Water diuresis in man
Water Diuresis in Man Practical Report
INTRODUCTION
The body needs to maintain equilibrium to function properly in everyday life. The most important substance it must regulate is water; water is everywhere in our body and its balance is essential for proper body function.
A very carefully regulated process is solute concentration. If there is a sudden increase in water which enters the extracellular fluid, sodium ions will then contribute less to the extracellular solute concentration as the ratio between water and solute has now changed. Osmolality is the amount of solute in a kilogram, hence the osmolality in the extracellular space has also decreased.
Water diuresis is the increase in urinary water excreted with little or no change in the solute excretion. Excess water needs to be excreted to maintain a good balance of water and solute inside the body.
The aim of this practical is to test the effects of strenuous exercise and desmopressin (anti-diuretic hormone) on urine flow and urine sodium concentration. We will be testing the hypotheses that vigorous exercise will decrease urine flow and increase urine sodium concentration, whereas desmopressin will have the opposite effect of decreased urine flow and increased sodium concentration.
MATERIALS AND METHODS
Refer to the BMS2031 2014 Laboratory Manual.
RESULTS
Table 1. Details of the subjects in your experimental group.
Subject
Sex (M/F)
Body weight
(kg)
Volume of water ingested (litres)
Procedure (control, desmopressin or exercise)
1
M
68
0.816
Exercise
2
M
120
1.44
ADH
3
F
62
0.744
Control
Table 2. Control Subject Data
Time at which bladder was emptied prior to practical class__-__
Sample 1
Drink water (12ml/kg body weight)
Sample 2
Sample 3
Sample 4
Sample 5
Sample 6
Time interval (min)
-
20
20
20
20
20
Volume (ml)
-
-
-
-
-
-
Urine flow (ml/min)
1.3
2.6
4.8
6.5
5.2
2.9
Na+ conc. (mmol/litre)
8.0
7.0
2.6
INTRODUCTION
The body needs to maintain equilibrium to function properly in everyday life. The most important substance it must regulate is water; water is everywhere in our body and its balance is essential for proper body function.
A very carefully regulated process is solute concentration. If there is a sudden increase in water which enters the extracellular fluid, sodium ions will then contribute less to the extracellular solute concentration as the ratio between water and solute has now changed. Osmolality is the amount of solute in a kilogram, hence the osmolality in the extracellular space has also decreased.
Water diuresis is the increase in urinary water excreted with little or no change in the solute excretion. Excess water needs to be excreted to maintain a good balance of water and solute inside the body.
The aim of this practical is to test the effects of strenuous exercise and desmopressin (anti-diuretic hormone) on urine flow and urine sodium concentration. We will be testing the hypotheses that vigorous exercise will decrease urine flow and increase urine sodium concentration, whereas desmopressin will have the opposite effect of decreased urine flow and increased sodium concentration.
MATERIALS AND METHODS
Refer to the BMS2031 2014 Laboratory Manual.
RESULTS
Table 1. Details of the subjects in your experimental group.
Subject
Sex (M/F)
Body weight
(kg)
Volume of water ingested (litres)
Procedure (control, desmopressin or exercise)
1
M
68
0.816
Exercise
2
M
120
1.44
ADH
3
F
62
0.744
Control
Table 2. Control Subject Data
Time at which bladder was emptied prior to practical class__-__
Sample 1
Drink water (12ml/kg body weight)
Sample 2
Sample 3
Sample 4
Sample 5
Sample 6
Time interval (min)
-
20
20
20
20
20
Volume (ml)
-
-
-
-
-
-
Urine flow (ml/min)
1.3
2.6
4.8
6.5
5.2
2.9
Na+ conc. (mmol/litre)
8.0
7.0
2.6
References: Widmaier, EP, Raff, H & Strang, KT (2014). Vander’s Human Physiology. The Mechanisms of Body Function. MCGraw Hill, Chapter 14, page 499.