menstrual pain, headaches, pain after
minor surgery, and soft tissue injuries.
The drugs reduce pain and inflamma-
tion by blocking the production of
(chemicals that cause
inflammation and trigger transmission
of pain signals to the brain).
NSAIDs may cause a wide range of side
effects, the most important of which are
nausea, indigestion, bleeding from the
stomach, and, sometimes,
noradrenaline Also known as norepin-
secreted by certain
nerve endings (principally those of the
sympathetic nervous system)
and by the
medulla (centre) of the
Noradrenaline's primary function is to
help maintain a constant blood pressure
by way of stimulating certain blood
vessels to constrict (narrow) when the
blood pressure falls. For this reason, it
may sometimes be injected in the
emergency treatment of
bleeding. (See also
used primarily in some
Norethisterone is sometimes
prescribed to postpone menstruation. It
is also used to treat
, menstrual disorders such as
, and certain
. It is occasionally
given by injection as a long-acting con-
traceptive. Possible side effects include
swollen ankles, weight gain, depression
and, rarely, jaundice.
nose The uppermost part of the respira-
tory tract, and the organ of
nose is an air passage connecting the
nostrils at its front to the
(the upper part of the throat) at its rear.
, which is made of car-
tilage at the front and bone at the rear,
divides the passage into 2 chambers.
The bridge of the nose is formed from
2 small nasal bones and from cartilage.
The roof of the nasal passage is formed
by bones at the base of the skull; the
walls by the maxilla (upper
the floor by the hard palate. Three con-
chae (thin, downward-curving plates of
bone) covered with
project from each wall.
Air-filled, mucous membrane-lined cav-
ities known as paranasal sinuses open
into the nasal passage. There is an
opening in each wall to the nasolacrimal
duct, which drains away tears. Project-
ing into the roof of the nasal passage
are the hair-like endings of the olfactory
nerves, which are responsible for the
sense of smell.
A main function of the nose is to filter,
warm, and moisten inhaled air before it
passes into the rest of the respiratory
tract. Just inside the nostrils, small hairs
trap large dust particles and foreign bod-
ies. Smaller dust particles are filtered
from the air by the microscopic hairs of
the conchae. The mucus on the conchae
flows inwards, carrying microorganisms
and other foreign bodies back towards
the nasopharynx to be swallowed and
destroyed in the stomach.
The nose detects smells by means of
the olfactory nerve endings, which, when
stimulated by inhaled vapours, transmit
this information to the olfactory bulb in
The nose is susceptible to a wide
range of disorders. Allergies (see
), infections such as colds
), and small
common. Backward spread of infection
from the nose occasionally causes a
serious condition called
. The nose is also particularly
prone to injury (see
). Obstruction of the nose may
be caused by a nasal
of swollen mucous membrane).
vessels, known as
monly affect the nasal cavity in babies.
Basal cell carcinoma
may occur around the nos-
tril. The nose may also be invaded by
cancers originating in the sinuses.
mucous membrane that lines the nose.
The most common causes of a nose-
bleed are fragile blood vessels, a blow
to the nose, or the dislodging of crusts
that have formed in the mucous mem-
brane as a result of a common cold or
infection. Rarely, recurrent nosebleeds
are a sign of an underlying disorder, such
(high blood pressure),