External features of the brain Flashcards
What are the three coverings of the brain?
Outer dura mater (periosteal and meningeal layer), arachnoid mater and pia mater
Folds of dura mater separate the brain into different sections, what are they?
Falx cerebri runs from the cristi galli to the occipital crest and separates the two cerebral hemispheres
Falx cerebelli separates the two cerebellar hemispheres
Tenorium cerebelli separates the cerebellum from the cerebrum
Diaphragma sellae is a small circular fold of dura mater that covers the sella turcica and has a small opening to allow the passage of the pituitary stalk
Where is the venous drainage ?
Dura mater makes the venous sinuses that deoxygenated blood run through
Where does the CSF and brain blood arteries flow?
They flows in the subarachnoid space to surround the brain and CSF provides buoyancy. CSF leaves the subarachnoid space via the arachnoid villi which protrude out into the dura mater and CSF leaves the brain and enters the bloodstream into the venous drainage.
Which meningeal layer travels into the ventricles?
The pia mater travels down into all the sulci and even into the ventricles to line them with the ependymal cells
What is different about the dura mater in comparison to the others?
The dura mater has its own blood supply and also is pain sensitive unlike the brain itself
Describe the process of CSF production.
CSF is firstly produced in the lateral ventricles by the choroid plexus. It flows into the third ventricle through the interventricular foramen (Monroe). From the third ventricle it goes into the fourth ventricle via the cerebral aqueduct. It leaves the fourth ventricle via medial and lateral apertures into the subarachnoid space.
What is the pathology of hydrocephalous?
Hydrocephalous is a condition in which there is too much CSF build up in the brain. Characterised by enlarged ventricles and often a block cerebral aqueduct. Causing an increase in intracranial pressure, a large head, narrow sulci and flattened gyri.
What is the insula and what is it associated with?
It is the cortex that is located deep to the lateral fissure on the underside of the temporal lobe. It associated with pain, empathy, full bladder and temperature.
Where is the uncus found
It is found at the anterior extremity of the Para hippocampal gyrus
Where is the amygdala found?
The amygdala is seen next to the hippocampus and deep in the temporal lobe. It is involved in fear and is part of the limbic system
Where is the primary motor cortex?
The precentral gyrus
Where is the primary sensory cortex?
The postcentral gyrus
What are the main fissures of the brain?
Longitundinal, lateral, parietooccipital, central
What separates the anterior and posterior lobe of the cerebellum? And which one is bigger?
The primary fissure separates them both and the posterior lobe is much bigger
