forebrain and ventricles Flashcards
what is the ventricular system comprised of?
white matter, grey matter and spaces that is an organised 3D collection of structures
when the brain is cut into coronal section what is seen?
depends on where the cut is made
through frontal: anterior to brainstem and therefore see it intact and see the temporal lobe, lateral ventricles and corpus callosum
if cut through centre then cut through brainstem and therefore can see the grey matter structures of the cerebrum, the cerebellum and the frontal or parietal lobe
if cute through back then can see the back of cerebellum and the parietal lobe
what can be seen in a sagittal section of the brain?
cortex and white matter
if it is medial then can see the C shape which is the ventricular system and the deep nuclei of grey matter
if it is mid sagittal then can see the corpus callosum, diencephalon, middle of midbrain, pons and medulla
what will you see in a horizontal slice of brain?
anything C shaped will appear twice, can see grey matter structures and cavities - corpus callosum will be anteriorly and posteriorly
inferior - part of the occipital and temporal lobe
middle - midbrain
what is the cerebrum for?
it is for associating words with colours, structures, tastes and smell - memorising, integrating, learning and understanding
what functions are the brainstem for?
primitive functions
what is the structures of the cerebrum?
it is the forebrain and therefore derived from the prosencephalon - it consists of two parts - the outer brain or cerebral hemisphere from the telencephalon and the inner from the diencephalon. Together they are responsible for higher level processing
what develops into the ventricular and nervous system?
dilations of the neural tube.
the tissue around the vesicles develops into the nervous system and the spaces into the ventricular system.
what develops into the hemispheres?
two lateral swellings of the telencephalon develop into them and are linked by the lamina terminalis
why is there C shaped cerebral hemispheres with squished diencephalon in centre?
the tissue around the telencephalon grows faster than everything else and obscures the diencephalon and overgrows the rest of the neural tube - first vesicle growing faster results in folding and inner and outer layer
what is the telencephalon in development?
two swellings either side of the midline connected by the lamina terminalis
what does the lamina terminalis develop?
the corpus callosum and the anterior commissure
what is the lumen of the neural tube filled with?
fluid - CSF
what shape are the lateral ventricles?
they are a C shape from the frontal to the occipital and temporal lobes
what is in the diencephalomn?
the thalamus, hypothalamus and a very small space - third ventricle
where is the fourth ventricle?
it is a diamond shaped space found between the pons, medulla and cerebellum and continues with the canal and spinal duct
where is the anterior most part of the ventricular system and what is this?
the anterior horn of the lateral ventricle and is found in the frontal lobe
what is the antrum and the body?
the body extends from the frontal through parietal and the antrum meets with the posterior horn in the occipital lobe
where is the inferior horn?
in the temporal lobe
what are the connects between ventricle for and what are they?
for the flow of CSF - lateral to third is the interventricular foramen and third to fourth is the cerebral aqueduct
what happens to fluid in the fourth ventricle?
it leaves via the lateral or median apertures or through the central canal and is allowed to bathe in the subarachnoid spaces
what is the course of the lateral ventricle?
it follows the lobes of the brain
why are many structures of each hemisphere C shaped?
the telencephalon folds over the developing diencephalon and as a consequences many internal structures are C shaped as well
when is the 5 vesicle stage?
5 weeks post conception and consists of the lateral, third and fourth ventricle, cerebral aqueduct and the central canal
what are the names for the lateral and median apertures of the fourth ventricles?
the media is the foramen of Magendie and the lateral are the formaina or Luschka
where is the third ventricle?
between the two thalami
what is contained within the ventricles that produces CSF?
choroid plexus - collection of blood vessels and specialised cells
what is the function of CSF?
floats around the ventricles and the subarachnoid space to give buoyancy, support, shock absorption and transport of waste and nutrients - once left fourth will bathe structures of the CNS up and down
what happens to the CSF eventually?
drains into the venous system via arachnoid granulations/villi and into sinuses predominately the superior sagittal sinus
what is a cistern?
where the subarachnoid space is expanded
what is the largest cistern?
the magna - at end of fourth ventricle