© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Chapter 20 Urinary System

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Elimination of Waste Products Summary Skin (perspiration) Dissolved salts Intestines (defecation) Solid wastes and water Lungs (exhalation) Carbon dioxide and water vapor Kidneys (urination) Nitrogenous wastes and salts dissolved in water to form urine

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Urinary System Excretion of nitrogenous wastes, salts, and water Two kidneys –Form the urine Two ureters One bladder One urethra

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 20-1 The organs of the urinary system of a female

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Functions of the Urinary System Excretion Aids in maintaining acid-base balance Renin helps maintain blood pressure Erythropoeitin stimulates red blood cell production Secretion of waste products in the form of urine Elimination of urine from the bladder where it is stored

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Kidneys Two bean-shaped organs located retroperitoneally Adipose capsule Renal fascia Hilum Renal pelvis Medulla and cortex

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 20-2 The internal structure of a kidney

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Medulla and Cortex Cortex is the outer granular layer –Consists of the functional unit called the nephron Medulla is the inner striated layer –Consists of radially striated cones called renal pyramids –The papilla empties into the calyces, which join together to empty into the renal pelvis

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Nephron (1 of 2) Basic structural and functional unit Each kidney has over 1 million Afferent arteriole Bowman’s capsule Glomerulus Efferent arteriole

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Nephron (2 of 2) Proximal convoluted tubule (PCT) Loop of Henle Distal convoluted tubule (DCT) Collecting tubule

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 20-3 Structure of the nephron

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Path of Urine Formation (1 of 2) Blood enters the afferent arteriole Glomerulus Bowman’s capsule Becomes filtrate PCT Loop of Henle DCT Collecting tubule

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Path of Urine Formation (2 of 2) Collecting tubule –At collecting tubule, approximately 99% of the filtrate has been reabsorbed Formed urine goes to the renal pelvis ureter bladder urethra urinary meatus

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Urine Formation in the Nephron Filtration Reabsorption Secretion Urinary output and urinalysis values

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 20-5 Filtration, reabsorption, and secretion are the main functions of the nephrons

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Control of Urinary Secretion Chemical control –Aldosterone –ADH –diuretics ● Nervous control –Action of nerve impulses on the blood vessels leading to the kidney

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Urinary Output 1,000-2,000ml of urine/day Volume will vary with diet, fluid intake, temperature and physical activity Urinalysis –Examines the urine –Most common noninvasive diagnostic test done

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Ureters Two ureters –One for each kidney Carries urine to the bladder for storage About inches long and ¼-inch wide Mucous membranes line ureters Smooth muscle fibers –Peristalsis to push urine down the ureter to the bladder

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Urinary Bladder/Urethra Hollow muscular organ Stores up to about 1 pint (500 ml) of urine Involuntary contractions of the bladder can be controlled to some extent by the nervous system Urine leaves the bladder through the urethra, then passes through the opening called the urinary meatus

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Urination Micturition Level of urine in the bladder is sensed by stretch receptors Requires coordinated contraction of the bladder muscles and the relaxation of the sphincters

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Disorders of the Urinary System (1 of 2) Acute kidney failure Chronic renal failure Glomerulonephritis Acute glomerulonephritis Chronic glomerulonephritis

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Disorders of the Urinary System (2 of 2) Hydronephrosis Pyelitis/Pyelonephritis Kidney stones or renal calculi Cystitis Incontinence Neurogenic bladder

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Effects of Aging (1 of 2) Kidneys shrink Changes result in decreased renal blood flow Kidney compromised in removing waste products Decreased glomerular filtration rate –Drug dosages have to be adjusted

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Effects of Aging (2 of 2) Glucose reabsorption also decreases –Hyperglycemia Loss of muscle tone in the urinary bladder Urinary incontinence

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Dialysis Passage of dissolved molecules through a semipermeable membrane Used for kidney failure Hemodialysis Peritoneal dialysis

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Kidney Transplants Living donor transplant Unrelated donor who has died Most important complication –Rejection of kidney by the recipient