Transcript Human Excretory System

Human Excretory System
Major Excretory Organs
•Lungs
•Large Intestine
•Kidneys
•Liver
•Skin (Integument)
Lungs and Large Intestine
• Lungs remove carbon dioxide from
the blood
• Large Intestine removes solid waste
(feces) from the body
Kidneys
• Primary organ of the excretory system
• Filters soluble waste products from the
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blood stream
Major renal vein and renal artery carries
blood to and from the kidney
Major regions of the kidney include the
cortex (outer layer) and medulla (inner
core)
Kidney (Renal) Anatomy
Major Filtering Unit of the
Kidney is called the Nephron
The Nephron takes out
wastes from the blood
and returns needed
chemicals back to the
bloodstream. The waste
(dissolved in water) is
collected and transported
to the ureter.
Major Urinary Waste Products
• Ammonia (NH3) is in the form of
Ammonium hydroxide (NH4OH)
• Ammonium hydroxide raises the pH
of the blood and needs to be
eliminated
• Ammonium hydroxide is converted to
urea (major) and uric acid (minor).
• Urea and uric acid are excreted in the
urine
What Happens to the Urine?
• Urine passes through the two ureters
and collects in the urinary bladder
• Urine leaves the bladder by both
involuntary and voluntary control
mechanisms
• Urine leaves the urinary bladder by
the urethra and is eliminated from
the body
Excretory System Pathologies
• Nephritis can be caused by bacterial infections or
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an autoimmune disorder; bloody urine and low
urine output are symptoms
Nephrosis results in large molecules being lost in
the urine and results in swelling throughout the
body
Urinary tract infections occur in the urinary
bladder and urethra and can normally treated by
antibiotics (women more prone to urinary tract
infections)
Kidney stones (different types) accumulate in the
kidney and cannot be passed through the urinary
tract easily; kidney stones are either passed with
significant pain or are surgically removed
Gout is a condition where uric acid cannot be
adequately excreted and builds up in the body
where it is deposited into joints resulting in
inflammation
Liver
• Removes excess amino acids from the
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blood (amino acids are the molecules that
make up protein) and converts them to
urea which is excreted by the kidneys.
Liver also breaks down hemoglobin from
old RBCs to form bile (bile helps break
down fats).
Bacteria from the large intestine are also
cleared by the liver.
Skin (Integument)
• Composed of two main layers (epidermis
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and dermis)
Also contains hair, nails, sweat glands, and
oil (sebaceous) glands
Sweat glands get rid of excess salts, urea,
and water (about 0.5 liters per day)
Evaporation of sweat also helps the body
to keep cool (evaporative cooling)