Webster's New World Medical Dictionary

basal cell
A small, round cell found in the lower
part, or base, of the epidermis.
basal cell carcinoma
The most common type of
skin cancer, which commonly presents as a sore
that seems to get better and then recurs and may
start to bleed. Basal cell carcinoma often occurs on
the face and neck, where the skin is exposed to sun-
light. These tumors are locally invasive and tend to
burrow in but not metastasize (spread) to distant
locations.
basal ganglia
A region of the base of the brain
that consists of three clusters of neurons (caudate
nucleus, putamen, and globus pallidus) that are
responsible for involuntary movements such as
tremors, athetosis, and chorea. The basal ganglia
are abnormal in a number of important neurologic
conditions, including Parkinson’s disease and
Huntington’s disease.
basal metabolic rate
The rate of metabolism, as
measured by the amount of heat given off when a
person is at rest; it is expressed as calories of energy
per hour per square meter of skin. The basal meta-
bolic rate can offer clues about underlying health
problems. For example, a person with an overly
active thyroid has an elevated basal metabolic rate.
basal temperature 1
Usually, a person’s tem-
perature on awakening in the morning. Because
changes in basal temperature accompany ovulation,
basal temperature is often tracked by women who
want to ensure or avoid pregnancy.
2
A crude
measure of thyroid function that is achieved by tak-
ing and comparing basal temperatures. This meas-
ure is now superceded by modern thyroid function
blood tests. Also known as Broda test.
base
A unit of DNA. There are four bases in DNA:
adenine (A), guanine (G), thymine (T), and cyto-
sine (C). The sequence of bases (for example, CAG)
constitutes the genetic code.