Compare and contrast how the body maintains blood calcium from the diet and from the bones.
What will be an ideal response?
Calcium homeostasis involves a system of hormones and vitamin D. Whenever blood calcium falls too low or rises too high, three body systems respond: the intestines, bones, and kidneys. The calcium in bones provides a nearly inexhaustible bank of calcium for the blood. The blood borrows and returns calcium as needed so that even with an inadequate diet, blood calcium remains normal—even as bone calcium diminishes. Blood calcium changes only in response to abnormal regulatory control, not to diet. A person can have an inadequate calcium intake for years and have no noticeable symptoms. Only later in life does it become apparent that bone integrity has been compromised.
Blood calcium above normal results in calcium rigor: the muscles contract and cannot relax. Similarly, blood calcium below normal causes calcium tetany—also characterized by uncontrolled muscle contraction. These conditions do not reflect a dietary excess or lack of calcium; they are caused by a lack of vitamin D or by abnormal secretion of the regulatory hormones. A chronic dietary deficiency of calcium, or a chronic deficiency due to poor absorption over the years, depletes the bones. Again the bones, not the blood, are robbed by a calcium deficiency
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The more intense your workout, the more your body relies on carbohydrates to fuel it. Duration and intensity affect the degree to which carbohydrates and fat contribute to overall energy production. Review the following statements on the effect that intensity and duration have on glucose and glycogen use and select all those that apply.
a. Blood glucose and muscle glycogen contribute less than a third of the energy needed to sustain high-intensity exercises. b. Stored muscle glycogen is not used for energy during low- to moderate-intensity physical activity. c. Completely depleting your glycogen stores will result in "hitting the wall." d. Lactate can be used for energy.
Vitamins can be divided into 3 groups: water-soluble, fat-soluble, and alcohol-soluble.
Answer the following statement true (T) or false (F)
Which of the following would be a good choice to increase the dietary fiber intake of a school-age child?
a. mix 1/2 cup of bran flakes with 1/2 cup of the child's favorite breakfast cereal b. offer whole fruits instead of fruit juice c. mix some black beans with the ground turkey when making tacos d. all of these are good strategies
A mother visits a physician because she is concerned her 4-month-old infant has lactose intolerance. What should the physician recommend for dietary changes to relieve the infant's lactose intolerance, and how will this impact the child's lactose tolerance in the future?