SUMMER 2010 BIO - 120

1. URINARY SYSTEM by Beatriz Bellini

3. adjust water

4. adjust electrolyte levels

6. THE URINARY SYSTEM Urine needs to be eliminated otherwise quickly become toxic to our organism, resulting in uremia. The filtration of wastes from the blood takes place in the nephrons. Millions of neuphrons make up each of out Kidneys, where the urine Body Metabolic Process Production of waste product. (urine) Its is one of the hardest working system of the body.

7. Each kidney drains urine and transports it to the urinary bladder. Then, urine moves from the bladder down the urethra to the outside of the body.

8. KIDNEYS The two kidneys are located in the lumbar region of the back above the waist on either side of the vertebral column and in form of a bean shape.

9. Hilum is located at the center of the kidneys, where the renal artery enters and the renal vein leaves the kidney. The renal artery delivers the blood that is full of waste products to the kidney. The renal vein returns the clean blood to our general circulation.

10. Inside of the kidney The outer portion is called cortex and the inner area is called medulla. Nephron is the functional unit of the kidney. Each nephron consist of the renal corpuscle (blood filtering portion) and the renal tubule. The reabsorption and secretion stages of urine production occur within the renal tubule.

11. Water and substances removed from bloodstream in the renal corpuscle flow into the renal tubules to finish the urine production process. TUBULE IS DIVIDED IN 4 SECTIONS: proximal convoluted tubule loop of Henle (nephron loop) distal convoluted tubule collecting tubule

12. URETERS The ureters are narrow tubes that lead from the kidneys to the bladder. Urine enters the ureter after it drains out of the renal pelvis.

13. URINARY BLADDER It is considered an elastic muscular sac that lies in the base of the pelvis just behind the pubic symphysis. Composed of three layers of smooth muscle tissue lined with mucous membrane containing rugae, folds that allow it to stretch. The bladder receives the urine directly from the ureters, stores it and excretes it in form of urine through the urethra. Voluntary muscle action controls the external sphincter, which opens on demand to allow the intentional emptying of the bladder. Involuntary muscle action causes the bladder to contract and the internal sphincter to relax.

14. URETHRA It is a tubular canal that carries the flow of urine from the bladder to the outside of the body.Urinary meatus is the external opening which urine passes out of the body. The urethra is 1 ½ inches long in the female and 8 inches long in the male. The male urethra has two functions, such as an outlet for urine and the passage-way for semen to leave the body.

15. ROLE OF KIDNEYS - HOMEOTASIS The kidneys are responsible for homeostasis or balance in your body. Maintain the body proper balance of water, chemicals, electrolytes and maintain the correct pH range with the body. If the body is low in water, the kidneys conserve it. If there is excesses of water in the body, the body will excrete it.

16. STAGES OF URINE PRODUCTION All wastes and unnecessary substances are removed from the bloodstream by the nephrons. However, urine is the final product of this entire process of waste elimination. There are three stages of urine production: Filtration – The first stage is the filtering particles in the renal corpuscle. Reabsorption – After filtration, the filtrate passes through the four sections of the tubule. Most of the water, electrolytes and nutrients are reabsorbed. Secretion – The final stage of urine production occurs when the special cells of the renal tubules secrete ammonia, uric acid, and other waste substances directly in to the renal tubule.

17. URINE is a normally straw colored to clear and sterile Adults bladder can hold 250 mL of urine. COMPOSITION OF URINE:

18. URINE COLOR CHART I am hydrated?