Comprehensive Study of the Anatomy of the Brain and Cranial Nerves

cerebrum

two cerebral hemispheres divided into four lobes

gyri

ridges or peaks of the brain

sulci

valleys of the brain

central sulcus

separates frontal and parietal lobes

lateral sulcus

separates temporal lobe from frontal and parietal lobes

precentral gyrus

in frontal lobe; important for motor control

postcentral gyrus

in parietal lobe; important for receiving sensory information

frontal lobe

parietal lobe

occipital lobe

temporal lobe

longitudinal cerebral fissure

separates two cerebral hemispheres; falx cerebri and superior and inferior sinuses run through fissure

diencephalon

includes the epithalamus, thalamus, and hypothalamus; sits on the midbrain and is considered central core of the brain

corpus callosum

connects right and left hemispheres

thalamus

encloses third ventricle; regulates autonomic nervous system

epithalamus

contains pineal gland that controls melatonin

hypothalamus

controls autonomic nervous system and endocrine system

brainstem

consists of midbrain, pons, and medulla oblongata; oldest part and central core of the brain; responsible for automatic survival functions

midbrain

frontal portion of brainstem; associated with CN III and IV

pons

between midbrain and medulla oblongata; part of brainstem; associated with CN V

medulla oblongata

most caudal portion of brainstem; continuous with spinal cord; associated with CN IX, X, and XII

cerebellum

large brain mass posterior to pons and medulla, and inferior to posterior part of cerebrum; checks & balances for cerebrum's

lateral ventricles

largest cavities of ventricular system; opens through interventricular foramen into 3rd ventricle

interventricular foramen

connects lateral ventricles to 3rd ventricle

3rd ventricle

slit-like cavity between left and right halves of diencephalon and continues with cerebral aqueduct to connect with 4th ventricle

cerebral aqueduct

connects 3rd and 4th ventricles

4th ventricle

pyramid-shaped in posterior part of pons and medulla; continues into cervical region of the spinal cord as central canal of spinal cord where CSF travels into subarachnoid space

internal carotid arteries

enters through carotid canal from common carotid; travels through the petrous part of the temporal bone and cavernous sinus to provide anterior blood supply to the brain via the anterior and middle cerebral arteries

petrous part of temporal bone

internal carotid arteries pass through to turn through the cavernous sinus

vertebral arteries

enters through transverse foramina of vertebrae and foramen magnum from common carotid to become the basilar artery

basilar artery

formed from the fusion of two vertebral arteries and later becomes the posterior cerebral arteries to provide posterior blood supply to the brain

anterior cerebral arteries

supply blood to medial and superior surfaces of brain and frontal lobes

middle cerebral arteries

supply blood to lateral surface of the brain and temporal lobes

posterior cerebral arteries

supply blood to inferior surface of brain and occipital lobe

anterior communicating artery

connects anterior cerebral arteries

posterior communicating arteries

connects posterior cerebral arteries to internal carotid arteries

cerebral arterial circle

group of vessels on ventral surface of brain; formed by anterior communicating artery, anterior cerebral arteries, internal carotid arteries, posterior communicating artery, and posterior cerebral arteries

CN I

olfactory nerve

passageway: cribriform foramina of ethmoid bone (to olfactory bulbs)

function: detects sensation of smell

CN II

optic nerve

passageway: optic canal

function: sense sensory information from eyes

CN III

oculomotor nerve

passageway: superior orbital fissure

function: motor nerve that innervates 4 of 6 ocular muscles

CN IV

trochlear nerve

passageway: superior orbital fissure

function: eye movements (ex. rotation)

CN V1

ophthalmic nerve; first of three divisions of trigeminal nerve

passageway: superior orbital fissure

function: touch, temperature, and pain sensations from upper face

CN V2

maxillary nerve; second of three divisions of trigeminal nerve

passageway: foramen rotundum (and infraorbital foramen)

function: touch, temperature, and pain sensations from lower face in maxillary region

CN V3

mandibular nerve; third of three divisions of trigeminal nerve

passageway: foramen ovale

function: touch, temperature, and pain sensations from lower face in mandibular region (and mastication)

CN VI

abducens nerve

passageway: superior orbital fissure

function: allows for lateral eye movement

CN VII

facial nerve; has five branches (temporal, zygomatic, buccal, mandibular, cervical)

passageway: internal acoustic meatus (and stylomastoid foramen)

function: facial expression

CN VIII

vestibulocochlear nerve

passageway: internal acoustic meatus

function: hearing and equilibrium

CN IX

glossopharyngeal nerve

passageway: jugular foramen

function: taste, touch, pressure, pain, and temperature sensations from tongue and swallowing

CN X

vagus nerve

passageway: jugular foramen down to thorax and abdomen

function: taste, hunger, fullness, gastrointestinal discomfort; parasympathetic nervous system

CN XI

accessory nerve

passageway: jugular foramen from cervical spine

function: swallowing, head / neck / shoulder movements

CN XII

hypoglossal nerve

passageway: hypoglossal canal

function: tongue movement

supraorbital nerve

innervates forehead, scalp, eyebrow, and upper eyelid

infraorbital nerve

innervates skin of lower eyelid, side of the nose, upper lip, and mouth

mental nerve

affects innervates skin of lower lip and chin

optic chiasm

point at which optic nerve fibers cross in the brain; in same area as cerebral arterial circle