Medical and Healthy Living Glossary - S
This page of our online glossary of medical and healthy living is for medical and healthy living terms beginning with the letter 'S'.
- Salicylates - Compounds related to salicylic acid, which is used in making aspirin and also as a preservative. Note that with some people, salicylates in food (particularly fruit) or medicine can produce allergic reactions such as an attack of asthma or hay fever.
- Salicylic Acid - A white antiseptic substance which destroys bacteria and fungi. Salicylic acid is used in ointments for treating corns, warts and other skin disorders.
- Saline Solution - A solution made from distilled water and sodium chloride. It is introduced into the body intravenously through a drip.
- Saliva - A digestive fluid in the mouth which is secreted by the salivary glands. Saliva starts the process of digesting food. It is a mixture of a large amount of water and a small amount of mucus, secreted by the salivary glands. Saliva helps to keep the mouth and throat moist, which allows food to be swallowed more easily.
- Saturated Fat (Saturated Fatty Acids) - A fat which has the largest amount of hydrogen possible. Saturated fat is the largest type of fat in meat, dairy products such as butter and cheese, palm oil and coconut oil. A high intake of saturated fat has been linked to an increased risk of heart disease.
- Scarlet Fever - An infectious disease, mainly of childhood, which is caused by the bacterium Streptococcus. The symptomsof scarlet fever appear after a few days and include sickness, sore throat, fever and a scarlet rash that may be widespread. Antibiotics are effective and also prevent any complications such as inflammation of the kidneys.
- Sclera (Sclerotic Coat) - The tough, outer white covering of the eyeball. The front part of the sclera is the transparent cornea, through which light enters the eye.
- Sensory Nerves (Afferent Nerves) - Nerves which register a sensation such as heat, taste or smell and carry impulses to the brain and spinal cord.
- Serotype - A group of closely related microorganisms or bacteria which have some
antigens in common.
- Shelf Life - The length of time a product is safe to eat as determined by the manufacturer and marked on the label.
- Shiatsu - A type of healing body massage in which the hands are used to apply pressure at acupuncture points on the body in order to stimulate and redistribute energy.
- Shiga Toxin - A poison released by certain types of bacteria including E. coli O157:H7.
- Sinusoids - The blood-filled spaces found in some tissues, such as in the liver and adrenal glands.
- Soluble Fibre - A form of fibre that is broken down into simpler components by the action of bacteria in the large intestine. Soluble fibre can help to reduce high blood cholesterol as it is is partly digested in the intestine and reduces the absorption of fats and sugar
into the body. Good sources include many fruits - especially fruits, green vegetables, (such as broad beans, peas and lentils) and certain cereals, including oats.
- Stabilisers - Substances that help to stabilise emulsions of fat and water and prevent any unwanted chemical changes. They also tend to thicken the emulsion or cause it to set. Gelatin, pectin and guar gum are some of the most commonly used stabilisers.
- Starch - A complex carbohydrate. It is the principal storage molecule of plants and the major source of energy and carbohydrate in the diet; it consists of glucose sub-units. Starch is broken down by the digestive process into forms of sugar. Bread, pasta, rice and potatoes are all excellent sources of starch.
- Stimulants - Any drug, food or drink that temporarily speeds up part of the body may be classed as a stimulant. However, the term is usually kept for those that mimic the natural effects of adrenaline, preparing the body and mind for instant action. Everyday stimulants include the caffeine found in coffee, tea and cola drinks as well as in chocolate, and the nicotine in tobacco.
- Strain - A variant of a species member. Also, a strain is where a muscle has been stretched or torn by a strong or sudden movement.
- Sulphites - Compounds of sulphur which are used in food preservation and brewing. When mixed with acid, sulphites release the gas sulphur dioxide, which kills yeasts and is also a bleaching agent. Sulphur dioxide can trigger asthma attacks in susceptible people.
- Superior Vena Cava - A branch of the large vein going into the heart. It carries blood from the head and the top part of the body.
- Synapse - The small gap at the junction between two neurons.
- Synovial Membrane or Synovium - The smooth inner membrane of a capsule that encloses a joint that moves freely. It secretes into the joint a thick lubricating fluid (synovial fluid), which may build up after injury to cause pain.
- Synthesis - The process by which complex substances are created from their simpler component parts. In protein synthesis, for example, amino acids obtained by the breakdown of proteins in food are carried by the bloodstream to the liver and to cells in other parts of the body, where they are assembled into new proteins.
- Systemic - A systemic disease is one that affects the entire body, and not just one part of it. An example of a systemic disease is systemic lupus erythematosus (SLE)- a chronic inflammatory disease of the connective tissue where red patches form on the skin and spread throughout the body.
- Systole - Contraction stage of the heartbeat when it pumps blood out (the opposite of diastole).
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