ion
Meaning of ion: An ion is an atom or molecule carrying an electrical charge, essential to processes such as nerve signaling and muscle contraction.
Definition of ion
An ion is an atom or molecule that carries a positive or negative electrical charge, resulting from having gained or lost one or more electrons compared with its neutral state. Common ions in the body include sodium, potassium, calcium, chloride, and phosphate, each carrying a specific charge and playing a distinct biological role.
Ions move across cell membranes through specialized channels and pumps, and this movement generates the electrical signals that allow nerve cells to communicate and muscle cells to contract. Ions also help maintain fluid balance between different body compartments and support numerous chemical reactions throughout the body.
Because so many body functions depend on ions being present in the right amounts and locations, laboratory tests that measure blood levels of specific ions, often grouped together as electrolytes, are used to help evaluate a wide range of medical conditions.
Used in a sentence
Blood testing was performed to check the patient's ion levels after several days of vomiting.
Good to know
An imbalance in a single ion, such as potassium or calcium, can affect nerve and muscle function throughout the body, not only in the tissue where the imbalance originates.
Word origin
Where “ion” comes from
Formed from Greek ion, meaning going, from ienai, meaning to go, chosen because ions were observed to move toward an oppositely charged electrode.