A chemical agent that causes cancer.

A disturbance to the normal beating of the heart.

The specialised muscle, found only in the heart, that is responsible for the regular contraction and relaxation of the heart (heart beat). It is under the control of the autonomic nervous system.

A term used to describe insufficient blood flow to the tissues, such that tissue damage occurs.

The principle, based on the theory of René Descartes, that mind and matter are qualitatively different, and that because the mind does not operate within the laws of physics it cannot be investigated scientifically. Descartes also postulated that the mind (or soul) was unique to humans.

Term describing metabolic reactions that result in the breakdown of materials and the release of energy.

An enzyme involved in the process of the removal of highly dangerous hydrogen peroxide from the cell. Catalase catalyses the breakdown of H₂O₂ to H₂O and O₂.

A substance that speeds up a reaction without itself undergoing any overall change in the process.

A class of neurotransmitters and hormones, including dopamine and noradrenalin.

A causal explanation is one given in terms of the mechanisms that underlie behaviour in a given individual at a particular point in time. It should be distinguished from a functional explanation.