Anatomy & Physiology
Laboratory-3
Fluid Balance
This is a lengthy practical class and must start promptly.
Background:
The Kidney controls body water and blood electrolyte balance despite inevitable loses which occur by other routes.
The aim of this laboratory exercise is to explore the mechanism of controlling the circulating volume. You will manipulate your circulating volume by consuming standardised (relative to body size) volume of fluids which are suspected of influencing your blood volume and osmolarity. Then you will determine that how rapidly and completely the ingested volume is eliminated.
Safety:
1. Lab coats must be worn
2. Use gloves to handle your bodily fluids.
3. Do not eat, chew, smoke or drink in the lab. Keep hands, pens etc. away from the mouth.
4. Always place all bags, coats etc. away from the working area.
5. Hands must be washed after handling body fluids.
· Do not participate in this lab if you diabetes or any renal problems
· You will be measuring volumes of your own urine. Follow the instructions below carefully and ensure you wash your hands after each measurement.
· Any spillages should be reported to a member of staff.
Materials:
Measuring cylinder
Drinking water
Coffee
Methods:
On arrival at the laboratory, divide yourself into 4 groups of about equal size. Allocate one test condition (see list below) to each of your group. Weight yourself, and estimate lean body mass (LBM) as 80% of body weight in kg for males and 70% for females.
Test Conditions:
Subject 1 nothing- acts as control
Subject 2 5 ml/Kg-1 water
Subject 3 20 ml/Kg-1 water
Subject 4 20 ml/Kg-1 water- after 60 or 60 minutes at the height of diuresis, exercise vigorously for 20 minutes on the bicycle.
Subject 5 20 ml/Kg-1 (water+ Coffee- ⅓ of your total amount)
Before coming to the lab you should have: -
· Emptied your bladder!!.
· Been allocated a number within your group to determine how much water you will need to consume for this experiment. 1= Nothing
2= 5ml/Kg of body weight
3= 20ml/Kg of body weight
4=20ml/Kg of body weight
5=20ml/Kg of body weight
Round your body weight to the nearest 5kg.E.g 52kg=50Kg, 78Kg=80Kg and use the table below to determine how much water you need to consume. The water will be provided in the lab.
Body Weight / Volume of water(ml) / No. of Cups5ml/kg / 20ml/kg / 5ml/kg / 20ml/kg
50 / 250 / 1000 / 1.25 / 5
55 / 275 / 1100 / 1.25 / 5.5
60 / 300 / 1200 / 1.5 / 6
65 / 325 / 1300 / 1.5 / 6.5
70 / 350 / 1400 / 1.75 / 7
75 / 375 / 1500 / 1.75 / 7.5
80 / 400 / 1600 / 2 / 8
85 / 425 / 1700 / 2 / 8.5
90 / 450 / 1800 / 2.25 / 9
95 / 475 / 1900 / 2.25 / 9.5
100 / 500 / 2000 / 2.5 / 10
This experiment takes exactly 2½ hours so it is important that as soon as you come into the class to consume the correct volume of water, take and start a timer and sit back down! (NB Make sure you have emptied your bladder first!!) It is important that you drink all the water as rapidly as possible so that the relevant physiological are activated quickly.
If you have diabetes or a renal problem, please do not participate in this lab. You can collect the data from your classmates.
The experimental time line is as follows:
1. Just prior to experiment empty your bladder into a measuring cylinder provided to determine volume accumulating during the time since last performance. Measure amount of urine produced and record.
2. Time = 0. Begin consuming your treatment drink. Finish the drink as rapidly as possible. This is important to activate the relevant physiological operations quickly.
3. Empty your bladder every 20 minutes for the next 2 - 2.5 hours.
Measure volume of urine produced each time and record. Total volume in 20 minutes will provide rate of urine formation (ml/hr-1)
Results:
1) Tabulate all your results on the blackboard to see the class picture.
2) Chart the lab information on a graph displaying urine output as a function of time.
3) Describe your results form comparing the total urine output for the four groups.
4) Describe and critically analyse the effect of exercise and coffee intake on urine out.