专业术语—口腔生理学术语S1(英文详解)（在线收听）

    Saturated solutions - Salts such as the apatites do not readily become ionized and dissolve in water. When no more ions can dissolve the solution is said to be saturated. The concentration of ions in a saturated solution, its solubility product, is constant for each salt, at a neutral pH. If the solution becomes more acidic, more ions can dissolve from the solid. Saliva is a super saturated solution of calcium phosphate.

    Schwann cells - members of a family of nerve-supporting (neuroglial) cells. The Schwann cell has an extensive cy lasm which allows it to wrap a myelin sheath around nerve axons.

    Sclerotic - hardened, as in sclerotic dentine, which is hardened by intratubular dentine in response to tooth wear, ageing and arrested caries.

    Secondary caries - caries which has occurred after a primary lesion has been restored. It is most commonly due to failure of the restoration at its margins, which have broken down and allowed a leak to develop between the restoration and the wall of the cavity. Caries bacteria which have been left behind during cavity preparation are unable to produce secondary caries if the margins of the restoration have achieved a proper seal against the tooth.

    Septa - the thin plate of bone between the roots of teeth ( Latin septum = a wall). Also the fibrous walls which separate sections of a gland. Septa separate sections of an orange or grapefruit.

    Serotonin - ( 5 Hydroxytryptamine) is present throughout the body, especially in blood platelets and in the intestines. Its release from blood platelets contributes to the pain, vasoconstriction and inflammation after injury. In nervous tissue it functions as a neurotransmitter, mainly in the midbrain in clusters of cells called the raphe, and in the medulla. The fibres of these cells connect with the forebrain, cerebellum and spinal cord. It therefore exerts a strong influence over arousal, sensory perception, emotion and thought. Drugs which slow down the removal of serotonin can reduce depression and pain.

    Serous - a watery secretion which resembles serum.

    Serum - the fluid component of blood from which the clotting protein fibrinogen has been removed.