Download Excretion - Structure - Hicksville Public Schools

AIM: How does excretion in
humans remove harmful
wastes?
Your Body’s Filter
Have you ever seen a water-purification system
attached to a faucet?
This system removes impurities from the water such as
arsenic or other chemicals that can be harmful to
people. As water passes through the filters contained in
the system, the impurities are trapped on the surface of
the filters. Eventually, the water that comes out of this
purifier is free of the impurities.
1. Your body has its own system for filtering blood. Why
might the blood in your body need to be filtered?
2. What organs do you think filter your blood?
3. How do you think the filtered materials leave your
body?
Label the
Diagram
Urinary System
• Blood in the artery
enters the kidney
• In the kidney the blood
gets cleaned of
metabolic waste
• The vein carries clean
blood back to the heart
• The ureter carries
urine to bladder
Urinary System
• The bladder is where
urine is stored
• When the bladder is full,
it sends a message to
the brain
• The urine (water, urea, &
other wastes) exits the
body through the
urethra.
The Hard-working Kidneys
• The two kidneys in the body receive
between 1100 – 2000 liters (1160 – 2100
quarts or 500 gallons) of blood per day –
but only produce 1 – 1.5 liters of urine/day.
• Because the body has only about 5.6 liters
of blood, your blood runs through the
kidneys to be cleaned about once every
four minutes.
Kidneys: How do they maintain
homeostasis?
• The primary organs
in excretion, play a
vital role in
maintaining the
homeostasis of body
fluids. They excrete
waste products &
regulate water &
salt balance in the
blood.
Nephron
Made of millions of
nephrons which
filter the blood of
SALT, WATER, and
UREA.
Nephron
Parts of the Nephron:
1)Glomerulus – tiny ball
of capillaries located at
the beginning of each
nephron tubule.
2) Bowman’s Capsule –
cup- shaped portion of
the nephron that
surrounds the
Glomerulus, collects
stuff filtered from the
blood
Nephron
Blood Processing:
1)Filtration – blood pressure
forces fluid (water, urea,
glucose, amino acids) from the
glomerulus into the Bowman’s
Capsule (not proteins).
2)Reabsorption – water and
dissolved nutrients, such as
glucose, salts, & amino acids,
are reabsorbed back into the
blood.
Blood Processing:
Nephron 3)Secretion – kidneys
remove certain substances
from the blood and add
them to the filtrate.
4)Excretion – now the
filtrate is called urine and
will be sent to the ureter,
the bladder, & then the
urethra to be excreted from
the body.
Other Excretory Organs
•Liver
•Lungs
•Skin
LIVER
•Destroys old RBCs
•Produces urea from
breaking down amino
acids (ammonia to urea)
•Stores glycogen
•Detoxifies many
harmful substances
Lungs
• Gets rid of :____ & _____
Skin (Integumentary)
Sweat Gland
• Gets rid of extra
heat
• Gets rid of water
and salt
• Has 2 to 5
million sweat
glands
How does our excretory system
help maintain homeostasis?
• Temperature balance
• Water balance
• Waste balance
• Gas balance