Anatomy Lab - 3 Flashcards
What separates the two hemispheres of the cerebellum?
Vermis
What is the folia?
Ridges in the cerebellum (equivalent to gyri)
What is the white matter called in the cerebellum?
Arbor vitae
What is the midbrain composed of?
Ventrally formed of two cerebellar peduncles which join the brainstem to the cerebral hemispheres
What is the pons?
Horizontally striated basal portion of pons with middle cerebellar peduncles passing laterally to the cerebellum
What is found in the medulla?
Pyramids (long tracts lying medially) with olives (bulges lateral to the pyramids)
What is important to note about the open medulla?
It is on the dorsal side
Which parts of the lateral ventricle lack choroid plexus?
Anterior and posterior horns
In which ventricle does the choroid plexus protrude?
Lateral aperture of the 4th ventricle
Also runs very close to the 7th cranial nerve
Where does CSF finally enter the subarachnoid space?
Via the two lateral apertures and one median aperture of the fourth ventricle
Describe the flow of CSF within the ventricles.
CSF flows from lateral ventricles via interventricular foramen to 3rd ventricle
3rd ventricle via cerebral aqueduct to 4th ventricle
4th ventricle via one median aperture and 2 lateral apertures to cisterna magna
Cisterna magna into subarachnoid space
Subarachnoid space into venous sinuses
What are subarchnoid cisterns?
Enlargements of subarachnoid space filled with CSF
Name the subarachnoid cisterns and where they are found.
Interpeduncular cistern (found between cerebral peduncles) Cerebromedullary cistern (cisterna magna) Pontine cistern (anterior/ventral to pons) Superior cistern (above the cerebellum and midbrain)
Where do the archnoid granulations/villi lie?
Found near midline on superior aspect of hemispheres
Sites where dura and arachnoid are adherent
What is the function of the arachnoid villi/granulations?
Drain CSF to venous blood (within superior sagittal sinus)
What does the vertebral artery supply?
Lateral areas of medulla
What are the branches of the vertebral artery?
Posterior inferior cerebellar artery
Anterior spinal artery
What does the anterior spinal artery supply?
Medial medulla
What does the posterior inferior cerebellar artery supply?
Lateral medulla
Posterior/inferior cerebellum
What forms the basilar artery?
Fusion of two vertebral arteries
What are the branches of the basilar artery?
Anterior inferior cerebellar artery
Pontine arteries
Superior cerebellar artery
What do the anterior inferior cerebellar arteries supply?
Supply anterior part of inferior cerebellum
What do the pontine arteries supply?
Most of the pons
What do the superior cerebellar arteries supply?
Superior aspect of cerebellum
Where do the posterior cerebral arteries travel?
Arise from basilar, curve laterally around the cerebral peduncles and give off small branches that penetrate the midbrain
What are the small branching arteries of the posterior cerebral artery called?
Central arteries (posteromedial group) Arise near start of the posterior cerebrals and penetrate the midbrain in the interpeduncular region
What is the name given to the superior colliculus and inferior colliculus?
Tectum
Where is the superior and inferior colliculi found?
Superior surface of midbrain
Where is the pineal gland found?
Below the splenium of the corpus callosum
What is the superior vs inferior colliculi involved in?
Superior = visual Inferior = auditory
What is found on the dorsal surface of the midbrain?
Superior and inferior colliculi which form the roof/tectum of the midbrain
What is the base of the peduncle called (with fibres running parallel to the long axis)
Crus / basis pedunculis
What is the substantia nigra made of?
Strip of black pigmented neurons
What connects the basal pons to the cerebellum?
Middle cerebellar peduncles
What is the function of the gracile/cuneate tracts?
Carry sensation from the body
What is the importance of the location of the gracile and cuneate tubercles?
Mark the position of the gracile and cuneate nuclei = where the tracts terminate and synapse
What does the open medulla form?
Floor of the 4th ventricle
What does the closed medulla look like?
A round tube, like the spinal cord
What are the pyramids on the medulla made of?
Bundles of motor or corticospinal fibres
What does the pyramidal decussation mark?
The boundary of the medulla and spinal cord
What do the olives mark?
Mark the position of a major nucleus (collection of nerve cell bodies) = inferior olivary nucleus (conveys information to the cerebellum)
Which is medial, cuneate or gracile?
Gracile
What forms the anterior part of the roof of the 4th ventricle?
Superior cerebellar peduncle on each side
Superior medullary velum in midline
What forms the middle regions of the roof of the 4th ventricle?
Cerebellum
What forms the posterior aspect of the roof of the 4th ventricle?
Inferior medullary velum (fragile membrane of pia mater and ependyma)
Ependyma lines the brain ventricles
What lines the brain ventricles?
Ependyma
Where is the choroid plexus found in the 4th ventricle?
Suspended from the posterior aspect of the roof
With what cistern is the inferior part of the cerebellar vermis most closely associated?
Cerebellomedullary cistern (cisterna magna)
Name the cranial nerves attached to the midbrain, pons, pontomedullary junction and medulla.
Midbrain - III and IV
Pons: V
Pontomedullary junction: VI, VII, VIII
Medulla: IX, X, XI (cranial root), XII
What bathes the outer surfaces of arachnoid granulations?
Venous blood
Name the openings between the ventricular system and the subarachnoid space.
Median and lateral apertures of the fourth ventricle
What forms the blood-brain barrier?
Endothelial cells of cerebral blood vessels, which have tight junctions between them
Arteries: most of the lateral side of the cerebral hemisphere
Middle cerebral artery
Arteries: Medial surface of the hemisphere, above the corpus callosum
Anterior cerebral artery
Artery: Medial aspect of the occipital lobe of the hemisphere
Posterior cerebral artery
Artery: midbrain
Posterior cerebral arteries
Arteries: Lateral part of the medulla
Vertebral artery - posterior inferior cerebellar artery
Arteries: supplying the pons
Pontine arteries (branch of basilar artery)
Arteries: cerebellum
Superior cerebellar artery, anterior inferior cerebellar artery, posterior inferior cerebellar artery
Which cerebellar peduncle contains most of the cerebellar efferent fibres?
Superior cerebellar peduncle
What is the arbor vitae?
Branching pattern made by white matter of cerebellum and covered by the cortex
What divides the cerebellum into anterior and posterior lobes?
Primary fissure
What do the nodule and two flocculi form?
Flucculonodular lobe = vestibular part of cerebellum
List the functional divisions of the cerebellum.
Flucculonodular lobe = vestibulocerebellum
Vermis and intermediate zone = spinocerebellum
Lateral zone = cerebrocerebellum
What is the deep nucleus of the cerebellum?
Dentate nucleus
Gives rise to most of the efferent fibres in the superior cerebellar peduncle