Since the late 1800s, medical textbooks
like Gray’s Anatomy have listed 78 organs
in the human body. But that tally has just
gone up, reports The Washington Post.
Irish researchers have determined
that the mesentery,
a sheet of tissue that
connects the intestines
to the abdominal wall,
should be categorized
as a bona fide organ. For
decades, it was widely
believed that the mesentery
was merely a series of fragmented
membranes. But after
re-examining its structure, two
scientists from the University
of Limerick concluded that
it is in fact one continuous
entity that plays a vital role
in preventing the intestines from flopping
around in the belly. They believe the
mesentery fits the broad definition of an
organ: a self-contained structure that performs
a specific bodily function. “Without
it,” says study author J. Calvin Coffey,
“you can’t live.” It remains unclear what
other purposes the mesentery serves, or to
which system of the body it belongs. But
the researchers say that reclassifying the
body part as an organ will encourage further
study, which could help shed light on
Crohn’s disease and other gut disorders.
Dinosaurs’ egg problem
Dinosaurs took much longer to incubate
their eggs than previously thought—a factor
that may have contributed to their demise.
Scientists at Florida State University came
to this conclusion after analyzing the teeth
of rare fossilized dinosaur embryos. Like
human teeth, reptile teeth are formed during
incubation from a liquid called dentin;
this calcified tissue builds up, adding a
new layer each day as the embryo develops.
“They’re kind of like tree rings,” lead
author Gregory Erickson tells CSMonitor
.com. “We could literally count them to see
how long each dinosaur had been developing.”
The researchers calculated that smaller
Protoceratops hatchlings took nearly three
months to develop, while the eggs of the
Hypacrosaurus, a duck-billed dinosaur that
grew to be about 30 feet long, incubated for
about six months. With such long incubations,
dinosaurs must have been very slow
reproducers—a trait that would hurt their
ability to rebuild their populations after
a comet or asteroid strike wiped many of
them out 65 million years ago. The discovery
may also help explain why birds, whose
eggs have significantly shorter incubation
times than dinosaurs’ did, survived the same
mass extinction event.
their eggs than previously thought—a factor
that may have contributed to their demise.
Scientists at Florida State University came
to this conclusion after analyzing the teeth
of rare fossilized dinosaur embryos. Like
human teeth, reptile teeth are formed during
incubation from a liquid called dentin;
this calcified tissue builds up, adding a
new layer each day as the embryo develops.
“They’re kind of like tree rings,” lead
author Gregory Erickson tells CSMonitor
.com. “We could literally count them to see
how long each dinosaur had been developing.”
The researchers calculated that smaller
Protoceratops hatchlings took nearly three
months to develop, while the eggs of the
Hypacrosaurus, a duck-billed dinosaur that
grew to be about 30 feet long, incubated for
about six months. With such long incubations,
dinosaurs must have been very slow
reproducers—a trait that would hurt their
ability to rebuild their populations after
a comet or asteroid strike wiped many of
them out 65 million years ago. The discovery
may also help explain why birds, whose
eggs have significantly shorter incubation
times than dinosaurs’ did, survived the same
mass extinction event.
Subscribe to:
Posts (Atom)