As a physician assistant in the Martha’s Vineyard Hospital emergency room, Aubrey Stimola Ryan is versatile — able to understand a variety of medical fields and collaborate with doctors of all specialties.

A registered physician assistant since 2009, Ms. Stimola Ryan’s role is to fill gaps in care when doctors are overburdened. In the ER, she finds herself working on anything from obstetrics to pulmonology to oncology. The unpredictability is what excites her most about the work.

“I never thought that I would wind up in the ER,” she said. “It was a big surprise to me how much I enjoyed it. But I’ve never been a nine-to-five person . . . I want to be moving.”

It is common, however, for the work of nurse practitioners and physician assistants to be misunderstood or second-guessed, she said, with patients not understanding her qualifications and wanting to see a medical doctor. But Ms. Stimola Ryan doesn’t let misconceptions about her job prevent her from being a force in the medical world, both on the Island and abroad.

In the last decade, Ms. Stimola Ryan has dedicated much of her free time to a global health initiative in Mwanza, Tanzania. There, she works with other physician and nursing assistants, also known as advanced practice providers, to teach a five-day emergency medicine course for nurses at the Bugando Medical Centre, sponsored by the World Health Organization.

Ms. Stimola Ryan’s work in Tanzania began in 2012, when she was offered a two-year global health fellowship at Mount Sinai Hospital in New York City, a program that previously accepted only medical doctors.

“These programs are traditionally very siloed,” she said. “Still, to this day I’m not entirely sure how it happened. I just applied and I got in, and I’ve still been the only physician associate they’ve had.”

Ms. Stimola Ryan has traveled to Tanzania four times since the fellowship, now funding the trips all on her own. She plans to go back again this fall.

Bugando is one of the largest health care facilities in the country, with more than 1,300 staff members — 700 of whom are nurses. The center sees people from all over rural Tanzania but most of its health workers have no education in emergency medicine, Ms. Stimola Ryan said.

“This is a huge area where there is almost no health care available,” she said. “Someone would pull into the emergency room with a truck full of people and you would jump in and check pulses and say ‘okay this one can come in here and this one goes to the morgue.’”

Ms. Stimola Ryan isn’t licensed to practice medicine in Tanzania but while there she accompanies nurses on their visits to patients, listens to presentations, answers questions and picks up Swahili on the way.

“I do know a lot of Swahili now . . . Well, most if it is medical Swahili but it’s still very helpful,” she said.

It’s her hope that the teaching program, and others like it, will eventually help lower the region’s morbidity and mortality rates, since medical emergencies will be more easily recognized and treated by staff.

Ideally, she said, her trips to Tanzania will become less frequent as the nurses learn enough to teach the course themselves.

“We don’t want, in global health, to be coming in and doing,” she said. “We want to be teaching and then having [the nurses] do the teaching from there on out. Our role is always just supportive. Global health is all about sustainability.”

Ms. Stimola Ryan also emphasized that traveling abroad isn’t necessary to provide aid to people who are in need. She often sees parallels between her work in Tanzania and on the Island.

“The ER is often that doorway into the medical world for people who have been outside of it for so long,” she said. “We have a lot of people who come into the ER acutely ill and, lo and behold, they haven’t had medical care in 10 or 20 years, either because it’s just been hard for them to get it, they’ve just moved to the Island or something else.”

Whether she’s teaching in Tanzania or working in the Island ER, Ms. Stimola Ryan and her fellow advanced practice providers are trained to give care where it’s needed. She hopes that patients know that they can put their trust in them.

“You are going to get the care, I promise you, in seeing advanced practice providers,” she said.