Topography of The Brain Flashcards
What does the diencephalon contain?
Contains the thalamus, hypothalamus and the pineal gland
What forms CSF?
Choroid plexus
Where does CSF escape into the subarachnoid space?
Roof of fourth ventricle has holes in it - CSF escapes from here into the subarachnoid space
Where absorbs CSF?
Arachnoid villi
What is the name given to a group of neuronal cell bodies in the central nervous system?
Called a nucleus, it is called a ganglion outside the central nervous sytem
Which cranial nerves have their nuclei that arise from the brainstem?
Cranial nerves 3 - 12
What are the funtions of the brainstem?
Pathway for fibre tracts running between higher and lower centres
Innervation of the head and neck since the brainstem nucleii are involved with 10 of the 12 cranial nerves
What is the cavity in the medulla oblongata?
4th ventricle
How does the medulla oblongata connect to the cerebellum?
Connects via the inferior cerebellar peduncle
What are the surface features of the medula oblongata?
Pyramids and their decussation
Olives laterally
Inferior cerebellar peduncle
Cranial nerves 9-12 from its surface
What are parts of the medulla labelled 1-3?
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1 - Pyramidal tract
2 - Medial lemniscus
3 - Inferior cerebellar peduncle
On the diagram, locate the cranial nuclei, inferior olivary process, nuclei of the reticular formation (vital centres), sensory nuclei (gracile and cuneate)
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Which ventricle lies posterior to the pons?
4th ventricle
What are the surface features of the pons?
Middle cerebellar peduncle
Cranial nerves 5,6,7 and 8 originate from its surface
Label the following diagram
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What does the midbrain develop from?
Mesencephalon
What is the central cavity in the midbrain?
The cerebral aqueduct
What are the surface features of the midbrain?
- Cerebral peduncle
- Superior cerebellar peduncle
- Corpora quadrigemina (superior & inferior colliculus)
- Origin of Oculomotor (CN III) & Trochlear (CN IV)
- IV nerve is the only nerve to originate posteriorly
What composes the corpora quadrigemina?
Superior and inferior colliculus
What is the superior and inferior colliculi responsible for?
Superior collicli - visual reflex
Inferior colliculi - auditory reflex
Label the following diagram
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Superior colliculi
Inferior colliculi
(form the corpora quadrigemina)
Superior cerebellar peduncle
What peduncle is present from the anterior view of the midbrain?
The cerebral peduncle - labelled as the black arrow on the left
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What does the cerebral aqueduct connect?
It is the central cavity of the midrain and connects the the 3rd and4th ventricles
What surrounds the cerebral aqueduct?
Peri aqueductal grey matter
Which is then surrounded by white matter with embedded nuclei
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What does the periaqueductal grey matter contain?
Nucleus for the 3rd and 4th cranial nerves
What separates the left and right lobes of the cerebellum?
The vermis
What are the lobes present in a cerebellum?
Anterior lobe
Posterior lobe
Flocculonoddular lobe
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What does the surface of the cerebellum contain?
Contains sulci and folia
What connects the cerebellum to the brainstem?
Three cerebellar peduncles
What part of the cerebellum may exist within the foramen magnum?
The tonsils of the cerebellum
Where does the information sent to the cerebellum arise from?
Comes from proprioceptors in the periphery
What forms the grey matter of the cerebellum?
- Cortex on the surface
- Deep nuclei
What forms the white matter of the cerebellum?
Arbor vitae
Cerebellar peduncles
What are the functions of the cerebellum?
- Posture maintenance
- Fine tuning motor activity
What are the three inputs for the cerebellum?
Information from the pyramidal tracts (motor intention of brain)
Information from ipsilateral proprioceptors from periphery
Information from vestibular nucleii re. balance & posture
What permits the travel of sensory information from the cerebellum to the cerebral cortex?
Cerebellum sends ‘blueprint’ back to cerebral cortex via superior cerebellar peduncle
When will abnormality in the cerbellum be obvious?
A condition called ataxia
Tasks causing difficulty include
- Finger – nose test
- Knee-heel test
- Walking in a straight line
Where does the third ventricle develop?
Develops deep within the cerebral hemispheres, around the third ventricle
What does the diencephalon develop from?
Develops from the diencephalic vesicle - part of the forebrain vesicle
What are the paired structures in the diencephalon and what type of mater are they?
Thalamus, Hypothalamus (and pituitary), Epithalamus (pineal gland). All are mainly grey matter
What structure makes up 80% of the diencephalon?
Thalamus
What is the thalamus denoted as in the diagram?
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Blue colour
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What is the role of the thalamus?
Sensory relay station
What are the groups of nucleii present in the thalamus?
Anterior
Medial
Lateral - involved in processing sensory information
What separates the hypothalamus from the thalamus?
Separated by the hypothalamic sulcus
What is the main function of the hypothalamus?
Main visceral control centre and is essential for overall homeostasis
What is included in the homeostatic control of the hypothalamus?
Autonomic Control Centre
Body temperature regulation
Regulation of food intake
Regulation of water balance & thirst
Regulation of sleep-wake cycle
Control of endocrine system functioning
Where do the internal carotid arteries enter the skull?
Through the carotid canal to supply the brain
Where do the two vertebral arteries enter the skull?
Through the foramen magnum to supply the brain
What are the branches of the ICA supplying the brain?
Anterior cerebral artery
Middle cerebral
Posterior communicating arteries
(ACA and MCA supply a large part of the cerebral hemispheres)
Where is the basillar artery formed and what forms it?
Formed on the ventral surface of the brainstem
Formed by the vertebrak arteries joining together
What does the vertebrobasillar system supply
Supplies the brainstem and the cerebellum
Where does the basillar arteriy end?
•The basilar artery finally ends at the level of the midbrain by dividing into two Posterior cerebral arteries (PCA) which supplies the posterior part of the cerebral hemispheres
What does the circle of willis protect against?
Protective feature against vaso-occlusion of large arteries
What are the labelled vessels?
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What does the anterior cerebral artery supply?
Medial aspect of cerebral hemispheres excluding Occipital lobe.
What does the middle cerebral artery supply?
Supplies the lateral aspects of the cerebral hemispheres
What does the posterior cerebral artery supply?
Inferior aspect of cerebral hemispheres and ocipital lobe
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Where do superficial and deep veins of the brain drain?
They drain into venous sinuses which lie between 2 layers of dura mater
What do the dural venous sinuses join together to form?
The dural venous sinuses join together to ultimately drain into the Internal Jugular Veins.
What are the following structures?
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What are the structures that pass throught the cavernous sinus?
OTOMCA
Occulomotor
Trochlear
Ophthalmic
Maxillary
Carotid Artery
Abducent