Chemical Elements in the Human Body (Major, Lesser, and Trace Elements)

Vocabulary flashcards covering the major elements and trace elements, with their roles as described in the lecture notes.

Oxygen (O)

Major element; about 65% of total body mass. Part of water and many organic molecules; used to generate ATP.

Carbon (C)

Major element; about 18.5% of total body mass. Forms backbone chains and rings of all organic molecules (carbohydrates, lipids, proteins, nucleic acids).

Hydrogen (H)

Major element; about 9.5% of total body mass. Constituent of water and most organic molecules; as H+, makes body fluids more acidic.

Nitrogen (N)

Major element; about 3.2% of total body mass. Component of all proteins and nucleic acids.

Calcium (Ca)

Lesser element; about 3.6% of total body mass. Contributes to hardness of bones and teeth; Ca2+ is needed for blood clotting, hormone release, contraction of muscle, and other processes.

Phosphorus (P)

Major element; about 1.0% of total body mass. Component of nucleic acids and ATP; required for normal bone and tooth structure.

Potassium (K)

Major element; intracellular cation; the most plentiful cation in intracellular fluid. Needed to generate action potentials.

Sulfur (S)

Major element; component of some vitamins and many proteins.

Sodium (Na)

Major element; extracellular cation; essential for maintaining water balance; needed to generate action potentials.

Chlorine (Cl)

Major element; extracellular anion; most plentiful extracellular anion; essential for maintaining water balance.

Magnesium (Mg)

Major element; Mg2+ needed for action of many enzymes.

Iron (Fe)

Major element; Fe2+ and Fe3+ are part of hemoglobin and some enzymes.

Trace elements

Group of elements including Al, B, Cr, Co, Cu, F, I, Mn, Mo, Se, Si, Sn, V, Zn; about 0.4% of total body mass.