Exercise 17: Brain and Cranial Nerves Flashcards
Function of the Olfactory Nerve (I)
Smell
Function of the Optic Nerve (II)
Provides vision
Function of the Oculomotor Nerve (III)
Controls muscles that turn the eyeball up, down, and medially
Controls the iris, lens, and upper eyelid
Function of the Trochlear Nerve (IV)
Eye movements
Function of the Trigeminal Nerve (V)
Most important sensory nerve of the face. Touch, temp, and pain sensations from upper (opthalmic) and lower face (maxillary and mandibular); mastication (mandibular)
Function of the Abducens Nerve (VI)
Lateral eye movements
Function of the Facial Nerve (VII)
Motor: facial expressions; secretion of tears, saliva, nasal, and oral mucus
Sensory: taste
Function of the Vestibulocochlear Nerve (VIII)
Hearing and equilibrium
Function of the Glossopharyngeal Nerve (IX)
Motor: swallowing, salivation, gagging
Sensory: taste, feelings of hunger/fullness, control of blood pressure and respiration
Function of the Vagus Nerve (X)
Major role in the control of cardiac, pulmonary, and
digestive functions
Swallowing, speech, regulation of viscera
Function of the Accessory Nerve (XI)
Swallowing; head, neck, and shoulder movements
Function of the Hypoglossal Nerve (XII)
Tongue movements for speech, food manipulation, and swallowing
Which cranial nerves are purely sensory?
Olfactory Nerve (I) Optic Nerve (II) Vestibulocochlear Nerve (VIII)
Which cranial nerves are primarily motor?
Oculomotor Nerve (III) Trochlear Nerve (IV) Abducens Nerve (VI) Accessory Nerve (XI) Hypoglossal Nerve (XII)
Which cranial nerves are mixed?
Trigeminal Nerve (V) Facial Nerve (VII) Glossopharyngeal Nerve (IX) Vagus (X)
Origin and Foramen of the Olfactory Nerve (I)
Origin: Olfactory mucosa in nasal cavity
Foramen: Cribriform foramina of ethmoid bone
Origin and Foramen of the Optic Nerve (II)
Origin: Retina
Foramen: Optic foramen
Origin and Foramen of the Oculomotor Nerve (III)
Origin: Midbrain
Foramen: Superior orbital fissure
Origin and Foramen of the Trochlear Nerve (IV)
Origin: Midbrain
Foramen: Superior orbital fissure
Origin and Foramen of the Trigeminal Nerve (V)
Origin: Face
Foramen: Superior orbital fissure (opthalmic division); foramen rotundum and infraorbital foramen (maxillary division); foramen ovale (mandibular division)
Origin and Foramen of the Abducens Nerve (VI)
Origin: Inferior pons
Foramen: Superior orbital fissure
Origin and Foramen of the Facial Nerve (VII)
Origin: taste buds of anterior 2/3 of tongue (sensory); pons (motor)
Foramen: Internal acoustic meatus and stylomastoid foramen
Origin and Foramen of the Vestibulocochlear Nerve (VIII)
Origin: cochlea, vestibule, and semicircular ducts of inner ear (sensory); pons (motor)
Foramen: Internal acoustic meatus
Origin and Foramen of the Glossopharyngeal Nerve (IX)
Origin: pharynx, middle and outer ear, posterior 1/3 of tongue, internal carotid artery (sensory); medulla oblongata (motor)
Foramen: Jugular foramen
Origin and Foramen of the Vagus Nerve (X)
Origin: thoracic and abdominopelvic viscera, root of tongue, pharynx, larynx, epiglottis, outer ear, dura mater (sensory); medulla oblongata (motor)
Foramen: Jugular foramen
Origin and Foramen of the Accessory Nerve (XI)
Origin: upper spinal cord (C1-C6)
Foramen: Jugular foramen
Origin and Foramen of the Hypoglossal Nerve (XII)
Origin: Medulla oblongata
Foramen: Hypoglossal canal
Meninges
3 connective tissue membranes that cover and protect the brain and spinal cord: the dura mater, arachnoid mater, and pia mater
Dura mater
Outermost meningeal layer; composed of periosteal layer (attached to inner surface of the skull) and meningeal layer (forms the outermost brain covering)
Arachnoid mater
Middle meningeal layer, weblike
Pia mater
Innermost meningeal layer made of delicate connective tissue
Highly vascular
Clings tightly to the brain
Location of the falx cerebri
Fold that dips into the longitudinal fissure, attaches to the crista galli of ethmoid bone
Location of the falx cerebelli
Runs along the vermis of the cerebellum
Location of the tentorium cerebelli
Horizontal dural fold that extends into the transverse fissure, separates the cerebrum from the cerebellum below
State the function of the arachnoid villi.
Permit CSF to be absorbed into venous blood.
They are projections of arachnoid tissue that protrude through dura mater.
State the function of the dural sinuses.
Spaces that collect blood that has circulated through the brain.
How is cerebrospinal fluid formed?
CSF is continually formed by the choroid plexuses, which are small capillary knots hanging from the roof of the ventricles.
How is cerebrospinal fluid circulated and drained in the brain?
CSF flows from lateral ventricles to the third ventricle via the interventricular foramina.
CSF flows from the third ventricle to the fourth ventricle via the cerebral aqueduct.
Most of the CSF circulates in the subarachnoid space and returns to the dural venous sinuses via the arachnoid villi.
Location and function of the primary somatosensory cortex?
Location: postcentral gyrus of the parietal lobe
Function: receives sensory information from sensory receptors and from proprioceptors
Location and function of the primary visual cortex?
Location: occipital lobe
Function: receives visual information from retina
Location and function of the primary auditory cortex?
Location: temporal lobe in the gyrus bordering the lateral sulcus
Function: receives sound information from receptors for hearing in inner ear
Location and function of the olfactory cortex?
Location: medial surface of temporal lobe, in uncus
Function: receives information from olfactory receptors in superior nasal cavity
Location and function of the primary motor cortex?
Location: precentral gyrus of the frontal lobe
Function: conscious control of voluntary movement of skeletal muscles
Location and function of Broca’s area?
Location: base of precentral gyrus of frontal lobe, just above lateral sulcus, in only one hemisphere
Function: controls muscles involved in speech production and plays a role in planning of nonspeech motor functions
