A 6-minute, videotaped segment of discourse in a medical school classroom problem-based learning session is analyzed for evidence of the kinds of meanings being constructed, their functions, and the linguistic, kinesic, and other means by which they are being made. Three interdependent discourse agendas are distinguished: construction, maintenance, and negotiation of group interpersonal relations; negotiated construction of thematic views of medical phenomena; and enactment of cultural and subcultural norms and formations. Nonverbal evidence is examined alongside speech. Focus of the analysis is on a perceived tension between the norms and strategies of medical diagnostic discourse, as practiced by the students, and the nature of the phenomena as they are constructed. The diagnostic approach and underlying medical terminology are viewed as typological, in semantic terms, while the natural phenomena require more topological approach. The coach/tutor is seen as taking a typological approach, and the students as bringing a topological perspective. A transcription of the discourse segment is appended. Contains 11 references. (MSE)