IRON
What type of anemia is characterized by small, pale red blood cells?
Hypochromic microcytic anemia.
What is iodine’s major function?
Synthesis of thyroid hormone (thyroxine).
Which mineral is part of more than 100 enzymes and supports wound healing?
Zinc.
What are the two major body fluid compartments?
Extracellular fluid (ECF) and intracellular fluid (ICF).
What is the chief cation of the ECF?
Sodium.
A patient receiving diuretics develops muscle weakness and cardiac arrhythmias. Lab results show low potassium. Explain potassium’s role in fluid balance and cellular function.
Potassium is the chief cation of the intracellular fluid (ICF). It maintains cellular osmotic pressure and electrical activity.
Low potassium disrupts nerve conduction and muscle contraction, leading to weakness and arrhythmias.
What are the four forms of iron in the body?
Transport iron, hemoglobin/myoglobin, storage iron, and cellular iron.
What hormone directs iodine uptake by thyroid cells?
TSH (thyroid-stimulating hormone).
Which mineral works with vitamin E as an antioxidant?
Selenium.
Which compartment contains plasma and interstitial fluid?
ECF.
What is the chief cation of the ICF?
Potassium.
A 28-year-old female with heavy menstrual cycles reports fatigue and shortness of breath on exertion. Laboratory results show low hemoglobin and low ferritin. The nurse notes the patient drinks tea with every meal. Explain the likely cause of her condition and one dietary intervention.
She has iron deficiency anemia due to chronic blood loss and possibly decreased iron absorption. Tea contains tannins that inhibit iron absorption.
Intervention: Increase intake of iron-rich foods and consume vitamin C (ascorbic acid) with meals to enhance absorption.
What three factors increase iron absorption?
Body need, vitamin C (ascorbic acid), and animal tissues.
What condition results from chronic iodine deficiency and causes thyroid enlargement?
Goiter.
Which mineral enhances insulin activity?
Chromium.
What are the three factors that control fluid balance?
Water, solutes, and separating membranes.
Water flows from what type of solution to what type?
From hypotonic to hypertonic.
A patient with liver cirrhosis presents with ascites and bilateral lower-extremity edema. Serum albumin is low. Explain the physiologic mechanism causing this fluid accumulation.
Low serum albumin decreases colloid osmotic pressure in capillaries. Without adequate plasma proteins to pull fluid back into circulation, fluid shifts into interstitial spaces, causing edema and ascites.
What genetic disease causes excessive iron absorption regardless of liver stores?
Hemochromatosis.
What severe condition occurs from iodine deficiency during fetal brain development?
Cretinism.
Which mineral protects bones and teeth from mineral loss?
Fluoride.
What two pressures control capillary fluid shift?
Hydrostatic pressure and colloid osmotic pressure.
What hormones help maintain hydration by conserving sodium and water?
ADH and aldosterone.
A patient admitted with severe vomiting and diarrhea has decreased blood pressure and low urine output. Which two hormone systems are activated, and what is their effect?
The renin-angiotensin-aldosterone system (RAAS) and ADH are activated.
Aldosterone causes sodium and water reabsorption in the kidneys.
ADH increases water reabsorption.
Together, they conserve fluid to restore blood volume and blood pressure.
What is the UL for iron and why can it be exceeded?
45 mg/day; can be exceeded with supplements and fortified foods.
How is iodine absorbed and excreted?
Absorbed as iodide; unused iodine excreted in urine.
Which mineral is part of sulfur-containing amino acids and keratin?
Sulfur.
What happens when serum albumin is low?
Edema develops.
What mechanism describes blood pressure pushing fluid out and proteins pulling it back in?
Capillary fluid shift mechanism.
A pregnant woman from an iodine-deficient region has an enlarged thyroid gland. What risk does this pose to the fetus, and why?
Severe iodine deficiency during pregnancy can lead to cretinism in the fetus, causing irreversible intellectual disability and impaired growth.
Iodine is required for thyroid hormone production, which is essential for normal brain development.