6: Physiology I Flashcards
Where is CSF produced?
Choroid plexus in brain ventricles
What is the normal volume of CSF?
150 ml
Which space does the CSF circulate in?
Which circulation does it drain into?
Subarachnoid space
Venous circulation
The CSF acts as a ___-absorber.
shock
The CSF supplies the brain with ___ and removes ___.
nutrients
metabolites
How can CSF be obtained to diagnose CNS diseases?
Lumbar puncture
Normal CSF is (clear / coloured).
coloured
What is the embryological origin of the nervous system?
Neural tube
The ___ ___ secretes CSF and is found in the walls of the ___.
choroid plexus
ventricles
What structure is formed by arteries invaginating the neural tube and is the origin of the choroid plexus?
Choroid fissure
The choroid plexus is highly ___.
vascular
CSF is produced by the choroid plexus and passes into the ___ before passing into the subarachnoid space.
bloodstream
Which ions need to be transported into epithelial cells to trigger CSF release?
Na+
HCO3-
Cl-
Secretion of CSF is dependent on the transport of ___ and ions into epithelial cells.
water
Sodium is (actively / passively) transported into epithelial cells of the choroid plexus.
actively transported
Which ventricles of the brain release CSF?
Through which structures does the CSF then pass into the subarachnoid space?
Lateral ventricles
Third ventricles
Fourth ventricles
Medial and lateral apertures
Once CSF has passed through the medial and lateral apertures and circulated in the subarachnoid space, where does it drain?
Dural venous sinus
What is the name given to the thick endothelium found in the capillaries of the brain?
Blood brain barrier
Which type of junction prevents molecules e.g toxins from passing through the blood brain barrier?
Tight junctions
Why is it difficult to deliver drugs directly to the brain?
Blood brain barrier
Anything causing ___ in the cranial cavity can cause increased intra-___ pressure.
swelling
increased intra-cranial pressure
What is hydrocephalus?
Accumulation of CSF in brain (caused by improper secretion or drainage) causing an increase in intracranial pressure
What happens to the ventricles in hydrocephalus?
Hypertrophy
What symptoms are produced by intracranial hypertension?
Headache
Papilloedema (swelling of optic disc causing visual disturbance)
Which nerve, important for vision, is included in the subarachnoid space?
CN II
What is papilloedema?
Optic disc swelling due to increased intracranial pressure
What causes of increased intracranial pressure can cause papilloedema?
Hydrocephalus
Swelling (tumours, hypertrophy)
What particular visual disturbances can be caused by papilloedema?
Enlarged blind spot
Blurry vision
Visual loss
What fluid does the ciliary body produce?
Aqueous humour
Where in the eye does aqueous humour circulate?
Anterior chamber
What is the purpose of aqueous fluid?
Nourishes structures of anterior chamber
Which structure does aqueous humour drain into?
Where exactly is this found?
Scleral venous sinus
Iridocorneal angle
What particular layers of the ciliary body produce aqueous humour?
Pigmented epithelium
Non-pigmented epithelium (outer)
Which ions are transported into pigmented -> non-pigmented epithelial cells to trigger production of aqueous fluid?
Na+
Cl-
Which enzyme helps Na+ and Cl- transport into ciliary body cells?
Carbonic anhydrase
Which contransporter is important in the transport of ions into the anterior chamber?
Na+/K+/2Cl- cotransporter
Inhibitors of which enzyme decrease aqueous fluid production?
Carbonic anhydrase
What are some examples of carbonic anhydrase inhibitors?
Dorzolamide
Acetazolomide
Overproduction of aqueous fluid causes raised ____ ___, which can cause which disease?
raised intraocular pressure
glaucoma
Which drugs are used to treat glaucoma?
How do they work?
Carbonic anhydrase inhibtors
Reduce secretion of aqueous fluid, reducing intraocular pressure
CSF concentration determines intra-___ pressure.
Aqueous fluid concentration determines intra-___ pressure.
CSF - intra-cranial pressure
Aqueous fluid - intra-ocular pressure
