The document provides an overview of the anatomy and physiology of the urinary system. It describes the key components - kidneys, ureters, bladder, and urethra. The kidneys filter waste from the blood to form urine. The ureters then transport urine from the kidneys to the bladder. The bladder stores urine until voiding. During urination, urine is expelled through the urethra. Together these structures precisely regulate chemical levels in the body and remove waste.

3. Anatomic and Physiologic Overview The urinary system comprises the kidneys, ureters, bladder, and urethra. A thorough understanding of the urinary system is necessary for assessing individuals with acute or chronic urinary dysfunction and implementing appropriate nursing care.

4. Anatomy of the Upper and Lower Urinary Tracts The urinary system—the structures of which precisely maintain the internal chemical environment of the body—perform various excretory, regulatory, and secretory functions.

5. Kidneys T he kidneys are a pair of brownish-red structures located retroperitoneally (behind and outside the peritoneal cavity) on the posterior wall of the abdomen from the 12th thoracic vertebra to the 3rd lumbar vertebra in the adult

7. Kidneys The kidney consists of two distinct regions: Renal Parenchyma Renal Pelvis

8. Kidneys The renal parenchyma is divided into the cortex and the medulla. The cortex contains the glomeruli, proximal and distal tubules, and cortical collecting ducts and their adjacent peritubular capillaries. The medulla resembles conical pyramids. The pyramids are situated with the base facing the concave surface of the kidney and the apex facing the hilum, or pelvis Renal Parenchyma

9. Kidneys The hilum, or pelvis, is the concave portion of the kidney through which the renal artery enters and the renal vein exits. The renal artery (arising from the abdominal aorta) divides into smaller and smaller vessels, eventually forming the afferent arteriole. Renal Pelvis

10. Kidneys The afferent arteriole branches to form the glomerulus , which is the capillary bed responsible for glomerular filtration. Blood leaves the glomerulus through the efferent arteriole and flows back to the inferior vena cava through a network of capillaries and veins. Renal Pelvis

13. Kidneys Each kidney contains about 1 million nephrons, the functional units of the kidney. Each kidney is capable of providing adequate renal function if the opposite kidney is damaged or becomes nonfunctional. Nephrons

15. Kidneys

16. Nephrons are struturally divided into two types: cortical and juxtamedullary.

17. Kidneys The glomerular membrane normally allows filtration of fluid and small molecules yet limits passage of larger molecules, such as blood cells and albumin. Kidney function begins to decrease at a rate of approximately 1% each year beginning at approximately age 30.

18. The glomerulus is composed of three filtering layers: the capillary endothelium, the basement membrane, and the epithelium.

20. Kidneys • Urine formation • Excretion of waste products • Regulation of electrolytes • Regulation of acid–base balance • Control of water balance • Control of blood pressure • Renal clearance • Regulation of red blood cell production • Synthesis of vitamin D to active form • Secretion of prostaglandins

21. Ureters U rine, which is formed within the nephrons, flows into the ureter, a long fibromuscular tube that connects each kidney to the bladder. The ureters are narrow, muscular tubes, each 24 to 30 cm long, that originate at the lower portion of the renal pelvis and terminate in the trigone of the bladder wall.

22. Ureters There are three narrowed areas of each ureter: ureteropelvic junction ureteral segment ureterovesical junction

23. Ureters The angling of the ureterovesical junction is the primary means of providing antegrade, or downward, movement of urine, also referred to as efflux of urine. This angling prevents vesicoureteral reflux, which is the retrograde, or backward, movement of urine from the bladder, up the ureter, toward the kidney. ureterovesical junction

24. Ureters The angling of the ureterovesical junction is the primary means of providing antegrade, or downward, movement of urine, also referred to as efflux of urine. This angling prevents vesicoureteral reflux, which is the retrograde, or backward, movement of urine from the bladder, up the ureter, toward the kidney. ureterovesical junction

25. During voiding ( micturition), increased intravesical pressure keeps the ureterovesical junction closed and keeps urine within the ureters. As soon as micturition is completed, intravesical pressure returns to its normal low baseline value, allowing efflux of urine to resume. Therefore, the only time that the bladder is completely empty is in the last seconds of micturition before efflux of urine resumes.

26. Ureters The angling of the ureterovesical junction is the primary means of providing antegrade, or downward, movement of urine, also referred to as efflux of urine. This angling prevents vesicoureteral reflux, which is the retrograde, or backward, movement of urine from the bladder, up the ureter, toward the kidney. ureterovesical junction

27. “ The left ureter is slightly shorter than the right” Did Y OU k now ?

28. Ureters The lining of the ureters is made up of transitional cell epithelium called urothelium. As in the bladder, the urothelium prevents reabsorption of urine. The movement of urine from the renal pelves through the ureters into the bladder is facilitated by peristaltic waves (occurring about one to five times per minute) from contraction of the smooth muscle in the ureter wall (Walsh, Retik, Vaughan & Wein, 1998).

29. Ureters Ureters functions as tubes that actively convey urine from the kidneys to the bladder.

30. Bladder T he urinary bladder is a muscular, hollow sac located just behind the pubic bone. The bladder is characterized by its central, hollow area called the vesicle, which has two inlets (the ureters) and one outlet (the urethrovesical junction), which is surrounded by the bladder neck.

31. Bladder Adult bladder capacity is about 300 to 600 mL of urine. In infancy, the bladder is found within the abdomen. In adolescence and through adulthood, the bladder assumes its position in the true pelvis.

32. Bladder The wall of the bladder comprises four layers: adventitia detrusor lamina propria urothelium

33. Bladder The urothelium layer is specialized, transitional cell epithelium, containing a membrane that is impermeable to water. The urothelium prevents the reabsorption of urine stored in the bladder urothelium

34. Bladder The bladder neck contains bundles of involuntary smooth muscle that form a portion of the urethral sphincter known as the internal sphincter. The portion of the sphincteric mechanism that is under voluntary control is the external urinary sphincter at the anterior urethra, the segment most distal from the bladder (Walsh et al., 1998).

35. Bladder The urinary bladder functions as a muscular sac that expands as urine is produced by the kidneys to allow storage of urine until voiding is convenient.

36. Urethra T he urethra arises from the base of the bladder: In the male, it passes through the penis; in the female, it opens just anterior to the vagina. In the male, the prostate gland, which lies just below the bladder neck, surrounds the urethra posteriorly and laterally.

37. Urethra The urethra is a muscular tube that drains urine from the body; it is 3–4 cm long in females, but closer to 20 cm in males.

38. Thank you.