Download The Excretory System

The Excretory
System
procedure
1. Mix a teaspoon of dirt and 150 mL of water in
a beaker. Stir the mixture until most of the dirt
is dissolved.
2. Add food coloring to the beaker.
3. Stir the mixture until all is mixed.
4. Layer a coffee filter over the neck of a second
beaker and secure with a rubber band.
Do not pull filters tightly across the top. Allow them
to dip a little.
procedure
5. Pour the dirt and water mixture onto the filter
paper. Pour slowly and carefully so as not to
overflow the filter.
6. In your spiral, describe what is happening in the
demonstration.
The nephron
Using the laptops, look up an image of a nephron.
Draw a picture of the nephron in your spiral.
Excretory System
• Why do our bodies need to filter waste
from the body?
– Maintain homeostasis
– Removal of harmful materials
– Removal of excess fluids, chemicals,
minerals, vitamins, salts, and other wastes
from the blood
Excretory System
• Organs
–
–
–
–
–
–
kidneys
ureters
urinary bladder
urethra
lungs
skin
• Organs of the Excretory System
sweat glands
lungs
Functions of Excretory System
• Rids blood of
wastes (urea)
• Controls blood
volume by removing
extra water
produced by cells
• Balances salts and
water so cells can function properly
Organs of the Excretory System
• kidneys – major
organs of the
excretory system that
filters blood and
eliminates urea,
excess water, and
other wastes
Organs of the Excretory System
Organs of the Excretory System
• ureters – two
narrow tubes that
urine flows through
to get to the
bladder
Organs of the Excretory System
• urinary bladder –
sac-like, muscular
organ that stores
urine
Organs of the Excretory System
• urethra – tube that urine travels to leave
the body
Other Organs of Excretion
There are other organs in our body that can
excrete substances
• Lungs – carbon dioxide and water
• Skin – sweat, water, some chemicals
• Liver – breaks down molecules, recycles
hemoglobin and turns it into bile
The Filtering Process
• Every drop of blood in your body passes
through the kidneys and is filtered 300
times a day
• nephrons – tiny structures
that filter blood in the
kidneys
Filtering Out Waste
• After entering the kidneys, blood flows
through smaller and smaller arteries
• The blood eventually reaches a cluster of
capillaries called nephrons
• In the nephron, urea, glucose, other
chemicals, and some water move out of
the blood and into the nephron
Filtering Out Waste
• Blood cells and proteins stay in the
capillaries
• Glucose, water, and small amounts of
other substances are reabsorbed into the
blood stream
• Urea and other wastes stay in the
nephrons
Filtering Out Waste
• The liquid left in the tube is urine
• The urine moves down the ureters and
into the bladder
• When the bladder is full, you feel the urge
to urinate
Filtering Summary
• 1. both wastes and needed materials are
filtered out of the blood
• 2. the needed material is returned to the
blood
• 3. the waste is eliminated in the urine
Analyzing Urine
• Some medical problems can be found by
testing urine
• Glucose – diabetes
• Protein – kidney failure
• Drug residue – drug abuse
Which is not a function of the
excretory system?
1. Removes wastes from the
2.
3.
4.
blood
Removes excess water from
the blood
Removes carbon dioxide from
the blood
Removes excess salt from the
blood
Which system does not include
an excretory organ?
1. Excretory system
2. Integumentary system
3. Cardiovascular system
4. Respiratory system
Where is urine stored until the
body is ready to eliminate it?
1.
2.
3.
4.
Kidneys
Ureters
Bladder
Urethra
Body systems that work
with the excretory system;
• circulatory system to carry waste
to the kidneys
• respiratory system to remove
carbon dioxide
• integumentary system to remove
salt
Comparing Cells to Body
What cell organelle helps to break down
waste?
lysosomes
What cell organelle packages waste?
golgi body