Cranial nerves Flashcards
What is the diencephalon?
thalamus and hyperthalamus
What are cerebellar peduncles?
White fibre tracts. 3 of these connect the cerebellum to the brainstem
What do all the ascending and descending pathways in the brain pass through?
Brainstem
How many of the cranial nerve nuclei pass through the brainstem?
9 - 3 to 12 (excluding 11)
What canal is in the closed medulla and what does it eventually form?
An extension of the central canla of the spinal cord that eventually widens to form the 4th ventricle in the open medulla ?
What is the organisation of the brain stem from the posterior to the anterior part? (Horizonal cross section)
Tectum (roof)
Ventricular system
tegmentum
base
What is the difference between the fibres in the optic nerve and optic tract?
In the optic nerve the axons have come from one eye but in the optic tract the axons have come from both eye. Therefore if you have an optic nerve legion it will effect one eye whereas if you have an optic tract legion it will effect both eyes
When viewing the midbrain as a horizontal cross section 4 bumps occur at the posterior, What are these called and what are they associated with?
Superior colliculi (on top)- visual Inferior colliculi (below superior)- auditory
What descending tracts go through the cerebral peduncles?
Cortcospinal- go to muscles below the head e.g. limb and trunk muscles Corticobulbar- go to muscles of the face and mastication
what cranial nerves emerge at the midbrain level?
III and IV
What are some key parts of the pons?
4th ventricle - ventricular system much larger in the pons than in the midbrain as in midbrain its only a small hole (aquaduct)
3 pairs of peduncles- Superior cerebellar peduncle, middle cerebellar peduncle and inferior cerebellar peduncle (these connect the cerebellum to the pons)
Which Cranial Nerves go through the pons?
V, VI, VII, VIII
What is just below the Pons?
Open upper medulla
Why is the open upper medulla named as such?
Because the forth ventricle doesn’t really have a roof the cerebellum forms this
What nucleus is in the open upper medulla?
Inferior olivary nucleus