Topography of the Brain Flashcards
What is a nervous “tract”?
Fibre pathway passing through the CNS carrying a specific modality
(eg. motor fibres/pain sensation)
What is white matter and what is grey matter?
White matter - myelinated axons
Grey matter - neuronal cell bodies
What are collections of neuronal cell bodies inside and outside of the CNS called?
- Inside CNS: nucleus
- Outside CNS: ganglion
What are the ventricles of the brain?
Spaces within the brain that are filled with CSF
What are the four ventricles of the brain and where are they?
- 2 lateral ventricles (L&R), within each cerebral hemisphere
- III ventricle, within the diencephalon
- IV ventricle, between pons, medulla and cerebellum
Where does the internal carotid artery enter the skull to supply blood to the brain?
- the foramen lacerum (carotid canal)
Where do the vertebral arteries enter the skull to supply the brain? What arteries are they a branch of?
- through the foramen magnum
- Branches of the subclavian arteries
What is the function of the circle of Willis?
Protection against occlusion of large arteries supplying the brain
Which arteries contribute to the circle of Willis?
- Internal carotid arteries
- Vertebral arteries (via Basilar artery)
What are the branches of the ICA supplying the brain?
- Anterior cerebral artery
- Middle cerebral artery
- Posterior communicating artery
What parts of the brain does the anterior cerebral artery supply?
Medial aspect of cerebral hemispheres, excluding the occipital lobe
What parts of the brain does the middle cerebral artery supply?
Lateral aspect of the cerebral hemispheres
What parts of the brain does the posterior cerebral artery supply?
Inferior aspect of the cerebral hemispheres, and the occipital lobe
Describe the venous drainage of the brain
Superficial and deep veins of the brain drain into sinuses which lie between the 2 layers of the dura mater
The sinuses then join and ultimately drain to the internal jugular veins
SLIDE ON EMBRYOLOGY - take a look
cba right now
What role does the brainstem play in providing innervation to the body?
- Pathway for tracts connecting the higher & lower centres
- Brainstem nuclei involved with 10/12 cranial nerves (III-XII)
- Responsible for producing the rigidly programmed automatic behaviours essential for survival
Where is the medulla?
At the base of the brainstem, anterior to the cavity of the IV ventricle
Continues as spinal cord past the foramen magnum
Which cranial nerves emerge from the surface of the medulla?
CN IX, X, XI, XII
How is the medulla connected to the cerebellum?
Via the inferior cerebellar peduncle
What are some of the surface features of the medulla?
- Pyramids and their decussation
- Olives
- Inferior cerebellar peduncle
- Cranial nerve roots (IX - XII)
Two parts of the medulla and their relationship to the IV ventricle?
- Cranial part (superior), open with the IV ventricle posteriorly
- Caudal part (inferiorly), closed around the IV ventricle
What cavity is posterior to the pons of the brainstem?
The IV ventricle
3 divisions of the brainstem?
- Midbrain
- Pons
- Medulla
Surface features of the pons?
- Middle cerebellar peduncle
- Cranial nerves V, VI, VII, VIII
