Overview of cranial nerves Flashcards
Which nerve(s) exit at cerebrum?
Optic (I) & Olfactory (II) nerves
Which nerve(s) emerge from midbrain?
Oculomotor (III) nerve
Trochlear (IV) nerve
Which nerve(s) emerge from pons?
Trigeminal Nerve (CN V)
Which nerve(s) emerge from pontomedullary junction?
Abducens nerve (CN VI) Facial nerve (CN VII) Vestibulocochlear nerve (VIII)
Which nerve(s) emerge from medulla?
Glossopharyngeal nerve (CN IX) Vagus nerve (CN X) Hypoglossal nerve (CN XII)
Which nerve(s) emerge mostly from spinal cord?
Accessory Nerve (XI)
The course of motor fibers of cranial nerves
- Originate in the brain
- carry motor signals from brain to structure they innervate
- Efferent fibers
The course of sensory fibers of cranial nerves
- Carry signals in opposite direction from receptors to brain
- Afferent fibers
What are 3 types of motor nuclei
Somatomotor nuclei (or GSE, general somatic efferent))
Branchiomotor or special visceromotor (SVM, SVE) )
General visceromotor (GVM or GVE) / parasympathetic, secretomotor (CN III., VII., IX., X.).)
The role of Somatomotor nuclei (or GSE, general somatic efferent))
- Innervates innervate striated muscles derived from somites (of the eye and tongue).
Describe (Branchiomotor or special visceromotor (SVM, SVE) )
- innervate striated muscles (but these muscles developed from brancial arches): muscles of mastication, facial expression, pharynx and larynx muscles
- The other name is special visceromotor because they innervate the wall of viscera (mouth, nose, larynx, pharynx) but striated muscles [instead of smooth muscles, see the next group] there.
Describe General visceromotor (GVM or GVE) / parasympathetic, secretomotor (CN III., VII., IX., X.).)
They innervate viscera: smooth muscles or glands (e.g. the sphincter muscle of the pupil, salivary glands, glands and smooth muscles of abdominal and thoracic viscera).
What are 4 types of sensory nuclei
GVS: General viscerosensory (or GVA)
SVS: Special viscerosensory (or SVA)
GSS: General somatosensory (or GSA)
SSS: Special somatosensory (or SSA)
The role of GVS: General viscerosensory (or GVA)
They receive afferent fibres input from interoceptors / chemo- and baroreceptors (carotid sinus, carotid body, abdominal and thoracic viscera).
The role of SVS: Special viscerosensory (or SVA)
for taste (an organ of special senses). -> Also relay neurons - they receive afferent inputs from the taste fibres coming from the taste buds (e.g. from the tongue).
Describe the role of GSS: General somatosensory (or GSA)
they receive afferent fibres from somatic (body) receptors: mechano-, noci- or thermoreceptors (from the skin, muscles and joints of the head)
Three different sensory subtypes of GSS: General somatosensory (or GSA)exist
-> They are
- epicritic: fine / discriminative touch and pressure, vibration
- protopathic: vitally important informations:
- pain
- rough (non discriminative, crude) touch - temperature - proprioceptive: the position of the muscles, joints (information from the body of the subject: „proper”=self) – afferent inputs from muscle spindles, tendon organs
describe SSS: Special somatosensory (or SSA)
They receive afferent fibres carrying vestibular and auditory signals (from the ear). They belong to organs of special senses (hearing and balance).
What are the 5 pure motor nerves?
- Oculomotor nerve (III) (+ para)
- Trochlear nerve (IV)
- Abducens nerve (VI)
- Accessory nerve (XI)
- Hypoglossal nerve (XII)
What are the 3 pure sensory nerves?
- Olfactory (I)
- Optic (II)
- Vestibulocochlear nerve (VIII)
What are the 4 mixed nerves?
- Trigeminal nerve (CN V)
- Facial nerve (CN VII) (+ para)
- Glossopharyngeal nerve (IX) (+ para)
- Vagus nerve (X) (+ para)
What are the 4 nerves that carry parasympathetic info.?
- Oculomotor nerve III - Motor/Para.
- Facial nerve VII - Mixed/Para.
- Glossopharyngeal nerve IX - Mixed/Para.
- Vagus nerve X - Mixed/Para.
Name 2 nuclei of oculomotor nerve
Oculomotor nucl.
Accessory oculomotor nucl. (Westphal-Edinger)
The role of Oculomotor nucl.
- Somatic efferent motor nucleus (SM: Somatomotor)
- Innervates the inferior and superior rectus, inferior oblique, medial rectus muscles of the eyebulb and the levator palpebrae superioris muscle.
