Excretory System

1. Excretory SystemExcretory System

2. ExcretionExcretion
Excretion is the removal Excretion is the removal
of wastesof wastes
Wastes from:Wastes from:
Cellular respirationCellular respiration
Digestion of foodDigestion of food
Cellular activitiesCellular activities

3. SkinSkin
Your skin is very Your skin is very
important to the important to the
excretory system.excretory system.
Excretes excessExcretes excess
WaterWater
UreaUrea
HeatHeat

4. What is Urea?What is Urea?
A common metabolic cellular A common metabolic cellular
waste product is ammonia. waste product is ammonia.
It can raise the pH of blood.It can raise the pH of blood.
The human body can The human body can
combine ammonia and combine ammonia and
excess CO2 to make Urea.excess CO2 to make Urea.
Urea is very soluble in water, Urea is very soluble in water,
making it an easy way to making it an easy way to
excrete excess nitrogenexcrete excess nitrogen

5. Lungs?Lungs?
The lungs are an The lungs are an
important organ of the important organ of the
excretory systemexcretory system
But what wastes do they But what wastes do they
get rid of?get rid of?

6. Carbon DioxideCarbon Dioxide
Carbon Dioxide is a Carbon Dioxide is a
waste product of cellular waste product of cellular
respirationrespiration
It makes the blood acidicIt makes the blood acidic
Our body needs to get rid Our body needs to get rid
of itof it

7. DiffusionDiffusion
We have no special We have no special
process for CO2 removalprocess for CO2 removal
Rely on simple diffusionRely on simple diffusion
AlveoliAlveoli
High to low High to low
concentrationconcentration
LungsLungs

8. LiverLiver
Liver is responsible for Liver is responsible for
detoxification of the bodydetoxification of the body
It converts ammonia to It converts ammonia to
ureaurea

9. CirrhosisCirrhosis
Scarring of the liverScarring of the liver
Usually caused by Usually caused by
alcoholismalcoholism

10. Large IntestinesLarge Intestines
Removal of water from Removal of water from
solid wastessolid wastes
Excretion of solid wastesExcretion of solid wastes
The act of defecation is The act of defecation is
not considered a part of not considered a part of
excretory systemexcretory system

11. KidneysKidneys
Kidneys are the most Kidneys are the most
important organ of the important organ of the
excretory systemexcretory system
Regulate pH of the bloodRegulate pH of the blood
Remove excess water, Remove excess water,
and urea to create urineand urea to create urine

12. Urinary SystemUrinary System
Kidneys feed UreterKidneys feed Ureter
Ureter connects to Ureter connects to
BladderBladder
Bladder stores urineBladder stores urine
Excreted through UrethraExcreted through Urethra

13. Excretion and HomeostasisExcretion and Homeostasis
Excretion is essentially a process of maintaining Excretion is essentially a process of maintaining
homeostasishomeostasis
To maintain a constant internal environment all To maintain a constant internal environment all
metabolic wastes need to be removedmetabolic wastes need to be removed