater and overlying dura mater 
• If filled with blood of fluid - Subdural hematoma 

• Deepest meninx
• Highly vascular areolar C.T.
• Tightly adhered to surface of the brain

• Clear fluid similar to blood plasma 
• Formed by choroid plexus 
• Transportation, buoyancy and protection

Lateral ventricles > Interventricular froamina > third ventricle > cerebral aqueduct > forth ventricle > central canal

• Tight junction between endothelial cells
• Thick, continuous basement membrane

• Press against capillaries 
• Secrete chemicals influencing permeability

• Gases, alcohol, anesthetics
• Glucose (via active transport)

• Two halves
• Joined by corpus collosum
• Divided by longitudinal fissure 
• Contain Gyri(folds) and Sulci(Grooves)
• Asymetric

• Personality 
• Higher thought
• Speech
• Voluntary movement 

Cutaneous sensation

• Vision
• Visual Memories

• Hearing
• Smell

• Interpretation of taste
• Emotional memory

Between gyri in same hemisphere

Between gyri across hemispheres

Between cerebrum and lower brain regions

• Contains:
• Pineal gland- Secretes melatonin
• Nuclei- responses to odors

• Paired oval masses of gray matter 
• Interthalamic adhesion joins lobes 
• Filters out unnecessary incoming sensory information
• Relays sensory information destined for cerebral cortex

• Inferior to thalamus 
• Attached to pituitary by infundibulum 
• Master control of ANS
• Body temp regulation
• Control of food & water intake 
• Emotional control center
• Regulates sleep awake cycle

• Between diencephalon & spinal cord 
• Contains sensory & motor tracts
• Includes: Mensencephalon(midbrain), Pons, medulla oblongata

• Composed of regions of occipital, temporal and parietal lobes 
• Integrates sensory, visual, and auditory information

• Involved in recognizing, understanding and comprehending spoken or written language 
• Must work together with motor speech area

• Nuclei with sensory reflex centers that coordinate movements of head, eyes, and trunk
• Cerebral aqueduct

• Carries sensory & motor info between medulla and midbrain
• Connects midbrain to cerebellum
• Respiratory center

• Centers for respiration, heart rate, blood vessel diameter 
• Vomiting, swallowing, sneezing, coughing, hiccuping 
• Connects spinal cord & brain

• Two hemispheres with central vermis
• Outer cortex or gray matter; deep white matter (arbor vitae)
• Transverse fissure w/tentorium cerebelli separates cerebrum & cerebellum 
• Governs subconscious aspects of skeletal muscle movements 
• Flocculondoular lobes

Contribute to equilibrium and balance

• A thin band separating cerebellar hemispheres
• Receives sensory info reporting torso position and balance

• Superior- Helps visually tract objects and control reflexes such as turning head or body
• Inferior- Control reflective turning to auditory stimuli

• Net like of gray and white matter in brainstem & lower diencephalon
• includes sensory neurons that project into cerebral cortex
• Helps maintain consciousness
• Helps maintain muscle tone 

• Ring of gray metter around upper brainstem and diencephalon
• "Emotional brain" - plays primary role in wide range of emotions
• Contributes to memory 

• 12 pairs 
• Originate from eyes, nose, inner ear, brain stem & spinal cord 

• CN I - Olfactory 
• CN II - Optic 
• CN VIII- Vestibulochlear

• CN III - Oculomotor 
• CN IV- Trochlear 
• CN VI- Abducens 
• CN XI- Accessory 

• CN V- Trigeminal 
• CN VII- Facial 
• CN IX- Glossalpharyngeal 
• CN X - Vagus 

• Oh (olfactoy)
• Once (optic)
• One (Olculomotor)
• Takes (Trochlear)
• The (Trigeminal)
• Anatomy (Abducens)
• Final (Facial)
• Very (Vestibulocohlear)
• Good (Glossalpharyngeal)
• Vacations (Vagus)
• Are (Accessory)
• Heavenly (hypoglossal) 

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