PHGY 209 Lecture Notes - Lecture 9: Vitamin B12 Deficiency, Pernicious Anemia, Intrinsic Factor
21 Feb 2018
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Hematocrit (taking into consideration that it is a number relative/proportional to plasma volume) Anemias: failure to produce, mature, survive: ineffective maturation: maturation failure anemia. Etiology: deficiencies of vitamin b12 and/or folic acid (both are required for normal synthesis of. Progenitors of rbcs are nucleated cells; when these cells begin to divide, vitamin b12 and folic acid are required for normal red cell maturation. Failure to decrease in size, thus released cells are larger and more susceptible to damage during narrow capillary traversing. Amount of hb is the same; just a failure to mature i. vitamin b12: usually failure to absorb (very little required: 1micogram/d) Main source is animal products (absent from diets of vegans) Intrinsic factor is found in the stomach which binds vitamin b12 to form a complex. Intrinsic factor is secreted by the same cells that secrete gastric acid (parietal cells). The complex travels along the gastrointestinal tract where the vitamin gets absorbed in the ileum.
