Formative 2 Flashcards
Does the olfactory nerve have afferent or efferent components
Afferent
If the olfactory nerve is damaged, it will result in anosmia on which side
Ipsilateral side
Where does CN I enter the cranial cavity
Enters via small holes in the cribriform plate of the ethmoid bone
CN I is commonly damaged in fractures to what?
Anterior cranial fossa
How is the optic nerve tested in an unconscious patient
By observing pupillary constriction in response to light
Where does CN II enter the skull
Via the optic canal
Where does the left and right branch of the optic nerve first join
Optic chiasm
What type of fibres does CN III carry and where to
Parasympathetic fibres from edigner-Westphal n in tegmentum to ciliary muscles and sphincter pupillary muscle
Damage to the oculomotor nerve will lead to ptosis (dropping) of the eyelid on which side
Opposite side
Damage to the abducens nerve will result in inability to…..
Abduct the affected eye
A person with trochlear nerve damage will complain of…..
Double vision as they look down eg when walking down the stairs
Which CNs pass through the superior orbital fissure and what other structures
3, 4, 6 and 7
Opthalmic vein
Sympathetic fibres
Where do the 3 trigeminal nerves pass through the skull
Opthalmic - superior orbital fissure
Maxillary - rotundum
Mandibular - ovale
Which nerve carries taste from the posterior 1/3 of the tongue
CN7 - facial nerve
Which nerve carries taste to the anterior 2/3 of the tongue
CN VII - hypoglossal
What supplies the submandibular salivary gland
Receives parasympathetic input from CN VII
Which CNs pass through the jugular foramen
IX
X vagus
XI accessory
Where does CN VII (facial) exit the skull
Internal auditory meatus
Where is the nucleus of CN 7 located
Tegmentum
CN VII runs a course closely related to….
The middle ear
What 2 things is CN VIII (Vestibulocochlear) concerned with
Balance and hearing
When CN VIII is diseased, it may cause…..
Rapid eye movements
Describe the Weber test
With comp,eye damage of CN VIII, when a tuning fork is placed in the middle of the forehead the sound is heard best on the opposite side as the damage
A tumour of CN VIII may cause paralysis of what due to what
Paralysis of the muscles of facial expression because the facial nerve is compressed
Where does CN VIII exit the cranial cavity
Internal auditory meatus
Vagus nerve carries parasympathetic fibres to which 3 organs
Heart
Lungs
Bowel
Where does CN X leave the brain
Medulla between pyramid and inferior cerebellar peduncle
CN X has a motor branch to all pharyngeal muscles except……
Stylopharyngeus which is innervated by CN IX
What effect does the vagus nerve have on HR and BP when stimulated
Decreases both
What type of fibres does the accessory nerve carry and where to
Purely motor to the trapezius and sternocleidomastoid
Which vein does CN XI (accessory) run in close proximity to
Internal jugular vein
CN XI exits the cranial cavity via….
The internal jugular foramen alongside the spinal cord
Where does CN XII (hypoglossal) leave the cranial cavity
Hypoglossal canal
Where are CN XII nerve cell bodies located
Within the medulla
Damage to CN XII will cause paralysis of which half of the tongue
Ipsilateral
The spinothalamic tract conveys nociceptive info to the……
Contralateral thalamus
Where is the spinothalamic tract found
Found in the anterolateral white matter of the spinal cord
After they deccusate, the fibres of the spinothalamic tract synapse…
In the thalamus before projecting into the neocortex
What is the middle ear filled with
Air
What is conductive deafness
Reduction in the mechanical transmission of sound waves to the oval window
What modifies the stiffness of the ossicullar chain
Tensor tympani and stapedius
Sounwaves enter the cochlea via the….
Oval window
How many times does the cochlea coil around the modiolus
2 1/2 - 2 3/4 times
What is the organ of corti
Specialised structure which rests on the basilar membrane
Contains auditory sensory cells
The scala vestibuli is continuous with the scala tympani via the,….
Helicotrema
Which antibiotics can damage the stereocilia of hair cells
Aminoglycoside
How many rows of inner vs outer hair cells are there
Can be 4-5 rows of outer hair cells
Only one single row of inner hair cells
What is the function of the semi circular canals
Detect rotational acceleration and deceleration
What detects the position of the head with respect to gravity and linear acceleration
Otolithic organs - utricle and saccule
How many semi circular canals are there and how are they arranged in relation to each other
3 in total
3 different planes
What does damage to the canals of one side result in
A Nystagmus with slow phase towards the damaged side and rapid reset away from it
Do the SSC in the left ear affect movement of the left/ right ear
Both eyes
What can pouring ice cold water in the external auditory meatus cause
Convection currents in the SSC and nystagmus
What are the otolithic organs filled with
Endolymph
What are mossy fibres and where are they derived from
Axons
Derived from various brainstem nuclei except inferior olivary nucleus
What are the output neurons from the cerebelllar cortex known as
Purkinje which are inhibitory in nature
What type of fibres are derived from the inferior olivary nucleus
Climbing fibres
Where does the cerebellum principally receive info from
Vestibular system - coordination, posture and balance
Do cerebellar lesions have ipsilateral or contralateral effect. Give eg
Ipsilateral
A lesion in the left lobe will result in decomposition of movement on the left hand side of the body
Give the 6 cerebellar disease. Hint: DANISH
Dysdiadochokinesis - inability to perform rapid alternating muscle movements
Ataxia - gait and posture
Nystagmus - eye makes repetitive, uncontrolled movements
Intention tremor - involuntary muscle contractions
Speech impairment
Hypotonia - decreased muscle tone
Where are olfaction and gestation represented
Ipsilaterally in areas including the post central gurus and insular cortex
Where do afferents from olfactory receptors synapse
Synapse with mitral cells in olfactory bulb before projecting to the primary gustatory cortex
How many receptors does a single glomerulus in the olfactory bulb take input from
Many receptors
Give the 3 CNs involved in taste sensation and each of their specific roles
CN VII (facial) - anterior 2/3 tongue CN IX (glossopharyngeal) - posterior 1/3 tongue CN X (vagus) - epiglottis
What are the 4 types of papillae and where are they located. Which is not concerned with taste
Fungiform - anterior 2/3
Foliage - edges, posterior 1/3
Circumvallate - rear
Filiform - cover most of upper surface. These are not gustatory, they’re mechanical
