1. Excretion

2. Excretion What is excretion?
Excretion is the removal of wastes made in the body
Source: adapted from

3. Products of excretion
1.Carbon dioxide – made from respiration in cells
2. Water – made from respiration in cells
3.Urea - is produced from excess protein in the liver

4. Organs of excretion

5. Excretion in the lungs
Carbon dioxide and some of the water is excreted by the lungs o c o H o c o H
Source:

6. 2. Excretion in the skin
Water, salt and a tiny amount of urea are excreted as sweat through the pores of the skin
section of skin
sweat gland
blood capillaries
pore
Source: adapted from

7. Structure of the Urinary System
bladder
urethra
renal vein
renal artery
kidney
ureter
bladder
urethra
Source:

8. Functions of the Urinary System
bladder
urethra
renal artery carries blood with waste products into the kidneys
renal vein carries purified blood out of the kidneys
kidney filters blood to remove urine
ureter carries urine to bladder
bladder stores urine
urethra excretes urine
Source: adapted from

9. Filtration in the kidneys – how urine is formed
water
salt
2 urea, some salts and water are removed from bloodstream by filtration in the kidneys and form urine
urea
1 blood containing water, salts and urea enters the kidney in the renal artery
Useful materials such as water leave the kidneys through the renal vein and are reabsorbed back into the bloodstream
the urine leaves the kidney in the ureter and goes to the bladder
Source: adapted from

10. Urine is then stored in the bladder before being released from the body
urethra
Source:

11. Virtual Dissection of Excretory System

12. Excretory Quizzes