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The use of recorded video in medical education is increasing. Video material may be assigned before scheduled sessions to create a flipped classroom. Here, the instructor may lead a session that is organized for discussion, interpretation, and reflection of the previewed content. We established conditions that lead to increased student participation and engagement with prerecorded content for a medical genetics section in a first-year medical school basic sciences integrated course. Preliminary analysis of an asynchronous video-based pre-professional program directed the design of video material to support a first semester medical genetics course. We compared student participation in, and opinion of, a flipped-classroom session based on written vs. video presentation of material. Student opinion was surveyed with audience response devices (clickers). Shorter videos that were created specifically for the course were preferred by students compared to recordings of previously delivered lectures. Students preferred videos to assigned reading material and consistent scheduling throughout the teaching semester increased student participation. Presentation of medical school content with previously recorded video material can be a useful teaching tool if properly implemented.

Paramecium calkinsi from tidal marshes survive a wide salinity range. Fluid output of contractile vacuoles of these cells decreased as salinity of the medium to which they were acclimated increased, and both pulse rate and vacuole volume were used to regulate output. When cells were first exposed to more dilute medium, contractile vacuoles greatly increased volume so that fluid output increased even though pulse rate decreased. In cells shifted to a more concentrated medium, contractile vacuole output decreased by decreasing pulse rate. The contractile vacuole is surrounded by a set of collecting structures which change form as the salinity changes. Distensible ampullae are found in media of low salinity and collecting canals are found in media of high salinity. When cells are shifted from high salinity to low, the number of ampullae increases and the number of canals decreases. When cells are shifted from low salinity to high, the number of ampullae decreases and the number of canals decreases. Other non-contracting vacuoles also appear in response to a hypoosmotic shock. These include vacuoles within the cell as well as "blisters" on the surface. The number and frequency of blisters increases with the size of the hypoosmotic shock. They detach from cells without resulting in any visible loss of cytoplasm. Non-contractile vacuoles may play a role in sequestering and removing excess water that the contractile vacuoles cannot handle.