1. The Urinary System

2. Functions of the Urinary System l Maintain Homeostasis of Blood –remove waste products –restore selected amounts of water and solutes l Maintain Blood Pressure –controls blood plasma volume l Helps regulate the body ’ s pH l Stimulates Red Blood Cell Production –erythropoietin (EPO)is produced by the kidney l Helps in many Metabolic Processes

3. Components of the Urinary System l Kidneys (2) l Ureters (2) l Bladder l Urethra

4. The Kidneys l Paired reddish organs shaped like a bean l Located just above the waist between the parietal peritoneum and the posterior wall of the abdomen (retroperitoneal) l About 10-12 cm long, 5 to 7.5 cm wide, and 2.5 cm thick l Concave border faces medially l Convex surface faces laterally l About the size of your fist

5. Internal Anatomy of the Kidney l Cortex = outer reddish area of the kidney l Medulla = inner brownish area of the kidney l Renal (Medullary) Pyramids = 8 to 18 triangular structures located within the medulla of each kidney l Renal Pelvis = a large cavity within the renal sinus that serves as an area to collect urine from the renal pyramids –calyces = channels into the renal pelvis

6. Nephrons l The functional units of the kidney –Filters blood by removing waste products –Forms urine l Portions of the nephron are located in both the cortex and medulla areas of the kidney l Generally - blood and urine flow from the outside area (cortex) to the inner regions (medulla) of the kidney Diagram showing the parts of the kidney and the nephron

7. Function of the Nephrons l Responsible for removing wastes from blood and regulating blood fluid and electrolyte balance –Controls blood concentration and volume –Regulates blood ph –Removes toxic wastes from the blood l Produces urine –The fluid and solutes removed from the blood

8. l The entire volume of blood in the body is filtered by the kidneys about 60 times each day l Filters about 180 liters (45 gallons) of fluid a day l Returns over 99% of the fluid back to the body

9. Components of Each Nephron l Renal Corpuscle = an expanded bulb like end of the nephron located in the cortex of the kidney –contains the Glomerulus and Bowman's Capsule l Renal Tubules = thin twisting ducts of tubes –portions of the renal tubule are located within both the renal cortex and medulla

10. The Renal Corpuscle l Glomerulus = a microscopic tuft or knot of blood vessels located in the renal cortex –where filtration of the blood takes place –contains holes or pores (Fenestrae) where small particles can filter out of the blood –afferent arterioles - efferent arterioles l Bowman ’ s Capsule = sac like structure that surrounds the glomerulus –the beginning of the renal tubules

11. The Renal Tubules l Folding twisting length of tubes where waste products are passed into the urine and water and salts are reabsorbed by the body l Composed of three main sections –Proximal convoluted tubule –Loop of Henle –Distal convoluted tubule l The entire length of the renal tubules surrounded by Peri- tubular capillaries –reabsorption of fluid back into the blood –Secretion of excess ions into urine

12. Urine Production l 3 process involved in urine production –All of these processes occur in the Nephrons of the kidneys –Glomerular filtration –Tubular Reabsorption –Tubular excretion and secretion l URINE - by-product of the activity of the kidneys

13. The Ureters l Tubes that carry urine from the kidneys to the urinary bladder l Actually an extension of the renal pelvis –25 to 30 cm long (10 to 12 inches) l Primary function is to simply transport urine –Gravity-hydrostatic pressure –Peristaltic action by muscularis layer

14. The Urinary Bladder l A hollow muscular organ that stores urine until excretion l Shape is dependent upon how much urine is present at any given time l When filled with urine it is somewhat pear shaped l Trigone = a small triangular shaped area formed by the openings of the ureters and the urethra

15. The Urethra l A small tube leading from the floor of the urinary bladder to the exterior of the body l The terminal portion of the urinary system that serves as the passageway by which to discharge urine from the body l Urethral orifice = the opening of the urethra to the exterior l External urethral sphincter = sphincter muscle controlling urination

16. Micturition The Process of Expelling Urine From the Bladder (Also Called Voiding or Urination)

17. Urinalysis = l The analysis of the volume, physical, chemical, and microscopic properties of urine l What minerals, salts, acids, proteins, blood, blood cells, sugars, and what concentration are present in the urine?

18. Physical Characteristic of Urine l Color = yellow or amber –can vary considerably with diet l Turbidity = clear when freshly voided but becomes turbid upon standing l Odor = usually odorless but may become ammonia like upon standing l pH = average is about 6.0 but can vary with diet (4.8 - 8.0) l Specific Gravity = dependent upon amount of material in solution SpG = 1.001 to 1.035

19. Chemical Composition of Urine l Water = 95% of total urine volume l 5% solutes from cellular metabolism or other outside sources such as drugs l Organic components of urine –Urea - uric acid - Creatine –Hippuric acid - Ketone bodies - others l Inorganic components of urine –NaCl - ca++ - NH4+ – Mg++ - PO4 (3-) - SO4 (2-) l UA teaching module Cornell university UA teaching module Cornell university UA teaching module Cornell university

20. Urine Volume l Normally about 1000 ml to 2000 ml (one to three quarts) per day l Influenced by: –Blood pressure l if blood pressure decreased = increased fluid reabsorption by the kidneys –Blood concentration l the kidneys maintain optimal blood concentration by controlling solute concentration in both blood and urine –Temperature l increased body temperature = increased fluid reabsorption to maintain plasma volume –Diuretics l increase urine production –Emotions –Hormones

21. Urinary System Disorders

22. Urinary Tract Infections (UTI ’ s) l A term used to describe an infection of a part of the urinary system or a abnormally large number of microbes present in the urine. l Much more common in females probably due to shorter urethra, easier trip for bacteria into bladder. l Individuals at risk include: –Pregnant women - renal disease. –Hypertension - diabetes. l Symptoms include burning or painful urination, pubic and back pain, chills, fever, nausea, vomiting, etc.

23. Cystitis l An inflammation of the urinary bladder (a cyst- is a contained sac) l Can be caused by injury, infection, or chemicals l Symptoms include burning sensation upon urination, painful urination, frequent urination, urgency (=I gotta go NOW), low back pain and possibly bed wetting

24. Diabetes Insipidus (DI) l A diabetic condition characterized by excretion of large volumes of urine –polyuria –5 to 15 l/day of extremely dilute urine l Caused by an ADH production disorder –hyposecretion of ADH from the pituitary gland which is located in the cranial cavity. l Patients exhibit extreme thirst (polydipsia)

25. Glomerulonephritis l Inflammation of the glomeruli of the kidneys l Can be caused by an allergic reaction to toxins given off by bacteria that have infected another part of the body l IS serious – –Can result in kidney failure

26. Incontinence l Inability to retain, urine, feces, or semen through the loss of sphincter control or because of cerebral or spinal lesions

27. Kidney Stones l Calculus or crystaline masses present in the pelvis of the kidney composed primarily of urates, oxalates, phosphates, and carbonates of varying size

28. Renal Failure l A decrease or cessation of glomerular filtration (less than 10% of function) l Acute renal failure (ARF) –Sudden worsening of renal function –May follow a case of hypovolemic shock l Chronic renal failure (CRF) –Progressive, irreversible decline in function –Can be caused by chronic glomerulonephritis, pyelonephritis, congenital polycystic disease, and traumatic loss of kidney tissue

29. Continuous Ambulatory Peritoneal Dialysis (CAPD) l Uses the patients peritoneum as the dialyzing membrane l A catheter is placed in the patients peritoneal cavity and a dialysate solution is allowed to enter the abdominal cavity l When the process is completed the dialysate solution is drained from the abdominal cavity and discarded l Always the possibility of infection

30. Hemodialysis Therapy l Filtering the blood by artificial means l Removing large, non diffusable particles from smaller diffusable ones through a selectively permeable membrane l Artificial kidney machinetypically performed 3 times a week from 4 - 6 hours per session

31. Kidney Transplant l A transplant provides a patient with a kidney that can keep up with the demands of a full, active life. l The new kidney removes waste products from the blood l A compatible donor must donate a kidney, can be from a living person (who will live with 1 kidney) or a donor who has lost life.