BILLINGS -- After 35 years as a smoker, Penny Piper is dying from emphysema, but the Billings woman knows her purpose will not end with her last breath.

Piper, 59, has willed her body to Montana State University's body donation program, which supplies cadavers to science programs at several colleges around the state.

"I don't think people realize how vital it is," Piper said. "I'm a firm believer that the soul is gone. You as a person are gone. All that's left is the receptacle you lived life in. Big deal if they carve it up and learn from it.

"If we had more people donating bodies as cadavers, just think how well we could teach our future doctors," she said. "Just think how many lives we could save."

Piper hopes her body will go to Rocky Mountain College, where about 60 students a year study cadavers in Claire Oakley's human anatomy and physiology class.

Rocky has three cadavers at any given time, which it buys from MSU for about $1,100 each. Preserved cadavers can be studied for up to five years.

MSU accepts as many as 25 bodies a year into the donation program. The bodies come only from Montana.

Piper researched the process online before calling Oakley, an acquaintance.

It wasn't the first time Oakley took a call from someone wanting to give her a body.

"It happens once a year," Oakley said.

An estimated 15,000 people in the United States donate their bodies to science each year, according to a 2004 study. About 2.5 million Americans die every year.

But the number of cadavers needed for education and research far outpaces the number donated, said Karissa Hughes, a junior at Rocky who will speak next month at a bioethics conference about the illegal cadaver trade.

"There's a huge demand," Hughes said.

And it's not just from colleges and medical schools. Some surgical procedures, such as joint replacements, rely on cadaver parts.

Trafficking black market body parts can be lucrative, Hughes said.

In New York earlier this month, a former oral surgeon reached a plea deal with prosecutors in which he admitted to stealing bodies from funeral homes to provide his company, Biomedical Tissue Services, with bones, skin and tendons to be used in transplants and other surgeries.

Michael Mastromarino also agreed to forfeit almost $5 million earned through his illegal activities.

Hughes said there probably isn't much of a market for illegal cadavers in Montana, partly because the state does not have a medical school and so needs fewer cadavers than other states.

Students who study cadavers at Montana colleges can be certain the bodies were legally obtained through MSU, she said.

Hughes has worked with the cadavers at Rocky and hopes to be part of a team of students who will dissect the next body that arrives.

"The relief is these people knew what was going to happen, and they gave their full consent," she said. "If they were just random people, I don't think I'd be OK with it."

"I just have the utmost respect" for body donors, Hughes said. "These people gave an amazing gift that many of us can't do."

Piper, who expects to live at least a couple more years, settled on donating her body after learning that emphysema precluded her from donating her organs.

"I feel very strongly I need to be able to help somebody learn something," she said. "It's a need within me."