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Kidneys and urination2


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Kidneys and urination2.ppt

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Kidneys and urination2

  1. 1. Kidneys and Urination <ul><li>Kidney </li></ul><ul><ul><li>Location and blood supply </li></ul></ul><ul><ul><li>Internal anatomy </li></ul></ul><ul><ul><li>Microscopic anatomy and function </li></ul></ul><ul><li>Ureter </li></ul><ul><li>Bladder and urethra </li></ul>
  2. 2. Location of kidney <ul><li>Retroperotoneal at mid-abdomen </li></ul><ul><li>T12-L3 </li></ul><ul><li>NAV enters at hilus </li></ul><ul><ul><li>Renal aa. off aorta </li></ul></ul><ul><ul><li>Renal vv to IVC </li></ul></ul><ul><ul><li>Nerves all autonomics--renal plexus </li></ul></ul><ul><li>Ureter--exits at hilus </li></ul><ul><li>“ Ad”renal gland superior to kidney--unrelated in function </li></ul><ul><ul><li>Own blood supply </li></ul></ul><ul><ul><li>Endocrine gland </li></ul></ul>
  3. 3. Internal anatomy of kidney <ul><li>NAV branch out from hilus </li></ul><ul><li>Collecting ducts unite and urine leaves through ureter at hilus </li></ul><ul><li>Cortex is outer/superficial tissue </li></ul><ul><ul><li>Light, granular </li></ul></ul><ul><ul><li>Functioning nephrons here </li></ul></ul><ul><li>Medulla is inner/deep tissue </li></ul><ul><ul><li>Darker </li></ul></ul><ul><ul><li>Pyramid-cone shape </li></ul></ul><ul><ul><li>Collecting tubules unite into ducts into ureter </li></ul></ul>
  4. 4. <ul><li>Lobe of kidney is medullary pyramid plus cortex around it </li></ul><ul><li>Cortex contains urine-concentrating nephrons </li></ul><ul><li>Medullary pyramids </li></ul><ul><ul><li>Tubules receive concentrated urine from cortex </li></ul></ul><ul><ul><li>Appear striated because contains parallel converging urine-collecting tubules </li></ul></ul><ul><li>Flow of urine </li></ul><ul><ul><li>Collecting tubes of medullary pyramid  minor calyx  major calyx  renal pelvis  ureter </li></ul></ul>Pg 679 Internal anatomy of kidney--details
  5. 5. Microscopic anatomy and function <ul><li>Nephron or urine-concentrating unit is in outer cortex--millions </li></ul><ul><li>Capillaries surround glomerulus (ball) and filtrate passes into duct </li></ul><ul><li>Counter-current exchange in ducts (Loop of Henle) concentrates urine) </li></ul>More details at “How Stuff Works” http://
  6. 6. Ureter--from kidney to bladder <ul><li>LAYERS OF URETER </li></ul><ul><li>External connective tissue--adventitia </li></ul><ul><li>Middle muscular layer--muscularis </li></ul><ul><ul><li>Smooth Muscle </li></ul></ul><ul><ul><li>Inner Longitudinal </li></ul></ul><ul><ul><li>Outer Circular </li></ul></ul><ul><ul><li>External longitudinal (on distal third) </li></ul></ul><ul><ul><li>Peristaltic action moves urine to bladder (and stones!!) </li></ul></ul><ul><li>Inner lining of transitional (stretchy) epithelium--Mucosa </li></ul>
  7. 7. Bladder <ul><li>Muscular (what kind?) sac that fills with urine from ureters </li></ul><ul><li>Anterior against pubis in pelvis (more with pelvis) </li></ul><ul><li>Filled with urine expands into abdomen </li></ul><ul><li>Blood supply from internal iliac arteries </li></ul><ul><li>Innervation is autonomic from hypogastric plexus </li></ul>
  8. 8. Layers of bladder wall <ul><li>Outer connective tissue--adventitia </li></ul><ul><li>Middle muscular layer (“detrusal” or expulsor)--inner and outer longitudinal fibers around middle circular fibers </li></ul><ul><li>Inner transitional (stretchy) epithelium </li></ul><ul><li>Bladder can expand 15 times its empty volume to hold 500 ml of urine </li></ul><ul><li>Trigone is triangle between ureters/urethra--persistent sight of infection </li></ul>
  9. 9. Urethra <ul><li>Drains urine from bladder to outside </li></ul><ul><li>Female = short tube </li></ul><ul><li>Males = long tube </li></ul><ul><ul><li>Prostatic, Membranous, Spongy (penile) portions </li></ul></ul><ul><ul><li>Also carries sperm </li></ul></ul><ul><li>Internal Urethral Sphincter </li></ul><ul><ul><li>Between bladder + urethra </li></ul></ul><ul><ul><li>Thickening of detrusor (smooth muscle) </li></ul></ul><ul><li>External Urethral Sphincter </li></ul><ul><ul><li>Within urogenital diaphragm </li></ul></ul><ul><ul><li>Skeletal muscle = voluntary control urination </li></ul></ul><ul><li>External Urethral Orifice </li></ul><ul><ul><li>Males = end of penile urethra </li></ul></ul><ul><ul><li>Females = anterior to vaginal opening, posterior to clitoris </li></ul></ul><ul><li>(more later with pelvis) </li></ul>
  10. 10. For nice review of kidneys and urination http:// Micturition = Urination <ul><li>Emptying bladder </li></ul><ul><ul><li>Stretch receptors in bladder respond when bladder full </li></ul></ul><ul><ul><li>Parasympathetic signals detrusor muscle to contract and internal urinary sphincter to open (also inhibits sympathetic pathways that would prevent urination) </li></ul></ul><ul><ul><li>Other brain receptors can inhibit urination by relaxing detrusor, and keep external urinary sphincter closed </li></ul></ul><ul><ul><li>Voluntary contraction of abdominal wall muscles increases abdominal pressure </li></ul></ul><ul><ul><li>Voluntary relaxation of external urethral sphincter </li></ul></ul>See pg 692, M&M
  11. 11. Ascent of the kidney in development <ul><li>Kidneys from intermediate mesoderm </li></ul><ul><li>Pronephric kidney in fetus shows segmental body plan </li></ul><ul><li>Fish with dorsal renal tissue lateral to vertebral column for most of length </li></ul><ul><li>In human, metanephric kidney migrates from inferior to superior </li></ul><ul><li>Variation in kidney shape not uncommon (horseshoe kidney </li></ul><ul><li>Ureter also from intermediate mesoderm </li></ul>