Excretion in human beings
Cells as a part of their activity they produce
nitrogenous compounds like urea and uric
acid. These are toxic in nature and are
to be excreted out from our body. Blood
collects these compounds and carry them
to the excretory system to filter them
out. The human excretory system consists
of a pair of kidneys, two ureters and
urinary bladder and urethra. Nephrons are
the functional units of kidneys which
actually filters the blood. Each nephron
consists of a cluster of capillaries and
a tube with cup-shaped end called
Bowman's capsule. Blood is filtered in
this capsule and toxic wastes like urea
uric acid creatinine along with water
are separated. Certain useful materials
like glucose, amino acids and salts are
also filtered but reabsorbed back into
the bloodstream. The water with toxic
waste molecules collected in the kidney
is called urine it is sent to the
urinary bladder through ureter. Once the
bladder is full
it creates an urge to urinate when we
relax the bladder muscles to urinate it
passes out through urethra
