Rheumatoid factors (RFs) Autoantibodies present in the
plasma of patients with rheumatoid arthritis which
seem to be directed against the patient’s own IgG
molecules.Risk factors Certain dietary, occupational or lifestyle
conditions that increase the chances of developing a
disease.Safe intake The amount of a nutrient judged to be suf-
ficient for the needs of most people (compare with
estimated average requirement, lower reference
nutrient intakeand reference nutrient intake).Seasonally affective disorder (SAD) A condition charac-
terized by changes of mood and eating and sleeping
patterns in winter associated with an inappropriate
secretion of melatonin.Secondary A term often used to refer to a condition
that arises from an existing disease. It is also used to
describe a stage of a disease.Secondary immunodeficiency diseases (SIDs) These
arise as a consequence of other conditions (compare
withprimary immunodeficiency diseases).Secondary tumors These are formed when a primary
tumor metastasizes and spreads to other tissues and
organs. Often loosely referred to as “secondaries”.Secretors Individuals who express the A, B and H blood
antigens on soluble proteins and secrete them into
saliva and other body fluids.Self Used inimmunologyto refer to the components that
make up the body itself (compare withnonself).Senescence The decline in the functions of almost all
parts of the body and at all levels of organization,
from cells to organ systems, seen on aging.Sepsis The presence of thepathogensin the blood of a
patient.Serum The clear straw-colored liquid remaining after the
blood has been allowed to clot and the clot and all the
cells have been removed.Severe combined immunodeficiency (SCID) A life threat-
ening clinical condition involving deficient numbers
of both B and T lymphocytes.Shock A patient goes into shock if the blood pressure falls
too low.Sickle cell anemia A hemoglobinopathy characterized by
the presence of crescent-shaped erythrocytes.Sign Something the clinician specifically looks or feels for,
such as redness or swelling of the skin, when examin-
ing the patient.Sinoatrial or SA node The “pacemaker” that generates
electrical impulses that regulate the rate of contrac-
tion of the heart.Small lymphocytes Mononuclear leukocytesinvolved in
thespecific immune response.Specific immune response The response that allows the
development of true specific immunity against an
infectious agent.Stenosis Failure of the heart valves to open appropriately
(compare withregurgitation, murmur).Strabismus A squint or abnormal alignment of the eyes.Stroke or cerebrovascular accident This occurs if the
blood supply to the brain is disrupted for sufficient
time that brain cells are permanently damaged or die
due to lack of oxygen. Strokes can be hemorrhagic
when a blood vessel bursts disrupting the normal
flow of blood and allowing it to leak into an area of
the brain and destroy it, or ischemic, which occurs
when the blood supply to part of the brain is cut off
either because ofatherosclerosisor because a clot is
blocking a blood vessel.Subclinical A stage at which a disease is established
even though any overtsignsandsymptomsare not
apparent.Superantigens Toxins secreted by bacteria such as
Streptococcus pyogenesorStaphylococcus aureusthat
stimulate the release of cytokines from immune cells
and produce an excessive inflammatory response
called systemic inflammatory response syndrome
(SIRS).Symptom An indication that a disease is present and
something of which the patient complains, for exam-
ple, nausea, malaise or pain.Syncope Fainting with a temporary loss of consciousness
resulting from a temporarily inadequate supply of
oxygen and nutrients to the brain.Syndrome A term applied to describe certain diseases
that are characterized by multiple abnormalities and
features that form a distinct clinical picture.Syngeneic stem cell transplants These involve donors
and recipients who are genetically identical, for exam-
ple between identical twins (see also allogeneicand
autologous).Systemic circulation The flow of blood from the left ven-
tricle to all the tissues of the body with the exception
of the lungs and back to the right atrium (compare
withpulmonary circulation).Systemic disease One that affects the whole body.GLOSSARYmmm W^dad\nd[Y^hZVhZ