Vit A Flashcards
AKA
____ soluble
necessary for
retinoic acid
lipid
formation of visual pigments in retinal photoreceptor cells
Source for betacarotene (provitamin a)
converted to ___ by the human body
process is ___, so excessive intake does not result in
BC is mostly found in
Animal sources provide
with absorption, become
best sources animal derived
plants
retinal
regulated, high levels of VA
dark colored veggies and fruits
preformed VA as retinal/retinol/retinoic acid
stored in lipid globules in hepatic stellate cells
liver, fish, eggs
Retinol needed for
retinoic acid for
Photoreceptor cells in eye
retinol converted to ___ in cone cells and ___ in rod cells
used for
normal vision
cell growth/differentiation
cone cells, absorb light and color vision, rod cells for motion/night vision
iodopsin, rhodopsin
absorbs light/transmitting to brain
Defic
areas
in resource rich areas, def assoc w
3rd MC in world
resource poor countries w malnutrition
fat malabsorption (PI, Celiac, LD, SI resect)
Main findings
Xerophthalmia
Hyperkeratization
Keratomalacia
further
persistent defic
also see
patho dryness of conjunctiva and cornea- dec lacrimal sec
Bitots spots
Softened cornea, scarring
corneal ulcer/necrosis
night blidness and def of visual pigmnet (irreversible)
skin cx- lost hair/hyperkeratosis
Toxicity
such as
acute sx after
results in
massive consumption of VA (animal source)
consuming polar bear liver
150mg in adults, 100mg in children
inc ICP- NV/vertigo/blurry vision/bulging fontanelle
Chronic toxicity results from
sx
labs
high dose VA for months
ataxia, vis impair, bone pain, skin changes (dry, alopecia)
elevated LFT, hyperlipidemia
