Urinary system


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  • Inner : longitudinal layerMiddle : circular layerOuter : longituinal layer
  • Inner : longitudinal layerMiddle : circular layerOuter : longituinal layer
  • LP
  • LP
  • Urinary system

    1. 1. Urinary System<br />
    2. 2. Urinary System<br />The urinary system (excretory system) is the organ system that produces, stores, and eliminates urine. In humans it includes two kidneys, two ureters, the bladder, the urethra, and two sphincter muscles.<br />
    3. 3. Kidney<br /><ul><li>The kidneys are bean-shaped organs with several functions, such as :
    4. 4. Regulation of electrolytes (e.g. sodium, potassium and calcium)
    5. 5. Regulation of blood pressure (via maintaining salt and water balance)
    6. 6. Serve the body as a natural filter of the blood
    7. 7. Responsible for the reabsorption of water, glucose, and amino acids
    8. 8. Produce hormones including calcitriol, erythropoietin, and the enzyme renin.</li></li></ul><li>kidney is divided into two major structures: superficial is the renal cortex and deep is the renal medulla.<br />
    9. 9. Ureters<br />2 muscular tubes that propel urine from the kidneys through renal pelvis to the urinary bladder<br />
    10. 10. Urinary Bladder<br />a distensible reservoir for urine<br />located in the pelvis, posterior to pubis symphysis<br />Size & shape change as it fills<br />Contains three openings:<br />two for ureters (Ureteric orifices)<br />One for urethra (Internal urethral orifice)<br />The triangular region defined by these three openings is called Trigone<br />
    11. 11.
    12. 12. Urethra<br /><ul><li>A fibro muscular tube that conveys urine from the urinary bladder to the exterior through “external urethral orifice”
    13. 13.  In males, the urethra travels through the penis, and carries semen as well as urine
    14. 14.  In females, the urethra is shorter and emerges above the vaginal opening.</li></li></ul><li>
    15. 15. Kidney<br />
    16. 16. Renal capsule<br />Tough capsule made of collagenous fibers and connected on the kidney by areolar tissue<br />As it proceeds medially towards the hilum, it connects with the connective tissue of the vessels which are entering kidney.<br />Perirenal fascia (or renal fascia envelope), encloses the kidneys and the suprarenal glands and contain the perirenal fat as cushioning for these structures.<br />
    17. 17.
    18. 18.
    19. 19. Cortex<br />It is brownish-red in color, 1 cm wide and lies beneath fibrous renal capsule. Medullary rays penetrate the cortex,<br />
    20. 20.
    21. 21.
    22. 22. Medulla<br />It consists of several large pyramids. Their apices (papillae) point towards the renal pelvis. It can be distinguished in 2 zones:<br />the reddish external zone (with internal and external striations);<br />the pale internal zone.<br />
    23. 23.
    24. 24. Lobules of kidney<br /><ul><li>The renal lobe is a portion of a kidney consisting of renal pyramidand the renal cortex above it.
    25. 25. The kidney is made up of 10-18 lobes.
    26. 26. The bases of the renal pyramids are enveloped by a cortex. Its apices are called renal papilla.
    27. 27. Renal papilla open to the renal pelvis via a branch of a renal pelvis called a calyx.
    28. 28. Cortex contain renal corpuscles , proximal & distal parts of tubules.</li></li></ul><li>
    29. 29. <ul><li>A cortical lobule(or renal lobule) is a part of a renal lobe. It consists of the nephrons grouped around a single medullary ray and draining into a single collecting duct.</li></ul>* Medullary ray<br /> Is the middle part of the cortical lobule or renal lobule, consisting of a group of straight tubes to the collecting ducts.<br />- Their name is potentially misleading – the "modullarly" refers to their destination, not their location.<br />
    30. 30. Nephrons<br />
    31. 31. Structure of nephron<br />Nephron:<br />Is the basic structural and functional unit of the kidney. <br /><ul><li>chief function is to regulate the concentration of water and soluble substances and to eliminate wastes from the body.
    32. 32. In humans, a normal kidney contains 800,000 to 1.5 million nephrons.</li></li></ul><li>PARTS OF NEPHRON<br />Subsections of Nephrons:<br /> 1.Renal corpuscle (glomerulus) <br />2.Proximal tubule <br /> a. Proximal Convoluted Tubule (PCT) <br /> b. Proximal Straight Tubule (PST)<br /> 3.Loop of Henle<br /> a. Descending Thin Limb (DTL) <br /> b. Ascending Thin Limb (ATL) <br /> c. Thick Ascending Limb (TAL) <br />
    33. 33. PARTS OF NEPHRON<br /> 4. Distal tubule <br /> a. Thick Ascending Limb (TAL) <br /> b. Macula densa<br /> c. Distal Convoluted Tubule (DCT) <br />5. Collecting Duct (CD)<br />
    34. 34. Podocytes:<br /> * Podocytes are highly specialized cells<br /> * envelope the glomerular capillaries with foot projections.<br /> * The podocytes are thus the visceral layer of the Bowmann's capsule and part of the filtration barrier of the glomerular filtration. <br />
    35. 35.
    36. 36.
    37. 37. Functions<br /><ul><li>reabsorption and secretion of various solutes such as ions (e.g., sodium), carbohydrates (e.g., glucose), and amino acids (e.g., glutamate).
    38. 38. Fluid in the filtrate entering the proximal convoluted tubule is reabsorbed into the peritubular capillaries, including approximately two-thirds of the filtered salt and water and all filtered organic solutes (primarily glucose and amino acids).</li></li></ul><li>* The loop of Henle(nephron loop)- a U-shaped tube that extends from the proximal tubule. It consists of a descending limb and ascending limb. It begins in the cortex, receiving filtrate from the proximal convoluted tubule, extends into the medulla as the descending limb, and then returns to the cortex as the ascending limb to empty into the distal convoluted tubule. <br />* The primary role of the loop of Henle is to concentrate the salt in the interstitium, the tissue surrounding the loop.<br />
    39. 39.
    40. 40.
    41. 41.
    42. 42.
    43. 43.
    44. 44.
    45. 45. Types of Nephrons<br />Juxtamedullarynephrons<br />Cortical nephrons<br />
    46. 46. Juxtamedullary nephrons<br /><ul><li>Located in the coticomedullary junction.
    47. 47. These have long loops of Henle that extend deep into the inner zone of the medulla.
    48. 48. Responsible for the production of concentrated urine.</li></li></ul><li>Cortical nephrons<br /><ul><li>85% of nephrons.
    49. 49. Located in the renal cortex
    50. 50. Have shorter loops of henle that extends only up to the outer zone of the medulla.</li></li></ul><li>Renal Interstitium<br />
    51. 51. Renal Interstitium<br />Is the Connective Tissue of the kidney parenchyma that surrounds the nephrons, ducts, and blood and lymph vessels.<br />Its volume, in the cortex, is relatively small, but increases in the medulla.<br />It includes fibroblast-like cells, mononuclear cells, and small bundles of collagen fibers in a highly hydrated proteoglycan matrix.<br />
    52. 52.
    53. 53. Renal Cortical interstitial cells<br /><ul><li>Fibroblast-like cells
    54. 54. Location: Cortex of the Kidney
    55. 55. Have long, tapering processes that are in contact with processes of like cells.
    56. 56. Cytoplasm contains occasional small lipid droplets and dilated cisternae of rough E.R. that may contain flocculent material of low electron density.
    57. 57. These interstitial cells are believed to produce the fibrous and amorphous components of the extracellular matrix.
    58. 58. Mononuclear cells
    59. 59. Location: Cortex of the Kidney
    60. 60. More or less spherical in shape
    61. 61. Have a large heterochromatic nucleus surrounded by a relatively thin rim of cytoplasm.
    62. 62. It is likely that they are early stages of monocyte-macrophage lineage.</li></ul>***Both of these cells synthesize and secrete collagen and glycosaminoglycans of the extracellular matrix.<br />
    63. 63. Renal Medullary interstitial cells<br /><ul><li>Location: Medulla of the Kidney
    64. 64. Fibroblast-like cells that differ from those of the cortex in their orientation and in their ultrastructure.
    65. 65. Highly pleomorphic cells
    66. 66. Presence of multiple lipid droplets
    67. 67. Have endocrine function in the regulation of systemic blood pressure.
    68. 68. Secretes Medullipin-I that is antihypersensitive.</li></li></ul><li>Histophyisiology<br />of the Kidney<br />
    69. 69. Histophysiology of the Kidney<br />Vasa recta containing descending arterioles and ascending venules act as countercurrent exchangers<br />Interaction between collecting ducts, loops of Henle, and vasa rectae is required for concentrating urine by the countercurrent exchange mechanism<br />
    70. 70.
    71. 71.
    72. 72.
    73. 73.
    74. 74.
    75. 75. Urinary System<br />Ureters, Urinary Bladder and Urethra<br />
    76. 76. Ureters…<br />
    77. 77. Ureters<br />Lined by “Transitional Epithelium (UROTHELIUM)” in the luminal surface of it’s wall<br />Smooth Muscle and CT in the remainder wall.<br />Inner : longitudinal layer<br />Middle : circular layer<br />Outer : longitudinal layer – – only at distal end of ureter<br />
    78. 78. Ureters<br />Consists of 3 major layers of tissue:<br /><ul><li>Mucosa
    79. 79. Muscular coat
    80. 80. Fibrous coat or</li></ul> Adventitia <br />
    81. 81.
    82. 82. Mucosa<br /> Inner layer<br />Consists of :<br />EPITHELIUM <br />transitional type, avascular and w/out lymphatics<br />LAMINA PROPRIA<br />w/ areolar CT and vascular <br />
    83. 83. Mucosa<br />The urinary sites have no muscularis mucosae, and therefore, the lamina propria and the submucosa tend to merge. Sometimes the connective tissue closest to the mucularis is called the submucosa. There is no distinct submucosa<br />
    84. 84. Mucosa<br />LP<br />
    85. 85. Mucosa<br />LP<br />
    86. 86. Muscular Coat <br />“Muscularis”<br />Consists of Smooth Muscle<br />Main function is peristalsis – –propel urine<br />Inner : longitudinal layer<br />Middle : circular layer<br />Outer : longitudinal layer – – only at distal end of ureter<br />
    87. 87.
    88. 88.
    89. 89. Muscular Coat <br />In contrast to the muscularis of the intestinal tract, this muscular coat of UT is not arranged in clearly defined longitudinal and circular layer. Instead, it is made up of anastomosing bundles of muscle fibers of varying orientation.<br />Although the inner bundles are predominantly of both layers, they grade with each other with no clearly defined boundary. <br />
    90. 90.
    91. 91. Fibrous Coat <br />“Adventitia” or “serosa”<br />Supporting layer of Fibrous CT<br />With Adipose tissue, vessels an nerves<br />
    92. 92.
    93. 93. Urinary Bladder<br />
    94. 94. Urinary Bladderwall<br /><ul><li>has the same tissue layers as the renal pelvis and ureter:
    95. 95. Mucosa
    96. 96. Muscularis
    97. 97. Serosa</li></li></ul><li>
    98. 98. Urinary Bladder wall: Mucosa<br />* innermost portion of the urinary bladder is the mucosa.<br />
    99. 99. Urinary Bladder wall: Mucosa<br />Layers you will found in Mucosa<br />Transitional Epithelium<br />Lamina Propria<br />2.1. subepithelial region<br />2.2. Deeper zone<br />
    100. 100. Urinary Bladder wall: Mucosa<br />Layers in mucosa:<br />
    101. 101. Urinary Bladder wall: Mucosa<br />Layers in mucosa:<br />2. Lamina Propria<br /> - wider in urinary bladder than in ureter<br /> - have two zones:<br /> - subepithelial region<br /> - deep zone<br />
    102. 102. Urinary Bladder wall: Mucosa<br />Lamina Propria: Subepithelial Region<br /> - denser with fine fibers<br /> - numerous fibroblasts<br />Lamina Propria: Deeper Zone<br />- Typical loose or moderately dense irregular connective tissue, which extends between the muscle fibers as interstitial connective tissue<br />
    103. 103. Urinary Bladder wall: muscularis<br /> similar to those in the ureter except for its thickness<br />A smooth muscle<br />smooth muscle of the bladder is called the detrusor muscle<br />Contraction of this muscle expels urine from the bladder.<br />
    104. 104.
    105. 105. Urinary Bladder wall: muscularis<br />Muscularis is subdivided into three layers of anastomoting smooth muscle(that’s why they can’t be clearly separated from each other), namely: <br /> a.) inner longitudinal layer<br /> b.) middle circular layer - thickest<br /> c.) outer longitudinal layer – most prominent and compact on the dorsal and ventral surfaces of bladder<br />The interstitial connective tissue(loose connective tissue) merges with the connective tissue of serosa<br />
    106. 106.
    107. 107. Urinary Bladder wall: Serosa<br />Located at the superior surface of the bladder<br />composed of a simple squamous epithelium overlying a small bit of connective tissue<br />Have two layers:<br />Superficial connective tissue<br />Peritonel mesothelium (outermost layer)<br />Beyond the serosa, covering the bladder is perivesical fat.  This is a layer of fat surrounding bladder<br />
    108. 108. Internal urethral sphincter<br />toward the opening of urethra, the muscle fibers form the involuntary internal urethral sphincter <br />A ring-like arrangement of muscle around the opening of urethra, in the region of trigone at the base of bladder<br />
    109. 109. Urethra…<br />
    110. 110. Urethra<br />Urine flow is controlled by two uretheral sphincters: <br /><ul><li> Internal urethral sphincter
    111. 111. start of the urethra
    112. 112. composed of smooth muscle
    113. 113. External urethral sphincter. 
    114. 114. composed of skeletal muscle</li></li></ul><li>Male Urethra<br />longer than the urethra of females<br />About 20 cm long <br />divided into three sections: <br />prostatic urethra<br />membranous urethra<br />spongy (penile) urethra.<br />
    115. 115. Prostatic Urethra<br />First portion<br />3 to 4 cm from the neck of the bladder to the prostate gland<br />Lined with transitional epithelium (urothelium)<br />
    116. 116. Prostatic Urethra<br />There are several openings: <br />ejaculatory duct <br />- receives sperm from the vas deferens and ejaculate fluid from the seminal vesicle <br />prostatic ducts <br />- where fluid from the prostate enters and contributes to the ejaculate,<br />prostatic utricle<br /><ul><li>which is merely an indentation.</li></ul>These openings are collectively called the “verumontanum”<br />
    117. 117. Transitional epithelium is the lining proximal to the ejaculatory duct and distal to this, it becomes psuedostratified or stratified columnar epithelium with occasional mucus-secreting goblet cells.<br />Most of the cells in the lumen are polygonal in outline with abundant microvilli. These microvilli tend to confine at the periphery, leaving the central area smooth.<br />
    118. 118. Membranous Urethra<br />Second part (shortest)<br />1 cm from the apex of the prostate gland to the bulb of the penis<br />It passes through external urethral sphincter, which is composed of skeletal muscles(voluntary)<br />Lined with pseudostratified columnar epithelium<br />
    119. 119. Spongy(penile) Urethra<br />Third part (longest)<br />About 15 cm through the length of the penis and opens on the body surface of the glands penis<br />Surrounded by spongy tissue called “corpus spongiosum” <br />Lined with pseudostratified columnar epithelium except at the distal part where it is lined with stratified squamous epithelium<br />
    120. 120. Spongy(penile) Urethra<br />Ducts of the “bulbourethral glands (cowper’s glands)” and the mucus-secreting “urethral glands (glands of Littré)” empty into this area.<br />*Bulbourethral glands (cowper’s glands)<br />- small exocrine glands present in the reproductive system of human males<br />*Urethral glands (glands of Littré)<br />- glands secrete mucus, which is incorporated into the semen, and are most numerous in the section of the urethra that runs through the penis<br />
    121. 121.
    122. 122. Female Urethra<br />Short<br />3 to 5 cm in length from the bladder to the vestibule of the vagina<br />Lined by stratified squamous epithelium before it terminates <br />Psuedostratifiedcolumnar epithelium at the midportion<br />
    123. 123. Female Urethra<br />In the lumen, there are openings of numerous small urethral glands <br />Other glands, paraurethral glands secreting alkaline secretion opens in each side of external urethral orifice.<br />Lamina propria is highly vascularized layer of loose CT with abundant elastic fibers<br />Urethral sphincter (voluntary) is composed of striated muscles.<br />
    124. 124. Female Urethra<br />Short<br />3 to 5 cm in length from the bladder to the vestibule of the vagina<br />Lined by stratified squamous epithelium before it terminates <br />Psuedostratifiedcolumnar epithelium at the midportion<br />