The Effects of Different Types of Fluids on the Renal
March 16, 2012.
Principles of Human Physiology
Kidneys are a key function to the human body because it regulates plasma
volume, ionic composition, osmolarity, pH, and removes metabolic waste products and
waste substances. All these regulations work together to maintain homeostasis in the
body. A person has five liters of blood circulating the body and twenty percent (which is
one liter) of blood is circulated to the kidneys. The functions of the kidneys are the
billions of nephrons they contain that filter the blood. Each nephron contains the renal
corpuscle and renal ...view middle of the document...
In the proximal convoluted tubule, one hundred percent of glucose and seventy percent of water and
sodium are reabsorbed. The purpose of the loop of Henle is to concentrate the urine and
to reabsorb water (in the descending limb) and ions (in the ascending limbs). The distal
convoluted tubule reabsorbs water and other ions. Lastly, the collecting duct reabsorbs
ions, water, urea, and bicarbonate.
There are three hormones that help the kidneys function properly and they are the
Anti-Diuretic Hormone (ADH), Aldosterone, and Atrial Natriuretic Peptide (ANP).
ADH is a vasoconstricitor that elevates blood pressure, increases water reabsorption,
plasma volume, urine specific gravity, and decreases urine flow rate. When ADH is
stimulated, it targets the distal tubule and collecting duct, which causes the reabsorption
of water. To inhibit ADH, the plasma osmolarity must be low and both plasma volume
and blood pressure must be high. The Aldosterone is produced in the adrenal cortex.
When a decrease in plasma osmolarity, volume, and pressure occurs, it stimulates the
Renin-Angiotensin-Aldosterone System (RAAS), which functions to increase sodium
reabsorption through the distal tubule. ANP is a hormone secreted by the cells in the
atria of the heart and is stimulated when an increase in plasma volume and vast amounts
of sodium is in the extracellular fluid; it inhibits the reabsorption of sodium in the distal
tubule and increases sodium excretion.
The purpose of this experiment was to determine the osmotic regulation of the
kidneys in keeping fluid balance in the body with the association of hormone regulation.
The subjects were chosen at random and placed into four different categories: Nondrinking,
Water, Coke, and Gatorade. Within the four different groups listed, the Coke
group should have a higher average urine flow rate compared to Gatorade, compared to Water group and the Non-drinking group will have a low urine flow rate. The Nondrinking
group will exhibit the highest average corrected urine specific gravity, followed
by the Coke, Gatorade, and Water groups.
Before the experiment was conducted, the subject(s) had to fast. Food and any liquids
must not be consumed five hours prior to the experiment. Three hours before the
experiment, an eight-ounce cup of water may be consumed. Urination is not allowed one
hour prior to the experiment. Weight and time of last excretion were recorded for
calculation purposes. Then the subject(s) were split into four different groups: the nondrinkers,
Water, Coke, and Gatorade. Calculations needed to be worked out beforehand
to determine how much fluid an individual had to take. The formula for the amount of
fluid intake is:
mLs of fluid intake = [body weight(lbs) x 7mLs/lbs] x 0.80 **
I was in the water group and I had to ingest 661mL of water.
Once the experiment began, the subject(s) had to urinate in a urinary measuring cup,
record the time, and calculate the urine flow...