Neurology Flashcards
Peripheral Nervous System
○ Sensory portion: specialized sensory receptors and organs that detect the state of the body or its surroundings
○ Afferent (to brain), efferent (to body/affected organ) nerve fibers that conduct impulses between receptors, sensory organs, CNS and peripheral effectors (skeletal muscle - Motor component)
Central Nervous System
- Brain
- Spinal Cord
- Autonomic NS - PSNS, SNS
General Function of Brain
stores information, generates thoughts
■ reactions in response to sensation
● Signals originate in Motor Nuclei → transmitted through the motor tracts within the CNS → Motor portion of PNS
Parts of the Brain
- Forebrain
- Brainstem
- Grey Matter
- White matter
Forebrain Components
- Telencephalon (cerebrum)
- Diencephalon
Components of Diencephalon
Diencephalon = forebrain
Thalamus, Hypothalamus
Components of Telencephalon
Forebrain
○ 2 hemispheres
○ Rhinencephalon
○ Corpus Callosum
○ Limbic System
○ Hippocampus
○ Ventriculus lateralis (lateral ventricle, ventriculus III (third ventricle)
○ Corpus Amygdaloideum
Components of the Brainstem
- Mesencephalon
- Metencephalon
- Myelencephalon
Mesencephalon
Tegmentum mesencephalic
Brainstem, midbrain
Metencephalon
Ventriculus IV
Pons
Cerebellum
Brainstem, hindbrain
Myelencephalon
Brain, hindbrain
Medulla oblongata
Grey Matter
Neuronal cell bodies
Axons with little myelination
White Matter
Myelinated Axons
Mnemonic for Cranial Nerve Functions (Sensory vs motor vs both)
Some
Say
Marry
Money
But
My
Brother
Says
Big
Brains
Matter
More
CN I
Olfactory = sensory
■ Function: Smell
■ Arises from primary olfactory cortex (temporal lobe)
■ Neurons from olfactory tracts → run to olfactory bulb (above cribriform plate of ethmoid bone)
■ Receives sensory information from nasal cavity’s olfactory neurons
CN II
Optic N = sensory
■ Function: Vision
■ Emerge from eye retinas
■ Pass through optic canal, unite at optic chiasm (partial decussation) → optic nerve fibers from optic tracts → synapse at different nuclei
● Suprachiasmatic nucleus in thalamus (sleep-wake cycle)
● Pretectal nucleus in midbrain (eye reflexes)
● Lateral geniculate nucleus in thalamus (sight)
CN III
Occulomotor N = Motor
■ Function: eye movement
■ Arises from ventral midbrain; runs through superior orbital fissure to eye
■ Splits into superior and inferior branch
● With proprioception - controls pupil constriction (sphincter pupillae), visual focusing (cilliaris) via ciliary ganglion
Superior Branch of CN III
Levator palpebrae superioris ( raises upper eyelid), superior rectus (elevates eye)
Inferior Branch of CN III
inferior oblique (abducts eyeball), medial rectus (adducts eyeball)
CN II synapse at what nuclei?
Suprachiasmatic nucleus in thalamus (sleep-wake cycle)
● Pretectal nucleus in midbrain (eye reflexes)
● Lateral geniculate nucleus in thalamus (sight)
CN IV
Trochlear Nerve (Primary motor, some sensory)
■ Function: eyeball movement
■ Arises from dorsal midbrain, runs around midbrain, follows oculomotor nerve through superior orbital fissure
■ Innervates superior oblique muscles (abducts, depresses, internally rotates eyeball)
CN V
Trigeminal Nerve (sensory, motor)
■ Function: facial movement, chewing, temperature, touch, pain
■ Emerges from pons; travels to trigeminal ganglion
■ Splits into ophthalmic, maxillary and mandibular nerves
Orbital Br CN V
exits through superior orbital fissure, gives sensory innervation to upper eyelid, nose, forehead , scalp
Maxillary Br CN V
Nerve exits through the foramen rotundum, gives sensory innervation to maxilla, nasal cavity, palate, cheeks skin
Mandibular Br CN V
exits through foramen ovale, gives sensory innervation to tongue (NOT taste), lower lip, lower teeth, temporal scalp; Motor innervation to chewing muscles
CN VI
Abducens nerve (motor)
■ Function: eyeball movement
■ Emerges from the pons, runs through superior orbital fissure
■ Innervates lateral rectus muscle (abduct eye)