Edexcel Level 3 BTEC Nationals in Health and Social Care

UNIT 13: PHYSIOLOGY OF FLUID BALANCEEssential guidance for tutorsDeliveryDelivery of this unit requires a clear understanding of scientific knowledge andprinciples, and should therefore be carried out only by an appropriately qualifiedperson. Some access to laboratory facilities may be useful but is not essential.The unit could be introduced by reviewing the microstructure of a typical animalcell, based on knowledge and understanding initially gained in Unit 5: Fundamentalsof Anatomy and Physiology for Health and Social Care.This should then be extended, with learners needing to understand cellmicrostructure in more detail, and the functions of the organelles — including theircontribution to the overall functioning of the cell. Delivery could include the use ofelectron micrographs, and possibly consideration of the contribution of differenttypes of microscopy to current knowledge and understanding of cells — if timeallows.Specific examples of cell types should be used to illustrate the functions of differentconstituents of cells, for example — secretory cells, muscle cells or ciliated epithelialcells. The significance of the phospholipid bilayer in the structure of cell membranesneeds to be understood.Consideration of the structure of cell membranes can then lead on to discussion ofthe means by which materials enter and leave cells, and the factors affecting thismovement. Some practical experiments could be carried out here so learners canobserve diffusion and osmosis and gain understanding of the significance of soluteconcentration and osmotic potential.This could be extended to discussion of the importance of water in the human body,the functions of water in relation to the structure of the water molecule, and inparticular its role as a solvent. This in turn could lead on to consideration of theimportance of aqueous solutions as media for metabolic reactions, and then to thecomposition of body fluids.The role of substances in solution needs to be discussed, including the role ofelectrolytes. Learners need to understand the importance of electrolytes, includingin the maintenance of the acid-base balance. A number of scientific concepts can beembedded here, including pH and the role of buffers, as indicated in the contentssection for learning outcome 3.Supporting practical activities could include, for example, investigating the solubilityof materials such as glucose or salt, measurement of pH, investigating thecharacteristics of acids and bases and the role of buffers.BN018467 – Specification – Edexcel Level 3 BTEC Nationals in Health and Social Care– Issue 1 – February 2007 © Edexcel Limited 2007185