Neuroanatomy 4: Cranial Nerves Flashcards
Which CN has functions outwith the head?
Vagus nerve
What is a cranial nerve associated with in the brain?
Association with streak of grey matter in the brain/ brainstem with one function
Which direction do most cranial nerves exit the brain? What are the exceptions?
Anteriorly
CN IV - posteriorly
CN VIII - laterally
Soma of sensory nerve cells are found within the CNS. True/ False?
False
In ganglia outside the CNS
Which CN is the only sensory modality that does not synpase in the thalamus before reaching the cortex?
Olfactory nerve
Which CNs have a nuclei of origin close to the midline?
CN III, IV, VI, (XII - closeish)
What is the modality and function of the olfactory nerve?
Sensory
Smell
What is the modalities and functions of the oculomotor nerve?
Somatic motor - levator ps., SR, MR, IR, IO
Parasympathetic - sphincter pupillae ciliary muscle
What is the ciliary ganglion controlled by?
Edinger westphal nucleus
What is the modality and function of the trochlear nerve?
Somatic motor - SO
What is the modality and function of the abducens nerve?
Somatic motor - LR
What is the modality and function of the hypoglossal nerve?
Somatic motor - geniog, hyog, stylog, intrinsic tongie muscles
What are the 3 functions of the trigeminal nerve and the 4 nuclei associated with it?
- Somatosensation of face with oral sparing (discriminative touch, vibration - PONTINE TRIGEMINAL NUCLEUS)
(pain, temperature - SPINAL NUCLEUS) - Proprioception associated chewing (TMJ, muscles of mastication, teeth) - MESENCEPHALIC NUCLEUS
- Motor control (muscles of mastication, tensor tympani, mylohyoid, A belly of digastric, tensor veli palatini) - MOTOR NUCLEUS
What are the trigeminal sensory nuclei?
Mesencephalic nucleus
Pontine trigeminal nucleus (PRINCIPAL)
Spinal nucleus
Where does the trigeminal sensory nucleus start and finish?
Midbrain
Cervical spinal cord
What is the only site in the CNS where cell bodies of primary afferent neurones live inside the CNS?
Mesencephalic nucleus
Why do we get bilateral representation of touch, vibration etc. in the cortex from the trigeminal nerve?
Most fibres of the ventral trigeminothalamic tract cross in the midline but some don’t
What are the 3 functions of the facial nerve and what 3 nuclei are associated with each?
- Motor supply to muscles of facial expression, stapedius - FACIAL MOTOR NUCLEUS
- Parasympathetic to pterygopalatine and submandibular ganglia - SALIVATORY NUCLEUS
- Taste to the A 2/3s of the tongue via chorda tympani - SOLITATORY NUCLEUS
What are the 4 functions of the glossopharyngeal nerve and what 3 nuclei are associated with each?
- Tactile sense, pain, temperature from P tongue and upper pharynx - SPINAL TRIGEMINAL NUCLEUS (small area of ear)
- Taste to P 1/3 of tongue - SOLITATORY NUCLEUS
- PS to otic ganglion (parotid gland) - SALVATORY NUCLEUS
- Motor supply to stylopharyngeus - NUCLEUS AMBIGUUS
What are the 4 functions of the vagus nerve and what 4 nuclei are associated with each?
- Tactile sense, pain, temperature from pharynx to abdomen - SPINAL TRIGEMINAL NUCLEUS
- Taste (epiglottis) - SOLITATORY NUCLEUS
- PS to ganglia serving thoracic and abdominal viscera - DORSAL (MOTOR) NUCLEUS
- Motor to muscles of pharynx and larynx (+ CN XI) - NUCLEUS AMBIGUUS
What CNs are supplied by the solitatory nucleus?
VII, IX, X
What CNs are supplied by the salvatory nucleus?
VII, IX
What CNs are supplied by nucleus ambiguus?
IX, X and cranial part of XI
List the areas of taste attributed to the solitary nucleus on the tongue and their sensory CN supply from front-back
A 2/3 - VII P 1/3 - IX Epiglottis - X Carotid sinus/ body - IX Aortic arch and viscera (pulmonary stretch receptors) - X
What tract provides the motor input to CN V, VII, X, XII
CST
What supplies input to PS efferents of CN III, VII, IX, X?
Hypothalamus directly and via reticular formation
What is reticular formation?
Network of loosely aggravated cells with cell bodies, axons and dendrites in the central core of the brainstem
What are the functions of the reticular formation?
Integrate CN reflexes
Conduct and modulate pain
Voluntary movement
Regulate autonomic activity
Integrate basic functions - respiration, SLEEP
Activate cerebral cortex (component of ARAS)
The spinal accessory nerve arises from…
Cervical spinal cord
Which part of a myelinated axons allows the spread of saltatory conduction?
Node of Ranvier
The afferent limb of the pupillary light reflex is controlled by which cranial nerve?
CNII
The efferent limb of the pupillary light reflex is controlled by which cranial nerve?
CNIII (thrEEE)
Which artery does CNIII travel close too, once exiting the midbrain, and can damage CNIII if there is an aneurysm?
Posterior communicating artery
