Organisation of brainstem Flashcards
What is the brainstem?
Part between brain and spial chord, anterior to cerebellum, but seperate
3 regions - midbrain pons and medulla
sits in posterior cranial fossa
Pineal gland sits rostral
Describe the exterior/posterior view of the brainstem
Pineal gland most rostral-circadians rhythms
Then “bulges”-superior colliculus (eye reflexes)
inferior colliculus (auditory reflexes)
Trochlear nerve (cranial nerve) exits there and goes to superior oblique
Beneath, 4th ventricle/Pons
Then medulla-with dorsal columns at back
2 columns on each side-medial has legs, lateral-arms
Describe the exterior/anterior view of the brainstem
Most cranial nerve exit there
Optic chiasm at top (central)
Just underneath, pituitary stalk connecting to infidibulum (central)
Bilateral bulge-mammilary body
Around that- cerebral peduncle (most motor nerve)
Then occulormotor (II) nerve-bilateral exit
Bellow, at level of pons, bilateral Trigeminal (IV) nerve + small other motor nerve (trocheal (III)
Pons also serves to connect cerebellum
Then at medullar/pons junction - 3 cranial nerve (bilateral)
most medially-abducens (V)
then Nerve VII (facial)-mainly facial expression
Then Vestibulochochlear (VIII)
Then arrive at the medulla
Top to bottom-glossopharyngeal (IX), vagus (X) and acessory (XI)
And more medially to that-hypoglossal (XII), and most medially, pyramids-which are continuations of cerebral peduncles
What are the 7 functional classes of cranial nerves
General somatic afferent- sensory from skin and mucous membrane
General visceral afferent-sensory from GI, heart, vessel, lungs
General somatic efferent- eye, tongue
General visceral efferent - pregagnlionic PSNS
Cranial specifically have
Special sonatic afferent-vision, hearing, equilibriu
Special visceral afferent-smell and taste
Special visceral efferent-muscle for chewing, facial, wswallow, vocal, turning hear
Describe the development of the brainstem
Alar plate and basal plate are seperated by sulcus limitans
At the brain stem, the neural tube opens up again-and motor neuclei (basal) medial and sensory (alar)-lateral
Describe the organisation of nuclei within a brainstem
Very center of brainstem has motor, exterior has sensory
Each can be split by their function
Motor central split in GSE, SVE and GVE
FOR GSE -midbrain has oculor, trochlear. Pons has abducens, medulla has Hypoglossal
FOR SVE-midbrain has nothing, pons had trigeminal anf facial, medulla has ambigus, spinal has acessory
for GVE- midbrain edingerwestfal, pons/medulla has salivory, ad medulla has vagus
What cranial nerve nuclei are in the motor GSE region
FOR GSE -midbrain has oculor, trochlear. Pons has abducens, medulla has Hypoglossal
What cranial nerve nuclei are in the motor SVE region
FOR SVE-midbrain has nothing, pons had trigeminal anf facial, medulla has ambigus, spinal has acessory
What cranial nerve nuclei are in the motor GVE region
for GVE- midbrain edingerwestfal, pons/medulla has salivory, ad medulla has vagus
What cranial nerve nuclei are in the sensory GVA/SVA region
Only medulla has solitarius
What cranial nerve nuclei are in the sensory GSA region
Trigeminal troughout the mid, pons, medulla and cervical
What cranial nerve nuclei are in the sensory SBA region
Pons has vestibucochlear
What are the key features of the midbrain to recognise on an image
Looks like mickey mouse profile (upside down)-general shape
Also has cerebral aqueduct (only in midbrain)
Mickey mouse ears-cerbral peduncles
and colliculi-make bumps other side of ears
And near ears-substantia nigra -black spot (except for parkinson’s-pale)
What are the key features of the pons to recognise on an image
Only place with 4th ventricle
Lot of transverse fibres
Cerebellum
What are the key features of the higher medulla to recognise on an image
CAn see end of 4th ventricle
Can see the pyramids (opposite of ventricle)
Worm/wave shaped Inferior Olivary nucleus
