1. Excretion

2. WARNING Human Excretion
As an organism carries on its life activities it produces Metabolic Wastes
Excretion - is the removal of cellular wastes from an organism.
WARNING
Excretion does not include the removal of undigested food (egestion)

3. Summary of Metabolic wastes Dehydration Synthesis-
Metabolic Activity
Waste Produced
Respiration
H2O and CO2
Dehydration Synthesis
H2O
Protein metabolism
Nitrogenous wastes
(contains nitrogen)
Other metabolic
processes
Mineral salts

4. II. Nitrogenous waste formation
Proteins are made up of long chains of Amino Acids.
The metabolism of proteins may result in an excess of amino acids.
Excess amino acids are broken down to form Nitrogenous Wastes.
The removal of an amino group (NH2) is called deamination

5. Nitrogenous wastes may exist in 3 forms that vary in toxicity and solubility
1. Ammonia - NH3 is very toxic and soluble in water. Removal is easy for an animal that lives in water
Ex: protozoan’s, hydra, fish
2. Urea - less toxic, and soluble in water
Ex: Human urine, earthworm
3. Uric Acid – is not soluble in water, and is therefore not toxic.

6. Uric acid forms solid crystals
Uric acid is formed by animals that need to conserve H20.
Ex: Birds, insects, and reptiles
Not all wastes are toxic
Ex: H20, Uric Acid
Non toxic wastes may be retained, released or recycled.
Ex: desert animals may recycle the water given off during respiration.
Ex: plants and algae may recycle the waste gases of photosynthesis and respiration.

7. Human Excretion Organs of Excretion Lungs - H2O and CO2
are wastes of respiration
Liver - excretory functions include
A. Breakdown of RBC’s
B. Produces Urea following
amino acid deamination

8. 3. Skin - water, salt and some Urea diffuse from blood into sweat glands, and are excreted as perspiration.
The primary function of perspiration is NOT excretion but rather temperature regulation. (an example of homeostasis)

9. Urinary System

10. Kidney Kidneys - perform two major functions 1. Excrete most urea
2. Control the concentration of most substances in the blood

11. Ureter
. Ureters - carries urine from the kidneys to the urinary bladder

12. Urinary Bladder
Urinary bladder - stores up to two cups of urine

13. Urethra
8. Urethra - periodically, urine is excreted from the bladder through the urethra.

14. The Nephron is the functional unit of the kidney

15. IV. Function of the Urinary System.
1. Renal Arteries - bring blood to the kidneys where microscopic nephrons are involved in both filtration and reabsorption.
2. Water, salts, urea, Amino acids and glucose are filtered from the glomerulus into the cup-like Bowman’s capsule.
3. As these materials move through the tubule of the nephron, water, minerals, and digestive end products are reabsorbed by active transport into the capillaries associated with the tubule diagram of Urinary system
4. After reabsorption the fluid that remains in the tubule is Urine
Renal Veins - carry filtered “clean” blood away from the kidney.

16. Malfunctions Of the
Excretory System

17. 1. Kidney diseases - malfunctions of the kidneys or the nephron caused by:
High protein diets
Infections
Lead or mercury

18. 2. Gout - a form of arthritis in which production of uric acid leads to crystal deposits in the joints, causing pain and stiffness.

19. Kidney Stone Calcium or chemical depsoits in the kidney
Most painful Urinary disorder
Caused by diet and heredity

20. Aorta Vena Cava Glomerulus Bowman’s Capsule Ureter capillaries
Urinary Bladder
Urethra
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