© KCL. WCED. PENTECH Keeping control STUDY this diagram EXPLAIN what is shown in this diagram. How might this balance differ during fasting? 1. Living cells can only function properly if they have the right conditions. Even small changes in temperature, concentration of solutions or amounts of chemicals, such as sugar, can disrupt or even kill cells. WATER GAIN 1300 cm 3 in drink 850 cm 3 in food 350 cm 3 formed during respiration 2500 cm 3 = total gain WATER LOSS 500 cm3 in sweat 400 cm 3 in breath 1500 cm 3 in urine 100 cm 3 in faeces 2500 cm 3 = total loss

© KCL. WCED. PENTECH Keeping control Quantity of sweat / urine produced (cm 3 / h) Outside temperature ( 0 C) sweat urine EXPLAIN what the graph shows DRAW and LABEL diagrams to show other temperature control mechanisms of the body. 50C50C 35 0 C

© KCL. WCED. PENTECH Keeping control 3. Camels - interacting with an extreme environment The camel can survive for days without water and be active in the full heat of the desert sun. It has tissues which can function over a wide range of temperatures. It saves water by not sweating until its body temperature reaches 40 0 C. However, by not sweating it can not keep cool. During the day its body temperature gradually increases, reaching 40 0 C by In the cold desert night heat energy is lost and its temperature then falls to 34 0 C by SKETCH a graph to show how the camel’s temperature varies over a 24 hour period. What is the advantage of: not sweating below 40 0 C? lowering the body temperature at dawn? PREDICT what would happen if the days were longer or hotter or the camel larger. CONCLUDE using this information what might have caused the extinction of the large dinosaurs

© KCL. WCED. PENTECH Keeping control © KCL. WCED. PENTECH Keeping control 4. Can eat dry food Can survive for 2 weeks without water and then drink 40 litres in 10 minutes Body tissues can become dehydrated Coarse light coloured hair on skin Only thin layer of fat under skin Thick pads of dead skin under feet Special kidneys can produce concentrated urine Fat stored in hump can be used in respiration to release water Special mouth can eat plants with spines and thorns Part of bodyAdaptationHow it helps the camel survive DISCUSS the information above and use it to COMPLETE the table

© KCL. WCED. PENTECH Keeping control 5. The amount of glucose in the blood must be kept constant to allow normal body functioning. If it falls due to fasting or rises due to over-eating the person may fall into a coma and possibly die. Fortunately most people produce a hormone called insulin in their pancreas which controls the blood sugar level. A diabetic person does not produce enough insulin and to stay healthy and has to inject it every day. Graph showing average variation for ten normal people in levels of blood glucose and insulin over 6 hours Meal eaten Exercise taken Meal eaten Blood glucose (mg/100cm 3 ) Time (hours) Blood Insulin DISCUSS what this graph shows and COMPLETE the diagram below. No more insulin is released Pancreas releases insulin High / Low level of glucose in the blood High / Low level of glucose in the blood

© KCL. WCED. PENTECH Keeping control Glucose in blood (mg/100cm 3 ) Time (hours) = Diabetic = Healthy person STUDY this graph DESIGN the investigation which might have produced the results shown in this graph. Key