Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neuro > Cranial Nerves > Flashcards

Cranial Nerves Flashcards

1
Q

Describe upper motor neuron

A

Usually located in the cerebral cortex
Axons project to owner motor neurons in brain stem and spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe location of lower motor neurons

A

Usually located in brain stem or spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Damage to upper motor neuron results in..

A

Paresis or paralysis
Spastic paralysis
Exaggerated tendon reflexes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Damage to lower motor neuron results in…

A

Paresis or paralysis
Flaccid paralysis
Loss of tendon reflexes
Rapid muscle atrophy of affected muscles
Fasciculation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe 1st to 3rd order neuron

A

1st - arise in cerebral cortex
2nd - internuncial, grey column of SC
3rd - lower MN in ant. Grey column

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the corticobulbar tract

A

Arises mainly in the lateral aspect of the primary motor cortex
• Synapse with cranial nerve nuclei. Most innervate cranial nerve nuclei bilaterally
• Unilateral innervation to the area of the facial nerve nuclei which supplies the muscles of the lower quadrant of the face

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Fibre types of cranial nerves

A

Efferent motor fibres
Afferent sensory fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

3 types of efferent fibres

A

General somatic efferents (GSE)
• Cell bodies in brainstem
• Innervate skeletal muscle derived from somites (III, IV, VI, XII)
Special visceral / Branchial motor efferents (SVE)
• Functionally identical to GSE
• Cell bodies in brainstem and innervate skeletal muscle derived from pharyngeal arches
• Visceral = in less developed animals (fish) pharyngeal arches give rise to smooth muscle or glands (V, VII,
IX, X, XI)
General visceral efferent (GVE)
• Cell bodies within brainstem – parasympathetic
• Innervate smooth muscles or glands (III, VII, IX, X)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the Afferent fibres

A

General somatic afferents (GSA)
• Cell bodies outside the CNS (ganglia)
• From joint, tendon, skin, muscle
• Pain, temperature, proprioception, touch and pressure
• Innervate specific nuclei in brainstem (V, VII, IX, X)
Special somatic afferents (SSA)
• Similar to GSA
• Transmit specialised sensory inputs e.g. sight, hearing (II, VIII)
Special visceral afferents (SVA)
• Similar to SSA
• Take information from chemoreceptors associated with viscera and senses e.g. taste and smell (I, VII, IX, X)
General visceral afferents (GVA)
• Receptors located in serous lining or smooth muscle of body viscera
• thirst, hunger, visceral pain, chemoreception (VII, IX, X)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the Olfactory nerve (CN1)

A

Sensory
Special sensory Afferent SVA fibres
Cell bodies in olfactory epithelium of nasal mucosa - no ganglion
Axons transmitted through cribriform plate of ethmoid bone to olfactory bulb
Postsynaptic fibres of secondary neurons form olfactory tract
Complex communication network sending fibres to autonomic centres and limbic system
Function : sense of smell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the optic nerve CN2

A

Sensory
Special sensory Afferent SSA fibres
Cell bodies in retina (first order) and retinal ganglia (second order)
Myelinated second order axons grouped together as the optic nerve and leave orbit via optic canal
Terminate in lateral geniculate body of thalamus and protectable area of midbrain
Cells in lateral geniculate body form geniculocarine tract, travel to primary visual cortex
Function: vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the cranial nerves of the midbrain

A

Oculomotor 3
Trochlear 4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the oculomotor nerve 3

A

Motor
General somatic efferents:
• Emerges from the midbrain
• All extraocular (skeletal) muscles except lateral rectus and superior oblique
• Control eye movements
• Also levator palpebrae superioris (elevates upper eyelid)
• From oculomotor motor nucleus
General visceral efferents:
• Parasympathetic
• Constrict pupils via sphincter pupillae and ciliary (smooth) muscles
• From Edinger-Westphal nucleus
• Sympathetic fibres leave ciliary ganglion with post ganglionic parasympathetic fibres
• Terminate in ciliary body
• Pupillary light and accommodation reflex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Parasympathetic effect on iris

A

Sphincter pupillae muscle contracts: pupil size decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Sympathetic effect on iris

A

Dilator pupillae muscle contracts
Pupil size increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the Trochlear nerve 5

A

Motor
Emerges on dorsal aspect of brainstem
General somatic efferents:
• Innervate superior oblique extraocular muscle: abducts, depresses and medially rotates eyeball
• Cell bodies in trochlear nucleus of midbrain
• the only cranial nerve formed by axons that cross the midline before their exit.

17
Q

What is the cranial nerve of the pons

A

Trgeminal 5

18
Q

Describe the trigeminal nerve

A

General somatic afferents (sensory root) Portio major
• 3 divisions transmit sensations of touch, pressure, nociception and thermal changes;
• Ophthalmic (V1), sup. Orbital fissure – upper eyelid, forehead &scalp
• Maxillary (V2), foramen rotundum – lower eyelid, upper lip & teeth, maxillary aspect of the face, lateral strip in temporal area
• Mandibular (V3) foramen ovale– lower lip & teeth, oral cavity, skin over mandible and lateral side of head rostral to ear
• 3 sensory nuclei form a continuous column from C2 to the midbrain
• Spinal trigeminal nucleus
• Principal sensory nucleus
• Mesencephalic nucleus
Special visceral efferents (motor root) Portio minor
• Bypasses trigeminal ganglion, travels with V
• Innervate muscles of mastication (temporalis, masseter, medial pterygoid and lateral pterygoid)
• Also mylohyoid, anterior belly of digastric, tensor tympani and tensor veli palatine
• 1 motor nucleus
Fibres conveying discriminative touch from the face and oral cavity terminate in the primary sensory nucleus
• Fibres carrying proprioceptive information from the masticatory muscles, extraocular muscles and periodontal
ligament receptors have their cell bodies in the mesencephalic nucleus not in the trigeminal ganglion.

19
Q

What are the cranial nerves of the pons-medulla junction

A

Abducens 6
Facial 7
Vestibulocochlear 8

20
Q

Describe the abducens nerve 6

A

General somatic efferent
• Innervates the lateral rectus
• Nucleus located in the pons
• Facial axons loop around it forming facial colliculus
• Leaves superior orbital fissure
• Interneurons go to contralateral oculomotor nucleus
• Allows lateral and medial rectus muscles to work together

21
Q

Describe the facial nerve

A

Mixed
• Special visceral efferent axons leave facial nucleus and are joined by GVE neurons from superior salivatory nucleus before leaving pons-medullary junction as nerve
• Mixed with these fibres are somatic afferents (taste from ant. 2/3 of tongue) and pinna form intermediate nerve
• Facial nerve exits stylomastoid foramen
Branchial motor component/ Special visceral efferent
• innervation to muscles of facial expression, platysma, stylohyoid, stapedius and posterior belly of digastric.
• Cell bodies in facial motor nucleus of pons
• Five motor branches
• Temporal
• Zygomatic
• Buccal
• Mandibular
• Cervical

22
Q

What are the 5 motor branches of the facial nerve

A

Temporal
Zygomatic
Buccal
Mandibular
Cervical

23
Q

Describe the parts of the facial nerve carried by the intermediate nerve

A

General visceral efferent (secretomotor)
• innervation to lacrimal, sublingual and submandibular glands, all glands of head except parotid and integumentary glands
• Cell bodies in superior salivatory nucleus
• Travel in nervus intermedius – divide to become greater petrosal & chorda tympani
Special visceral afferent
• (taste) innervation to anterior 2/3 of tongue
• Cell bodies in geniculate ganglion
• Enters solitary tract and terminates in gustatory nucleus within solitary nucleus
General somatic afferent
• (pain, touch, temperature) fibres transmit information from external ear and external acoustic meatus travel in nervus intermedius and terminate in the spinal trigeminal tract
General visceral afferent
• (sensation from soft palate, nasal cavity and middle ear) fibres with cell bodies in geniculate ganglion
• terminate in the spinal trigeminal tract

24
Q

Describe the vestibulocochlear nerve 8

A

Sensory
2 separate nerves enclosed within the same connective tissue sheath - vestibular nerve and cochlear nerve
Both enter brainstem at pontomedullary junction

25
Q

Describe the vestibular nerve

A

Cell bodies in vestibular ganglion
• Neurons project to vestibular nuclei of pons and medulla
• Medial and inferior vestibular nuclei have connections to cerebellum
• Lateral vestibular nucleus sends a large group of axons ipsilaterally down the spinal cord to form the lateral vestibulospinal tract
• All nuclei in vestibular complex send axons bilaterally to CN III, IV & VI nuclei via MLF
• Vestibular axons in descending MLF (medial vestibulospinal tract) inflorescence lower motor neurons in cervical spinal cord

26
Q

Describe the cochlear (auditory) nerve

A

Cell bodies in spinal ganglion of cochlea
Neurons project to cochlear nuclei of medulla
Cross midline to enter superior olivary nucleus - medial geniculate nucleus of thalamus
Small number of axons leave sup. Olivary nucleus and provide innervating to stapedius

27
Q

What are the cranial nerves of the medulla

A

Glossopharyngeal 9
Vagus 10
Accessory 11
Hypoglossal 12

28
Q

What are the fibre types of the glossopharyngeal nerve 9

A

• Special visceral afferents: taste from posterior 1/3 of tongue (inferior ganglion)
• General visceral afferents: sensation from posterior 1/3 of tongue, pharynx and carotid sinus (inferior ganglion) go to NTS
• General somatic afferents: sensation from external ear (superior ganglion) – enter spinal trigeminal tract
• Special visceral efferents/ branchial motor: motor innervation to stylopharyngeus muscle from nucleus ambiguus of medulla
• General visceral efferents: parasympathetic innervation of parotid gland from inferior salivatory nucleus of
medulla

29
Q

Describe the glossopharyngeal nerve 9

A

Mixed
Leaves skull via jugular foramen
Inferior ganglion - visceral Afferent
Superior ganglion - somatic Afferent
Composed of 5 fibre types

30
Q

Describe the Vagus nerve 10

A

Mixed
Extends throughout neck, thorax, and abdomen to colon
• Special visceral afferents: taste from epiglottis to solitary nucleus (via inferior ganglion)
• General visceral afferents: sensation from abdominal organs, heart lungs etc. pharynx, larynx, oesophagus and trachea as well as inputs from chemoreceptors in carotid body to monitor blood CO2, these go to NTS (cardio respiratory portion)
• General somatic afferents: general sensation from pharynx, larynx, oesophagus, trachea external ear and external acoustic meatus (superior ganglion) – nucleus spinal trigeminal tract
• Special visceral efferents / Branchial motor: motor innervation to all pharyngeal and laryngeal muscles (except for stylopharyngeus and tensor veli palatini) from nucleus ambiguus of medulla
• General visceral efferents: parasympathetic innervation from dorsal motor nucleus to thoracic and abdominal viscera e.g. heart, GI tract, influenced by hypothalamus, olfactory system, reticular formation & NTS. Dorsal nucleus located in vagal trione

31
Q

Describe the accessory nerve CN11

A

Motor
•Once thought to have two parts: cranial and spinal accessory nerve roots
• Cranial root since found to be composed of vagus nerve fibres from nucleus ambiguus
• Accessory nerve arises from spinal accessory nucleus in posterolateral ventral horn of the cervical spinal cord (C2 – C5 levels)
• Emerges from spinal cord in lateral funiculus (between ventral and dorsal spinal nerve roots) and ascends to enter foramen magnum
• Special visceral efferent innervation to sternocleidomastoid, trapezius and intrinsic laryngeal muscles

32
Q

Describe the hypoglossal nerve (12)

A

Motor
Cellbodies located in hypoglossal nucleus of the medulla
General somatic efferent innervating to extrinsic muscle (except palatoglossus) and intrinsic muscles of ipsilateral side of tongue

33
Q

Where are motor nuclei

A

• Most medial CN motor nuclei XII, VI, IV, III
• Located adjacent to midline and anterior to ventricular space
• Alpha motor neurons that these nuclei innervate originate from paraxial mesoderm that migrated to the occipital region (tongue) and orbit
• Functional component is SE, they innervate skeletal muscles that migrated through pharyngeal arches
• Laterally adjacent to the SE forming a discontinuous column are the nuclei that constitute the craniosacral (parasympathetic) division
-Nuclei dorsal motor vagus – X
-Inf salivatory nucleus – IX
-Sup. Salivatory nucleus - VII (intermediate part)
-Edinger-Westphal nucleus – III
• Give rise to preganglionic axons that terminate in a peripheral ganglion, that give rise to postganglionic fibres that innervate a visceral structure
• Classified as visceral efferent / VE preganglionic parasympathetic
Most lateral discontinuous motor column forming by
-Nucleus ambiguous – IX & X
-Facial motor nucleus – VII
-Trigeminal motor nucleus - V
• Muscles innervated originate from mesoderm that migrates into pharyngeal arches

34
Q

Describe sensory nuclei

A

Most medial solitary tract & nucleus
• No matter what cranial nerve returns visceral afferent info. The central processes of these primary afferent fibres contribute to the solitary tract, the fibres of which terminate in the solitary nucleus
• VA info from VII, IX & X, taste & visceral sensations of thorax & abdomen
Vestibular and cochlear nuclei receives sensory input from vestibular apparatus and cochlea
Although SA pain and temp sensations enter brain stem on 4 diff nerves, the central processes of these primary Afferent fibres Exeter the spinal trigeminal tract and terminate in the medially adjacent spinal trigeminal nucleus

Neuro (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions