W4a. Renal 1- kidney (till convoluted tubules).pdf
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ANAT3009/3909: Functional Systems Histology Renal System...
ANAT3009/3909: Functional Systems Histology Renal System – Part 1 Dr Katie Dixon Image source: University of Southern California Copyright COMMONWEALTH OF AUSTRALIA Copyright Regulation WARNING This material has been reproduced and communicated to you by or on behalf of the University of Sydney pursuant to Part VB of the Copyright Act 1968 (the Act). The material in this communication may be subject to copyright under the Act. Any further reproduction or communication of this material by you may be the subject of copyright protection under the Act. Do not remove this notice H2O Drugs Plasma Vitamin D Homeostasis Acid-base Endocrine Ions Waste Functions of the kidney HOMEOSTASIS Maintain the stability of the extracellular fluid volume, electrolyte composition and osmolarity (solute concentration) 1) H2O balance to prevent osmotic fluxes IN/OUT of cells cells swell/shrink 2) Plasma volumes regulates arterial blood pressure 3) Acid-base balance via H+ and HCO3- urinary output 4) Ion concentrations and balance : Na+, K +, Ca +, H +, Mg + HCO3-, PO43-, Cl- Functions of the kidney 5) Excretion of waste products of metabolism (Urea from proteins, bilirubin from haemoglobin) 6) Endocrine functions Erythropoietin production stimulates erythrocyte production Renin production (RAS system) 7) Activation of Vitamin D [25OHD > 1,25(OH)2D3] 8) Excretion of drugs, non-nutritive materials Kidney http://www.stritch.luc.edu/lumen/MedEd/Radio/curriculum/Surger y/Renal_mass.htm http://www.meddean.luc.edu/lumen/meded/radio/curriculum/Mec hanisms/renal_mass_path.htm Kidney Source: © Elsevier, Inc., www.netterimages.com. Kidney iii Source: Histology a text and atlas. Pawlina 8th ed. NEPHRON ê COLLECTING DUCT ê MINOR CALYX ê MAJOR CALYX ê RENAL PELVIS ê URETER ê BLADDER ê URETHRA ê OUT Kidney Internal Structure From macroscopic to microscopic Source: NIH National Institute of Diabetes and Digestive and Kidney Diseases Nephrons distal proximal Renal Corpuscle Convoluted Tubules Loop of Henle Collecting Duct Source: Histology a text and atlas. Pawlina 8th ed. Low power H+E kidney section capsule medullary ray 1 bloodvessels Source: Histology a text and atlas. Pawlina 8th ed. Parts of the nephron in the cortex Often capillaries Convoluted tubules + blood vessels Renal corpuscle 200µm diameter sphere can be found they and medulla in cortex Medullary rays straight parts of (loops of Henle & collecting ducts) Renal corpuscle Renal corpuscle renal vessels Scanning electron micrograph - vascular corrosion casting Source: Dr. Fred Hossler, Dept. of Anatomy and Cell Biology, J.H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee Renal corpuscle (spherical, 200µm diameter) Consists of: 1) Glomerulus = capillary loops 2) Bowman’s Capsule = double-layered epithelial cup 8 3) Urinary Space = true space Dist voluted tubule Bowman's capsule vitteral 2 1 parietal layers 3 urinaspare Renal corpuscle simple Parietal layer squamousepithelium of Bowman’s Cap. Visceral layer urinary space Glomerulus: Capillaries, mesangial cells + podocytes filteration important for proximal convoluted tubule there we have opening of it Renal corpuscle Bowman’s Capsule has 2 parts: 1. Parietal layer simple squamous epithelium 2. Visceral layer Podocyte cells (epithelial derived) 2 1 Podocytes – visceral layer of Bowman’s Capsule cell body Podocyte cytoplasmic processes Scanning electron microscope image Filteration Apparatus Podocytes – visceral layer of Bowman’s Capsule A urinary space C capillary lumen B nucleus of podocyte o Filtration apparatus A my it B Urinary A foot space processes of podocytes Endothelial tellslining aka andgapsfifties'Iated pedicle Capillary lumen basement glomerular membrane in exam N A I not identifiable Mesangial cells Located between the capillaries and podocytes (hard to identify) secrete an extracellular matrix role Contractile can affect blood flow Phagocytic to clear away cell debris Source: Histology a text and atlas. Pawlina 8th ed. mesangial tell urinary space nucleus Mesangial cell pod podont podocytes of a Pedicles P podocyte endothelialcell BS bowmans space (urinary) BM basement membrane RBC C capillary lumen M mesangial cell nucleus MM mesangial cell cytoplasm Tubules in cortex « Proximal & Distal Convoluted Tubules simple cuboidal epithelium Medullary Rays « run parallel with each other loop of Henle & collecting tubules simple cuboidal epithelium Medullary rays Simple cuboidal epithelium Lumen Tubules run parallel to each other transverse section http://www.lab.anhb.uwa.edu.au/mb140/CorePages/Urinary/ Proximal convoluted tubules Initial & major site of reabsorption mm mmmm Cuboidal epithelial cell lining 1 Specific modifications for absorption function 1. Microvilli on apical surface 2. Junctional complex on lateral surface 3. Plicae on lateral surface 4. Basal striations 5 5. numerous mitochondria needed energy 4 in basal region for reabsorption Proximal convoluted tubules Proximal lumen bi hagqg microvilli 1 of ¬p 1kclear lumen and clean 2 ¬ 3 P 4 I 1. Mitochondria endothelial tell 2. Basal infolding 3. Basement membrane 4. Lumen of capillary Distal convoluted tubules Only 1/3 as long as proximal CTs Cuboidal epithelial cell lining Specific modifications for absorption function 1. very few, short microvilli 2. Junctional complex on lateral surface 3. Plicae on lateral surface 4. Basal striations fifying smaller beless 5. Numerous mitochondria in basal region Source: Histology a text and atlas. Pawlina 8th ed. Distal convoluted tubules P D D P shorter tubules than proximal = see less profiles of distal tubules p Collecting ducts simple cuboidal or columnar epithelium IÑnan tubule distal T.vn 0 larger 0 Source: siumed.edu Connective tissue in the kidney Very minimal connective tissue surrounding the nephrons, tubules & blood vessels Mostly functional tissue (parenchyma) To be continued…
