How the kidney works

2. How the kidney works

3. How the kidney works Learning objectives today: • to explain how the kidney works using key terms • Ultrafiltration • Reabsorption • Reabsorption of water / ADH • to be able to draw a flow diagram describing the role of ADH in controlling blood concentration, using the terms • Receptors • Processing centre • Effector

4. Water Gain Drinks Food Respiration Water loss Sweating Breathing Faeces Excretion of urine Plasma concentration must be kept constant within a narrow range . . .

5. The urinary system Urea = waste product produced by breakdown of protein Urea = formed in the liver Urine = Urea & other ions/waste dissolved in water Kidney = produces urine (removes urea from blood) Bladder = stores urine

6. How the kidney works The kidney tubule is called the nephron The fluid in the kidney is called the filtrate

7. How the kidney works The kidney tubule is called a nephron The fluid in the kidney tubule is called filtrate.

8. How the kidneys work . . . 1. Ultrafiltration • filtering small molecules from the blood to form urine (water, salt and urea); 2. Reabsorption important substances • reabsorbing all the sugar; • reabsorbing as much salt as the body requires; 3. Reabsorbing water • reabsorbing as much water as the body requires; • excreting the remaining urine, which is stored in the bladder;

9. How the kidney works ADH (anti diuretic hormone) + ADH H2O

10. Water balance and the kidney • The role of the hormone ADH • The effect of alcohol & ecstasy TASKS • Video • Notes using revision guide • Exam question

11. ADH is the hormone that controls how much urine is made Blood salt high more ADH  Concentrated urine Blood salt low less ADH  Dilute urine ADH controls the reabsorption of water from the kidney tubule into blood

12. Ecstasy increases ADH production – concentrated urine Alcohol decreases ADH production – dilute urine

13. The role of ADH