Eijkman’s syndrome, a complex of nervous
symptoms in animals deprived of vitamin B 1 , is named
for him.
Einthoven, Willem (1860–1927) DutchPhysiologist
Willem Einthoven was born on May 21, 1860, in
Semarang on the island of Java, Indonesia, to Jacob
Einthoven, an army medical officer in the Indies, and
Louise M. M. C. de Vogel, daughter of the then-
director of finance in the Indies.
Upon the death of his father, Einthoven and his
family moved to Holland and settled in Utrecht, where
he attended school. In 1878 he entered the University
of Utrecht as a medical student. In 1885, after receiving
his medical doctorate, he was appointed successor to
A. Heynsius, professor of physiology at the University
ofLeiden, where he stayed until his death.
He conducted a great deal of research on the heart.
To measure the electric currents created by the heart,
he invented a string galvanometer (called the Einthoven
galvanometer) and was able to measure the changes of
electrical potential caused by contractions of the heart
muscle and to recordthem by creating the electrocar-
diograph (EKG), a word he coined. The EKG provides
a graphic recordof the action of the heart. This work
earned him the Nobel Prize in physiology or medicine
for 1924. He published many scientific papers in jour-
nals of the time. He died on September 29, 1927.
electrochemical gradient The relative concentration
of charged ions across a membrane. Ions move across
the membrane due to the concentration difference on
the two sides of the membrane as well as the difference
in electrical charge across the membrane.
electrode potential Electrode potential of an elec-
trode is defined as the electromotive force (emf) of a
cell in which the electrode on the left is a standard
hydrogen electrode and the electrode on the right is the
electrode in question.
See alsoREDOX POTENTIAL.
electrogenic pump Any large, integral membrane
protein (pump) that mediates the movement of a sub-
stance (ions or molecules) across the plasma membrane
against its energy gradient (active transport). The
pump, which can be ATP-dependent or Na+-dependent,
moves net electrical charges across the membrane.electromagnetic spectrum The entire spectrum of
radiation arranged according to frequency and wave-
length that includes visible light, radio waves,
microwaves, infrared, ultraviolet light, X rays, and
gamma rays. Wavelengths range from less than a
nanometer, i.e., X and gamma rays (1 nanometer is
about the length of 10 atoms in a row), to more than
a kilometer, i.e., radio waves. Wavelength is directly
related to the amount of energy the waves carry. The
shorter the radiation’s wavelength, the higher its
energy. Frequencies of the electromagnetic spectrum
range from high (gamma rays) to low (AM radio). All
electromagnetic radiation travels through space at the
speed of light, or 186,000 miles (300,000 km) per
second.electron Anegatively charged subatomic particle of
an atom or ion.electron acceptor A substance that receives elec-
trons in an oxidation-reduction reaction.electronegativity Each kind of atom has a certain
attraction for the electrons involved in a chemical
bond. This attraction can be listed numerically on a
scale of electronegativity. Since the element fluorine
has the greatest attraction for electrons in bond-
forming, it has the highest value on the scale. Metals
usually have a low electronegativity, while nonmetals
usually have high electronegativity. When atoms react
with one another, the atom with the higher elec-
tronegativity value will always pull the electrons
away from the atom that has the lower electronega-
tivity value.electron magnetic resonance (EMR) spectroscopy
See ELECTRON PARAMAGNETIC RESONANCE SPEC-
TROSCOPY.108 Einthoven, Willem