MANUAL PHYSIOLOGY PRACTICAL - Repository:The Medical ...

FM/UOJ
Experiment K1
EFFECTS OF VARIOUS FACTORS ON FLOW OF URINE
When blood flows into the kidney, the plasma is filtered into the tubules,
required substances are reabsorbed, some substances are excreted and the remaining
fluid with waste products flows into the ureters, then into the urinary bladder and out
as urine. Urine flow is the volume of the urine that comes into the bladder from both
kidneys in a unit time (ml/min). The flow depends on the glomerular filtration rate,
osmolality of the medulla (counter current mechanism), the amount of the solutes in
the lumen and the level of anti diuretic hormone.
The aim of the practical is to demonstrate the effects of water, saline,
frusemide, and dehydration on urine flow and its specific gravity. The specific gravity
is measured as an index to the concentration of urine. At the end of the class, the
students are expected to have understood the factors affecting urine flow and skilled
in measuring the flow and specific gravity of urine.
Instruments:
Measuring glasses of different capacities, urinometer and beakers
The urinometer has a bulb and a shaft, the bulb has some heavy material to
hold the instrument floating vertically when placed in liquids. The shaft is calibrated
from 1.000 to 1.060 in steps of 0.020. The small divisions represent 0.002.
Method
The students are divided into groups and one male and a female from each
group undergoes a particular procedure. All results are displayed on the board so that
the students can compare and discuss the results of different procedures.
The subjects will go to the toilet and empty their bladder at zero time. They
will go with a beaker and collect their urine in the beaker at the end of the next 30
minutes and hand over to the others in the group for measurements. The subjects
should follow the specific procedure mentioned below. They will collect their urine
every 30 minutes for the next 150 minutes making the total duration 180 minutes.
The volume and specific gravity of each sample should be measured. If the volume is
too low for measurements of specific gravity, the urine could be retained and added to
the next sample for measurement of specific gravity. Also record the sensations of
the subjects at different phases of each procedure, especially of thirst and preference
to salt.
Kidney
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