L1 & L2 - Cranial nerves Flashcards
Types of neurones
Motor - efferent -> moves externally from CNS to muscles, glands, and other structures
Sensory - afferent -> moves towards CNS, after sensing an external/internal signal
Types of motor neurones
Somatic motor – innervate skeletal muscles (voluntary movement)
Visceral motor (sympathetic - F/F) – innervate smooth/cardiac muscle, glands
Visceral motor (parasympathetic - rest) – innervate smooth/cardiac muscle, glands
Types of sensory neurones
Somatic (general) sensation – detect touch, pain pressure, temperature, chemical stimulation
Special sensation – Olfaction, vision, gustation, equilibrium, audition
Visceral sensation – From viscera from organs (?), e.g. stretch of GI tract
CNS: what is it, what is it composed of, and what does it do?
Central nervous system
Brain and spinal cord
Coordinates and integrates incoming and
outgoing neural signals - E.g. thinking, learning
PNS: what is it, what is it composed of, and what does it do?
Peripheral nervous system - containing only mixed nerves leaving the vertebral column
31 pairs of spinal nerves:
* 8 pairs of cervical nerves
* 12 pairs of thoracic nerves
* 5 pairs of lumbar nerves
* 5 pairs of sacral nerves
* 1 pair of coccygeal nerves
Conduct neural impulses to and from the CNS
Cranial nerves: what are they, how are they named, what types of nerves are they and what do they do?
12 pairs of cranial nerves emerging from the CNS (mostly brain) anteriorly to posteriorly and exit the skull anteriorly to posteriorly
Numbered with Roman numerals from anterior to posterior, I to XII
May be motor, sensory or mixed nerves
Conduct neural impulses to and/or from CNS
The 12 cranial nerves
I - Olfactory
II - Optical
III - Oculomotor
IV - Trochlear
V - Trigeminal
VI - Abducens
VII - Facial
VIII - Vestibulocochlear
IX - Glossopharyngeal
X - Vagus
XI - Spinal accessory
XII - Hypoglossal
Olfactory nerve: what cranial nerve number is it, what is its function, and where does it enter the skull?
I
Conveys special sensory fibres from the nasal epithelium concerning olfaction (smell)
cribriform foramina
Optical nerve: what cranial nerve number is it, what is its function, and where does it enter the skull?
II
conveys special sensory fibres from the retina concerning vision
optic canal
Oculomotor nerve: what cranial nerve number is it, what is its function, what types of muscles does it innervate, what other fibres does it contain, and where does it enter the skull?
III
Uses extraocular/intraocular muscles to move the eyeball from the outside/inside
- Extraocular muscles (sympathetic fibres) include:
- Levator palpebrae superiors (elevates eyelid upper)
- Medial rectus
- Superior rectus
- Inferior rectus
- Inferior oblique
- Intraocular muscles (parasympathetic fibres) include:
- Sphincter pupillae - constrict pupil, stop light waves
- Ciliary muscle - focussing light onto the retina
Proprioceptive fibres from EO muscles (LPS, MR, SR, IR and IO)
superior orbital fissure
Proprioceptive fibres: what are they, what do they do, and where are they found?
Fibres that have a sensory function
Conveys information about muscles/teeth, and is also used as pathways for extraocular muscles (?)
Found with motor-only neurones
Trochlear nerve: what cranial nerve number is it, what is its function, and where does it enter the skull?
IV
Innervates somatic motor fibres - superior oblique muscles (also containing proprioceptive fibres for these muscles as well)
superior orbital fissure
Trigeminal nerve: what cranial nerve number is it, what is its name derived from, what three divisions does it have, where does it arise from, originate from, and exit the skull from, what roots does it have and where do they run from, and what information does it convey?
V - also the largest cranial nerve
Derives its name from Latin - tri (three) + gemini (twins)
V1 - Ophthalmic nerve (sensory only)
V2 - Maxillary nerve (sensory only)
V3- Mandibular nerve (sensory and motor)
It arises between the pons and the middle cerebellar peduncle
The trigeminal nerve originates from the brain stem
Exits the skull through:
* Superior orbital fissure (V1)
* Foramen rotundum (V2)
* Foramen ovale (V3)
Across the middle cranial fossa, V1 and V2 run through the cavernous sinus
- A large sensory root
- A small motor root
Somatic motor fibres to:
* Muscles of mastication
* Mylohyoid
* Tensor tympani
* Tensor veli palatini
* Anterior belly of digastric
General sensory fibres from:
* Face
* Oral, orbital + nasal cavities
* Anterior part of the head
* Most of the dura mater
Proprioceptive fibres from:
* Muscles of mastication
* Mylohyoid, TVP, etc
* Maxillary teeth
* Mandibular teeth
Abducens nerve: what cranial nerve number is it, what information does it convey, and where does it exit the skull?
VI
Somatic motor fibres to:
* Lateral rectus
Proprioceptive fibres from:
* Lateral rectus
Superior orbital fissure
Facial nerve: what cranial nerve number is it, what information does it convey, where does it arise from, and where does it exit the skull?
VII
Somatic motor fibres to:
* Muscles of facial expression
Parasympathetic fibres to:
* Lacrimal gland
* Submandibular gland
* Sublingual gland
Special sensory fibres from:
* Anterior 2/3 of the tongue –gustation (taste)
Proprioceptive fibres from:
* Muscles of facial expression
Arises from the ventral part of the brainstem between the pons and medulla
The main part of the facial nerve (to facial muscles) exits skull through the stylomastoid foramen
