1. Chapter: Digestion, Nutrition & Excretion
Table of Contents
Chapter: Digestion, Nutrition & Excretion
Section 4: Excretion

2. Functions of the Excretory System4
Functions of the Excretory System
1. Undigested material is eliminated by your large intestine.
2. Waste gases are eliminated through the combined efforts of your circulatory and respiratory systems.

3. Functions of the Excretory System4
Functions of the Excretory System
3. Some salts are eliminated when you sweat.
Respiratory, Digestive, Urinary, and skin function together as parts of your excretory system.
If wastes aren’t eliminated, toxic substances build up and damage organs.

4. Functions of the Excretory System4
Functions of the Excretory System
The urinary, digestive, and respiratory systems, and the skin are the excretory system.

5. The Urinary System 4 The urinary system:
The Excretory System 4
The Urinary System
The urinary system:
1. cleans the blood of wastes produced by the cells.
2. removes excess water
3. balances the amounts of certain salts and water

6. Organs of the Urinary System
The Excretory System 4
Organs of the Urinary System
The main organs of the urinary system are two bean-shaped kidneys.
The path of urine:
Kidney Ureter Bladder Urethra

7. Organs of the Urinary System
The Excretory System 4
Organs of the Urinary System
The kidneys filter blood that contains wastes collected from cells.

8. Filtration in the Kidney
The Excretory System 4
Filtration in the Kidney
A kidney is made up of about 1 million tiny filtering units called nephrons

9. Filtration in the Kidney
The Excretory System 4
Filtration in the Kidney
The first filtration occurs when water, sugar, salt, and wastes from the blood pass into the cuplike structure.
Left behind in the blood are the red blood cells and proteins.

10. Filtration in the Kidney
The Excretory System 4
Filtration in the Kidney
Capillaries perform the second filtration.
Most of the water, sugar, and salt are reabsorbed and returned
to the blood.
These collection capillaries merge to form small veins, which merge to form a renal vein in each kidney.

11. Filtration in the Kidney
The Excretory System 4
Filtration in the Kidney
Purified blood is returned to the main circulatory system.
The liquid (Urine) left behind flows into collecting tubules in each kidney.
Urine, contains excess water, salts, and other wastes that are not reabsorbed by the body.

12. Urine Collection and Release
The Excretory System 4
Urine Collection and Release
The urine in each collecting tubule drains into a funnel-shaped area of each kidney that leads to the ureter
Ureters are tubes that lead from each kidney to the bladder.

13. Urine Collection and Release
The Excretory System 4
Urine Collection and Release
The bladder is an elastic, muscular organ that holds urine.
The urethra is a tube that carries urine from the bladder to the outside

14. Urinary Diseases and Disorders
The Excretory System 4
Urinary Diseases and Disorders
Waste products that are not removed build up and act as poisons in body cells.
Without excretion, an imbalance of salts occurs.

15. Urinary Diseases and Disorders
The Excretory System 4
Urinary Diseases and Disorders
Kidney failure occurs when the kidneys don’t work as they should.

16. Dialysis 4 A person who has only one kidney still can live normally.
The Excretory System 4
Dialysis
A person who has only one kidney still can live normally.
If both kidneys fail, the person will need to have their blood filtered by an artificial kidney machine.
This is called dialysis