As we flip our calendars to ‘2022,’ some things will never change: the sun will rise in the east and set in the west; birds will keep singing; and COVID-19 will stubbornly persist. And humans will continue to discover new things about themselves.
That’s right, we still haven’t figured out human anatomy in its entirety. Let’s take a look at two key findings that we (we, the scientific community) discovered in the past year.
If you put your hands near your cheeks and clench your jaw, you will notice a certain muscle in action. This muscle is called the “masseter,” and it is the most prominent of the jaw muscles. The traditional understanding of the masseter—as explained in anatomy textbooks—is that it consists in two parts: a superficial and a deep layer.
Yet a recent study by Dr. Szilvia Mezey of the University of Basel and Professor Jens Christoph Turp from the University Center for Dental Medicine Basel describes an additional third layer. The layer is the deepest of the three. It is attached to the lower jaw, located close to the ear.
“This deep section of the masseter muscle is clearly distinguishable from the two other layers in terms of its course and function,” says Mezey. What is its function? To stabilize the lower jaw. It also is the only part of the masseter muscle that can pull backwards –towards the ear.
You won’t get very far without a kidney. The four-and-a-half inch bean-shaped organ plays a vital role in dispelling toxins and waste products from the body. Those without a kidney (up to half-a-million people in the US alone) depend on intensive dialysis procedures just to survive. According to a New York Times article, there are more than 100,000 Americans on waiting lists for transplants, and twelve people on the lists die every day.
People on the waiting lists received welcome news when surgeons at NYU Langone Health found functioning kidneys in an unlikely source: pigs.
“With the family’s consent, the [surgeons] attached the pig’s kidney to a brain-dead patient who was sustained on a ventilator, and then followed the body’s response while taking measures of the kidney’s function,” states the article.
This latest attempt of xenotransplantation—the process of moving organ, tissue, or cells between two different species—faces significant ethical, medical and regulatory obstacles before becoming established practice. Yet, in the 54 hours under observation, the organ “worked normally, making urine and the waste product creatinine ‘almost immediately,’” according to surgeon Robert Montgomery.
“It just looked like any transplant I’ve ever done from a living donor,” said the surgeon. “A lot of kidneys from deceased people don’t work right away, and take days or weeks to start. This worked immediately.”
Surgeons have attempted xenotransplantation to human patients before: in the 1960s, with chimpanzee kidneys, and in 1983, with a baboon heart. Most patients died shortly after the procedure.
Pig organs, however, are considered particularly advantageous for humans, as they can grow to adult human size in just six months. “Pig heart valves are transplanted routinely into humans, and some patients with diabetes have received pig pancreas cells,” states the article. Patients with significant burns sometimes wear pig skin as a temporary graft.
To read more about pig kidney transplantation, click here.
And to sink your teeth into the new jaw muscle finding, click here.