Biology of Disease

Mixed acid–base disorder The situation in which a patient
presents with more than one acid–base disorder.

Monoclonal antibody An antibody that recognizes only a
single specificepitopeon an antigen and which is pro-
duced by a clone of identical plasma cells. Compare
withpolyclonal antibody.

Monocyte A type ofmononuclear leukocyte that circu-
lates in the blood for about 72 hours before entering
solid tissues and developing into amacrophage.

Mononuclear leukocytes (MNs) One of the two main
groups of leukocytes, which can be distinguished
from the other polymorphonuclear leukocytes in
having a more rounded nucleus. They are subdivided
into monocytes, large granular lymphocytes and
small lymphocytes.

Morbidity The effects of a disease on the patient.

Mortality This describes the possibility of a disease caus-
ing death: usually expressed as a percentage.

Murmurs The characteristic sounds formed when abnor-
malities of the valves and heart structures cause a
turbulent blood flow.

Mutation A change in thegenotype, which occurs as
a result of incorrect replication of DNA or from a
random change to it caused by physical or chemical
agents.

Myocardial infarction (“heart attack”) A medical emer-
gency that occurs when some or all of the blood sup-
ply to the heart muscle through the coronary arteries
is cut off.

Myocardium The cardiac muscle-rich wall of the heart.

Natural killer (NK) cells A type oflarge granular lym-
phocytethat kills virus-infected cells and some tumor
cells nonspecifically.

Neoplasm or neoplastic diseases Often used synony-
mously withcancer, means, literally, “new tumor” or
“new mass”.

Nephrons The functional units of the kidney: each is
composed of a tuft of capillaries called a glomerulus,
and a tubule.

Neutrophil One of the three types ofpolymorphonuclear
leukocyte(seebasophiland eosinophil).

Nocosomial infections Those acquired in hospital.

Nonessential A nutrient that the body can make from
other nutrients and which does not need to be sup-
plied in the diet (compare withessential).

Nonhemolytic febrile transfusion reaction Transfusion
of leukocytes may lead to adverse reactions, such as
nonhemolytic febrile transfusion reactions. Such

patients exhibit flushing, fever, rigors and hypoten-

sion. These may be caused by the reaction between

antibodies and leukocyte antigens in the recipient,

resulting in the lysis of donated leukocytes and release

of cytokines from them.

Nonself Used inimmunologyto signify macromolecules

or cells that are foreign to the body (compare with

self).

Nonspecific defences The first line of immunological

defence including responses such asinflammation

and theacute phase response.

Normal range Seereference ranges.

Notifiable diseases Diseases for which clinicians are

legally required to supply details of all new cases to a

central register.

Nuclear envelope The outer and inner nuclear mem-

branes that separate the nucleus from the cytoplasm.

Nucleocytoplasmic transport The movement of materi-

als between the nucleus and cytoplasm of a cell.

Nutrition The study of food and nutrients and how they

are used by the body.

Nutritional diseases Diseases that result from an inap-

propriate intake of nutrients.

Oligomenorrhea Infrequent or irregular menstrua-

tion associated with a number of clinical disorders.

Compareamenorrheaandgalactorrhea.

Oliguria Passing less than 400 cm^3 of urine per day (com-

pare withanuria).

Oncogenes One of the two major groups of genes linked to

cancer: they are mutated forms of normal genes called

proto-oncogenes (seetumor suppressor genes).

Oncology The branch of medicine involved with the study

ofmalignant tumors, their epidemiology, diagnosis

and treatment.

Opisthotonos An involuntary arching of the head, neck

and spine backwards.

Opportunistic infections Infections that occur when a

decline in the immunological functions of an indi-

vidual makes them susceptible to infections by micro-

organisms that are normally nonpathogenic.

Opportunistic pathogen A microorganism that causes

opportunistic infections.

Opsonization The process by which phagocytic cells bind

readily to bacterial cells coated with activated com-

plement protein, C3b, promoting phagocytosis of the

cells.

GLOSSARY

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