Diseases of kidney and urinary tract

							       APPLIED
ANATOMY & PHYSIOLOGY
OF THE URINARY SYSTEM



         DR. S Chakradhar   1
                 Functional Anatomy and Physiology
   Kidney size = 11-14cm
   Located retro - peritoneally on either side of vertebral column,
   Extends from T12 to L3.
   Left kidney is slightly higher than Right.
   Kidneys receive about 20-25% of the cardiac output.




                                   DR. S Chakradhar                    2
   Gross structure




                      Dr S Chakradhar   3
Nephron
 It is the structural & functional unit of kidney.
Parts
 Glomerulus / Renal Corpuscles
 Renal tubule
     Bowman's Capsule / Glomerular Capsule
     Proximal Convoluted tubule
     Descending limb of loop
     Loop of Henle
     Ascending limb of loop
     Distal convoluted tubule
     Collecting duct




                                   DR. S Chakradhar   4
                   Proximal
   Glomerulus     Convoluted
                    Tubule

                                Distal
                             Convoluted
                       Loop of Henle
                                Tubule
                      Thick ascending
                           limb
 Loop of Henle                          Collecting
Thin descending                           Duct
      limb


                      Loop of Henle
                      Thin ascending
                           limb
DR. S Chakradhar   6
   Blood Supply
   Blood Supply
Glomerulus ( Renal Corpuscle)
 Capillary tuft surrounded by bowman’s capsule
 Bowmen’s space ( urinary space)
 Components:
    Capillaries: endothelial cells
    Podocytes ( visceral epithelium): podocytes foot processes
    Mesengial cells
    Parietal epithelium
Podocytes




            Dr S Chakradhar   10
Mesangial Cells
 Lie in the central region of the glomerulus.
 Contraction of these cells decreases GFR while relaxation increases GFR




                                Dr S Chakradhar                       11
Filtration barrier
 Capillary endothelium,
 Basement membrane, and
 Visceral Epithelium (podocytes)


Filtration slits

      Capillary Space
   GBM
           Endothelium




                            Podocyte
   Urine formation




                      DR. S Chakradhar   13
DR. S Chakradhar   14
Juxta - glomerular apparatus
 Macula densa – modified cells of distal tubule near afferent arteriole
  are taller
 Juxtaglomerular cells are myoepithelial cells in afferent arteriole.
  They secrete rennin
 Polkissen cells/Lacis cells -outside the kidney glomerulus near the
  macula densa and bound laterally by afferent and efferent arterioles.
Renin Angiotensin




                    DR. S Chakradhar   16
Functions of the kidneys:
 Formation & secretion of urine
 Control of the internal environment
    Salt, water, osmolarity, plasma volume/ BP
    Acid-base control; H+, HCO3-
    Other ions; K+, Ca++, phosphate, Mg++
 Excretion; urea, creatinine, urates, drugs
 Endocrine
    Renin, angiotensin, aldosterone axis
    1,25 OH Vit D3
    Erythropoietin




                               DR. S Chakradhar   17
          Summary
Think of the kidney as an organ of


       homeostasis
   not as an organ of excretion
   Lower Urinary Tract





                          DR. S Chakradhar   19
   Micturation





                  DR. S Chakradhar   20