The Excretory and Urinary System worksheet - Free Printable

1. Human feces is not an example of excretory waste because it consists of undigested food material and bacteria that were never absorbed into the bloodstream or metabolized by the body’s cells; excretion involves removing metabolic waste products from cellular processes.

2. The lungs are considered excretory organs because they eliminate carbon dioxide, a waste product of cellular respiration, from the bloodstream during exhalation.

3.
a. P - Renal artery
Q - Renal vein
R - Ureter
S - Urinary bladder
T - Urethra

b. Place an X on the kidneys (the two bean-shaped organs).

c. The sphincter muscle controls the release of urine from the urinary bladder through the urethra by contracting to hold urine in and relaxing to allow urination.

d. Blood in P (renal artery) contains higher levels of urea and other waste products compared to blood in Q (renal vein), which has had those wastes filtered out by the kidneys.

e. No, this is not a normal sample. Normal urine should contain water, salts, and urea, but not sugar or proteins. The presence of sugar may indicate diabetes, and proteins may suggest kidney damage or disease.