Week 6 - External features of the brain Flashcards
What connects the left and right hemispheres of the cerebrum?
What seperates the 2 large hemispheres?
How many lobes is each hemisphere divided into?
corpus callosum
the deep longitudinal fissure separates them.
divided into 4 lobes.
The surface of the cerebrum is the cerebral cortex. The cerbral cortex is folded.
What are the folds known as? and what are the grooves known as?
folds = gyri
- is a pre and post central gyrus
grooves = sulci.
- is a central, lateral and parieto-occipital sulcus
what is the functional role of the frontal lobe.
frontal lobe = motor area
- has the precentral gyrus = primary motor coretx area.
What is the function of the parietal lobe?
parieteal = sensory area
- has post central gyrus - primary somatosensory area.
What is the function of the Occipital lobe?
occipital = visual area
- occipital poles = primary visual cortex,
What is the function of the temporal lobe?
temporal = auditory area
Where is broca’s area and why is it important?
What happens if there is Broca’s aphasia?
Broca’s area is in the precentral cortex
- needed for production of speech
- so broca’s aphasia causes a defecit in speech and language production.
The understanding of words is Wernicke’s
What is the role of the cerebellum?
What seperates the cerebellum?
What are the high number of folds called?
What is the name of the ‘tree of life’ in the cerebellum.
- for the coordination of movement
- motor learning
- found in the posterior cranial fossa
Tentorium cerebelli seperate it.
- has highly folded cortex-folia.
- The tree of life = arbor vitae and is composed of white matter.
The brain and spinal cord are covered with membranes called meninges.
What are they suspended in and what are the 3 layers called?
meninges are suspended in CSF.
3 layers : DAP
dura mater (outer layer)
arachnoid mater (middle)
Pia mater (inner)
what does ‘dura mater’ mean?
what are the 2 layers within the dura mater?
What are the 4 infoldings of the dura?
means tough mother.
- 2 layers = periosteal and meningeal
-4 inholdings:
- falx cerebri
- falx cerebelli
- Tentorium cerebelli
- Diaphragma sellae.
which of the 3 meningeal layers that surrounds the brain and spinal cord is very thin and cannot be see with the nakes eye?
The pia mater - it is adhered to the surface of the brain and spinal cord.
what are the following meningeal spaces between….
- Epidural/extradural
- Subdural
- Subararachnoid
- betweeb skull and dura
- between dura and arachnoid
- between arachnoid and pia.
What is the significance of the CSF?
- protects the brain by providing cushion against trauma.
- provides nutrients to the brain
- Prevents nerves and blood vessels from being compressed between the brain and skull.
Functions
* The CSF acts as a shock absorber.
* Provides buoyancy preventing compression.
* Homeostasis and metabolism
Where is CSF produced?
CSF is produced by the chroid plexus
it is ciruclated through the ventricles and is reabsorbed into the dural sinuses by the arachnoid villi.
describe the steps in the CSF ventricular system.
- The CSF produced in the lateral ventricles moves through the interventricular foramen (of Monro) into the 3rd ventricle.
- Then descends through the cerebral aqueduct into the 4th ventricle.
- In the 4th ventricle the CSF can drain either through the medial or lateral apertures (Magendie, Luschka).
- CSF passing through the median aperture goes into the Cisterna Magna
- CSF passing through the two lateral apertures goes into the cerebellopontine cisterns.
- CSF then drain into the subarachnoid space.
- Finally CSF is reabsorbed into the dural venous sinus through arachnoid granulations.
Where is CSF reabsorbed?
into the dural venous sinus through arachnoid granulations.
What is hydrocephalus?
when CSF flow is blocked, CSF builds up and increases the pressure within the cranial cavity.
Enlarged lateral ventricles can show this on a x-ray scan.
