1. Excretory System Kidney

2. Things that are excreted: Large intestine/rectum/anus Feces - digestive system waste Lungs CO 2 and Water Skin - sweat glands Salts and water Kidneys ?????????????????

3. Houston, we have a problem Our diets are very rich in protein We don’t use all of the amino acids that are put into our blood after the digestion of proteins Our liver is left to deal with these amino acids

4. Amino Acid Structure

5. The C’s, O’s and some of the H’s are turned into glucose and stored by the liver The N and 3 H’s become ammonia - YIKES!

6. Ammonia Ammonia (NH 3 ) is quite toxic to cells We clean with ammonia, because ammonia can break down cell membranes (think: bacteria cells)

7. To the Rescue The liver takes two of these ammonia molecules along with CO 2 and sticks them together to make a substance called UREA

8. Kidneys’ Job It is the kidneys’ job to deal with this urea Excrete it with water as Urine

9. Urinary System

10. kidney anatomy Blood flows to the kidneys from the heart Artery off of aorta to kidneys Breaks up into capillaries inside of kidney Blood returns to the body from the renal vein Venules in kidney collect into renal vein

11. Kidney Nephron Inside the kidney there are 1,000s of nephrons - these do the job of filtering the blood

12. Inside the nephron Each nephron has a capillary that associates with it This capillary enters the capsule of the nephron The capillary forms a “knot” = glomerulus The “knot” creates lots of pressure This pressure forces urea and water into the nephron tube = Urine

13. The capillary leaves the capsule and becomes a venule The venule collects with other venules into the renal vein The renal vein leaves the kidney and travels back to the heart

14. Urine Urine travels through the kidney nephron tubule The tubule connects to the ureter Ureter drains into the bladder Sphincter muscle at the base of the bladder Urine leaves the bladder through the urethra

15. Kidney Animations Click on the links below to watch kidney animations: http://highered.mcgraw- hill.com/sites/9834092339/student_view0/c hapter50/basic_renal_processes.html http://www.kidneypatientguide.org.uk/HKW anim.php