Urinary System

1. Chapter 28 Urinary System

2. Principle players – kidneys, ureters, bladder, urethra The balancing act of blood plasma

3. Blood enters kidney Kidney regulates water content in blood Regulates electrolytes Regulates Ph level overview

4. Oval, yet concave on medial side called the hilum- arteries, veins, and ureters attach there 4.3 X 2.7 X 1.2 inches Left slightly larger than right Retroperitoneal location on either side of the vertebral column T-12 to L-3 Right is lower due to liver Remains in place due to connective tissue and renal fasciae Covered by tough fibrous covering kidney

7. Renal cortex – outer surface • Renal medulla – inner surface • Pyramids comprise most of this tissue pg 831 • Points of pyramid called papilla and this leads to a calyx (urine is collected before exiting) • From the calyx, urine flows into the renal pelvis and then to the ureter terminology

11. 1,200 cc blood flows through for filtration each minute! Abdominal artery branches into the renal arteries Renal arteries branch into smaller segmental, interlobar, arcuate interlobular arteries and finally afferent arterioles From there to glomerular capillaries, efferent arterioles (not venules) then peritubular capillaries Capillary blood then drains in reverse direction into venules and then to the normal pressure gradient Vessel structure

12. Will the renal vein drain into the superior or inferior vena cava?

13. 28-34 cm in length Exit the medulla at L-1 Extends from kidney to bladder Runs at an oblique angle approx. 2 cm into bladder – closes when bladder is full – prevents backup into kidney and back flow F – it is very close to ovary and cervix M – close to prostate and seminal vesicle 3 layers – muscle, mucus, fibrous Peristalsis moves urine to bladder in addition to gravity ureters

14. Muscular (smooth)hollow organ Posterior to symphysis pubis Anterior to rectum Inferior to parietal peritoneum F – sits on anterior vagina and front of uterus M – rests on prostate bladder

18. Muscles – crisscrossing bundles running in all directions Lined with mucosal lining that forms rugae allowing distendability 3 openings Cont.

19. Reservoir for urine Expels urine from body with assistance from urethral sphincter muscle Function of bladder

20. Mucus membrane lined tube Extends from bladder floor (trigone) to outer surface of body F – posterior to pubis, anterior to vagina – 1.2 inches M – 7.9 in., passes through prostate and joined by 2 ejaculatory ducts and then to the base of penis and to the urethra In the male, it serves two purposes - urethra

21. What are they?

22. Why then does urine not mix with semen?

23. CNS Spinal cord Nerve supplying the bladder Trauma to the exterior Injury to what part(s) of the body will disallow urinary control?

24. Voiding Outer sphincter must relax in the bladder Bladder contracts Urine exits bladder Through urethra External sphincter will open and close (closure must be learned to control) micturition

25. Basic functional unit of the kidney • 2 main parts – renal corpuscle and tubule • 1.25 mil. - makes up mass of each kidney • Urinary flow: • Renal corpuscle • Bowman’s capsule • Proximal convoluted tubule • Loop of Henle • Distal convoluted tubule • Collecting duct - concentration Nephron

26. Bowman’s capsule 2 layers of epithelial cells with a space in between where fluids, waste, and electrolytes pass through Filtration here forms urine Renal corpuscle

27. Fine capillaries A bowman’s capsule and the glomerulus inside is known as a renal corpuscle Contains large “pores” for increased porosity glomerulus

29. Second part of the nephron First part of the renal tubule Closest to Bowman’s capsule Contains thousands of microvilli which increase surface area Proximal tubule

31. Descending and ascending segment The loop dips deep into the medulla of the kidney The length of the loop is important to the production of concentrated or dilute urine Loop of henle

32. Beyond the loop of Henle The juxtaglomerular apparatus is located where the afferent arteriole lies next to the distal tubule Most important in regulating blood pressure due to renin release (renin causes vessel constriction therefore increases blood pressure) Distal tubule

33. Mechanicoreceptors - renin changes vessel dilation Chemoreceptors – in macula densa – results in urine concentration receptors

36. Ducts flow into larger ducts and then to the renal pyramids then to calyces Bowman’s capsules and convoluted tubules found in cortex of kidney Loops of henle go deep into the renal medulla Collecting duct

37. 95% water 5% nitrogenous waste, toxins, mineral salts Color – clear-amber Amount – 1000-2000 cc excreted per day Polyuria – over 2500 cc – CAUSE? Anuria – less than 75 cc – CAUSE? Oliguria – less than 400cc – CAUSE? Urine factoids

38. Nocturia • Glycosuria • Dysuria • Incontinence • Proteinuria • Specific gravity – normal – 1.010-1.025 • High – nephritis, DM • Low - nephritis • Acidity - slightly acidic • High acid– (low Ph) – acidosis, fever, starvation • Alkaline – bacterial infection Terms

39. physiology

40. Process blood plasma Excrete urine Chief function of the kidney

41. Maintains homeostasis!

42. Kidneys most important organ of the body in regulating acid-base balance and fluid and electrolyte balance Occurs by regulation of the water and electrolytes leaving the blood to equal amounts entering system

43. Sodium Potassium Chloride Nitrogen waste (urea) Kidney failure causes serum rise in:

44. Rise in these levels will result in what condition?

45. Influence rate of ADH Influence rate of aldosterone Synthesis of Vit D Synthesis of erythropoietin Synthesis of prostaglandins Other duties of the kidney:

46. Filtration – movement of water and protein free solutes from plasma Tubular reabsorption – movement of molecules out of tubules and into the peritubular blood Tubular secretion – movement of molecules out of the peritubular blood and into tubule for excretion Urine formed by three processes:

47. Hydrostatic pressure gradient forces the filtration of plasma into the nephron Resorption of useful materials must then take place to return to the blood

48. First step in blood processing Occurs in the renal corpuscles Blood flows through Glomerulus then to the Bowman’s capsule Cells and plasma proteins do not filter out With the normal effective filtration pressure of 10 mmHg., 125 ml. per minute occurs in both kidneys 1.5 liters of urine voided each day, therefore, 99% of the filtrate must be reabsorbed from the tubular segment of the nephron filtration

49. Blood pressure can change the diameter of the afferent and efferent arterioles and thus change filtration rate What would happen if the diameter constricts dramatically? Dilates? Hemorrhage? Dehydration ?

50. Second step Passive and active transport mechanisms from renal tubules Water, nutrients, electrolytes reabsorbed from proximal tubules Sodium causes a positive charge of interstitial fluid with respect to the tubule fluid – this causes a drive of negatively charged filtrate into the interstitial fluid and then to the peritubular blood reabsorption