Cranial Nerves - Topic 8 Flashcards
What are somatic nerve fibres and what kinds of information do they carry?
General sensory.
* pressure, touch, pain, temperature, body position and movement.
Specialisations at the end of somatic nerve dentrites are called…?
receptors
How many special senses do special sensory nerves carry information about?
5
Special sensory nerves carry information from highly specialised and complex organs dedicated to sensing the special senses. In contrast General sensory nerves carry information from…?
Simple specialisations at the end of the nerve dendrites, called receptors.
How many sensory nerve fibre types do we have? What are they?
3
- Somatic (general) sensory
- Special sensory
- Visceral sensory
What kind of information do visceral sensory nerve fibres carry?
Carry information about deep changes to body tissues and organs, that we are often not even conscious of.
What kind of sensory fibres carry information from the carotid artery about changes in blood pressure?
Visceral sensory fibres
There are two types of motor nerve fibres, based on the level of conscious control we have over them. What are they?
- Voluntary (skeletal muscle) - can be controlled consciously
- Autonomic (cardiac muscle, smooth muscle, glands) - Cannot be controlled consciously - Parasympathetic and Sympathetic subtypes.
What are the two sub-types of autonomic motor nerve fibres?
- Parasympathetic - resting activities - rest and digest
* Sympathetic - during stressful situations ie increase cardiac muscle contraction etc
Many tissues have both sympathetic and parasympathetic nerve fibres controlling increase/decrease in activity. True or false?
True. ie parasympathetic fibres in digestive system increase activity, but sympathetic fibres decrease activity of digestive system during stressful situations.
What is a cluster of nerve cell bodies found outside the CNS called?
Ganglion (pl. ganglia)
What are the ‘relay stations’ in the PNS two neurons meet and communicate?
Ganglion
Where are ganglia found?
In the PNS in relation to sensory pathways (afferent) and autonomic nerve pathways (efferent)
Where are ganglia found in the autonomic nerve pathways?
- sympathetic motor pathways (found near CNS)
* Parasympathetic motor pathways (near target organ)
What important structures pass through the foramen magnum to enter the skull?
- Spinal cord
- Vertebral arteries
- part of CN XI Accessory Nerve
Which smaller foramen is anterior to the Jugular foramen, on the base of the temporal bone?
Carotid canal
Foramen posterior to the carotid canal, on the border of the temporal and occipital bone at the base of the skull?
Jugular foramen
Foramen at the anterio-lateral part of the lateral pterygoid process?
Foramen ovale
Foramen found lateral to the occipital condyles?
Jugular foramen
What exits the skull through the jugular foramen?
- Internal Jugular vein
- CN IX Glossopharyngeal
- CN X Vagus
- PART OF CN XI Accessory Nerve
What passed into the skull via the Carotid Canal?
Internal carotid artery
Which nerve exits the skull through the stylomastoid foramen?
CN VII Facial nerve (after it’s passed through it divides into 5 branches)
Name the oval shaped foramen in the Sphenoid bone.
Foramen ovale
What exits the skull through the foramen ovale?
CN V3 Mandibular branch of the trigeminal nerve.
Foramina on either lateral side of the foramen magnum in the occipital bone.
Hypoglossal canal
What exits the skull via the hypoglossal canal?
CN XII Hypoglossal Nerve
Viewed from the Internal base of the skull, the foramen in the thick, bony (petrous) part of the temporal bone, anterior to the jugular foramen, is….?
the Internal auditory meatus (Internal acoustic meatus)
What passes via the internal auditory meatus?
CN VII Facial Nerve and CN VIII Vestibulocochlear Nerve.
What exits the skull via Foramen Rotundum?
CN V2 Maxillary nerve (branch of trigeminal nerve)
Where is the foramen rotundum?
Just anterior to the foramen ovale, in the sphenoid bone.
What gap in bone does the first branch of the trigeminal nerve CN V1 opthalmic nerve, pass through to reach the eye socket.
Superior orbital fissure (in the sphenoid bone in the posterior eye socket)
What kind of nerve fibres does CN III Occularmotor carry?
Voluntary motor fibres to some eye muscles, and parasympathetic nerve fibres (to muscles controlling pupil dialation)
What kind of fibres does CN I Olfactory Nerve carry?
Special sensory only
What kind of fibres does CN II Optic nerve carry?
Special sensory only
At the base of the brain, CN V Trigeminal nerve is comprised of two parts. What are they?
A large sensory root
A small motor root
What kind of fibres does CN IV Trochlear nerve carry?
Voluntary motor fibres only (supplying several eye muscles)
What are the 3 branches of the sensory component of CN V Trigeminal nerve?
CN V1 Opthalmic (passes through superior orbital fissure in the sphenoid bone)
CN V2 Maxillary (exits skull through foramen rotundum)
CN V3 Mandibular (exits skull through foramen ovale)
What path does the motor root of CN V trigeminal follow?
The voluntary motor fibres run alongside sensory fibres of CN V3 Mandibular nerve and supply movement information to TMJ muscles.
Which muscles does the Trigeminal nerve provide motor supply for?
- Temporalis
- Masseter
- Both Pterygoid muscles
- Anterior Belly of the Digastric muscle
- Mylohyoid
- Tensor veli palatini
- Tensor tympani
Where is the Trigeminal ganglion located?
Just before it splits into 3 branches and emerges through Superior orbital fissure (V1), Foramen rotundum (V2) and foramen ovale (V3)
What does CN VI Abducent (Abducens) nerve do?
Provide motor innervation to only one muscle that helps to move the eye.
Which of the cranial nerves has the longest pathway through the skull?
CN VII Facial Nerve
Which nerve passes into the internal auditory meatus, travelling through the temporal bone?
CN VII Facial Nerve
Which nerve gives off branches that provide parasympathetic fibres to the sublingual and submandibular salivary glands, the tear glands and the mucus glands of the nasal cavity?
CN VII Facial nerve
The branch of CN VII Facial nerve that gives rise to the 5 branches which provide motor innervation to the facial muscles, exits the skull where?
Stylomastoid foramen
What kind of fibres does CN VIII Vestibulocochlear nerve carry?
Special sensory only
Which 2 nerves comprise CN VIII Vestibulocochlear Nerve and what are their functions?
- Vestibular Nerve - Special Sensory Information about our sense of balance.
- Cochear Nerve - Special Sensory carrying information about hearing.
What happens at the vestibular ganglion?
Axons from balance neurons join with the axons from hearing neurons and form the CN VIII Vestibularcochlear nerve carrying information to the brain.
CN VIII enters the skull via which opening?
Internal auditory meatus