Lecture Medical assisting: Administrative and clinical procedures with anatomy and physiology (4e) – Chapter 26

CHAPTER 26 The Urinary System © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-2 Learning Outcomes 26.1 Describe the structure, location, and functions of the kidney 26.2 Define the term nephron and describe its structure 26.3 Explain how nephrons filter blood and form urine 26.4 List substances normally found in urine © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-3 Learning Outcomes (cont.) 26.5 Describe the locations, structures, and functions of the ureters, bladder, and urethra 26.6 Explain how urination is controlled 26.7 Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the urinary system © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-4 Introduction Kidneys Kidneys Ureters Ureters Bladder Bladder Urethra 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 © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-5 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 © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-6 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 © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-7 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 © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-9 Nephrons • Removes waste products from the blood • Each kidney contains about 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 Tubules Composed of a group of capillaries called a glomerulus  Glomerulus is surrounded by Glomerulus Bowman’s capsule  Blood filtration occurs in corpuscle  Renal Corpuscles © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-11 Nephrons (cont.) Afferent Arteriole Glomerulus  Afferent arterioles deliver blood to the glomeruli  Efferent arterioles carry blood from the glomeruli to peritubular capillaries Efferent Arteriole Peritubular Capillaries Veins of the Kidney © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-12 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! © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-16 Tubular Secretion • Third process of urine formation • Substances move from blood in the peritubular capillaries into the renal tubules • Secreted substances – Drugs – Hydrogen ions – Waste products Tubular Secretion © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-18 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 © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-19 Apply Your Knowledge Match the following: ANSWER: B Second process in urine formation _ A Glomerular filtration C Substances move from blood into renal tubules _ B Tubular reabsorption A Depends on filtration pressure _ C Tubular secretion C Third process of urine formation _ A First process of urine formation _ B Filtrate flows into the proximal convoluted tubule _ Nice Job! © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-21 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 © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-22 Previous © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-23 Urination Brain stem and cerebral cortex Impulses to contract urethra; inhibit Spinal cord micturition impulse until ready to urinate Parasympathetic nerves stimulate detrusor muscle Stretch receptors Bladder distends – External urethral sphincter relaxes – Micturition reflex – impulses from pons and hypothalamus – Detrusor muscle contracts – Urine expelled © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-24 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 Urethra © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-25 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 _ © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-26 Diseases and Disorders of the Urinary System Disease/Disorder Description Acute renal failure Sudden loss of kidney function; may be reversible with treatment Chronic renal failure Kidneys slowly lose ability to function; not reversible Cystitis 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 © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-27 Diseases and Disorders of the Urinary System Disease/Disorder Description Polycystic kidney disease Enlargement of kidneys because of the presence of many cysts within them; slow, progressive disease Pyelonephritis Complicated urinary tract infection; starts with a bladder infection and spreads to both kidneys; can be acute or chronic Renal calculi Kidney stones; can become lodged in ducts within kidneys or ureters © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-28 Apply Your Knowledge Matching: ANSWER: A Complicated urinary tract infection A Pyelonephritis _ C Inability to control urination _ B Glomerulonephritis E Kidney stones _ C Incontinence D Slow loss of kidney function _ D Chronic renal failure F Bladder infection _ E Renal calculi B Inflammation of the glomeruli _ F Cystitis H Kidney enlargement due to cysts _ G Acute renal failure G Sudden loss of kidney function _ H Polycystic kidney disease G O O D J O B! © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-29 In Summary 26.1 The retroperitoneal kidneys are composed of the outer renal cortex and inner renal medulla Their function is to remove metabolic waste from the body 26.2 A nephron is a single kidney cell It is composed of a renal corpuscle containing the glomerulus and Bowman’s capsule and the three sections of the renal tubule: proximal convoluted tubule, loop of Henle, and distal convoluted tubule © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-30 In Summary (cont.) 26.3 The nephrons filter blood and form urine through three processes: glomerular filtration, tubular reabsorption, and tubular secretion 26.4 Some of the components of urine include water, urea, uric acid, trace amounts of amino acids, and various ions 26.5 The two ureters are long tubes extending from each renal pelvis that bring urine to the bladder for storage The urethra is the muscular tube extending from the bladder that allows urine to be expelled from the body © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-31 In Summary (cont.) 26.6 Urination is controlled by a variety of factors including bladder distention, parasympathetic nerve stimulation, brain impulses affecting urethral sphincters, and contractions of the detrusor muscles of the bladder 26.7 The diseases and disorders of the urinary system include infections of the bladder and kidneys, bladder control, and the different types of renal (kidney) failure and disease These are discussed in more detail in the Pathophysiology section of this chapter © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26-32 End of Chapter 26 This too shall pass—just like a kidney stone ~H Madson © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d [...]... Com panies, Inc A ll rights reserv e d 26- 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 © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26- 19 Apply Your Knowledge Match the following:... Nice Job! © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26- 21 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... 26- 22 Previous © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26- 23 Urination Brain stem and cerebral cortex Impulses to contract urethra; inhibit Spinal cord micturition impulse until ready to urinate Parasympathetic nerves stimulate detrusor muscle Stretch receptors Bladder distends – External urethral sphincter relaxes – Micturition reflex – impulses from pons and hypothalamus –. .. muscle contracts – Urine expelled © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26- 24 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 Urethra © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26- 25 Apply Your... hormones – Antidiuretic hormone (ADH) – Aldosterone – Both increase water reabsorption, which decreases urine production Tubular Reabsorption © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26- 16 Tubular Secretion • Third process of urine formation • Substances move from blood in the peritubular capillaries into the renal tubules • Secreted substances – Drugs – Hydrogen ions – Waste... reserv e d 26- 29 In Summary 26. 1 The retroperitoneal kidneys are composed of the outer renal cortex and inner renal medulla Their function is to remove metabolic waste from the body 26. 2 A nephron is a single kidney cell It is composed of a renal corpuscle containing the glomerulus and Bowman’s capsule and the three sections of the renal tubule: proximal convoluted tubule, loop of Henle, and distal... 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26- 30 In Summary (cont.) 26. 3 The nephrons filter blood and form urine through three processes: glomerular filtration, tubular reabsorption, and tubular secretion 26. 4 Some of the components of urine include water, urea, uric acid, trace amounts of amino acids, and various ions 26. 5 The two ureters are long tubes extending from each renal... rights reserv e d 26- 31 In Summary (cont.) 26. 6 Urination is controlled by a variety of factors including bladder distention, parasympathetic nerve stimulation, brain impulses affecting urethral sphincters, and contractions of the detrusor muscles of the bladder 26. 7 The diseases and disorders of the urinary system include infections of the bladder and kidneys, bladder control, and the different types.. .26- 13 Urine Formation • Glomerular Filtration – First process occurs in renal corpuscles – Fluid part of the blood is forced from glomerulus into Bowman’s capsule • Becomes glomerular filtrate Glomerulus © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26- 14 Urine Formation (cont.) • Factors affecting glomerular filtration – Filtration pressure – amount of pressure... include infections of the bladder and kidneys, bladder control, and the different types of renal (kidney) failure and disease These are discussed in more detail in the Pathophysiology section of this chapter © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv e d 26- 32 End of Chapter 26 This too shall pass—just like a kidney stone ~H Madson © 2011 The McGraw -Hill Com panies, Inc A ll rights reserv