Urinary System1. The urinary system is one of the main systems of the human organism.
2 It consists of 2 kidneys, 2 ureters, the urinary bladder, urethra and urinary meatus.
3. The kidneys are located in the lumbar region of the spine behind the abdominal cavity.
4 They are bean-shaped, fist-sized organs and weigh half a pound each.
5. The kidney consists of an outer cortex region and an inner medulla region.
6 2 ureters are muscular tubes lined with mucous membrane.
7 They convey urine from the kidney to the urinary bladder.
8. The urinary bladder is a hollow, muscular, distensible sac in the pelvic cavity. It serves as a temporary reservoir for urine.
9. Urethra is a membranous tube through which urine is discharged from the urinary bladder.
10. The external opening of the urethra is called meatus.
11. The process of forming urine begins in the glomerulus as water, salts, sugar, urea and other wastes (creatinine and uric acid) filter out from glomerulus into ,Bowman's capsule which encloses each glomerulus.
12. Large molecules like proteins remain in the bloodstream and cannot pass through walls of the glomerulus into Bowman's capsule
13. The kidney filters out of the blood not only the waste product urea, but much water, sugar and salts.
14. The process of reabsorption of materials back into the bloodstream takes place through the walls of renal tubules.
15. After reabsorption fluid becomes more concentrated.
16. The urine consists of 95 percent of water, 5 percent of urea, creatinine, acids, salts and some bile pigments.
17. The renal tubules carry urine to the rena pelvis then to the ureters and the urinary bladder where the urine is temporarily stored.
18. The exit area of the bladder to the urethra is closed by sphincters which do not permit
urine to leave the bladder.
19. When the bladder fills up, sphincters open and the urine through urethra and urinary
meatus is expelled from the body.
20. The function of the urinary system is to eliminate wastes and regulate the amount of
water in the organism.
21. There are many diseases of the U.S. e.g. nephritis, nephrolithiasis, kidney cancer,
cystitis, urethritis etc.
