Second-year UC Davis medical student Nathan Osborn trades in his stethoscope to wield a pick Saturday as he digs a trench for utility lines at a Habitat for Humanity project site in Oak Park. Students and other volunteers from the medical center worked construction projects for two Oak Park homes. "It exposed the students to a broader definition of health care," said Amerish Bera, clinical professor of medicine, who spearheaded the inaugural community-service effort. That definition takes the whole patient -- including income level and housing circumstances -- into account, Bera said. The event also was designed to bring students from different years together. The students have said they hope to continue collaborating on a regular basis with Habitat for Humanity, Bera said.