Download The Excretory System 38-3

The Excretory System
Function of the Excretory
System

To eliminate wastes products from the
body
Kidneys



They remove waste products from the
blood;
Maintain blood pH;
Regulate the water content of the blood



The ureter carries urine from the kidneys
to the urinary bladder
The urinary bladder is a saclike organ
where urine is stored
The functional parts of the kidney are
called nephrons, they filter out impurities
from the blood
Filtration


Filtration is the process of passing a liquid
or a gas through a filter
Filtration mainly takes place in the
glomerulus, which is a network of
capillaries encased in a hollow cup called
Bowman’s capsule
Reabsorption


Reabsorption is when liquid is taken back
into a vessel
Amino acids, fats, glucose and water all
get reabsorbed by the Bowman’s capsule
into the blood
Urine Formation


Urine contains mainly urea, excess salts
and water
The loop of Henle is a section of the
nephron tubule in which water is
conserved and the volume of urine is
minimized
Control of Kidney Function


The activity of the kidneys is controlled
mainly by the actual composition of the
blood
Regulatory hormones are released to in
response to the composition of blood
Homeostasis by Machine

For people who have damaged kidneys,
dialysis machines can perform many of the
functions of the kidneys.