Edexcel Level 3 BTEC Nationals in Health and Social Care

UNIT 13: PHYSIOLOGY OF FLUID BALANCEThe distribution of water within the body can be introduced at this stage, in terms ofintracellular and extracellular fluids. Discussion of the composition of, andrelationship between, blood, tissue fluid and lymph could be useful here. Learnersneed to understand the role of intercellular fluid as the environment of the cells, andits importance in homeostasis. Differences in the constituents of the different bodyfluids can be discussed here, as can the various means by which the human bodytakes up and loses water.This will lead on to a discussion of the importance of water balance in the body, andthe means by which this is achieved. Charts and models could be used to illustratethe gross anatomy of the renal system, including the kidneys. Dissection of a kidneywould also be a useful vehicle for learning. The structure and functioning of thekidney tubules, and their role in water maintenance, require tutor input.Relevant practical activities could include chemical tests to investigate thecomposition of synthetic urine. Discussions could include, for example, considerationof the effect of sweating on a hot day in relation to the volume of urine produced.This would link different aspects of homeostasis and lead on to examination of theadjustments individuals make to their fluid intake according to factors such asenvironmental temperature and exercise.Learners could, if appropriate, be encouraged to relate their learning to health orsocial care settings. For example, observations in placements of how the fluidbalance of patients/service users is managed could enhance learning. The use ofintravenous drips for rehydration could also be explained here.Knowledge and understanding of the homeostatic control of water in the human bodyshould then be applied to consideration of dysfunctions in relation to water balance.Case studies would be useful here, or small group work in which learners gatherarticles from the media/health and social care literature about relevant topics suchas dehydration, renal failure, or transplantation. Context setting could also berelated specifically to groups who are particularly vulnerable to dehydration, forexample infants and young children, older people or those with food poisoningsymptoms.AssessmentFour assignments could be used for the basis of evidence for this unit.The first, based on cell microstructure and physiology, could be used as a vehicle forthe evidence required for P1 and M1. A well-annotated diagram, supported by somewritten work, should be sufficient for this purpose. Care should be taken to ensurethe authenticity of learners’ work, in particular in relation to images and descriptivework downloaded from the internet or taken from textbooks. Specific examples ofcell types should be used by learners to support their explanation of how thefunctions of the main cell components relate to overall cell function, for M1.A second assignment could then be used to assess P2, M2 and D1, in relation to themovement of materials into and out of cells. For P2 learners are required to explainthe ways in which materials move into and out of cells, extending this for M2 toinclude a description of factors that influence this.186BN018467 – Specification – Edexcel Level 3 BTEC Nationals in Health and Social Care– Issue 1 – February 2007 © Edexcel Limited 2007