L9 - organisation of the nervous system Flashcards
what counts as PNS?
any neuron that projects outside of brain /spinal cord
what is grey matter
cell bodies
what is white matter
axon tracks - pale due to myelin
define gyri
folds in brain
define sulci
grooves between folds in brain
define fissure
big divisions in brain (3 in total)
what is the central canal
hollow canal that runs through length of spinal cord and is continuous with ventricular system of brain
what can be found in the central canal
CSF
describe the lateral ventricles
2 hollow C shaped ventricles one either side of brain
order of ventricles
2 lateral ventricles connected to the 3rd ventricle which is connected to the 4th which has openings into the central canal
where is 4th ventricle located
between medulla and cerebellum
what connects the 3rd and 4th ventricle
cerebral aqueduct
functions of the CSF
buoyancy
protection
removal of waste products
what happens to the CSF?
reabsored back into venous bloodstream
how many meninges layers are there
3
what are meninges layers
layers around the CNS
name the 3 meninges
- pia mater (inner)
- arachnoid mater
- dura mater (outer)
describe pia mater structure
fine, delicate inner layer
vascular
2 cells thick
impermeable layer for containing CSF
pia mater function
protection
allows entry of blood vessels to CNS
provides impermeable layer for maintaining CSF
describe arachnoid mater structure
middle layer, surrounds pia mater
silky - web like
arachnoid mater function
protection
upper limit of sub arachnoid space
what is the subarachnoid space?
space between pia mater and arachnoid mater
what fills the subarachnoid space and from where
CSF from brain ventricles
describe dura mater structure
outer layer
tough
attached closely to cranium
dura mater function
protection
composed of two layers which separate to form sinuses carrying venous blood
how is CSF reabsorbed back into venous bloodstream
goes from subarachnoid space to the superior sagittal sinus via arachnoid granulations
name of sinus in dura mater
superior sagittal sinus
what are the lobes of the cerebral cortex named after
The nearest bone of the skull to them.
what can failure to reabsorb CSF lead to
hydrocephalus.
what connects lateral ventricles to 3rd ventricle
interventricular foramen
