This study tested the possibility that interactive lectures explicitly based on activating learners' prior knowledge and driven by a series of logical questions might enhance the effectiveness of lectures. A class of 54 students doing the respiratory system course in the second year of the Bachelor of Medicine and Bachelor of Surgery program in my university was randomized to two groups to receive one of two types of lectures, "typical" lectures (n = 28, 18 women and 10 men) or "constructivist" lectures (n = 26, 19 women and 7 men), on the same topic: the regulation of respiration. Student pretest scores in the two groups were comparable (P > 0.1). Students that received the constructivist lectures did much better in the posttest conducted immediately after the lectures (6.8 +/- 3.4 for constructivist lectures vs. 4.2 +/- 2.3 for typical lectures, means +/- SD, P = 0.004). Although both types of lectures were well received, students that received the constructivist lectures appeared to have been more satisfied with their learning experience. However, on a posttest conducted 4 mo later, scores obtained by students in the two groups were not any different (6.9 +/- 3 for constructivist lectures vs. 6.9 +/- 3.7 for typical lectures, P = 0.94). This study adds to the increasing body of evidence that there is a case for the use of interactive lectures that make the construction of knowledge and understanding explicit, easy, and enjoyable to learners.
1. We believe that the ultimate goal of cardiovascular regulatory mechanisms is not the regulation of arterial blood pressure (BP), but the maintenance of tissue blood flows commensurate with metabolic requirements. Thus, elevated BP can potentially contribute to optimizing tissue blood flows under select circumstances; for example, when there are primary defects in autoregulation of tissue blood flows. 2. The hypothesis that a primary defect in autoregulation of tissue blood flows may be responsible for the development of hypertension is presented. It is argued that, in this context, at least part of the rise in BP may be reflexly driven by a 'metaboreflex', a homeostatic mechanism acting to regulate tissue blood flows. 3. We argue that in the context of primary defects in autoregulation of tissue blood flows, the ability to generate and sustain a hypertensive phenotype increases the lifespan of species (i.e. if it were not for this adaptive hypertensive phenotype, death due to circulatory failure would occur much earlier). 4. Experimental and clinical evidence that indirectly supports the hypothesis is reviewed briefly and a means for testing this hypothesis is suggested.
One method of grading responses of the descriptive type is by using Structure of Observed Learning Outcomes (SOLO) taxonomy. The basis of this study was the expectation that if students were oriented to SOLO taxonomy, it would provide them an opportunity to understand some of the factors that teachers consider while grading descriptive responses and possibly develop strategies to improve scores. We first sampled the perceptions of 68 second-year undergraduate medical students doing the Respiratory System course regarding the usefulness of explicit discussion of SOLO taxonomy. Subsequently, in a distinct cohort of 20 second-year medical students doing the Central Nervous System course, we sought to determine whether explicit illustration of SOLO taxonomy combined with some advice on better answering descriptive test questions (to an experimental group) resulted in better student scores in a continuous assessment test compared with providing advice for better answering test questions but without any reference to SOLO taxonomy (the control group). Student ratings of the clarity of the presentation on SOLO taxonomy appeared satisfactory to the authors, as was student understanding of our presentation. The majority of participants indicated that knowledge of SOLO taxonomy would help them study and prepare better answers for questions of the descriptive type. Although scores in the experimental and control group were comparable, this experience nonetheless provided us with the motivation to orient students to SOLO taxonomy early on in the medical program and further research factors that affect students' development of strategies based on knowledge of SOLO taxonomy.
It is common to see chapters on acid-base physiology state that the goal of acid-base regulatory mechanisms is to maintain the pH of arterial plasma and not arterial Pco(2) (Pa(CO(2))) or plasma HCO(3). A hypothetical situation in which the Pa(CO(2)) of arterial plasma is 80 mmHg and the plasma HCO(3) concentration is 48 mM is presented and analyzed to get over this misconception. As per the modified Henderson equation, the pH of arterial plasma would be 7.4; however, we explain that this may be associated with intracellular acidosis due to intracellular hypercapnia and that derangement of homeostasis is evident from the occurrence of respiratory depression and, eventually, coma in the patient described. This suggests that the ultimate goal of acid-base regulatory mechanisms is not just the maintenance of the pH of arterial plasma but the maintenance of the steady-state pH of intracellular fluid as well.