c. Circulating blood enters the cluster of capillaries known as the glomerulus.
Water, electrolytes, and small organic molecules are filtered from the capillary blood
and pass into the capsule. Blood cells and large protein molecules cannot pass through
the glomerulus into the capsule.
d. The "filtrate" (water and solutes filtered from the blood) passes from the
capsule into the tubule. In the tubule, water and usable chemical products are
reabsorbed.
e. The final waste product, urine, drains from the last loop of the nephron's
tubule into a collecting tubule for drainage into the renal pelvis.
2-8.
CHARACTERISTICS OF URINE
a. Composition. Normal urine is composed of about 95 percent water and 5
percent solutes. Normal solutes found in urine include:
(1)
Urea.
(2)
Creatinine.
(3)
Uric acid.
(4)
Ketone bodies.
(5)
Potassium.
(6)
Sodium.
(7)
Chloride.
b. Specific Gravity. The specific gravity of urine depends upon the amount of
solutes present. The greater the concentration of solutes, the higher the specific
gravity. Normal range for specific gravity is from 1.008 to 1.030.
c. Appearance. Urine is a transparent (clear) fluid. Color varies from pale
yellow to dark amber, depending upon its concentration. (Concentration is the ratio of
solutes to water.)
(1)
Dilute urine may be pale, straw colored, or even appear colorless.
(2) Concentrated urine appears highly colored (for example, bright yellow or
deep amber).
(3) Turbid (cloudy) urine is usually considered abnormal. It may be the
result of blood, pus, sperm, or bacteria present in the urine.
MED918
2-7
Previous Page
