Learning Objectives: To know the role of the kidney To be able to label a diagram of the human excretory system To be able to label a section through the kidney and a nephron To understand the role of ADH and interpret data about the presence of substances during the passage through the kidney

To regulate the volume and composition of body fluids, removing waste products from the body and expelling the waste and excess water from the body in the form of urine.

Your kidneys remove the poisonous substances which your cells produce. Our bodies break down the protein in our food into amino acids. The diagram shows what happens to these amino acids: Amino acids in blood Protein in your cells Urea in your blood Some are used for growth and repair Some are not used – they are broken down in the liver

Urea is made in the liver from amino acids. Urea is a poisonous substance. Your kidneys remove it from your blood. They also remove excess salt (ions) from your blood. The urea and salts are dissolved in water to make a liquid called urine.

The kidneys filter about 1.3 litres of blood a minute. All the body’s blood flows through the kidneys every 10 minutes, so blood is filtered 150 times a day.

The renal artery carries ‘dirty’ blood (with waste) into the kidneys The renal vein carries cleaned blood away from the kidneys The bladder is a bag that stores urine Ureters are tubes which carry urine to the bladder The urethra is a tube which carries urine out of your body The kidneys remove urea and other waste The sphincter is a ring of muscle that keeps the bladder closed until you go to the toilet

Renal artery Renal vein Ureter Medulla Cortex Pelvis Nephron within the kidney

Collecting duct Capillary knot Bowmans capsule Tubule Capillary network

‘Dirty blood’ Bowman’s Capsule Useful substances are reabsorbed into the blood Urine (urea and water) Urine ‘Cleaned blood’ Capillary Tubule Urine goes to the bladder Useful substances Urine The diagram below shows a flattened section of the nephron

‘Dirty blood’ Bowman’s Capsule Useful substances are reabsorbed into the blood Urine (urea and water) Urine ‘Cleaned blood’ Capillary Tubule Urine goes to the bladder Useful substances Urine Blood is filtered through the capillary knot. Nearly all the blood except red cells filters through into the nephron The liquid in the nephron contains useful substances like glucose and vitamins. These are then absorbed back into the blood (reabsorbed). The liquid left in the nephron is urine. It contains urea and water and other unwanted substances. It then goes through the collecting duct and ureters to the bladder.

Complete the postcard to explain your journey through the excretory system. You are a water molecule travelling through the blood. Celia Ciliated Epithelial Cells Urinary Tract Front of Postcard Back of Postcard Dear Celia the Ciliated Epithelial Cell, I have been on the most incredible journey! It all started when… Wish you were here…

If there is too little water in your blood then the body detects this and the pituitary gland produces anti-diuretic hormone (ADH). ADH increases the permeability of the tubules, and allows the kidneys to reabsorb more water, making a more concentrated urine. The more ADH, the more concentrated the urine.

Too much water in body Too little water in body Water in urine Urine colour Presence of ADH A littleYellow ColourlessA lot Drag the boxes below to complete the table More ADH Less ADH

Time after drinking (mins) Volume of urine (ml)Salt concentration (ml) normal level

Produce a leaflet for someone with a kidney problem, outlining the advantages and disadvantages of the use of dialysis or transplantation. Remember to use science to explain the procedures and remember to use more than 2 sources of information to improve the reliability.

To know the role of the kidney To be able to label a diagram of the human excretory system To be able to label a section through the kidney and a nephron To understand the role of ADH and interpret data about the presence of substances during the passage through the kidney Learning outcomes

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