Nervous System Part 3 - Meninges and Ventricles Flashcards
what are minenges?
the protective layers surrounding the brain
what are ventricles of the brain?
areas of the brain that produce cerebral spinal fluid
what are the three layers of meninges surrounding the brain?
outermost: dura mater
- arachnoid mater
innermost: pia mater
what does dura mater translate to?
tough mother
what is the dura mater for?
the external layer of the meninges that is really important for protection of the brain
what does arachnoid mater translate to?
spider mother
what does pia mater translate to?
tender mother
which meninge layer is attached right to the brain and the spinal cord itself?
pia mater
what does arachnoid mater get its name from?
the little fibrous attachments that connect the arachnoid and the pia mater
- they are called trabeculae
- they look like spider webs
what is between the arachnoid and pia mater? (in the subarachnoid space)
cerebral spinal fluid (CSF)
when the dura mater goes more internally to the brain, what is usually there?
in the big fissures of the brain
what follows the dura mater? why
the other meninges layers
- this is so that it allows cerebral spinal fluid from the subarachnoid space to get access to all the areas of the brain
what is the cerebral spinal fluid important for?
protection and nourishment of brain tissue
what do we get when we have the dura mater and the other meninges following down a fissure in the brain?
a dural fold (looks like the inside folds on those big sweet peppers lol)
what happens between the two layers of the dura mater when the dural folds form?
a space called the ‘venous sinus’ forms between the two layers of dura mater when they separate
what are venous sinuses for?
they are areas for drainage of poorly oxygenated blood around the brain (technically veins)
where do venous sinuses form?
within the dural folds
what does the venous sinuses collect?
poorly oxygenated blood from around the brain and they bring it back towards the heart just like any other good vein
in a few spaces of our venous sinuses, what will we get?
a few spots will get outcroppings of arachnoid mater (called arachnoid granulations/villi)
what does the outcroppings of arachnoid mater (arachnoid granulations/villi) in the venous sinuses allow?
this allows the subarachnoid space to send waste products and old cerebral spinal fluid into the venous system
what are arachnoid granulations/villi?
the outcroppings of arachnoid mater in the venous sinuses
what keeps the brain nice and safe from impact?
the cerebral spinal fluid
what are the functions of cerebral spinal fluid?
- protection
- buoyancy (fluid helps lift the brain up so its not fully pressured onto the vertebrae)
- a marker of the health of the nervous system
what are the four ventricles of the brain?
- the two lateral ventricles
- third ventricle
- fourth ventricle
the two lateral ventricles follow which shape?
the basal nuclei
- kind of a C shape from an lateral view and also the anterior view
what are the two lateral ventricles connected by?
together and to the third ventricle by the interventricular foramen
where is the third ventricle of the brain?
tucked into the thalamus. the thalamus surrounds it
how is the third ventricle connected to the fourth ventricle?
by the aqueduct or the cerebral aqueduct
where is cerebral spinal fluid made?
in all four brain ventricles
where is choroid plexus located?
in the ventricles of the brain
what is the choroid plexus?
some crumbly brown stuff in the ventricles of the brain
what is the choroid plexus made of?
- blood capillaries
- specialized cuboid epithelial cells called ependymal cells
what do we do when we want to make cerebral spinal fluid?
- plasma from the blood is going to flow through the ependymal cells
- the ependymal cells will add other substances like proteins
- and CSF comes out into the ventricles
if we want the CSF to leave the ventricles and go into the subarachnoid space, how will they leave the ventricles?
through the lateral (2) or median apertures which all open into the subarachnoid space and sometimes leak into the spinal cord because the spinal cord is also surrounded by meninges and subarachnoid space
what are the two places the CSF can go after the fourth ventricle?
- the subarachnoid space
- central canal (just flow down the fourth ventricle)
what is the central canal?
a little opening in the middle of the spinal cord that runs all the way down.
- this is how we get CSF all the way down through the spinal cord for nutrients and protection more centrally in the spinal cord
