Brainstem and Cranial Nerves Flashcards
3 divisions of the brainstem? Which is the bulgey bit? Which is continuous with the spinal cord?
- Medulla oblongata (this is continuous with the spinal cord)
- Pons (bulgey bit)
- Midbrain
NOT THE HINDBRAIN
Pineal gland secretes X and maintains YY
melatonin
Circadian rhythm
What hormone relies on the circadian rhythm
Cortisol
Pineal gland sits on the roof of the midbrain - XX
the tectum
What of importance is on the tectum (3)
- Superior colliculus
Inferior colliculus
4th cranial nerve - Trochlear nerve
What muscle does the trochlear supply
The superior oblique
Superior colliculus function …
Coordinates movement of neck and eyes
Inferior colliculus function …
Auditory reflex- defensive reflex to a loud noise
What is dorsally on the pons
4th ventricle
Where is the 4th ventricle
on the pons dorsally
What is in the dorsal medulla
Dorsal columns - sensory information coming up to the thalamus and the rest of the brain from the spinal cord
What levels do you find the gracile fasciculus
Cervical, as well as the lumbar and thoracic regions which only have the gracile with info coming from the leg
What levels do you find the cuneate fasciculus
Only cervical
Names of the two tracts of the dorsal column?
Cuneate fasciculus
Gracile fasciculus
which nerve can you see in a dorsal view of the brainstem
4th - trochlear
Which nerves can you see from the ventral view of the brainstem
CNI- Olfactory nerve Optic chiasm of the optic nerve Oculomotor nerve (CNIII) Trigeminal nerve (CNV) Abducens nerve (CNVI) Facial nerve (CNVII) Vestibulocochlear nerve (CNVIII Glossopharyngeal nerve (CNIX) Vagus nerve (CNX) Accessory nerve (CNXI) Hypoglossal nerve (CNXII)
Olfactory never projecst through the base of the skull to the XX
olfactory bulb
what happens at the optic chasm
Crossing over if the optic nerves (CNII)- half the fibres (relating to the temporal visual field) cross over at the optic chiasm, and the nerves follow back in optic tract and end up in the occipital lobe where image is constructed
Oculomotor arises in the gap between the two XX
cerebral peduncles
Abducens supplies …
the lateral rectus muscle which abducts the eye (extrinsic eye muscle)
The pyramids of desussation are a continuation of the XX
corticospinal tract
GENERAL SOMATIC AFFERENT (GSA) nerves function?
Sensation from skin and mucous membranes
GENERAL VISCERAL AFFERENT (GVA) nerves function?
Sensation from GI tract, heart, vessels and lungs
GENERAL SOMATIC EFFERENT (GSE) nerves function?
Muscles for eye and tongue movements
GENERAL VISCERAL EFFERENT (GVE) nerves function?
Preganglionic parasympathetic enervation of the body (basically the Vagus nerve)
SPECIAL SOMATIC AFFERENT (SSA nerves function?
Vision, hearing and equilibrium
SPECIAL VISCERAL AFFERENT (SVA) nerves function?
) Smell and taste (taste is more complex because there are multiple CNs behind it)
SPECIAL VISCERAL EFFERENT (SVE) nerves function?
Muscles involved in chewing, facial expression, swallowing, vocal sounds and turning head
Order from lateral to medial: GSE, GSA, GVA, GVE
GSA, GVA, GVE, GSE
SVVS
AAEE
How to spot cross section of the midbrain?
Midbrain looks like upside down Mickey Mouse
Features on a cross section of the midbrain? (5)
Cerebral aqueduct (drains the 3rd ventricle
Cerebral peduncles
you may see the colliculi
substantia nigra
Substantia nigra is important in …
initiating movement
Disease that effects the substantia nigra? How would this look on a cross section
Loses colour (depigmented) in Parkinson’s disease because cells die
Features on a cross section of the pons? (3)
4th ventricle
Transverse fibres connecting either side of the cerebellum
Middle cerebellar peduncle
Features on a cross section of the medulla? (3)
4th ventricle
Pyramids (corticospinal tract)
Inferior olivary nucleus
What does the Inferior olivary nucleus look like
Squirmy should be an easy spot
Features on a cross section of the lower medulla? (3)
Central canal
Dorsal columns
Pyramidal decussation may be seen (fibres crossing over)
Easy way to spot the pons?
Transverse fibres connecting either side of the cerebellum
Easy way to spot the medulla?
Pyramids or the inferior olivary nucleus
Easy way to spot the lower medulla?
Diagonal fibres of the pyramidal decussation
What is the LATERAL MEDULLARY SYNDROME
THROMBOSIS OF VERTEBRAL ARTERY OR POSTERIOR INFERIOR CEREBELLAR ARTERY (PICA)- blood vessels supplying lateral part of medulla
Symptoms of lateral medullary syndrome? (6)
Vertigo
- Ipsilateral cerebellar ataxia (will have a broad based gate, and will shuffle)
- Ipsilateral loss of pain/thermal sense (face)
- Horner’s syndrome (constriction of the pupil)
- Hoarseness, difficulty in swallowing
- Contralateral loss of pain/thermal sense (trunk and limbs)