Physiology Flashcards
What sites of the brain do not have a BBB
pinneal gland
cirumventricular organs
Where is CSF produced
n the secretory epithelium of the choroid plexus
What is contained in normal CSF
it is clear and colourless
contains little protein
little immunoglobulins
What is hydrocephalus
accumulation of CSF in the ventricular system or around the brain
susequent enlargement of one or more ventricles and increase in CSF
What is normal pressure hydrocephalus
triad of dementia, incontinence and gait disturbances
What is idiopathic intracranial hypertension
condition seen in obese females usually of childbearing age
can cause papilloedmea, headaches etc
no imaging features of hydrocephalus
What is the purpose of the aqueous humour
a specialised fluid that bathes the structures within the eye
procides oxygen and metabolites and contains bicarbonate
What is the function of bicarbonate in the aqueous humour
buffers the protons produces in the cornea and the lens
What are the two epithelial layers in the ciliary body and posterior surface of the iris
the pigment epithelium of the retina
the non pigmented epithelium layer
What happens when photoreceptors are exposed to light
they hyperpolarise
they are usually depolarised
What enables the brain tp perceive light
the change in sodium with light (sodium channels closed in light and open in dark)
What is different about photoreceptors compared to other neurons
they are usually at a depolarised resting membrane potential of -20 compared to -70 of most cells
What happens to sodium channels when exposed to light
they close
what happes to the membrane potential with light exposure
hyperpolarises
What effect does light have on the visual pigment molecules
light converts 11 cis retinal to all trans retinal (vit A)
