2k. Cranial Nerves - Types of Innervation Flashcards
Motor Innervation of Myotome Muscle
- Neurone Arrangement
Upper motor neurones cell body in the motor cortex.
Synapses in brainstem nuclei III, IV, VI and XII
Lower motor neurone travels in cranial nerves to the myotome in the head/neck
Motor Innervation of Myotome Muscle
- Cranial Nerves
III (oculomotor)
IV (trochlea)
VI (abducens)
XII (hypoglossal)
Motor Innervation of Myotome Muscle
- Myotome 1
Innervated by cranial nerve III (oculomotor)
- Levator palpebrae superioris
- Dorsal rectus
- Ventral rectus
- Medial rectus
- Ventral oblique
Motor Innervation of Myotome Muscle
- Myotome 2
Innervated by cranial nerve IV (trochlear)
- Dorsal oblique
Motor Innervation of Myotome Muscle
- Myotome 3
Innervated by cranial nerve VI (abducens)
- Retractor bulbi
- Lateral rectus
Motor Innervation of Myotome Muscle
- Myotomes 5-8
Innervated by cranial nerve XII (hypoglossal)
- Geniohyoideus
- Sternothyrohyoid complex (myotome 9 C1 contribution)
- Intrinsic tongue muscles
- Genioglossus
- Hyoglossus
- Styloglossus
Motor Innervation of Pharyngeal Arch Derived Muscle
- Cranial Nerves
V (trigeminal) VII (fascial) IX (glossopharyngeal) X (vagus) XI (accessory) with input from cervical nerves 3-5
Motor Innervation of Pharyngeal Arch Derived Muscle
- Neurone Arrangement
Upper motor neurone cell body in the motor cortex
Synapses in brainstem nuclei V, VII, IX, X and XI
Lower motor neurone travels in cranial nerve to the pharyngeal arch-derived muscle in the head/neck
Motor Innervation of Pharyngeal Arch Derived Muscle
- Arch 1
Innervated by cranial nerve V3 (mandibular division of the trigeminal)
- Jaw muscles except caudal digastricus and occipitomandibularis (equine)
- Masseter
- Temporalis
- Medial pterygoid
- Lateral pteygoid
- Rostral belly of digastricus
- Myohyoideus
- Tensor palatini
- Tensor tympani
Motor Innervation of Pharyngeal Arch Derived Muscle
- Arch 2
Innervated by cranial nerve VII (fascial)
- Caudal belly of digastricus
- Occipitomandibularis in horses
- Stylohyoideus
- Superficial muscles of fascial expression
- Orbicularis oculi
- Orbicularis ovis
- Zygomaticus
- Buccinator
- Frontal
- Mentalis
- Levator nasolabialis
- Maxillonasolabialis
- Pre-auricular
- Retro-auricular
- Ventral auricular
- Interscutularis
- Stapedius
Motor Innervation of Pharyngeal Arch Derived Muscle
- Arch 3
Innervated by cranial nerve IX (glossopharyngeal)
- Ceratohyoideus
- Stylopharyngeus
Motor Innervation of Pharyngeal Arch Derived Muscle
- Arch 4-6
Innervated by cranial nerve X (vagus)
- Palatinus
- Levator palitini
- Pharyngeal muscles except stylopharyngeus
- Pterygopharyngeus
- Palatopharyngeus
- Hypopharyngeus
- Thyropharyngeus
- Cricopharyngeus
Recurrent laryngeal branches innervate: - Dorsal cricoarytenoideus (DCA) - Lateral cricoarytenoideus hypoglotticus - Transverse cricoarytenoideus - Thyroarytenoidues (vocalis and vestibularis)
Cranial laryngeal branches inervate:
- Cricoarytenoideus
Motor Innervation of Pharyngeal Arch Derived Muscle
- Arch 7
Innervated by cranial nerve XII (hypoglossal) and cervical nerves 3-5
Dorsal branch innervates:
- Trapezii
- Omotransvasaries
- cleidobrachialis
Ventral branch innervates:
- Cleidomasteideus
- Sternocephalicus
Motor Innervation of Viscera
- Neurone Type
Parasympathetic
Motor Innervation of Viscera
- Cranial Nerves
III (oculomotor)
VII (fascial)
IX (glossopharyngeal)
X (vagus)
Motor Innervation of Viscera
- Neurone Arrangement
Neurone cell body in the brainstem
Synapses in parasympathetic brainstem nuclei III, VII, IX and X
Pre-ganglionic neurone travels to the parasympathetic ganglion.
Post-ganglionic neurone travels to the viscera
Motor Innervation of Viscera
- Cranial Nerve III (Oculomotor)
Long pre-ganglionic fibres run in cranial nerve III (oculomotor) to the eye and synapse with the post-ganglionic neurones, which are called the short ciliary nerves, in the ciliary ganglion.
The short ciliary nerves innervate:
- Iris, causing pupil constriction
- Ciliary body, causing contraction that allows animals to focus on nearby objects
Motor Innervation of Viscera
- Cranial Nerve VII (Fascial)
Cranial nerve VII (fascial) gives off the greater superficial petrosal nerve where pre-ganglionic neurones synapses in the pterygopalatine ganglion.
The post-ganglionic neurones provides parasympathetic innervation to:
- Lacrimal glands
- Nasal glands
- Palatine glands
The cranial nerve VII (fascial) gives off the chorda tympani where pre-ganglionic neurones synapse in the submandibular ganglion
The post-ganglionic neurones provide parasympathetic innervation to:
- Mandibular salivary gland
Motor Innervation of Viscera
- Cranial Nerve IX (Glossopharyngeal)
Cranial nerve IX (glossopharyngeal) gives off the petrosal nerve where pre-ganglionic fibres synapse with the post-ganglionic fibres in the otic ganglion.
The post-ganglionic fibres provide parasympathetic innervation to:
- Parotid salivary gland
- Orbital salivary gland (carnivores)
Motor Innervation of Viscera
- Cranial Nerve X (vagus)
Provides parasympathetic innervation to:
- Laryngeal glands
- Oesphageal glands
- Heart
- Lungs
- GI tract to the midgut:hindgut boundary
Innervation of Special Sense Organs
- Smell Neurone Arrangement
Cranial nerve I (olfactory)
Olfactory epithelium transduces smell into an electrical signal.
Olfactory nerve sends axons through the cribriform plate to the olfactory bulb where it is processed.
Synapses in:
- Olfactory bulb
- Olfactory tubercle
- Piriform cortex
Innervation of Special Sense Organs
- Vision Neurone Arrangement
Cranial nerve II (optic)
Photoreceptors transduce light into an electrical signal.
Bipolar cell
Retinal ganglion cell
Synapses in:
- Lateral geniculate nucleus in thalamus
- Occipital lobe
Innervation of Special Sense Organs
- Taste Cranial Nerve Involvement
Rostral tongue:
Cranial nerve VII (fascial), via the chorda tympani
Palate:
Cranial nerve VII (fascial) via the superficial petrosal nerve
Caudal tongue:
Cranial nerve IX (glossopharyngeal)
Throat:
Cranial nerve X (vagus)
All synapse in the gustatory nucleus of the brainstem
Innervation of Special Sense Organs
- Taste Neurone Arrangement
Rostral tongue:
V3 (mandibular) division of cranial nerve V (trigeminal), via the chorda tympani
Palate:
Cranial nerve V (trigeminal) via the superficial petrosal nerve
Caudal tongue:
Cranial nerve IX (glossopharyngeal)
Throat:
Cranial nerve X (vagus)
Innervation of Special Sense Organs
- Taste Neurone Arrangement
Neurones from cranial nerve VII, IX and X all synapse in the gustatory nucleus.
decussate at the medial lemniscus
Synapse in the caudo-ventral nucleus of the thalamus
Synapse in the sensory cortex
Common Chemical Sense
- Cranial Nerve
Cranial nerve V (trigeminal)
Somatic Sensory Innervation
- Cranial Nerves
III (oculomotor)
IV (trochlea)
V (trigeminal)
VI (abducens)
Somatic Sensory Innervation
- Neurone Arrangement
Sensory information travels in the dendrites of the 1st order sensory neurones, which has its cell body in the trigeminal nuclei of the brainstem.
The axon travels to the trigeminal nuclei of the brain, where it synapses
The 2nd order sensory neurone synapses in the thalamus
The 3rd order sensory neurone synapses in the sensory cortex
Somatic Sensory Innervation
- Importance
Food acquisition
Somatic Sensory Innervation
- Cranial Nerve V (Trigeminal)
- All of face
- Eye surface
- Some ear canal
- Nasal cavities
- Much of mouth
Somatic Sensory Innervation
- Cranial Nerve VII (Fascial)
- Ear canal
Somatic Sensory Innervation
- Cranial Nerve IX (Glossopharyngeal)
- Pharynx
- Caudal 1/3rd of the tongue
- Middle ear
- Carotid sinus
- Carotid body
Sympathetic Innervation
- Neurone Arrangement
Pre-ganglionic cell body in the thoracic spinal segments.
Axon passes through:
- Stellate ganglion
- Ansa subclavia
- Middle cervical ganglion
- Vagosympathetic trunk
- Cranial cervical ganglion
Post-ganglionic neurones are small and run along arteries or nerves
Sympathetic Innervation
- 3 Functions
- Directly antagonises parasympathetic innervation
- Dilates the iris - Indirectly antagonists parasympathetic innervation
- Reduces blood flow to glands to reduce their secretion - Neutral in areas
- No effect on ciliary body
