The Urinary System. Medical Assisting Third Edition. Booth, Whicker, Wyman, Pugh, Thompson The McGraw-Hill Companies, Inc. All rights reserved

Transcription

1 The Urinary System PowerPoint presentation to accompany: Medical Assisting Third Edition Booth, Whicker, Wyman, Pugh, Thompson

2 30-2 Learning Outcomes 30.1 Describe the structure, location, and functions of the kidney Define the term nephron and describe its structure Explain how nephrons filter blood and form urine List substances normally found in urine.

3 30-3 Learning Outcomes (cont.) 30.5 Describe the locations, structures, and functions of the ureters, bladder, and urethra Explain how urination is controlled Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the urinary system.

4 30-4 Introduction Kidneys Ureters Bladder Urethra System functions to remove waste products from the blood Main functional units of the kidneys are the nephrons Nephrons filter the blood and form the urine

5 30-5 The Kidneys Functions Remove metabolic waste products from the blood Secrete the hormone erythropoietin, which stimulates bone marrow to produce red blood cells Secrete the hormone renin, which helps regulate blood pressure Description The kidneys are bean-shaped organs that lie behind the peritoneal cavity (retroperitoneal) on either side of the vertebral column.

6 30-6 The Kidneys (cont.) Renal sinus concave depression of the surface of the kidney Hilum point of entry for the renal artery, renal vein, and ureter Renal pelvis expansion of the ureter that further divides into calyces Kidney

7 30-7 The Kidneys (cont.) Renal cortex outermost portion of the kidney that covers the pyramids and dips down between them Renal medulla middle portion that also divides into renal pyramids Renal column portion of the cortex between pyramids Kidney

8 30-9 The Kidneys: Nephrons Removes waste products from the blood Each kidney contains about 1 million nephrons Made of a renal corpuscle and a renal tubule Extend from the Bowman s capsule of a nephron Consist of three parts: Proximal convoluted tubule Loop of Henle Distal convoluted tubule Renal Corpuscles Composed of a group o called a glomerulus Glomerulus is surround Bowman s capsule Blood filtration occurs Glomerulus

9 30-11 The Kidneys Nephrons (cont.) Afferent Arteriole Glomerulus Efferent Arteriole Peritubular Capillaries Veins of the Kidney Afferent arterioles deliver blood to the glomeruli Efferent arterioles carry blood from the glomeruli to peritubular capillaries

10 30-12 Apply Your Knowledge What are the functions of the kidney? ANSWER: The kidney removes metabolic waste products from the blood, secretes erythropoietin to help regulate RBC production, and secretes renin to help regulate the BP. Correct!

11 30-13 Urine Formation: Glomerular Filtration First process occurs in renal corpuscles Fluid part of the blood is forced from glomerulous into Bowman s capsule Becomes glomerular filtrate Glomerulus

12 30-14 Urine Formation: Glomerular Filtration (cont.) Factors affecting glomerular filtration Filtration pressure amount of pressure that forces filtrate from the glomerulus into Bowman s capsule. Determined by blood pressure Rate of filtration sympathetic nervous system control Constriction of afferent arterioles decreases filtration pressure

13 30-15 Urine Formation: Tubular Reabsorption Second process in urine formation Glomerular filtrate proximal convoluted tubule Nutrients, water, and ions pass through the walls of the renal tubule into the peritubular capillaries Water reabsorption depends on hormones Antidiuretic hormone (ADH) Aldosterone Both increase water reabsorption, which decreases urine production Tubular Reabsorption

14 30-16 Urine Formation: Tubular Secretion Third process of urine formation Secreted substances Drugs Substances move from blood in the peritubular capillaries into the renal tubules Hydrogen ions Waste products Tubular Secretion

15 30-18 Urine Formation (cont.) Urine composition Mostly water Urea and uric acid Formed by the breakdown of proteins and nucleic acids Trace amounts of amino acids and various ions Secretion of waste products helps maintain the acid-base balance

16 30-19 Apply Your Knowledge Match the following: ANSWER: B Second process in urine formation C Substances move from blood into renal tubules A Depends on filtration pressure C Third process of urine formation A. Glomerular filtration B. Tubular reabsorption C. Tubular secretion A First process of urine formation B Filtrate flows into the proximal convoluted tubule Nice Job!

17 30-21 Ureters, Urinary Bladder, and Urethra (cont.) Urinary bladder Expandable muscular organ Stores up to 600 ml urine on average Detrusor muscle smooth muscle in wall of bladder Trigone triangle on internal floor of bladder formed by urethra and ureters Micturation Process of urination Stretching of bladder triggers process Approximately 150cc of urine Bladder

18 30-22 Ureters, Urinary Bladder, and Urethra (cont.) Impulses to contract urethra; inhibit micturition impulse until ready to urinate Brain stem and cerebral cortex Parasympathetic nerves stimulate detrusor muscle Bladder distends Spinal cord Stretch receptors Urination External urethral sphincter relaxes Micturation reflex impulses from pons and hypothalamus Detrusor muscle contracts Urine expelled

19 30-23 Ureters, Urinary Bladder, and Urethra (cont.) Urethra Tube that moves urine from the bladder to the outside world Shorter in females patient education Urinate when urge occurs Drink adequate clear fluids Wipe front to back Urinate after intercourse

20 30-24 Apply Your Knowledge True or False: ANSWER: T Ureters move urine by peristalsis. trigone F The detrusor is formed by the openings of the ureters and urethra. T The process of micturition is triggered when the bladder contains about 150 ml urine. ureters F The urethra move urine from the kidney to the bladder. F The urethra is longer in females. males T Contraction of the detrusor muscle pushes urine from the bladder.

21 30-25 Diseases and Disorders of the Urinary System Disease/Disorder Description Acute renal failure Chronic renal failure Cystitis Sudden loss of kidney function; may be reversible with treatment Kidneys slowly use ability to function; not reversible Urinary bladder infection; more common in females Glomerulonephritis Inflammation of the glomeruli of the kidney; one cause of chronic renal failure Incontinence Inability to control urination

22 30-26 Diseases and Disorders of the Urinary System Disease/Disorder Polycystic kidney disease Pyelonephritis Renal calculi Description Enlargement of kidneys because of the presence of many cysts within them; slow, progressive disease Complicated urinary tract infection; starts with a bladder infection and spreads to both kidneys; can be acute or chronic Kidney stones; can become lodged in ducts within kidneys or ureters

23 30-27 Apply Your Knowledge Matching: ANSWER: A Complicated urinary tract infection C Inability to control urination E Kidney stones D Slow loss of kidney function F Bladder infection B Inflammation of the glomeruli H Kidney enlargement due to cysts G Sudden loss of kidney function A. Pyelonephritis B. Glomerulonephritis C. Incontinence D. Chronic renal failure E. Renal calculi F. Cystitis G. Acute renal failure H. Polycystic kidney disease GO O D JO B!

24 30-28 In Summary The organs of the urinary system include the kidneys, ureters, bladder, and urethra The kidneys remove metabolic waste products from the blood and secrete erythropoietin and renin Urine travels through the ureters to the bladder Stretching of the bladder triggers micturition reflex Urine travels from the bladder through the urethra to the outside world

25 30-29 This too shall pass just like a kidney stone. ~H. Madson