Download 3.5 Excretory System

Chapter 3 Human Body
Lesson 5 Excretory System
Main Idea
The kidneys remove waste from the blood and produce urine which is stored in the
bladder.
Vocabulary
Urinary system (156) – removes excess water and waste products in the blood
other than carbon dioxide
Kidneys (156) – bean shaped organs that filter waste out of the blood
Urine (156) – waste product consisting of waste and excess water
Nephron (158) – structures in the kidneys that separate waste from the useful
material in the blood
Bladder (160) – an organ that temporarily stores urine
Urethra (160) – the tube that carries urine from the bladder to the outside of the
body
What does the excretory system do?
Main Idea
The excretory system removes waste products from the body.
Supporting Details
A. The excretory system removes the waste products from the body.
B. Different waste products are:
a. Solid waste and some gas waste through the digestive process
b. Carbon dioxide through the respiratory process
c. Liquid waste through the urinary system
d. Sweat through the integumentary system
C. Urinary system removes excess water and waste products.
D. Urinary system includes kidneys, bladder, and urinary tract.
E. Kidneys are bean shaped organ that filter waste out of the blood.
a. Useful particles are sent back to the blood
b. Produces urine consisting of excess water and waste.
F. The intergumentary system gets rid of waste through the sweat glands.
a. Excess water, salts, and waste build up in the sweat glands.
b. The substances leave the body through the skin in the form of sweat.
G. Parts of the excretory system
a. Liver – breaks down toxins in the blood
b. Kidneys – filter waste out of the blood and produce urine
c. Ureters – tubes that carry urine from the kidneys to the bladder
d. Bladder – stores urine until it can be released
e. Urethra – tubes that carry urine from the bladder to the outside of the
body.
How does your body filter blood?
Main Idea
The liver and kidneys filter waste from the blood.
Supporting Details
A. Liver breaks down toxins (poisonous substances) in the blood.
B. Kidneys filter the blood removing substances that the body does not need or
no longer need.
a. The kidneys return substances to the blood that are needed.
b. The kidneys control the amount of chemicals in your blood.
c. All of ones blood passes through his / her kidneys 60 times a day.
C. Operation of the kidneys
a. Blood enters the kidneys through the renal artery and flows into
smaller capillaries.
b. The capillaries carry the blood to nephrons, tiny filters.
c. Nephrons separate the useful material from the waste.
i. Nephrons are cup-like capsules attached to a long slightly coiled
tube.
ii. Capillaries form a tightly coiled ball near the capsule of the
nephron.
D. Operation of the nephrons
a. When blood flows through the tightly coiled ball of the capillaries,
waste and blood plasma are forced through the walls of the capillaries
into the nephrons.
b. The nephron tubes are surrounded by capillaries. As the plasma and
waste move down the tubes, useful substances (i.e. nutrients) pass
through the walls of the tubes and back into the capillaries. The
capillaries lead to a renal vein carrying the cleansed blood out of the
kidneys.
c. The waste and excess water flow into collecting ducts attached to the
nephrons. The water and waste are processed into urine.
E. Everyday, our kidneys produce 2.5 pints of urine from 45 gallons of blood
they filter.
How does your body eliminate waste?
Main Idea
Urine is stored in the bladder and leaves the body through the urethra. Sweat is
waste that is removed through the skin.
Supporting Details
A. The bladder is an organ that temporarily stores urine.
a. Humans can comfortably store urine for several hours.
b. The bladder can hold up to 1 ½ pints of urine.
B. Urine flows from the kidneys to the bladder through tubes called ureters.
C. When the bladder is full, a signal is sent through the nervous system to the
brain telling you it is time to empty your bladder.
D. The bladder releases the urine into the urethra, tubes that carry the urine
outside of the body. (Urination)
E. Other releases of waste
a. Other waste is eliminated from the body through the skin as sweat.
b. Sweat consists of water, excess salt, and other waste products.
c. Sweat is collected in the sweat glands.
d. When enough sweat has been collected in the sweat glands, it is
pushed to the surface as droplets through the pores connected to the
gland.
e. When the droplets reach the surface of the skin, the air and your body
heat causes the sweat droplets to evaporate.
f. The evaporating droplets remove the excess heat and cool your body
down.
F. What is the difference between antiperspirants and deodorants?
a. Antiperspirants contain fragrance, but they also contain chemical
compounds that block the pores to stop the discharge of perspiration.
No sweat, no odor.
b. Deodorant allows the release of perspiration, but prevents odor by
combating it with antiseptic agents, which kill odor-causing bacteria.
What happens if kidneys stop working?
Main Idea
Dialysis is the treatment to help people with kidney disease. It filters the blood.
Supporting Details
A. More than 13 million people in the United States suffer from some form of
kidney disease as a result of cancer, diseases, or injury.
B. When the kidneys stop working properly, they can no longer properly filter
blood resulting in chemicals and other waste products building up in the
blood.
C. Dialysis is a treatment that carries out the function of the kidneys.
a. It removes the waste and extra water from the blood and prevents
them from building up.
b. A patient’s blood is redirected to a tube to an artificial kidney machine.
c. The machine filters all of a patients blood and flows the blood back to
the patient’s circulatory system.
d. The machine filters all of a patient’s blood in about 4 hours.