L3: Trace Elements Lecture Review

Comprehensive vocabulary flashcards covering the definitions, clinical conditions, analytical methods, and laboratory evaluations of trace elements and heavy metals.

Trace Elements

Minerals present in living tissues in small amounts that function as enzyme cofactors, electron donors/acceptors in oxidation-reduction reactions, and provide stability to certain structural biomolecules.

Heavy Metals

Naturally occurring elements that have a high atomic weight and a density greater than $5\times$ that of water (e.g., Pb, Hg, Tl, Cr, Cd, As).

Essential Trace Elements

Elements required by the body in trace amounts that, when deficient, result in an impairment of normal health, function, or development which is corrected by physiologic supplementation.

Activator

An inorganic enzyme cofactor, which includes trace elements and some electrolytes.

Royal blue top

The general tube or container used for trace element, toxicology, and nutritional analyses.

Tan top

A specialized tube used exclusively for lead (Pb) determinations, containing the anticoagulant $K_2EDTA$.

Atomic Absorption Spectrophotometry (AAS)

The most commonly used method for trace metals, measuring element concentration by the absorption of light while the element is in an unionized, unexcited ground state.

Atomization

The process of breaking the chemical bonds of molecules in a sample using heat (flame or graphite furnace) to recover free atoms for analysis.

Inductively-Coupled Plasma (ICP)

The fourth state of matter, containing equal positive and negatively charged particles, used as an excitation source in Atomic Emission Spectroscopy.

Atomic Emission Spectroscopy (AES)

An analytical method where detection and quantification are based on the light emitted as excited atoms return to their ground state.

Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

An analytical combination that utilizes ICP to ionize atoms and Mass Spectrometry to separate them based on their mass-to-charge ratio.

Anodic Stripping Voltammetry

An electrochemical technique where metal ions are pre-concentrated onto an electrode via negative voltage and then stripped off through oxidation when the voltage becomes more positive.

Adsorptive Stripping Voltammetry

An electrochemical technique based on intermolecular forces (like van der waals) where a substance adsorbs onto an electrode and is later stripped off.

Aluminum (Al)

A non-essential trace element that is the most abundant metal in the earth’s crust; chronic toxicity resembles Alzheimer’s disease.

Arsenic (As)

A tasteless, odorless toxic metalloid that binds to sulfhydryl groups in proteins like keratin and amino acids like cysteine.

Rice Water Diarrhea

A clinical symptom associated with acute arsenic exposure, similar in appearance to that caused by cholera.

Mee’s Lines

White lines formed on the fingernails when arsenic binds to the sulfhydryl groups in keratin.

Blackfoot Disease

A complication of chronic arsenic exposure resulting in peripheral vascular disease of the extremities, leading to numbness and gangrene.

Cadmium (Cd)

A soft, bluish-white metal whose absorption from the gut is inversely proportional to the body's iron stores.

Itai-Itai

A severe type of osteomalacia and osteoporosis resulting from the long-term consumption of cadmium-contaminated rice.

Chromium ($Cr^{3+}$)

The biologically active valence state of chromium that is essential in the metabolism of glucose and fats as a component of glucose tolerance factor.

Copper (Cu)

The 3rd most abundant trace element in the human body, serving as a cofactor for enzymes like Lysyl Oxidase and Superoxide Dismutase.

Ceruloplasmin

The principal copper-containing protein (binding 6 atoms) that plays a role in oxidizing iron for incorporation into hemoglobin.

Menke’s Disease

A rare X-linked recessive congenital defect of copper absorption characterized by brittle or 'kinky' hair (Pili Torti).

Wilson’s Disease

An autosomal recessive disease resulting from impaired biliary copper excretion, causing excess copper deposits often seen as Kayser-Fleischer rings.

Kayser-Fleischer Rings

Green to brown discolorations in the periphery of the cornea caused by copper deposits.

Iron (Fe)

The most abundant essential trace element in the body, existing in ferrous ($Fe^{2+}$) and ferric ($Fe^{3+}$) states.

Transferrin

Also known as siderophilin, it is the plasma protein that binds ferric iron ($Fe^{3+}$) for delivery into cells.

Hemochromatosis

Also known as Bronze Diabetes, an autosomal recessive iron overload disorder resulting in high iron absorption and accumulation in the liver.

Basophilic Stippling

RBC inclusion bodies formed when lead (Pb) inhibits pyrimidine 5’ nucleotidase, preventing the clearance of degraded RNA.

Mercury (Hg)

Also known as quicksilver or hydrargyrum, it is a liquid metal at room temperature that reacts with proteins having sulfhydryl groups.

Minimata Disease

A condition caused by methylmercury poisoning from the daily consumption of large quantities of contaminated fish and shellfish.

Locura Manganica

Also known as manganese madness, a condition described in miners suffering from acute manganese aerosol intoxication.

Molybdenum (Mo)

A trace element that serves as a cofactor for Sulfite Oxidase, an enzyme crucial for the final stages of protein degradation and energy production.

Keshan’s Disease

An endemic cardiomyopathy associated with a deficiency in Selenium (Se).

Acrodermatitis Enteropathica

A genetic disorder affecting zinc absorption characterized by scaly, erythematous plaques in the periphery.

Reinsch Test

A general screening test for heavy metals based on their ability to oxidize elemental copper, resulting in a black or gray plating on the copper wire.