Webster's New World Medical Dictionary

eukaryote
An organism that consists of one or
more cells with a nucleus and other well-developed
compartments. Eukaryotes include all organisms
except bacteria, viruses, and blue-green algae,
which are prokaryotes, so people are eukaryotes.
See also 
prokaryote.
euphenics
A discipline that aims to improve the
outcome of a genetic disease by altering the envi-
ronment. The term euphenics is from a Greek word
meaning “normal appearing.” For example, people
with phenylketonuria (PKU) can avoid the expres-
sion of their disease by staying on a low-phenylala-
nine diet and avoiding major sources of
phenylalanine such as diet soft drinks sweetened
with aspartame.
euphoria
Elevated mood. Euphoria is a desirable
and natural occurrence when it results from happy
or exciting events. An excessive degree of euphoria
that is not linked to events is characteristic of hypo-
mania and mania, which are abnormal mood states
associated with bipolar disorders. See also 
bipolar
disorder.
euploid
The normal number of chromosomes
for a species. In humans, the euploid number of
chromosomes is 46; with the notable exception of
the unfertilized egg and sperm, in which it is 23.
Eustachian tube
The tube that runs from the
middle ear to the pharynx. The function of the
Eustachian tube is to protect, aerate, and drain the
middle ear and mastoid. The Eustachian tube per-
mits the gas pressure in the middle ear cavity to
adjust to external air pressure. When you are
descending in an airplane, the Eustachian tube
opens when your ears “pop.” It is harder to get air
into the middle ear than get it out, which is why we
have more trouble with our ears when a plane is
descending than when it takes off. Occlusion of the
Eustachian tube can lead to the development of mid-
dle ear infection (otitis media). The Eustachian tube
opens into the nasopharynx. The Eustachian tube
measures only 17 to 18 mm, and it is horizontal at
birth. As it grows to double that length, it grows 
to be positioned at an incline of 45 degrees in