respiration feeding responsiveness growth reproduction movement and Excretion is one of the characteristics of all living things feeding respiration reproduction growth responsiveness movement excretion and www.juniorscience.ie

Excretion Excretion is the removal of toxic chemical substances Toxic substances are poisonous and can harm the cells of the body if not removed www.juniorscience.ie

Excretory Organs We have 3 excretory organs Kidneys Lungs and Skin www.juniorscience.ie

Kidneys The kidneys remove urea and salts they clean our blood If your kidneys are damaged you may need to go on a dialysis machine www.juniorscience.ie

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structure Kidneys renal vein renal artery kidney ureter bladder urethra renal vein renal artery kidney structure ureter bladder urethra www.juniorscience.ie

function bladder urethra renal artery carries blood to kidney renal vein carries blood from kidney kidney filters blood to remove urea function ureter transports urine to bladder bladder stores urine urethra releases urine www.juniorscience.ie

urea, which is toxic, is produced in the liver from excess protein Toxic urea is removed by and carried by blood to the kidney excess protein from our food is carried from the gut by blood www.juniorscience.ie

1 blood containing water, salts and urea enters the kidney 2 urea, some salts and water are removed from bloodstream by kidney and form urine 3 the urine leaves the kidney in the ureter salt urea www.juniorscience.ie

urine is stored in the bladder before being released from the body urethra www.juniorscience.ie

Lets dissect our own kidneys in the lab! www.juniorscience.ie

carbon dioxide and water are waste products of the process of respiration in all the cells of the body energy water carbon dioxide www.juniorscience.ie

the carbon dioxide and some of the water is carried to the lungs by the blood to be excreted www.juniorscience.ie

Can you remember how we can prove there is water and Carbon dioxide in our breath?? Test for Carbon dioxide = Limewater Test for water = Cobalt Chloride paper www.juniorscience.ie

Human skin has sweat glands which lead to pores at the surface – water, salt and a tiny amount of urea is excreted as sweat through these pores section of skin sweat gland blood capillaries pore www.juniorscience.ie

In Summary We have 3 excretory organs Organ Product excreted Lungs Carbon dioxide + water Skin Sweat which is water and salt Kidneys Urea and salts in urine www.juniorscience.ie

Questions www.juniorscience.ie

One or Two? HINT How many of each of the following are in the human urinary system? Kidney Bladder Renal artery Renal vein Ureter Urethra bladder urethr www.juniorscience.ie

Bladder structure and function urethr Why is the bladder shaped like a plastic bag? Why is the bladder situated below the kidneys? There is a small circular muscle at the exit to the bladder. Why? www.juniorscience.ie

A D C B Kidney location Which answer places the kidney in the correct area of the body? A B C D B www.juniorscience.ie

Kidney The kidney is usually covered in a layer of hard fat. Can you suggest a reason for this? www.juniorscience.ie

Kidney All the blood in the body is filtered by the kidney, but when it is cut open there is almost no blood visible. Can you think of a reason for this? www.juniorscience.ie

Water - where and when? Water is released from the body by the lungs, the skin and the kidney at different rates under different conditions. How do you think each of the three excretory organs would react on a very hot day? ? www.juniorscience.ie

Excretion OB2-OB23 OB20 understand the structure and function of the urinary system: bladder, renal artery, renal vein, ureter, urethra and kidney OB21 name the products of excretion: CO2, water and urea OB22 understand the function of the skin in the excretion of waste products made in the body OB23 recall that waste products are removed from the bloodstream by filtration in the kidneys in the form of urine, which contains urea, water and salts, and that urine is stored in the bladder before being released from the body www.juniorscience.ie