Anatomy and Physiology - Chemical Level of Organization

Vocabulary flashcards covering the chemical foundations of anatomy and physiology including atomic subparticles, isotopes, half-life, ionic and covalent bonds, and electronegativity.

Atom

The smallest particle that exhibits the chemical properties of an element.

Proton

A positively charged subatomic particle with a charge of $+1$ located inside the nucleus of an atom.

Neutron

A neutrally charged subatomic particle with a charge of $0$ located inside the nucleus of an atom.

Electron

A negatively charged subatomic particle with a charge of $-1$ that orbits around the nucleus of an atom in shells.

Nucleus (Atomic)

The center of an atom where protons and neutrons are located.

Electronegativity

An atom's attraction for negatively charged electrons; it increases from bottom-left to top-right on the periodic table.

Atomic Number

The number of protons in the nucleus of an atom, which equals the number of electrons in an electrically neutral atom.

Average Atomic Mass

The mass of the atomic nucleus (protons plus neutrons), representing the average mass of all naturally occurring isotopes of an element.

Major Elements

Elements that make up the vast majority of human body mass (greater than 1\text{\null}\% by weight), with oxygen being the most abundant at 65\text{\null}\%.

Minor Elements

Elements present in the human body in smaller relative quantities (less than 1\text{\null}\% by weight).

Isotopes

Atoms of the same element that have the same number of protons but differ in the number of neutrons in their nucleus, altering their atomic mass.

Half-life

The amount of time required for half of a given isotope or substance to break down or be eliminated.

Physical Half-life

The time required for half of an unstable radioisotope to decay or break down into a more stable form.

Biological Half-life

The time required for half of a drug, medication, or substance to be eliminated or metabolized from the body.

Scintigraphy

An imaging technique that creates diagnostic visuals of organs or glands using the uptake of radioactive isotopes.

Octet Rule

The principle that an atom is most stable when its outermost (valence) shell is filled with $8$ electrons (or $2$ electrons in the innermost shell).

Valence Electrons

The electrons located in the outermost shell (valence shell) of an atom.

Ion

An atom that has acquired an electrical charge by gaining or losing one or more electrons.

Cation

A positively charged ion formed when an atom donates or loses one or more electrons.

Anion

A negatively charged ion formed when an atom receives or gains one or more electrons.

Ionic Bond

A chemical bond formed through the donation and transfer of electrons from one atom to another, binding oppositely charged ions together.

Covalent Bond

A chemical bond formed when two atoms share one or more pairs of electrons.

Nonpolar Covalent Bond

A covalent bond in which two atoms share electrons equally because they have similar electronegativities.

Polar Covalent Bond

A covalent bond in which electrons are shared unequally between atoms because one atom is more electronegative than the other.

Hydrogen Bond

A weak attraction between a hydrogen atom in a polar molecule and another atom, which is weak individually but collectively very strong.