No abstract

Circadian rhythms in DNA synthesis are described for the tongue epithelium, five different regions of the alimentary canal (gut)--esophagus, stomach, duodenum, jejunum and rectum--and bone marrow in a group of BDF1 male mice. A circadian rhythm is also described for the mitotic index in the corneal epithelium in the same mice. The data document for the first time in the same animals the dramatic variation in cell division encountered from one region of the gut to another. This variation is seen in the amplitudes of the rhythms as well as in the over-all 24-hour means. On the contrary, the phasings of the rhythms in the different regions of the gut are remarkably similar. In this study, where the mice were standardized to 12 hours of light (0600-1800) alternating with 12 hours of darkness, the peak of the DNA-synthesis rhythm occurred around the time of transition from dark to light, and the trough around the time of transition from light to dark. The implications of these findings, and those of others, to the study of cell kinetics and to cancer chemotherapy are discussed.

No abstract

"Anatomizing" is a new verb some use to describe the breaking apart of a complex entity such as the human body, into isolated tidbits of information for study, which can never equal the complex, integrated whole. Although popular with first-year medical students, this practice of "tidbitting" anatomical information into easy to memorize facts or tables of facts does not prepare medical students for the inevitable task of dealing with the integrated structure-function of the human body, both normal and diseased, as patient managers. Examination questions drive the cognitive methods students will use to learn content. Asking students on examinations for recall of previously memorized tidbits fosters the cognitive learning behavior of only memorization. Examination questions, however, can be constructed that assess student understanding and integration of the content, that is, student use of cognitive and metacognitive methods of higher order learning that will foster high-quality learning producing better practitioners and lifelong learners. This kind of efficient student learning needs to begin in the first year of medical school.Learning more efficiently and at deeper levels of understanding is especially pertinent as the contact hours in anatomy courses continue to decrease.