Minerals, Nutrition, Vitamins, and Trace Elements Flashcards
Magnesium is the second most abundant intracellular ion with the majority residing in the ___, ___, and ___.
bone; muscle; soft tissue.
Function of Magnesium.
Acts as a cofactor for over 300 enzymes; neuromuscular activator; role in metabolic pathways.
Where is magnesium absorbed and regulated?
Absorbed within the intestines and regulated via the kidneys.
Which hormone is responsible of increased tubular reabsorption and GI absorption of magnesium?
Parathyroid Hormone (PTH).
What hormones are responsible for increasing Mg concentrations?
Aldosterone and Thyroxine.
Clinical usefulness of magnesium.
Cardiovascular, metabolic, and neuromuscular disorders.
What is the most common cause of hypomagnesemia?
Drug induced hypomagnesemia.
What are miscellaneous causes of hypomagnesemia?
Reduced magnesium intake, decreased magnesium absorption, increased renal excretion, increased endocrine excretion.
How does hypertension affect magnesium levels? Hypotension?
Hypertension - decrease
Hypotension - increase
What is the most common cause of hypermagnesemia?
Acute or chronic renal failure.
What medications may cause hypermagnesemia?
Antacids, enemas, cathartics, other therapeutics.
Decreased neuromuscular reflexes and hemostasis conditions may cause a increase in ___.
magnesium.
Reference range of magnesium.
0.63 - 1.0 mmol/L.
What are the three dyes used for colorimetric measurement of magnesium?
Formazen dye, methylthymole blue, calmagite (reddish-violet complex).
Reference method of magnesium measurement.
Atomic absorption.
The primary source of calcium in the body is held within where?
The bones.
Neuromuscular irritability may the be result of low ___.
calcium.
What is the major form of calcium?
Ionized (active) Calcium.
Free calcium is highly dependent on ___ and ___ status.
albumin; pH.
What three hormones regulate calcium?
PTH, vitamin D, and calcitonin.
As calcium increases, PTH ___.
Decreases.
The parathyroid will detect low blood calcium, which stimulates PTH. How does this process affect bone resorption, urinary loss, and vitamin D production?
Increased bone resorption; decreased urinary loss; increased vitamin D production.
The parathyroid will detect high blood calcium, which suppresses PTH. How does this process affect bone resorption, urinary loss, and vitamin D production?
Decrease bone resorption; increase urinary loss; decrease vitamin D production.
Reference range for calcium.
8.6 - 10.0 mg/dL.
Critical values of calcium.
<6 or >14 mg/dL.
How does acute pancreatitis and vitamin D deficiency affect calcium?
Low calcium levels.
Symptoms of hypocalcemia.
Neuromuscule irritability, CNS changes, cardiac changes.
What is the most common condition for hypercalcemia?
Primary hyperparathyroidism - caused by tumor producing PTH.
Which body systems would be affected by an increased calcium?
Neurologic, GI, Renal, Skeletal, Cardiovascular.
What method is used for calcium measurement?
Colorometric: dye binding.
Reference method to measure calcium.
Atomic absorption.
What are specimen requirements for calcium testing?
Whole blood collected anaerobically in heparinized tube.
How would air exposure affect calcium testing?
pCO2 and H decreases, resulting in decreased calcium.
What is defined as the major intracellular anion?
Phosphorus.
PTH ___ calcium and ___ phosphorus.
increases; decreases.
Vitamin D ___ calcium and ___ phosphorous.
increases; increases.
Growth hormone ___ phosphorus.
Increases.
Reference range of phosphorous.
2.4 - 4.4 mg/dL.
What are some conditions that can result from hypophosphatemia?
Hyperparathyroidism, vitamin D deficiency, decreased intestinal absorption, and increased renal excretion.
What are common diseases where hypophosphatemia may occur?
DKA, COPD, TPN treatment, malignancy.
What are common diseases where hyperphosphatemia may occur?
Acute/chronic renal failure, hypoparathyroidism, chemotherapy, vitamin D toxicity, and intravascular hemolysis.
What is the ideal specimen for phosphorus testing?
Serum or lithium heparin plasma.
Phosphorus undergoes ___ making it elevated in the AM and low in the PM.
Circadian Rhythm.
What testing method is used for phosphorus testing?
Colorimetric.
Bone turnover-remodeling is regulated what hormones?
PTH and Vitamin D.
What analytes can be used to assess bone function?
Vitamin D, PTH, Calcium, Magnesium, Phosphate.
Calcitonin is a tumor marker for ___.
Thyroid.
Why is it not unusual for ALP to be elevated in children?
Due to bone development.
Describe Osteopenia.
A condition that begins as you lose bone mass and your bones get weaker.
Describe osteoporosis.
Decreased bone mass due to aging.
Describe osteomalacia.
Decreased mineralization in the bone; can be caused by Rickets in children or Vitamin D deficiency.
Describe Osteitis fibrosa.
Increased bone reabsorption; histopathological bone lesion. Can be common in hyperparathyroidism and renal failure.
Describe Paget’s Disease.
Increased osteoclastic activity resulting in disordered, excessive osteoblastic activity.
What analytes are elevated in Paget’s Disease?
Calcium and ALP.
Describe osteogenesis imperfecta.
An inherited condition that may lead to low bone mass and fractures due to collagen defects.
What biochemical assessment markers can be used to assess nutrition levels?
Macronutrients: carbohydrates, proteins, fats
Micronutrients: minerals, vitamins, trace elements
A decreased albumin level in a patient with known lack of nutrition indicates what?
Patient is in a starvation mode for low protein state for a long period of time.
What are the fat soluble vitamins?
Vitamin A, E, K, and D.
What are the water soluble vitamins?
Vitamin B complexes, Vitamin C, and carnitine.
Vitamin A (retinol) function.
Vision; growth, reproduction, and immunity.
