1. 1 Chapter 9 Excretory System  consists of the kidneys, ureters, urinary bladder and urethra

2. The kidneys 2

3. How much do you know about your kidneys? 3 http://www.betterhealth.vic.gov.au/BHCV2/BHC ARTICLES.NSF/pages/Quiz_The_urinary_syste m?OpenDocument

4. Answers to kidney quiz 4 1.B 2.B 3.A 4.A 5.A 6.C 7.B 8.A

5. URINARY SYSTEM - OVERVIEW 5 http://www.youtube.com/watch?v=qxb2_d9ilEw

6. 6 Kidney Structure human kidney

7. 7 Functions of the kidneys removal of metabolic wastes (urea, uric acid) from the blood and excretion to the outside of the body regulation of blood pressure (aldosterone) regulation of ion (Ca 2+, Na + ) absorption regulation and conservation of water in the body

8. Fig. 36.8

9. 9 1. There are approximately 1 million nephrons in each kidney. Why so many?

10. The nephron 1.Glomerular filtration – into Bowman’s Capsule 1.Solute Reabsorption – from proximal tubule to capillary 3.Water Reabsorption – from proximal tubule and Loop of Henle to capillary 4. Tubular Secretion – from capillary to distal tubule 4 STAGES OF URINE FORMATION

11. Fig. 36.11

12. 12 The nephron

13. Page 678

14. 14 Urine Formation Urine is the final product of the processes of: glomerular filtration: substances move from blood in glomerulus to the Bowman’s capsule solute reabsorption: nutrients i.e. glucose, potassium and sodium ions, and many other substances the body can use water reabsorption tubular secretion

15. 15 Step 1: Glomerular Filtration The first step in urine formation is filtration of substances out of the glomerular capillaries into the Bowman’s capsule Filtrate includes: water, sodium, chloride ions, glucose, amino acids, urea, other small solutes Filtrate does NOT include: red and white blood cells, platelets, plasma proteins

16. 16 Glomerular Filtrate and Urine average amounts over a 24 hour period

17. 17 Step 2: Solute Reabsorption sodium, chloride, glucose, amino acids are actively transported from the filtrate to the blood in the proximal tubule There are many mitochondria in the cells of the proximal tubule (for ATP)

18. Step 3 WATER REABSORPTION 18 Water reabsorption begins in the proximal tubule (osmosis resulting from active transport of ions, glucose, etc from filtrate into blood)

19. 19 Step 4: Tubular Secretion transports substances (such as H +, K +, drugs, other solutes) from the capillary into the distal tubule active transport – distal tubule has many mitochondria for ATP

20. 20 Urine Composition about 95% water usually contains urea, uric acid, and creatinine (break down product from creatine phosphate used up in muscles) may contain trace amounts of amino acids and varying amounts of electrolytes volume varies with fluid intake, diuretics (caffeine & alcohol) and environmental factors (heat, humidity)

21. Ureters 21

22. 22 Urinary Bladder hollow, distensible, muscular organ located within the pelvic cavity, posterior to the pubic bone

23. 23 Urinary Bladder

24. 24

25. 25 Urethra tube that conveys urine from the urinary bladder to the outside of the body

26. Urine colour chart 26

27. 27 Life-Span Changes kidneys appear scarred and grainy kidney cells die by age 80, kidneys have lost a third of their mass kidney shrinkage due to loss of glomeruli proteinuria may develop (protein in urine) renal tubules thicken harder for kidneys to clear certain substances bladder, ureters, and urethra lose elasticity bladder holds less urine

28. ANIMATION REVIEW 28 http://www.sumanasinc.com/webcontent/ani mations/content/kidney.html