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25 Cards in this Set
- Front
- Back
Describe the basic functions of calcium & where it is stored |
calcium salts in bone provide structural integrity of the skeleton: 80% of calcium is found within cortical bone, 19% is found within the sponge-like Trabecular bone. Calcium ions in extracellular & cellular fluids are essential to normal function of a host of biochemical processes including Neuromuscular excitability, blood coagulation, hormonal secretion, enzymatic regulation. |
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Describe the basic functions of phosphorous |
ATP, Phosphate bufer system, DNA, RNA, Phospholipids, Nucleotides, Covalent modifications, Signaling molecules |
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Describe the basic function of Vitamin D (Calcitrol) |
Raises blood calcium in 3 ways 1. Increases Calcium ion absorption b y the small intestines by increasing the transcription of TRPV6 through a steroid receptor. 2. increase calcium & phosphate resorption from the skeleton as it binds to hematopoietic stem cells & cause differentiation of osteoclasts. 3. Weakly promotes the reabsorption of calcium ions by the kidney cells (less Ca+ excreted) |
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Describe the location of Magnesium in the body |
mineral found in large quantities in bones & muscles |
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Describe the digestion, absorption & food sources of Vitamin D |
- de novo synthesis & Diet: fatty fish, oils, fortified foods like milk, cereal, & breads - Age decreases the ability of skin to produce Vitamin D3 due to decreases in kidney & liver function. - Sunscreen & obesity decrease the body's ability to synthesize Vitamin D3 |
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Describe the digestion, absorption & food sources of Magnesium |
Carrier facilitated process - TRPM6 Simple diffusion: kidneys control the amount of magnesium by altering excretion. Magnesium lactate & Magnesium Chloride are good supplements b/c of their high bioavailability. Sources: seeds, nuts, legumes, milled cereal grains, milk & dark green vegetables.
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Describe the digestion, absorption & food sources of Phosphorous |
- organically bound phosphate is broken down in the intestines by phosphatase - absorption is dependent on the proximal portion of the duodenum in low pH - phosphorus from vegetarians is in the form of phytate which is poorly digested by humans Sources: meats, eggs, nuts, legumes, fortified cereals & grains - yeast from breads produce phytase which is an enzyme needed to breakdown phytates |
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Describe the digestion, absorption of Calcium |
Absorption: Duodenum (acidic medium) higher rate of calcium absorption. - ~30% of dietary calcium absorbed - largest amount of calcium absorption occurs in the ileum Actively transport by TRPV6 in the intestines. Vitamin D stimulates transcription of this calcium transporter. Initiated by low serum Calcium levels. - Calcium is absorbed more efficiently in an acidic environment |
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Describe Food sources of Calcium |
Dark green leafy vegetables, sardines, canned slamon, Clams, oysters,
fortified foods: orange juice, milk, tofu, breads, ice cream, yogurt, cheese
Dietary fiber (>30g/day), phytates, & oxalates found in foods like rhubarb inhibit calcium absorption |
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List the clinical s/sx & diseases associated with deficiencies of Vitamin D |
Rickets: disorganized & hypertrophy of chondrocytes, failure of cartilage calcification & endochondral ossification, the metaphyses of rapidly growing bones are widened, uneven, concave or cupped due to the delay or absence of calcification. Osteomalacia: lack of mineralization (poor osteoid), osteopenia, deep bone pain. Osteoporosis: cause is related to calcium loss due to high meat protein diets, phosphorylated soft drinks, smoking, lack of exercise, high caffeine intake. Treatment: elimination of risk factors, exercise, calcium supplements, Estrogen administration. Hypocalcemia: Hypophosphatemia: |
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List the clinical s/sx & diseases associated with deficiencies of Calcium |
CATS go numb: convulsions, arythmias, tetany, numbness/parasthesias in hands, feet, around mouth & lips
Osteomalacia & colon cancer |
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List the clinical s/sx & diseases associated with deficiencies of Phosphorous |
Rare Patients taking drugs called phosphate binders.
- Problems include a decrease in ATP, GTP, UTP, CTP, TTP & other organic phosphates.
- Neural, muscular, skeeltal, hematologic, renal & other abnormalities |
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List the clinical s/sx & diseases associated with deficiencies of Magnesium |
Rare but includes tremors, muscle spasms, mood swings, anorexia, nausea, vomitting.
Causes: renal disease, diuretic therapy, malabsorption, hyperthyroidism, pancreatitis, Kwashiokor, Diabetes, Parathyroid gland disorders |
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What populations are at risk for Vitamin D deficiencies |
Breastfed infants, older adults, people with limited sun exposure, darker skin pigments, certain religious groups (sun exposure),
Malabsorption syndrome, severe liver disease, kidney disease, drugs, higher latitudes, |
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List the clinical signs and diseases associated with vitamin D toxicity. |
Hypercalcemia, hypophosphatemia, calcification of soft tissue, constipation, polyuria, polydipsia, kidney stones, headaches, weakness |
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List the clinical signs and diseases associated with Calcium toxicity. |
Constipation, Nausea, Poor appetite, vomiting, muscle twitches, weakness. > 2000 mg per day Hypercalcemia, calcification in kidneys, malabsorption of other minerals (iron, zinc, magnesium) |
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Explain the importance of calcium and vitamin D for bone health and prevention of osteoporosis. |
1. Roles in the prevention of: colon & breast cancer
2. Vitamin D allow more calcium to be taken up into the body, and calcium is a necessary component of strong bones = removal of calcium will decrease the density of bone and lead to osteoporosis |
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Define EAR, RDA, AI, UL, DRI |
Estimated average requirement Recommended dietary allowance adequate intake tolerable upper intake level Dietary reference intakes |
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Describe the effect of PTH on the kidneys |
PTH increases Vitamin D synthesis by stimulating 1-alpha hydroxylase activity
stimulates calcium reabsorption yet stimulates phosphorus excretion |
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Describe the effect of PTH on the bones |
Osteoclasts have no PTH receptors Osteoblastic stromal cells + RankL receptors + PTH increase generation of active bone resorbing osteoclasts |
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Describe the effect of PTH on the intestines |
PTH has the secondary effect on calcium absorption through the activity of Vitamin D |
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Describe phosphorus regulation |
PTH controls phosphorus Vitamin D controls phosphorus |
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Describe the synthesis of Vitamin D |
Vitamin D3 synthesis occurs in Keratinocytes in the skin 7-dehydrocholesterol is photoconverted to previtamin D3, then spontaneously converts to Vitamin D3 Pre-vitamin D3 will become degraded by over exposure to UVB light & thus is not overproduced. 1,25-dihydroxy-D (Calcitriol) feeds back to inhibit its production |
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Describe the behavior of Calcitonin |
secreted from the C-cells in the thyroid
lowers Calcium levels in the blood by promoting the deposition of calcium into bone by inhibiting osteoclasts. |
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Describe the daily recommendations |
4-8y = 100% Calcium, 150% Vitamin D 14-18y = 130% Calcium, 150% Vitamin D 51-70y = 100% Calcium, 150% Vitamin D 70y+ = 120% Calcium, 133% Vitamin D
100% calcium = 1000 mg 150% Vitamin D = 600 mg |