Excretory System
How Excretion Works
Maintaining Excretory Health
Excretory System Problems
The excretory system uses several organs to remove all
types of wastes from the body.
• Excretion is the process of removing wastes
from the body, waste is produced in the form of
solids, liquids, and gases.
Lungs expel carbon dioxide when exhale, sweating is
another form of excretion, sweat removes excess
water and salts through pores, this regulates body
temperature, sweat evaporates on the surface of the
skin, it cools the body, sweating too much can cause
dehydration
Solid waste produced in digestive system is eliminated
through large intestine, the bacteria that lives in the
large intestine converted food into semi-solid mass
called feces
• Liver removes toxins from the blood, it is
the first organ to receive chemicals
absorbed from the small intestine, it
detoxifies the body by processing and
excreting into bile such things as drugs,
alcohol, and some cellular waste
• Urinary system consists of kidneys,
bladder, ureters and urethra, main function
is to filter waste and extra fluid from the
blood, urine is liquid waste material, it
consists of water and body wastes that
contain nitrogen
• Kidneys are bean shaped organs size of fist,
near the middle of the back, just below the rib
cage, one on each side, remove waste products
from the blood through tiny filters called
nephrons – functional units of the kidneys,
nephrons consists of ball formed of small blood
capillaries called a glomerulus, attached to
small renal tubule that acts as filtering funnel,
kidneys adjust amount of salts, water and other
materials excreted according to body’s needs,
they monitor and maintain the body’s acid-base
and water balances, when the body becomes
dehydrated, the pituitary gland releases
antidiuretic hormone causes thirst and allows
the kidneys to balance the fluid levels
• From kidneys, urine travels to bladder through
the ureters – tubes that connect the kidneys to
the bladder, each ureter is about 8 to 10 inches
long, muscles tighten and relax to force urine
down and away from the kidneys, this takes
about 15 seconds
• Bladder is a hollow muscular organ located in
pelvic cavity, it stores about 2 cups or urine
comfortably for two to five hours, sphincter
muscle keep urine from leaking, this closes
tightly like a rubber band around the opening
into the urethra – tube that leads from the
bladder to the outside of the body
Healthful behaviors will help keep your excretory
system.
• Drink at least eight 8-ounce glasses of water
each day.
• Limit your intake of caffeine and soft drinks,
which can increase the amount of water lost
through urination.
• Follow a well-balanced eating plan
• Practice good hygiene to prevent harmful
bacteria from causing infection.
• Get regular medical checkups. Report changes
in bowel habits and in the frequency, color, or
odor of urine
Excretory system problems commonly result from infection
or blockage
• Disorders can have several different
causes, including infection, blockage of
urine, or natural aging, two common
disorders are:
• cystitis – inflammation of the bladder,
caused by a bacterial infection, if
untreated can spread to the kidneys
• Urethritis – inflammation of the urethra,
caused by bacterial infection
• Kidney Problems:
Nephritis – inflammation of the nephrons
Kidney stones – forms when salts in the urine
crystallize into solids, stones move into the
ureter, may block the passage of urine, smaller
stones may pass through, larger ones can be
broken up using shock waves, some cases
surgery is required
Uremia – serious condition associated with
decreased blood filtration by kidneys, leading to
abnormally high levels of nitrogen waste
products remaining in the blood, wastes are
poisonous to body cells and can cause tissue
damage or death if accumulate
• Kidney Failure: lose the ability to function, caused
by infection, decreased blood flow, or diseases that
damage kidney tissue. This are treatments:
• Hemodialysis – a technique in which an artificial
kidney machine removes waste products from the
blood, machine filters the blood, takes three to five
hours, done three or four times per week
• Peritoneal dialysis – peritoneum, thin membrane
that surrounds the digestive organs to filter the
blood, substances that promotes the removal of
toxins enter into the abdomen through a catheter
and are drained after filtration is complete
• Kidney transplant – replacement of a
nonfunctioning kidney with a healthy one from an
organ donor