Essential Ions in Biology

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Questions and Answers

What role does iron play in the respiratory chain?

It acts as a structural component of hemoglobin.

It serves as an electron carrier. (correct)

It functions as an enzyme in cellular respiration.

It is primarily responsible for ATP production.

Which of the following correctly describes how iron is transported in the blood?

Through myoglobin found in the liver.

In complex with ferritin in plasma.

Via transferrin, a glycoprotein. (correct)

Bound to hemoglobin exclusively.

What form is iron stored in within ferritin?

Fe+1 form.

Fe+3 form. (correct)

Elemental iron.

Fe+2 form.

What is the primary function of hemosiderin?

Act as a storage protein for iron. Signup and view all the answers

Which statement about iron absorption is accurate?

Fructose promotes iron solubility for absorption. Signup and view all the answers

What condition may arise from iron deficiency?

Anemia. Signup and view all the answers

How quickly does the intestine respond to iron depletion during erythropoiesis?

More rapidly than when liver iron storage is reduced. Signup and view all the answers

Which protein is known for facilitating iron transport from the intestinal mucosa?

Transferrin. Signup and view all the answers

What primarily causes decreased oxygen carrying capacity in the blood?

Excessive blood loss Signup and view all the answers

Which of the following can lead to anemia due to decreased blood formation?

Renal insufficiency Signup and view all the answers

What requirement must be met by iron compounds used for replacement therapy?

Must be biologically available Signup and view all the answers

In which case are parenteral iron preparations indicated?

Defect in iron absorption due to partial gastrectomy Signup and view all the answers

What is considered a lethal dose of iron for humans?

150 to 200 mg/kg body weight Signup and view all the answers

What characterizes stage one of iron poisoning?

Gastrointestinal distress Signup and view all the answers

What is a common treatment for iron poisoning?

Gastric lavage Signup and view all the answers

Which complication may occur months after surviving iron poisoning?

Gastrointestinal scarring Signup and view all the answers

What is the primary route of administration for deferoxamine when used for iron chelation?

Parenteral Signup and view all the answers

Which iron preparation is considered the drug of choice for treating uncomplicated iron deficiency anemia?

Ferrous sulfate Signup and view all the answers

What potential issue can arise from orally administered iron in relation to tetracycline?

Decreased absorption of tetracycline Signup and view all the answers

What form of iron is resistant to oxidation and may be superior to ferrous sulfate?

Ferrous fumarate Signup and view all the answers

What is a common gastrointestinal side effect of iron salts?

Irritation of gastrointestinal mucosa Signup and view all the answers

What is the primary ingredient in Imferon?

Ferric hydroxide complexed with dextran Signup and view all the answers

How does ferrous gluconate compare to ferrous fumarate and sulfate in terms of irritation?

Equally irritating when equivalent doses are taken Signup and view all the answers

Which route is used for the administration of Iron sorbitex injection?

Intramuscular Signup and view all the answers

What is the typical dosage for ferrous sulfate for treating iron deficiency?

300 mg, two or three times a day Signup and view all the answers

What is a possible side effect of Iron sorbitex that may occur in urine?

Dark coloration on standing Signup and view all the answers

Which iron preparation occurs as pale, bluish green crystals or granules?

Ferrous sulfate Signup and view all the answers

What is the estimated daily intake of copper for an adult?

2-5 mg Signup and view all the answers

What is one of the roles of copper in metabolism?

Synthesis of ceruloplasmin Signup and view all the answers

Why might copper supplements not be necessary for the general population?

Most people obtain sufficient copper from food and water Signup and view all the answers

How does copper assist in preventing anemic conditions?

By facilitating iron absorption Signup and view all the answers

What is the pH range for Imferon?

5.2 - 6.5 Signup and view all the answers

What is one potential effect of large doses of selenium salts when administered orally?

Causes intestinal irritation Signup and view all the answers

Which condition may selenium be used therapeutically to treat?

Kwashiorkor Signup and view all the answers

What role does iodine play in the body?

Synthesis of thyroid hormones Signup and view all the answers

What is the usual daily iodine requirement for an average male?

140 micrograms Signup and view all the answers

Which of the following is a pharmacological action of iodine?

Functions as an expectorant Signup and view all the answers

Loss of adequate dietary iodine can lead to what condition?

Enlargement of the thyroid gland Signup and view all the answers

What is the main pharmacological use of sulfur therapeutically?

Cathartic action Signup and view all the answers

What factor does NOT influence the uptake of iodine by the thyroid gland?

Concentration of iodine in the diet Signup and view all the answers

Study Notes

Essential and Trace Ions

Iron is vital for cell metabolism, electron transport in the respiratory chain, and oxygen transport in higher organisms.
Iron's ability to exist in different oxidation states and form coordination complexes underpins its functions.

Iron Occurrence and Function

Blood System:
- Hemoglobin: Contains heme units with ferrous iron responsible for oxygen transport.
- Plasma: Transferrin protein transports iron in the blood.
Tissue:
- Functional Iron: Myoglobin and other cellular hemes involved in cellular respiration.
- Storage Iron: Ferritin and hemosiderin store iron in the liver, spleen, and bone marrow.
  - Ferritin is water-soluble, stores iron in the Fe+3 form, and is incorporated and released in the Fe+2 form.
  - Hemosiderin is water-insoluble and may be a dehydrated form of ferritin.

Iron Absorption and Deficiency

Iron transport into the intestines is facilitated by ascorbic acid and fructose, keeping iron in a soluble ferrous state.
Intestinal iron absorption is more rapid when erythropoiesis (RBC production) is stimulated.
Iron deficiency leads to anemia, characterized by reduced RBC count or hemoglobin content in the blood.
Anemia results in diminished oxygen-carrying capacity of the blood.
Anemia can be caused by excessive blood loss, blood destruction (due to agents or defective hemoglobins), or decreased blood formation (due to nutrient deficiencies, infections, kidney issues, or malignancies).

Iron Replacement Therapy

Iron compounds for replacement therapy must be biologically available (water-soluble) and non-irritant.
Ferrous sulfate is the standard for comparison with other iron salts.
Sustained-release iron formulations minimize irritation.
Parenteral iron preparations are indicated when oral therapy is ineffective or contraindicated (e.g., malabsorption, gastrointestinal diseases).

Iron Overdose

Iron overdose can be serious and even fatal, particularly in children.
The human lethal dose is estimated to be 150-200 mg iron/kg body weight.
Iron poisoning progresses in stages, with gastrointestinal distress, cardiovascular collapse, shock, and potential death.

Iron Poisoning Treatment

Treatment involves gastric lavage, administration of salts to create insoluble iron salts, deferoxamine to prevent iron absorption, and chelation by deferoxamine to remove iron through urine.

Iron Interactions

Oral iron can interfere with tetracycline absorption.
Ferrous salts can aggravate gastrointestinal diseases.

Official Iron Products

Ferrous sulfate (FeSO4.7H2O): Widely used oral iron preparation, considered the drug of choice for uncomplicated iron deficiency anemia. Can be irritating to the gastrointestinal mucosa.
Ferrous fumarate: Resistant to oxidation, potentially superior to ferrous sulfate and gluconate.
Ferrous gluconate: Good bioavailability, but potential for gastrointestinal irritation.

Parenteral Iron Administration

Iron dextran injection (Imferon): Colloidal solution of ferric hydroxide complexed with dextran, administered intramuscularly for severe iron deficiency anemia when oral therapy is ineffective.
Iron sorbitex injection (Jectofer): Solution of an iron complex, administered intramuscularly.

Copper

Copper is essential for enzymes, hemoglobin synthesis, and bone formation.
The average daily intake is 2-5 mg.
Copper is absorbed from the stomach and upper small intestine, transported in the blood as a copper albumin complex, and ends up in the liver bound to ceruloplasmin.
Copper is found in various forms in the brain and blood cells.

Copper Functions

Hemoglobin Formation: Facilitates iron absorption and stimulates enzymes involved in heme and globin biosynthesis.
Oxidative Phosphorylation: Copper is a constituent of cytochrome oxidase, essential for ATP production.

Selenium

Selenium has a role in cellular respiration and acts as an antioxidant.
High doses can cause intestinal irritation and interfere with blood vessels and blood-forming organs.
Selenium sulfide is used for seborrheic dermatitis (dandruff).

Sulfur

Sulfur is distributed throughout the body in proteins, mucopolysaccharides, and sulfolipids.
Dietary sulfur comes from plant and animal foodstuffs.
Sulfur has been used therapeutically as a cathartic, parasiticide, and stimulant.

Iodine (Iodide)

Iodide is essential for thyroid hormone synthesis (triiodothyronine (T3) and thyroxine (T4)).
Iodine is reduced to iodide in the intestinal tract, making iodide salts the preferred form for administration.
The daily iodine requirement for an average male is 140 micrograms, and for a female is 100 micrograms.

Iodine Functions

Biochemical Role: Synthesis of thyroid hormones.
Pharmacological Actions: Fibrinolytic, expectorant, and bactericidal.

Iodine Absorption and Deficiency

Iodine uptake is influenced by thyroid tissue characteristics, blood iodide levels, and thyroid-stimulating hormone (TSH) levels.
Iodine deficiency leads to thyroid enlargement (goiter).

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Description

Explore the crucial roles of essential ions, particularly iron, in biological systems. This quiz covers iron's function in oxygen transport, its occurrence in blood and tissue, and the mechanisms of absorption and deficiency. Test your knowledge on how iron influences metabolic processes.