Glossary S

Salt

Any compound of a base and an acid; any compound of an acid some of whose replaceable atoms have been substituted. Can refer to different forms of a drug or supplement. E.g. Morphine sulfate and Morphine hydrchloride are two different forms of Morphine, with the "sulfate" and "hydrochloride" indicating the different salts.

Sed./Sedimentation Rate

See Erythrocyte Sedimentation Rate (ESR).

Sedative

Having a soothing, calming, or tranquilizing effect; a drug that produces a sedative effect.

Selective Serotonin Reuptake Inhibitor (SSRI)

A class of drugs that inhibit the reuptake of serotonin in the central nervous system. Often used as anti-depressants.

Semantic memory

Semantic memory is the memory for meanings and general (impersonal) facts, that do not have a specific context. It includes context free facts and the meanings of words.

Serotonin

A hormone and neurotransmitter found in many tissues, with multiple properties including inhibition of gastric secretion, stimulation of smooth muscles, production of vasoconstriction, transmission of impulses between nerve cells, and regulation of cyclic body processes.

Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)

A class of drugs that inhibit the reuptake of both serotonin and norepinephrine in the central nervous system.

Skeletal Muscle

One of the three types of muscle, making up most of the musculature structure of the body, that powers movement of the skeleton, such as standing, walking and lifting.

SLE

Systemic Lupus Erythematosus: what is commonly called Lupus. An Autoimmune condition that can affect any part of the body, including the internal organs.

Sleep stages

Sleep proceeds in cycles of REM and the four stages of NREM, the order normally being: Stages 1-2-3-4-3-2-REM. Stages 3 and 4 are considered to be deep sleep, with delta-waves making up more than 50% of the brain wave-patterns in Stage 4 sleep.

Smooth muscle

Muscle tissue that contracts without voluntary control, found in the walls of internal organs, blood vessels, and hair follicles.

SNRI

See Serotonin-Norepinephrine Reuptake Inhibitor (SNRI).

Somnolence

Drowsiness or sleepiness, particualrly unnaturally or in excess.

SSRI

See Selective Serotonin Reuptake Inhibitor (SSRI).

Stage 4 sleep

See Sleep stages

Subcutaneous

Beneath the skin.

Supraspinal

Above the spine

Sympathetic nervous system

The part of the autonomic nervous system that is concerned especially with preparing the body to react to situations of stress or emergency; it contains chiefly adrenergic fibers and tends to depress secretion, decrease the tone and contractility of smooth muscle, and increase heart rate. In general it inhibits or opposes the physiological effects of the parasympathetic nervous system.

sympathomimetic

A medicine that encourages or mimics any of the effects of the sympathetic nervous system, e.g. epinephrine (adrenaline), norepinephrine (noradrenaline) and dopamine.

Synapse

A connection between nerve cells, by which nervous excitation is transferred from one cell to the other.

Syndrome

A set of symptoms occurring together without a known distinct cause.