Vitamins Flashcards
Where does fat get absorbed in the GI tract?
Jejunum
What is the first step?
Digestion by lipases into smaller particles (emulsions)
What is the second step?
Bile salts come in and form even smaller particles.
Why do we need them?
Because they increase the surface that the hydrophilic lipases can work on. Remember that lipids are hydrophobic molecules and that stabilizes them in a hydrophilic environment such as the lumen of the gut!
Ok, we broke them down to monoglycerides (FFAs). How are they absorbed?
Directly, because they are hydrophobic, hence lipophilic.
How do they reach the apical lumen?
With the help of bile salts.
Are bile salts absorben with them?
NO, they are absorbed in terminal ileum
What else is absorbed along with fats?
Fat-soluble vitamins (A,D,E,K)
Vit E helps in…
…membranes
Vit E def causes…
…acanthocytosis, hemolysis, SC degeneration
Vit E overdose decreases levels of…
vit K!
Vit A def causes..
Night blindness think of rhodopsin->retinal), keratomalacia, xerosis cutis (the same in the skin), bitot spots, IMMUNOSUPRESSION.
Vit A overdose causes…
Teratogenesis, dry skin and hepatotoxicity (think of isotretinoin in acne) in chronic basis.
Acute toxicity consists of…
nausea vomitting vertigo and blurred vision
What vitamin has differenct presentation in adults and children?
VitD
