So with a pain in her belly last week, and concerned that it could be a liver ailment, the married mother of four felt most comfortable going to Puentes de Salud, the Spanish-friendly free clinic held Thursday nights in the basement of St. Agnes Medical Center.

The South Broad Street clinic, whose name means "bridges of health," was established in 2004 as a charitable partnership between medical and nursing students, mostly from the University of Pennsylvania, and organizations, including the advocacy group Juntos, to focus on the needs of South Philadelphia's burgeoning Latino population, which was 6,200 in 2000 and estimated at 15,000 to 18,000 last year.

"The fact that I can speak in Spanish here makes me feel more comfortable," Loyola said through an interpreter in an examining room where volunteer medical and pre-med students took her health history and a volunteer doctor examined her.

"Buenos dias. Me llamo Dr. Mallya," physician Giridhar Mallya said as he entered the room.

A few minutes later he prescribed an oral medicine that Loyola can get through a special $5-a-month pharmacy program run by Walmart, K-Mart and Target - chosen by Puentes because they are all conveniently located in South Philadelphia where most Puentes patients live.

In addition to the peace of mind Loyola gets from speaking about her health problems in her native language, she is grateful for the free services.

"I have no health insurance and no money," she said, adding that her family came to the United States from Mexico City in 2006, lived in Denver for a year and a half, and last September moved to Philadelphia, where her husband works as a shipping and receiving clerk.

The Puentes staff never asks about patients' immigration status; most patients, like Loyola and others interviewed this week, didn't volunteer it.

Though most patients receive basic primary care, there are occasions when someone presents with a serious problem, like the woman a few weeks ago who needed a CT scan to rule out brain damage after she slipped and fell on her head, or the woman last week who had persistent blood in her urine with no obvious cause.

In serious cases, which present the potential for loss of life, limb, or permanent damage to internal organs, Puentes helps patients apply for emergency medical assistance, federal money dispensed by the state.

In an examining room next to Loyola's, 42-year-old Silvano Tlapechco had a manageable problem. He was there for a follow-up appointment to monitor treatment for an inflamed prostate.

Tlapechco (pronounced "klah-pesh-ko") said he barely supported his family of four as a farmhand in Puebla, Mexico, before they came to the United States in 2003. Now he works for a produce company in the Italian Market, which he described as a "10 times better" job than he had in Mexico, but he still asked that it not be named, fearing possible fallout.

Against the backdrop of the nation's fierce immigration-policy debate, Puentes' founders are unwavering.

"Legal? Illegal? My job is to take care of people. A life is a life," said physician Steve Larson, the group's medical director and a professor at the Hospital of the University of Pennsylvania Medical School.

Raised in Woodbury Heights, Larson, 47, a graduate of Haverford College and the Penn medical school, had his eyes opened to the problems of providing low-cost health care for marginalized people when he worked at a public hospital in Guatemala during that country's 1988 civil war.

In subsequent years he explored health-care delivery systems in Honduras, Nicaragua, El Salvador, Mexico and Costa Rica.

Then, for 13 years beginning in 1993, he worked at Project Salud, a well-known migrant health center in Kennett Square, Chester County.

"The majority of my patients made less than $13,000 a year; housing opportunities were limited; public transportation was nonexistent in the rural countryside; lack of immigration papers and language barriers were the norm," Larson said.

"Today I realize that these variables which impacted so heavily on the health and well being of my patients have a name: social determinants of health."

Grounded in that holistic ethos, Puentes, which serves 15 to 20 patients a night, strives to be more than a take-these-pills-and-call-again operation.

On any given night its sofa-lined waiting room might be the setting for a short presentation by law students about landlord-tenant relations or immigration and customs enforcement policies. "Promotoras," lay people trained to promote Puentes in the Latino community, might give a presentation on public health. Nursing students might speak about nutrition.

Matthew O'Brien, Puentes' director of community research who, like Mallya (his classmate at Brown medical school) is a fellow in the Robert Wood Johnson Clinical Scholars Program, thinks Puentes can be a new model for health-care delivery because it goes beyond simple acute care and tries to teach patients how to manage chronic conditions, the fastest-growing problem in medicine.

"Coronary artery disease, high blood pressure, diabetes, these kind of things account for a tremendous amount of our health-care spending," especially among immigrants, O'Brien said.

"That's where the burden of disease is at this point."