Histology of the Kidney Flashcards Preview

CVPR: Renal > Histology of the Kidney > Flashcards

Flashcards in Histology of the Kidney Deck (13)
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1

Anatomical features of the kidney

  • capsule surrounds outer cortex of kidney
  • under cortex ==> medullary pyramids
    • pyramids = collection of nephrons + collecting ducts
  • collecting ducts ==> empty at tip of pyramid (papilla) into calyx
  • Calices ==> renal pelvis ==> ureter @ hilum
    • hilum = central region
    • hilum also = site of entry of renal artery and vein

2

Vasculature/blood flow (renal artery ==> renal vein)

  • renal artery ==> interlobar arteries = between medullary pyramids
  • ==> arcuate arteries ==> interlobular arteries ==> afferent arterioles ==> glomerular capillaries
  • filtration @ glomeruli ==> efferent arterioles
    • @ outer cortex ==> capillary plexus @ tubules and extend as vasa recta into medulla
    • @ medulla ==> enter directly into medullary region
  • capillaries ==> interlobular veins ==> arcuate veins ==> interlobar veins ==> renal vein

3

Nephron: general characteristics

  • basic fxn unit of the kidney
  • =renal corpuscules + renal tubules
    • corpuscules @ cortex
    • tubule @ extends into medulla
    • loop of Henle = bend of tubule

4

Renal corpuscle characteristics

  • =where blood filtration occurs
  • =glomerulus (capillary network) + Bowman's capsule (epithelial capsule)
  • glomerulus
    • interior = mesangium (mesangial cells)
    • endothelial lining
  • Basal lamina = filtration barrier
  • Bowman's capsule
    • outer layer = parietal epithelium

    • layer of podocytes = visceral epithelium of Bowman's capsule

    • begining of urinary space

5

Filtration barrier characteristics

  • = fenestrated endothelium + shared basal lamina + filtration slits between podocytes
  • filtration = driven by hydrostratic pressure of blood
  • fenestrae prevent cellular components from contacting basal lamina, but all other components can pass through

6

Elements of blood that do not readily enter filtrate @ Bowman's capsule

  • large proteins/cellular components
  • mlx > 60-70,000 MW in size (albumin, etc.) <== prevented by basal lamina
  • negative mlx have more difficult passing through

7

Purpose of mesangial cells

  • =connective tissue
  • supports glomerular structure
  • secrete matrix that is continous w/basal lamina
  • mesangial cells = phagocytic ==> maintian filtration lamina

8

Main sections of the tubular portion of nephron

  1. proximal convoluted and straight tubule
  2. thin descending loop of Henle
  3. thin ascending loop of Henle
  4. ascending thick loop of Henle
  5. distal convoluted tubule
  6. collecting tubule

9

Proximal tubule characteristics

  • cuboidal epithelium + microvilli brush border on luminal side
  • cells @ luminal surface connected by tight jxns
  • basolateral side
    • extensive folds
    • Na+/K+ ATPase ++ ==> drives uptake of sodium, glucose, amino acids via facilitated diffusion

10

Loop of Henle general characteristics

  • thin descending ==> thin ascending ==> thick ascending
  • thin = simple squamous
    • maintains osmotic salt gradient in medulla
  • thick = cuboidal
    • active sodium transport

11

Distal tubule general characteristics

  • cuboidal + microvilli 
  • acid-base regulation
  • Na+/K+ ATPase transporters

12

Collecting tubules/ducts

  • cuboidal
  • =principal + intercalated cells
    • principal = active transporters
    • intercalated = secrete H+ + reabsorb bicarbonate (acid-base regulation)
  • ADH ==> regulates water permeability/reabsorption by collecting ducts
  • ducts join together and drain ==> papillary ducts ==> minor calices

13

Juxtaglomerular complex characteristics

  • =specialization of cells @ vascular pole of renal corpuscle
  • JG cells = modified smooth muscle cells @ wall of afferent arteriole
    • contain renin granules ==> control systemic/local BP w/release