The Urinary System

1. 11 The Urinary System

2. Learning Outcomes Animal Organ-System and Its Functions: The URINARY System - STEM_BIO11/12- IVa-h-1 • Give the functions of the Urinary organ-system • Identify the structures and functions of the Urinary organs • Evaluate how Excretion Occur • Describe the Pathophysiology of the Urinary System

3. (15 mins) Film Viewing https://www.youtube.com/watch?v=H2VkW9L5QSU Buzz Session1. What is the importance of the Urinary System? 2. What is it made of? Structures and parts/functions?3. How does Excretion occur; its pathways? 4. What are disorders of the Excretory System? Describe.

4. Introduction • 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 Urinary System Organs Kidneys Ureters Bladder Urethra

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

6. Kidney 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

7. Kidney 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

8. Renal Corpuscles • Composed of a group of capillaries called a glomerulus • Glomerulusis surrounded by Bowman’s capsule • Blood filtration occurs in corpuscle Glomerulus Renal Tubules • Extend from the Bowman’s • capsule of a nephron • Consist of three parts: • Proximal convoluted tubule • Loop of Henle • Distal convoluted tubule Nephrons • Removes waste products from the blood • Each kidney contains about 1 million nephrons • Made of a renal corpuscle and a renal tubule

9. Afferent Arteriole Glomerulus Efferent Arteriole Peritubular Capillaries Nephrons (cont.) Blood Flow Through Nephron • Afferent arterioles deliver blood to the glomeruli • Efferent arteriolescarry blood from the glomeruli to peritubular capillaries Veins of the Kidney

10. 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. Glomerulus 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

12. Urine Formation(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. Tubular Reabsorption 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

14. 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 Tubular Secretion

15. Urine Formation (cont.) • Urine composition • Mostly water • Ureaand 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. ANSWER: B Apply Your Knowledge Match the following: ___ Second process in urine formation A. Glomerular filtration ___ Substances move from blood into renal tubules B. Tubular reabsorption ___ Depends on filtration pressure C. Tubular secretion ___ Third process of urine formation ___ First process of urine formation ___ Filtrate flows into the proximal convoluted tubule C A C A Nice Job! B

17. Bladder 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

18. Previous

19. Brain stemandcerebralcortex Impulses to contract urethra; inhibit micturition impulse until ready to urinate Spinal cord Parasympathetic nerves stimulate detrusor muscle Stretch receptors Bladderdistends Urination • External urethral sphincter relaxes • Micturition reflex – impulses from pons and hypothalamus • Detrusor muscle contracts • Urine expelled

20. Urethra 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

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

22. Diseases and Disorders of the Urinary System

23. Diseases and Disorders of the Urinary System

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

25. APPLICATION: 1. Explain how Urination occur? 2. What are the common Urinary disorders? 3. How is the knowledge about Urinary system made you appreciate life? 4. Tracing of Urination/Urine Formation.

26. End of Chapter 11 This too shall pass—just like a kidney stone. ~H. Madson