The movement of either eye into an up/right, up/left, down/right, down/left, up, down, right, or left position of gaze involves the linked and associated contractions and relaxations of multiple eye muscles, of the same eye and of the opposite eye, at the same time.ith the left eye looking to the right, if the IO muscle also were to contract, the front of this eye would move upward as well. Both eyes then would be looking up and to the right. This yoked or conjugate movement of these two muscles, right SR and left IO, is depicted in the first (top/left) image of the chart above.
Phytatesâwhich are present in whole-grain breads, cereals, legumes, and other foodsâbind zinc and inhibit its absorption [ 2, 12, 13 ]. Thus, the bioavailability of zinc from grains and plant foods is lower than that from animal foods, although many grain-and plant-based foods are still good sources of zinc [ 2 ].
In general, the digestive system is set up to maximize absorption; there is no regulation of the amounts of substances absorbed into the body. A notable exception is iron, in which daily dietary absorption is regulated so that it matches daily iron loss.The reason that absorption must be carefully regulated is that the body does not possess a physiological mechanism for regularly eliminating iron from the body.he transferrin saturation (percent of transferrin occupied by iron) is measured to determine if an individual has an excessive load of iron in the body. The normal transferrin saturation is in the range of 20-45%. Iron absorption by the enterocyte is programmed to match the body's needs.