Download Excretory System

Do Now 1
1. What is one major waste product produced by every cell in the
body?
2. Where does the waste product go in order to be excreted?
3. How does the waste product get to the excretory organ?
4. What are some other excretory organs?
Do Now #2
1. Which human excretory structure aids in the maintenance of
normal body temperature?
a)
b)
c)
d)
Sweat gland
Nephron
Liver
Urinary bladder
2. An individual running a marathon may experience periods of
oxygen deprivation that can lead to
a)
b)
c)
d)
Anaerobic respiration in muscle cells, forming lactic acid
Aerobic respiration in muscle cells, generating glycogen
Anaerobic respiration in liver cells, producing glucose
Aerobic respiration in liver cells, synthesizing alcohol
3. What is the name of the process that builds up large molecules
such as starch?
Do Now 3 - Skin
1. What would happen if sweat glands become blocked?
2. Why do people pour water on themselves on a hot day after
running?
3. Why do you urinate less when you run and sweat?
Excretory System
How does the Excretory System help
maintain homeostasis?
Excretory System
 Helps the body maintain homeostasis by excreting
metabolic wastes through sweat, urine, and exhalation.
Where does the waste come from?
 Cells carrying out their life functions
Carbon dioxide comes from – Aerobic Cellular Respiration
Water comes from – Aerobic Cellular Respiration
Urea comes from – Breakdown of proteins and amino acids
Organs of the Excretory System
•
•
•
•
Liver
Lungs
Skin
Urinary System
Label
1 - Liver
Functions:
1. Waste removal
 removes worn out red blood cells (120 days)
 Removes alcohol and other poisons from blood
2. Detoxification – converts harmful substances into inactive or less
toxic substances
 Converts harmful ammonia into safer urea
2 - Lungs
Function:
1. Waste removal – lungs remove CO2 and some H2O vapor
 Carbon Dioxide & Water Vapor are waste products of:
Cellular Respiration
Equation:
Equation:
3 - Skin
Functions:
1. Protection – keeps harmful pathogens from entering the body
2. Excretion – removes water, salts, and urea from the
blood as sweat
3. Regulation – helps control your body temperature
Skin “Excretion”
How does the skin remove metabolic waste in sweat?
 The circulatory system transports waste around the blood
 Capillaries, containing blood, are next to sweat glands so
waste (urea, salts and water) diffuse into sweat glands and
excreted as sweat
Skin “Regulation”
How does the skin regulate or control body temperature?
 Sweat glands excrete sweat (water, urea, salts)
 Sweat evaporates off skin taking heat away with it!
(evaporation is a cooling process)
 So, your body sweats to cool down!
Negative Feedback Mechanism
1. If your body gets hot, what does your body do to stop itself from
being too hot or getting even hotter?
2. If your body gets cold, what does your body do to preserve or
conserve heat?
4 – Urinary System
Urinary system includes 4 major organs:
1. Kidney
2. Ureter
3. Bladder
4. Urethra
Kidney
Function:
 Kidneys filter metabolic wastes from the blood to produce urine
 Kidneys control the concentration of substances in the body fluids
 Made up of millions of nephrons that are the actual filters of the
kidney
Nephrons:
 About 1.25 million
nephrons found in
each kidney
 Filters and cleans
blood
 Create Urine
Urine - concentrated waste (salts, urea, amino acids, glucose, water)
How Do Nephrons Create Urine?
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1. Filtration
Where does the Urine go?
After urine formation, it goes to:
1. Ureter – two tubes from each kidney
that carry urine to the bladder
2. Bladder – temporary storage site of
urine until it is time to be released
3. Urethra – one tube that carries the
urine from the bladder to the outside
of the body
Final Stop for Urine
Excretory Review