Nervous System and Cranial Nerves Flashcards
What are the two main parts of the nervous system?
- Central nervous system = brain and spinal cord
- Peripheral nervous system = cranial nerves and spinal cord branches
What is the difference between Afferent and Efferent fibres?
Afferent fibres carry information TO the CNS
Efferent fibres carry information OUT of the CNS
What are 2 examples of afferent fibres?
- Somatosensory fibres (skeletal muscle)
- Viscerosensory fibres (cardiac muscle, smooth muscle, glands)
What are 2 examples of efferent fibres?
- Somatomotor = commands skeletal muscle
- Visceromotor (Automatic nervous sytem) = commands viscera (parasympathetic and sympathetic)
What are the 5 main features of cranial nerves?
- 12 pairs
- Can contain afferent and efferent fibres
- Impulses from base of the brain
- Leave through openings in the cranial fossa
- Supply head and neck
What are the 2 main features of spinal nerves?
- 31 pairs
- Carry impulses from spinal cord
What are the 8 relevant openings in the cranial fossa (anterior to posterior)?
- Cribiform plate
- Optic canal
- Superior orbital fissure
- Foramen rotundum
- Foramen ovale
- Internal acoustic meatus
- Jugular foramen
- Hypoglossal canal
What is cranial nerve 1?
Olfactory nerve
What are the fibre types, the cranial fossa exit, and the sensory location for the olfactory nerve (CN1)?
Fibre type = special sensory (smell)
Exit = cribiform plate
Sensory location = mucosa of nasal cavity
What is cranial nerve 2?
Optic nerve
What are the fibre types, the cranial fossa exit, and the sensory location for the optic nerve?
Fibre type = Special sensory (sight)
Exit = Optic canal
Sensory location = Retina
What are cranial nerves 3, 4, and 6?
3 = Oculomotor nerve
4 = Trochlear nerve
6 = Abducent nerve
What are the fibre types, the cranial fossa exit, and target location for the oculomotor, trochlear, and abducent nerves?
Fibre types = all 3 have motor fibres, but oculomotor also has parasympathetic fibres
Exit = Superior cranial fossa
Target = Motor fibres to eye muscles, parasympathetic firbes to ciliary msucles and iris
What is cranial nerve 5?
The trigeminal nerve
The trigeminal nerve arises as a short trunk before entering the trigeminal ganglion and viding into three divisions. What are these divisions?
- Opthalmic division
- Maxillary division
- Mandibular division
What are the fiber types, the cranial fossa exit, and the sensory organs of the opthalmic nerve?
Fibre type = sensory
Exit = superior orbital fissure
Sensory organs = orbit, nasal cavity, paranasal sinus, and face
What are the fibre types, the cranial fossa exit, and the sensory organs of the maxillary nerve?
Fibre type = Sensory
Exit = Foramen rotundum
Sensory organs = palate, nasal cavity, maxillary sinus + teeth, pharynx
What is the fibre type, the cranial fossa exit, and the target organs of the mandibular nerve?
Fibre type = Sensory and motor
Exit = Foramen ovale
Sensory organ = mandibular teeth, meninges, face
Motor organ = muscles of mastication
What is cranial nerve 7?
The facial nerve
What are the fibre types and cranial fossa exits for the facial nerve?
Fibre types = sensory, special sensory, motor, and parasympathetic
Exits = Internal acoustic meatus + stylomastoid foramen
The facial nerve targets 4 organs. What are they?
- External ear (sensory)
- Taste ant 2/3 tongue, soft palate (special sensory)
- Muscles of facial expression, neck, and ear (motor)
- Submandibular, sublingual, lacrimal, nasal, and palatine glands (parasympathetic)
The facial nerve forges the facial canal and branches. What are these?
- Greater petrosal nerve
(Parasympathetic = lacrimal, nasal, and palatine + taste = palate) - Facial nerve proper
(Motor = face, Parasympathetic = submandibular + sublingual glands, Taste = 2/3 of tongue via chords tympanic)
The Facial nerve exits via stylomastoid foramen to supply the neck msucles. It enters and divides in parotid gland to 5 facial branches. What are they?
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
What is cranial nerve 8?
The vestibulocochlear nerve
What are the fibre types, the skull exit, and the target organ for the vestibulocochlear nerve?
Fibre type = Special sensory
Exit = Internal acoustic meatus
Target organ = Ear
What is cranial nerve 9?
The glossopharyngeal nerve
What are the fibre types, the cranial fossa exit, and target organs for the glossopharyngeal nerve?
Fibre types = Sensory, special sensory, parasympathetic, and motor
Exit = Jugular foramen
Targets = Post 1/3 tongue, pharynx, nose, palate, middle ear, parotid gland, and stylopharyngeus
What is cranial nerve 10?
The vagus nerve
What are the fibre types, cranial fossa exits, and target organs for the Vagus nerve?
Fibre types = Sensory, parasympathetic, and motor
Exit = Jugular foramen
Targets = Larynx, pharynx, abdomen, thorax, pharyngeal, and laryngeal
What is cranial nerve 11?
The spinal accessory nerve
What is the fibre type, the cranial fossa exit, and the target organ for the spinal accessory nerve?
Fibre types = Motor
Exit = Jugular foramen
Target = Sternocleidomastoid and trapezius
What is cranial nerve 12?
The hypoglossal nerve
What are the fibre types, the cranial fossa exit, and the target organ of the hypoglossal nerve?
Fibre types = Motor
Exit = Hypoglossal canal
Target = Muscles of tongue
What are the 12 cranial nerves?
- Olfactory nerve
- Optic nerve
- Oculomotor
- Trochlear nerve
- Trigeminal nerve (Ophtalmic, Maxillary, Mandibular)
- Abducent nerve
- Facial nerve
- Vestibulocochlear nerve
- Glossopharyngeal nerve
- Vagus nerve
- Spinal accessroy nerve
- Hypoglossal nerve
