Cranial Nerves Flashcards
Describe and name functions of CN I.
Name - Olfactory Nerve
Olfaction = sense of smell
Info
- Receptors that detect olfactory stimuli line the superior portion of the nasal cavity
- Their axons enter the skull via the olfactory foramina (cribriform plate of the ethmoid bone) and synapse with neurons in the ipsilateral olfactory bulb
- These neurons relay the signals to the primary olfactory area
Sensory
- Special sensory (smell)
Somatic Motor
- None
Automatic Motor
- None
Describe and name functions of CN II.
Name - Optic Nerve
Info
- At the back of each eyeball, an optic nerve emerges that contain axons carrying signals related to visual stimuli
- Optic nerves meet at the optic chiasma where some axons cross
- Axons continue posteriorly via the optic tracts and synapse with neurons in thalamus
- These neurons relay the signals to the primary visual area
Sensory
- Special sensory (vision)
Somatic Motor
- None
Automatic Motor
- None
Describe and name functions of CN III.
Name - Oculomotor Nerve
Info
- Originates in the midbrain
- Enters the orbit iva the superior orbital fissure (sphenoid bone) and carries motor signals to some of the extrinsic eye muscles
- Carries autonomic (parasympathetic) signals to intrinsic (smooth) eye muscles that constrict the pupil and adjust the shape of the lens
Sensory
- None
Somatic Motor
- Extrinsic eye muscles
Automatic Motor
- Intrinsic eye muscles
Describe and name functions of CN IV.
Name - Trochlear Nerve
Info
- Originates in the midbrain
- Enters the orbit via the superior orbital fissure (sphenoid bone) and carries motor signals to one of the extrinsic eye muscles
Sensory
- None
Somatic Motor
- Extrinsic eye muscles
Automatic Motor
- None
Describe and name functions of CN V.
Name - Trigeminal Nerve
Info
- Emerges front he pons and has 3 branches
1. Ophthalmic (V1) - exits cranial cavity via superior orbital fissure
2. Maxillary (V2) - exits cranial cavity vis foramen rotundum
3. Mandibular (V3) - exits cranial cavity via foramen ovale
- Once outside the skull the branches provide somatic sensory innervation to the face
- V3 also carries motor signals to the muscles of mastication
Sensory
- Somatic sensations from the face
Somatic Motor
- Muscles of mastication
Automatic Motor
- None
Describe and name functions of CN VII.
Name - Facial Nerve
Info
- Emerges from the pons and exits the skull via the internal auditory meatus and stylomastoid foramen (temporal bone)
- Once outside the skull, the nerve splits into branches that…
- Carry motor signals to the muscles of the facial expression
- Carry automatic (parasympathetic) signals to most of the salivary glands
- Contains axons carrying signals related to taste from the anterior portion of the tongue
Sensory
- Special sensory (taste)
Somatic Motor
- Muscles of facial expression
Automatic Motor
- Salivary Glands
Describe and name functions of CN VIII.
Name - Vestibulocochlear Nerve
Vestibular = balance
Cochlear = hearing
Info
- Has 2 branches
1. Vestibular branch - carries signals related to balance from the semicircular canals in the inner ear
2. Cochlear branch - carries signals related to hearing from the cochlea in the inner ear
- The branches merge and pass through the internal auditory meatus (temporal bone) before entering the medulla oblongata
Sensory
- Special sensory (balance)
- Special sensory (hearing)
Somatic Motor
- None
Automatic Motor
- None
Describe and name functions of CN IX
Name - Glossopharyngeal Nerve
Glossus = tongue
Pharynx = throat
Info
- Emerges from the medulla oblongata and exits the skull via the jugular foramen (temporal bone)
- Once outside the skull, the nerve splits into branches that:
- Carry motor signals to one of the muscles of the pharynx
- Carry autonomic (parasympathetic) signals to one of the salivary glands
- Contains axons carrying signals related to taste from the posterior portion of the tongue
- Contains axons carrying signals from receptors in the carotid arteries
Sensory
- Special sensory (taste)
- Visceral sensory (arotids)
Somatic Motor
- Pharynx
Automatic Motor
- Salivary gland
Describe and name functions of CN X
Name - Vagus Nerve
Info
- Emerges from the medulla oblongata and exits the skull via the jugular foramen (temporal bone)
- Once outside the skull, the nerve travels down the neck and into the thoracic cavity, splitting into branches that:
- Carry motor signals to most of the muscles of the pharynx and larynx
- Carry autonomic (parasympathetic) signals to the heart, lungs, and organs of the digestive system
- Contains axons carrying signals from receptors in the arch of the aorta
Sensory
- Visceral sensory (aorta)
Somatic Motor
- Pharynx
- Larynx
Automatic Motor
-Thoracic and abdominal organs
Describe and name functions of CN XI.
Name - Accessory Nerve
*Technically not a “cranial nerve”
Info
- Branches from the C1-C5 spinal nerves merge and enter the skull via foramen magnum (occipital bone)
- The nerve immediately turns around and exits the skull via the jugular foramen (temporal bone)
- Travels down the neck and innervates the trapezius and SCM
Sensory
- None
Somatic Motor
- Trapezius
SCM
Automatic Motor
- None
Describe and name functions of CN XII.
Name - Hypoglossal Nerve
Glossus = tongue
Info
- Emerges from the medulla oblongata and exits the skull via a small canal in the occipital bone
- Once outside the skull, it innervates the tongue muscles
Sensory
- None
Somatic Motor
- Tongue muscles
Automatic Motor
- None
Describe the origin, sensory and motor functions of CN I - Olfactory.
Origin
- Nose
Sensory
- Smell
Motor
- None
Describe the origin, sensory and motor functions of CN II - Optic.
Origin
- Eye
Sensory
- Vision
Motor
- None
Describe the origin, sensory and motor functions of CN III - Oculomotor.
Origin
- Midbrain
Sensory
- None
Motor
S: extrinsic eye muscles
A: intrinsic eye muscles
Describe the origin, sensory and motor functions of CN IV - Trochlear.
Origin
- Midbrain
Sensory
- None
Motor
- Extrinsic eye muscles
Describe the origin, sensory and motor functions of CN V - Trigeminal.
Origin
- Pons
Sensory
- Face (somatic)
Motor
- Muscles of mastication
Describe the origin, sensory and motor functions of CN VI - Abducens.
Origin
- Pons
Sensory
- None
Motor
- Extrinsic eye muscles
Describe the origin, sensory and motor functions of CN VII - Facial.
Origin
- Pons
Sensory
- Taste
Motor
S: tuscles of facial expression
A: salivary glands
Describe the origin, sensory and motor functions of CN VIII - Vestibulocochlear.
Origin
- Inner ear
Sensory
- Balance
- Hearing
Motor
- None
Describe the origin, sensory and motor functions of CN IX - Glossopharyngeal
Origin
- Medulla Oblongata
Sensory
- Taste + carotids (visceral)
Motor
S: pharynx
A: salivary gland
Describe the origin, sensory and motor functions of CN X - Vagus.
Origin
- Medulla Oblongata
Sensory
- Aorta (visceral)
Motor
S: pharynx, larynx
A: thoracic/abdominal organs
Describe the origin, sensory and motor functions of CN XI - Accessory.
Origin
- Spinal cord (C1-C5)
Sensory
- None
Motor
- Trapezius
- SCM
Describe the origin, sensory and motor functions of CN XII - Hypoglossal.
Origin
- Medulla oblongata
Sensory
- None
Motor
- Tongue muscles
Which nerve passes through the optic foramen?
CN II
Which nerve passes through the supraorbital fissure?
CN III, CN IV, CN V, CN VI
Which nerve passes through the foramen ovale?
CN V
Which nerve passes through the olfactory foramen?
CN I
Which nerve passes through the foramen magnum?
medulla oblongata, CN XI, vertebral arteries
Which nerve passes through the carotid foramen?
internal carotid artery
Which nerve passes through the foramen rotundum?
CN V
Which nerve passes through the internal auditory meatus?
CN VII, CN VIII
Which nerve passes through the stylomastoid foramen?
CN VII
Which nerve passes through the jugular foramen
CN IX, CN X, CN XI, internal jugular vein
Which nerve passes through the transverse foramen?
vertebral artery, vein, sympathetic nerves
