Transcript Excretion

Excretion
Excretion
What is excretion?
• Excretion is the removal of wastes made in
the body
Source: adapted from www.juniorscience.ie
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
Organs of excretion
Excretion in the lungs
• Carbon dioxide and some of the water
is excreted by the lungs
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Source: www.juniorscience.ie
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
pore
sweat gland
blood capillaries
Source: adapted from www.juniorscience.ie
Structure of the Urinary System
renal
artery
renal vein
ureter
bladder
urethra
urethra
Source: www.juniorscience.ie
Functions of the Urinary System
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
urethra
bladder stores urine
urethra excretes urine
Source: adapted from www.juniorscience.ie
Filtration in the kidneys – how urine
is formed
water
salt
urea
1
blood containing
water, salts and urea
enters the kidney in
the renal artery
3
Useful materials such as
water leave the kidneys
through the renal vein and
are reabsorbed back into
the bloodstream
2
urea, some salts and water
are removed from
bloodstream by filtration in
the kidneys and form urine
4
the
urine leaves the kidney
in the ureter and goes to
the bladder
Source: adapted from www.juniorscience.ie
Urine is then stored in the bladder before being
released from the body
urethra
Source: www.juniorscience.ie
Virtual Dissection of Excretory
System
• http://www.whitman.edu/biology/vpd/excret
ory.html
Excretory Quizzes
• http://www.kidshealth.org/misc/how_the_b
ody_works/urinary_quiz.html
• http://www.whitman.edu/biology/vpd/excqu
iz.html