Week 4 SDL and Practical: Brainstem, cerebellum and cranial nerves Flashcards
Which sub divisions of the brain make up the brainstem?
mesencephalon (midbrain)
metencephalon (pons)
myelencephalon (medulla oblongata)
Where is the pyramidal decussation?
anterior median fissure of the medulla oblongata
Where is the gracile tubercle and fascicle located in the brainstem?
midline dorsal medulla
What structures are located in the dorsal medulla?
- lateral and medial geniculate nucleus
- superior and inferior colliculus
- trochlear nerve
- interpeduncular fossa
- superior, middle and inferior cerebellar peduncle
- choroid plexus in roof of 4th ventricle
- cuneate/gracile tubercle/fasciculus
State all the features on the ventral surface of the medulla oblongata
pyramids olives anterior median fissure decussation of pyramids antero-lateral sulcus postero-lateral sulcus CN IX, X, XI, XII
State all the features on the ventral surface of the pons
basilar groove
CN V, VI, VII, VIIII
State all the features on the ventral surface of the midbrain
optic chiasma optic tract pituitary stalk mammillary bodies cerebral peduncles interpeduncular fossa CN III, IV
How is the medulla divided?
into the open medulla and the closed medulla
the medulla becomes open when the central canal opens into the 4th ventricle
What is the function of the cerebellum?
co-ordination of movement
maintenance of balance and posture
To which region of the brainstem does each cerebellar peduncle connect
superior- midbrain
middle - pons
inferior - medulla
Which 3 arteries supply the cerebellum and are they part of the anterior system of vessels (internal carotid system) or of the posterior system (vertebral baislar)
All originate from the vertebral basilar system:
- superior cerebellar artery (SCA)
- anterior inferior cerebellar artery (AICA)
- posterior inferior cerebellar artery (PICA)
What is dysdiadochokinesis?
impaired ability to perform rapid, alternating movements
caused by cerebellar damage
What is past pointing and how do you test it?
past pointing - the inability to place a finger or some other body part accurately on a selected point
-finger-to-nose test
What is the test for dysdiadochokinesis?
ask patient to clap by alternating the palmar and dorsal surfaces of the hand as fast as possible
repeat with other hand
Which cranial nerves emerge from the cerebellopontine angle?
CN VII, VIII
Which cranial nerve emerges from the interpeduncular fossa?
CN III
Which cranial nerve emerges immediately lateral to the medullary pyramid?
CN XII
Which cranial nerves emerges lateral to the olive?
CN IX, X
Which cranial nerve emerge from the dorsal surface of the brainstem
CN IV
What is the consequence of damage to the olfactory nerve?
anosmia - absence of sense of smell
Which cranial nerve supplies the dura?
trigeminal
Where are the cell bodies of most of the trigeminal sensory fibres located?
in the trigeminal ganglion - located in the lateral wall of the cavernous immediately lateral to the pituitary gland
Which two reflexes are associated with the trigeminal nerve
- corneal reflex - an involuntary blinking of the eyelids elicited by stimulation of the cornea (such as by touching or by a foreign body)
- jaw-jerk reflex
What is trigeminal neuralgia?
chronic pain caused by trigeminal nerve - even mild stimulation of your face such as brushing your teeth or putting on makeup - may trigger a jolt of excruciating pain
Where do the 5 branches of the facial nerve arise?
within the parotid gland
The chorda tympani carries fibres between which nerves?
facial nerve to supply taste to the anterior 2/3rds of tongue and the lingual nerve as it contains secretory fibres for the sublingual and submaxillary glands
Which nerve supplies the lacrimal gland?
the greater petrosal nerve (branch of facial nerve)
What is tinnitus?
ringing in ear
Which nerve innervates the vocal folds?
vagus nerve
What is the gag reflex, which cranial nerve does it test and why is it important?
- Pharyngeal reflex when something touches the roof of your mouth, the back of your tongue or throat or the area around your tonsils
- glossopharyngeal nerve
- Prevents choking and keeps us from swallowing potentially harmful substances
what are the two parts of the accessory nerve?
- cranial part
- spinal part
What are autonomic ganglia?
- clusters of neuronal cell bodies and their dendrites
- they are essentially a junction between autonomic nerves originating from the central nervous system and autonomic nerves innervating their target organs in the periphery
What are the four autonomic ganglia of the head and neck?
- pterygopalantine
- ciliary
- otic
- submandibular
What is the function of the pterygopalantine ganglia?
receives parasympathetic fibres from the facial nerve and supplies the lacrimal glands, palantine glands and mucosa of the nasal cavity
What is the function of the otic ganglia?
receives parasympathetic fibres from the glossopharyngeal nerve and supplies the parotid gland
What is the function of the submandibular ganglia?
receives parasympathetic fibres from the facial nerve and supplies the submandibular and sublingual glands
Which cranial nerves are involved in the pupillary light reflex and how do we test it?
- CN II and CN III
- dim the lights and look at a distant object
- shine torch into eyes from each side
- look to see if patients pupils constrict in response to light
What are the symptoms of horner’s syndrome?
- partial ptosis
- constricted pupil (miosis)
- reduced facial sweating
- facial flushing
What is the substantia nigra?
in the midbrain
dopamine containing neurons
What structure seperates the two cerebellar hemispheres
vermis
What are nodules?
ventral part of vermis of cerebellum
found on the midline on the superior surface
What seperates the anterior and posterior lobes of the cerebellum?
primary fissure
In what way do fibres run across the pons?
transverse
because it attaches the two hemispheres on the left and right
Which cranial nerves go through the jugular foramen?
CN IX, X and XI
In a hypoglossal nerve lesion, does the tongue deviate away from the side of lesion or toward the side of lesion?
toward the side of lesion