Organisation of the Brainstem and Cranial Nerves Flashcards
what are the major divisions of the brain stem?
midbrain, pons and medulla oblongata
pons and medulla belong to hindbrain
what are the dorsal columns role?
fine touch and proprioception
what is the roof of the midbrain called?
tectum
what is the pineal gland involved in?
melatonin production and circadian rhythm
what is the superior colliculus involved in?
coordination of the eye and neck movement
what is the inferior colliculus involved in?
auditory responses
what does the trochlear nerve (CN IV) innervate?
superior oblique muscles of the eye
what features originate from the midbrain?
- optic chiasm
- mammilary (memory and limbic)
- cerebral peduncle (corticospinal fibre tract that holds cerebrum to brainstem)
- CN 3 oculomotor nerve
function of CN III- oculomotor nerve?
conjugate eye movement
what nerve originate from the pons
CN 5- trigeminal nerve
function of CN V- trigeminal nerve
muscles of mastication/chewing
what features meet at the pontomedullary junctions?
CN 6, CN 7, CN 8
abducens
facial
vestibulocochlear
function of CN VI- abducens nerve?
lateral rectus muscle
function of CN VII- facial nerve?
musculature of the face
function of CN VIII- vestibuolcochlear nerve?
balance and hearing
what features originate from the medulla?
-pyramidal decussation
- CN 9, 10, 11, 12
glossopharyngeal
vagus
accessory
hypoglossal
function of CN IX- glossopharyngeal nerve?
- taste sensation to anterior third of tongue
- pharynx function (stylopharyngess from 3rd arch)
- parotid salivary gland
function of CN X- vagus nerve?
PNS innervation to the viscera
function of CN XI- accessory nerve?
sternocleidomastoid and trapezius
function of CN XII- hypoglossal nerve?
intrinsic muscles of the tongue
general functional classification?
General Somatic Afferent
General Visceral Afferent
General Somatic Efferent
General Visceral Efferent
where do GSA fibres go?
skin, mucous membrane sensation
where do GVA fibres go?
GI tract, heart, vessels and lungs
where do GSE fibres go?
muscles for eye and tongue
where do GVE fibres go?
preganglionic PNS
what is the special function classification?
Special somatic afferent
Special visceral afferent Special visceral efferent
where do SSA fibres come from?
vision, hearing, equilibrium
where do SVA fibres come from?
smell and taste
where do SVE fibres comes from?
chewing, facial expression, swallowing, vocal sounds, turning head
how are sensory and motor nuclei positioning in the embryonic spinal cord? what is this due to?
due to splitting of the alar plate, the sensory nuclei are located laterally and motor nuclei remain medial
what are the cranial nerve nuclei in the midbrain (rostral)?
sensory- V (trigeminal)
motor- Edinfer Westphal, III (oculomotor), IV (trochlear)
what are the cranial nerve nuclei in the pons?
sensory- V (trigeminal), VIII (vestibulocochlear)
motor- V (trigeminal), VI (abducens), VII (facial), salivary
what are the cranial nuclei in the medulla?
Sensory – V (Trigeminal), solitarius.
Motor – Salivary, X (vagus), ambiguus, XII (hypoglossal)
what are the cranial nuclei in the cervical spinal cord?
sensory - V (trigeminal)
motor- IX (accessory)
how would you identify the midbrain internal structure?
upside down Mickey Mouse
the aqueduct is unique to the midbrain
what does the aqueduct do?
connect the 3rd and 4th ventricles
what is damaged in the midbrain in Parkinson’s disease?
Substantia Nigra- pigmented nucleus
where does the cerebral peduncle come from?
motor cortex
where is the pons in relation to the 4th ventricle?
the pons is the floor of the 4th ventricle
the majority of the ventricle is here
what is the middle cerebellar peduncle?
attachment of pons to cerebellum
what direction fibres does the pons have?
transverse
these are unique to the pons
what are located in the medulla?
inferior olivary nucleus (unique to medulla)
4th ventricle
what are located din the pons?
4th ventricle
middle cerebellar peduncle
transverse fibres
what are located in the midbrain?
inferior colliculus
cerebral aqueduct
substantia nigra
cerebral peduncle
what is located in the lower medulla?
dorsal columns
central canal
pyramidal decussation
what is Lateral Medullary Syndrome?
thrombosis of the vertebral artery or the Posterior Inferior Cerebellar Artery (PICA)
what are the symptoms of Lateral Medullary Syndrome?
o Vertigo.
o Ipsilateral cerebellar ataxia.
o Ipsilateral loss of pain/thermal sense (face).
o Contralateral loss of pain/thermal sense (trunk and limbs) – spinothalamic tract affected.
o Horner’s syndrome – sympathetic tract affected.
o Hoarseness, difficulty swallowing.
where is the lesion for LMS?
what is located there?
lateral medulla:
- vestibular nerve
- inferior cerebellar peduncle
- trigeminal nerve
- ambiguus nerve
- spinothalamic tract
- sympathetic tract
which cranial nerves originate from the midbrain?
3 and 4
NB 1 and 2 come from the cerebrum
which cranial nerves originate from the pons?
5-8
which cranial nerves originate from the medulla?
9-12
what is the manifestation of oculomotor palsy?
what stroke shows a CNIII palsy presentation?
- ptosis (down and out)
- mydriasis
- loss of pupillary reflex
Weber’s sydrome: at the midbrain where CN 3 comes from affecting the corticospinal tract therefore presents with hemiparesis aswell
