The history of anatomy
as a science extends from the earliest
examinations of sacrificial victims to the
sophisticated analyses of
the body performed by modern scientists. It has been
marked, over time,
by a continually developing understanding of the
functions of organs
and structures in the body. Methods have also advanced
advancing from examination of animals through
dissection of cadavers to technologically complex
techniques developed in the last century.
begins at least as early
as 1600 BC, the date of publication of an Egyptiananatomicalpapyrus that has survied to this
day; this treatise identifies a number of organs and
shows a basic knowledge of blood vessels.
The earliest medical
scientist of whose works any great part survives today
is Hippocrates, a Greek
physician active in the late 5th and early 4th
centuries BC (460-377
BC). His work demonstrates a basic understanding of
structure, and the beginnings of understanding of
certain organs, such
as the kidneys. Much of his work, however, and much of
that of his
students and followers later, relies on speculation
empirical observation of the body.
In the 4th century BC, Aristotle
and several contemporaries produced a more empirically
based on dissection of animals; works produced around
this time are the
first to identify the difference between arteries and veins, and the relations between
organs are described more accurately than in previous
The first use of human cadavers for anatomical research occurred later in
the 4th century BC, when Herophilos and Erasistratus performed dissections of
cadavers in Alexandria under the auspices of the Ptolemaic
Herophilos in particular developed a body of
anatomical knowledge much
more informed by the actual structure of the human
body than previous
works had been.
The final major
anatomist of ancient times was Galen,
active in the 2nd century AD. He compiled much of the
obtained by previous writers, and furthered the
inquiry into the
function of organs by performing vivisection on animals. His collection of
drawings, based mostly on dog anatomy, would hold as a
of the ancient world" for 1500 years. The original text is long
gone, and his work was only known to the Rennaissance
doctors through the careful custody of Arabic
medicine, since the
Church destroyed it as heresy. Hampered by the same
restrictions as anatomists for centuries after him,
Galen assumed that
anatomical structures in dogs were the same as for
Anatomical research in
the past hundred years has taken advantage of
technological developments and growing understanding
of sciences such
as evolutionary and molecular biology to create a thorough
understanding of the body's organs and structures.
While disciplines such as endocrinology have explained the purpose of
glands that previous anatomists could not explain,
medical devices such as MRI machines and CAT
have enabled researchers to study the organs of living
today in anatomy is centered in the field of molecular
biology, as the
macroscopic aspects of the field have now been
catalogued and addressed.
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Anatomy first found wide acceptance as a
science in ancient Greece.
(a) Hippocrates is regarded as the father of
medicine because of the sound principles of medical practice he
(b) The Greek philosophy of body humors
dominated medical thought for over 2,000 years.
(c) Aristotle pursued a limited type of
scientific method in obtaining data; his writings contain some
6. Alexandria was a center of scientific
learning from 300 to 30 B.C.
(a) Human dissections and vivisections were
performed in Alexandria.
(b) Erasistratus is referred to as the
father of physiology because of his interpretations of various
7. Theoretical data was deemphasized during
the Roman era.
(a) Celsus’s eight-volume work was a
compilation of medical data from the
(b) Galen was an influential medical writer
who made some important advances in anatomy; at the same time he
introduced serious errors into the literature that went
unchallenged for centuries.
(c) Science was suppressed for nearly
1,000 years during the Middle Ages, and
dissections of human cadavers were prohibited.
(d) Anatomical writings were taken from
Alexandria by Arab armies, and thus saved from destruction
during the Dark Ages in Europe.
8. During the Renaissance, many great
European universities were established.
(a) Andreas Vesalius and Leonardo da Vinci
were renowned Renaissance men who produced monumental studies of
the human form.
(b) De Humani Corporis Fabrica, written by
Vesalius, had a tremendous impact on the advancement of human
anatomy. Vesalius is regarded as the father of human anatomy.
9. Two major scientific contributions of the
seventeenth and eighteenth centuries were the explanation of
blood flow and the development of the microscope.
(a) In 1628, William Harvey correctly
described the circulation of blood.
(b) Shortly after the microscope had been
perfected by Antoni van Leeuwenhoek, many investigators added
new discoveries to the rapidly changing specialty of microscopic
10. The cell theory was formulated during
the nineteenth century by Matthias Schleiden and Theodor
Schwann, and cellular biology became established as a science
separate from anatomy.
11. A trend toward simplification and
standardization of anatomical nomenclature began in the
twentieth century. In addition, many specialties within anatomy
developed, including cytology, histology, embryology, electron
microscopy, and radiology.
Private tutoring on demand and spot availability.
Muscle (from Latin musculus
"little mouse" ) is contractile tissue of the
body and is derived from the mesodermal layer of
embryonic germ cells. Its function is to produce
force and cause motion, either locomotion or
movement within internal organs. Much of muscle
contraction occurs without conscious thought and
is necessary for survival, like the contraction
of the heart, or peristalsis (which pushes food
through the digestive system). Voluntary muscle
contraction is used to move the body, and can be
finely controlled, like movements of the finger
or gross movements like the quadriceps muscle of
the thigh. There are 2 types of muscle movement,
slow twitch and fast twitch. Slow twitch
movements act for a long time but not very fast,
whilst fast twitch movements act quickly, but
not for a very long time.
Agonist A muscle that causes motion.
AntagonistA muscle that can move the joint
opposite to the movement produced by the
Target The primary muscle intended for
Synergist A muscle that assists another
muscle to accomplish a movement.
StabilizerA muscle that contracts with no
(b): muscle attatchment that moves least,
generally more proximal.
(a): muscle attatchment that moves most,
generally more distal.
Abduction: Lateral movement away from the
midline of the body
Adduction: Medial movement toward the midline
of the body
Circumduction: circular movement (combining
flexion, extension, adduction, and abduction)
with no shaft rotation
Extension: Straightening the joint resulting
in an increase of angle
Eversion: Moving sole of foot away from
Flexion: Bending the joint resulting in a
decrease of angle
Hyperextension: extending the joint beyond
Inversion: Moving sole of foot toward medial
Pronation: Internal rotation resulting in
appendage facing downward
Protrusion: Moving anteriorly (eg: chin out)
Supination: External rotation resulting in
appendage facing upward
Retrusion: Moving posteriorly (eg: chin in)
Rotation: Rotary movement around the
longitudinal axis of the bone
The cell is the structural and functional unit
of all living organisms, and is sometimes called the
"building block of life."Some organisms, such as
bacteria, are unicellular, consisting of a single cell.
Other organisms, such as humans, are multicellular.
(Humans have an estimated 100 trillion or 1014
cells; a typical cell size is 10 µm; a typical cell
mass is 1 nanogram.) The largest known cell is an
cell theory, first developed in 1839 by Schleiden and
Schwann, states that all organisms
are composed of one or more cells. All cells come from
cells. Vital functions of an organism occur within
cells, and all cells
contain the hereditary information necessary for
regulating cell functions and for transmitting
information to the next generation of cells.
word cell comes from the Latin cellula,
a small room. The name was chosen by Robert Hooke when
he compared the cork cells he saw to the small rooms
monks lived in.
Skeletal muscle is made up of thousands of
cylindrical muscle fibers often running
all the way from origin to insertion. The fibers
are bound together by connective tissue through
which run blood vessels and nerves.
Each muscle fibers contains:
an array of myofibrils that are
stacked lengthwise and run the entire length
of the fiber.
an extensive smooth endoplasmic
multiple nuclei arise from the fact that each
muscle fiber develops from the fusion of many
cells (called myoblasts).
number of fibers is probably fixed early in
life. This is regulated by myostatin, a
cytokine that is synthesized in muscle cells
(and circulates as a hormone later in life).
Myostatin suppresses skeletal muscle
development. Cattle and mice with inactivating
mutations in their myostatin genes develop much
larger muscles. Some athletes and other
remarkably strong people have been found to
carry one mutant myostatin gene. These
discoveries have already led to the growth of an
illicit market in drugs supposedly able to
adults, increased strength and muscle mass comes
about through an increase in the thickness of
the individual fibers and increase in the amount
of connective tissue. In the mouse, at least,
fibers increase in size by attracting more
myoblasts to fuse with them. The fibers attract
more myoblasts by releasing the cytokine
interleukin 4 (IL-4). Anything that lowers the
level of myostatin also leads to an increase in
Because a muscle fiber is not a single cell, its
parts are often given special names such as
sarcolemma for plasma membrane
sarcoplasmic reticulum for
sarcosome for mitochondrion
sarcoplasm for cytoplasm
although this tends to obscure the essential
similarity in structure and function of these
structures and those found in other cells
The secretory cells can release their secretory
products by one of three mechanisms.
corresponds to the process of
exocytosis. Vesicles open onto the
surface of the cell, and the
secretory product is discharged from
the cell without any further loss of
designates a mechanism in which
part of the apical cytoplasm of the
cells is lost together with the
secretory product. The continuity of
the plasma membrane is restored by
the fusion of the broken edges of
the membrane, and the cell is able
to accumulate the secretory product
anew. This mechanism is used by
apocrine sweat glands, the mammary
glands and the prostate.
designates the breakdown and
discharge of the entire secretory
cell. It is only seen in the
sebaceous glands of the skin.
, branch of biology concerned with the study of body
various organisms, including humans.
Comparative anatomy is concerned
with the structural differences of plant and animal
Gunther von Hagens, the German anatomist
who created "Body Worlds,"
poses with one of his displays. The exhibit puts real
on show, such as this one in Dallas. (Media Credit:
Associated Press)Christopher Placek
The study of
similarities and differences in anatomical structures
forms the basis
of both plants and animals. Embryology (see embryo)
deals with developing plants or animals until hatching
or birth (or
germination, in plants); cell biology covers the
internal anatomy of
the cell, while histology
is concerned with the study of aggregates of similarly
cells, called tissues. Related to anatomy is morphology,
comparative study of the corresponding organs in humans
There are four major types of tissue present in the
epithelial tissue (see epithelium), muscular tissue (see muscle), connective tissue, and nervous tissue (see nervous
Human anatomy is often studied by
considering the individual systems
that are composed of groups of tissues and organs; such
the skeletal system (see skeleton), muscular system, cutaneous system (see skin), circulatory system
(including the lymphatic system), respiratory system (see respiration), digestive system, reproductive system, urinary system, and endocrine system.
Little was known about human anatomy in ancient times
dissection, even of corpses, was widely forbidden. In
the 2d cent., Galen,
largely on the basis of animal dissection, made valuable
to the field. His work remained authoritative until the
14th and 15th
cent., when a limited number of cadavers were made
available to the
medical schools. A better understanding of the science
reflected in the discoveries of Vesalius, William Harvey, and John Hunter. Various modern technologies have
significantly refined the study of anatomy: X rays, CAT
scans, and magnetic
imaging (MRI) are only several of the tools used today
to obtain clear,
accurate representations of the inner human anatomy. In
1994, for the
first time, a detailed three-dimensional map of an
entire human being
(an executed prisoner who volunteered his body) was made
worldwide via the Internet using data from thousands of
CAT scans, and MRIs of tiny cross sections of the body.[H.
Gray, Gray's Anatomy (1987).]
hemispheres. Its floor is the corpus callosum.
from frontal and parietal lobes
motor and somatic sensory areas
expressive speech area
(not pursuit or vergence)
area; lesions cause apraxia, neglect
areas for language, calculation; lesions cause
area for vision; eye-field for pursuit movements
(and the adjacent gyri)
the occipital lobe
association area, including memories of complex scenes
area; also called Wernicke's area; part of the
association area for
association cortex for
olfaction. Afferents from all sensory association
areas. Efferents to
to collateral sulcus)
association cortex for remembering people's faces