Recent technological advances have allowed for such dramatic and amazing views of the inside of our bodies that watching the footage can feel like you're in a science fiction film or on an imaginary expedition.
In such a science fiction journey, the 1966 film "Fantastic Voyage," a group of scientists and their submarine were miniaturized so they could be injected into a body in order to eliminate an otherwise unreachable brain clot.
"I use clips from that movie when I lecture about these new technologies," said Dr. Steven Palter, the medical and scientific director of Gold Coast IVF in Syosset, N.Y. "Now, physicians can actually see the workings of the body and understand it in a way that they never could before."
Palter, who has a medical technology blog called docinthemachine.com, is a pioneer of methods capable of producing spectacular high-definition surgical images.
He is one of more than 200 scientists and experts who were recruited to advise the makers of a documentary titled "Inside the Living Body," which premieres Sept. 16 on the National Geographic Channel.
Among others who contributed to the unique, cradle-to-grave depiction of the inner workings of our bodies are the British scientific photographer and biologist David Barlow, known for his work producing extraordinary views from inside the womb, and Stephen Marsh, a cellular biologist who is executive producer of the documentary.
Given new advances in technology, "The whole idea was to make a seamless voyage through one body," said Marsh. "We all have external appearances that are very different, but our internal lives are surprisingly similar."
Palter obtained his footage by advancing well-established procedures that allow doctors to insert cameras through small incisions and view the target areas of their surgeries. He successfully hooked up high-definition cameras and, he said, was awestruck by the results.
"With high definition, we're seeing things that we had never seen before … with depth perception, clarity and detail … because now it's enormously clear and magnified. We have views that you don't get with your naked eye."
"As we turned the ovary over, we saw this developing egg that just happened to be there at that point in the cycle," he said. "The image is so sharp and recorded with such clarity that it's a higher-resolution image than virtually any surgeon has ever seen."
In England, Marsh supervised the assembly of sequences depicting the development that takes place inside our bodies as we age. The sequences also use computer scenes generated from high-resolution MRI and CT scans of human beings. The information from the scans is digitized into virtual images of internal areas where cameras can't go.
Some scenes are reminders of things we collect too much of in a lifetime. Palter's high-definition view of fat cells lining a stomach are, in their own way, frightening. "That's commonly seen in surgery," Palter said. "It's just that now we see it more clearly. In some people, it's so bad that there's almost no room to work inside, where there's just an enormous amount of fat."
Some of Marsh's favorite scenes are of small things we take for granted but never visualize — our salivary glands. "It's almost like an alien monster, squirting out," he said.
To get the shot, Barlow squirted lemon juice into the back of a hungry subject's mouth and used a high-speed camera to capture the reaction of the salivary glands.
As the documentary notes, the glands are also a part of our immune systems, since saliva contains an enzyme that destroys bacteria. And tiny as they are, the glands produce a half gallon of saliva every day.
This documentary also surveys, in often stunning images, many of the reasons we change so much as we age. For instance, our cells clone themselves every day to reduce the wear and tear on our organs. Old cells die; new copies take their place.
But as that process goes on, we also copy the imperfections in our DNA, and those defects accumulate as we age. If you've ever used a photocopier, you know what happens: Copies made from copies lose a little quality with each duplication.
Over a lifetime, according to the documentary, we completely replace the bone in our face every 10 years; so your 70-year-old face is a seventh-generation copy of your baby face.
And the imperfections are exaggerated with each copy.
"It's all one complex system that is ticking along, according to this clock that we know eventually will end our lives," Barlow said. "But in the meantime, that's what makes us such a marvelous machine."
The technology used for the National Geographic Channel is also clearly on its way to helping revolutionize medical care. Palter contributed to the development of what's called an auto-fluorescent laparoscope, which exposes diseased tissue inside the body that a surgeon couldn't otherwise see.
"Instead of using visible light, it makes the disease fluoresce," Palter said. "If you look with your naked eye, you see nothing. When you switch on the light and the filters, all of a sudden the disease is glowing green, and you can see disease that's beyond the resolution of your naked eye."
Hippocrates, the fifth century B.C. physician who is considered the father of modern medicine, was known for taking the fear of mystical superstition out of medicine. Marsh believes that some fear still exists in the discomfort many people feel about their bodies, and that having the ability to see what's inside those frontiers, and how they work, will help add balance to the most important of all fields of medicine: how we treat ourselves.
"We're given one chance to have our life," Marsh said. "Modern society has taken us away from our physical beings, and I think that's had a damaging effect, in many ways, on how we live our lives, what we eat, how we behave. Hopefully, this [technology] can redress the balance in saying, 'Hey, this is who we are, this is what we've got. Listen to it, and don't be afraid of it.'"