19 The Urinary System

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19 The Urinary System

• I. Macroscopic Kidneys
• II. Nephrons
• III. Renal Corpuscle
• IV. Proximal Convoluted Tubule
• V. Loop of Henle
• VI. Distal Convoluted Tubule
• VII. Collecting Tubules Ducts
• VIII. Blood Flow
• IX. Ureter Bladder
• X. Urethra

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I. Macroscopic Kidneys

• A. Capsule hilus (19.1)
• B. Renal sinus
• 1. renal pelvis
• 2. major calyces
• 3. minor calyces
• C. Renal medulla
• 1. renal pyramids
• a. papilla
• 2. Renal column
• D. Renal cortex

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II. Nephrons

• A. Components (19.1)
• 1. renal corpuscle
• 2. PCT
• 3. loop of Henle
• 4. DCT
• 5. (collecting tubule duct)

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II. Nephrons

• B. Relationship to cortex and medulla (19.1)

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III. Renal Corpuscle

• A. Glomerulus (19.3)
• 1. afferent arteriole
• 2. efferent arteriole
• 3. vascular pole
• 4. fenestrated capillaries (19.4)

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III. Renal Corpuscle

• B. Bowmans capsule
• 1. visceral layer
• a. podocytes (19.3)

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III. Renal Corpuscle

• B. Bowmans capsule
• 1. visceral layer
• a. podocytes
• 1) primary processes (19.5)

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III. Renal Corpuscle

• B. Bowmans capsule
• 1. visceral layer
• a. podocytes
• 2) secondary processes (pedicels, foot
  processes) (19.5,19.6)

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III. Renal Corpuscle

• Secondary processes interdigitate around
  glomerular capillaries. The narrow space between
  processes is the filtration slit. 19-5

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III. Renal Corpuscle

• B. Bowmans capsule
• 1. visceral layer
• a. podocytes
• 3) filtration slits (19.7)

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III. Renal Corpuscle

• B. Bowmans capsule
• 1. visceral layer
• a. podocytes
• 3) filtration slits
• a) 25 nm wide (19.8)
• 4) basement membrane

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III. Renal Corpuscle

• B. Bowmans capsule (19.3)
• 2. urinary space
• 3. parietal layer
• 4. urinary pole

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III. Renal Corpuscle

• B. Bowmans capsule
• 5. EM view (19.4)

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III. Renal Corpuscle

• C. Structure/function 19.7
• 1. glomerular filtrate
• 2. most blood components smaller than 70 kDa

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IV. Proximal Convoluted Tubule

• A. Overview (19.3,19.13)
• 1. begins at urinary pole
• 2. simple cuboidal epithelium
• 3. longer than DCT

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IV. Proximal Convoluted Tubule

• B. Cell structure
• 1. brush border (19.14,19.15)
• a. microvilli 1 mm

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IV. Proximal Convoluted Tubule

• B. Cell structure
• 2. basal border (19.4)
• a. membrane invaginations
• 1) Na/K-ATPase
• b. parallel mitochondria
• (recall salivary glands)

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IV. Proximal Convoluted Tubule

• C. Function 19.16
• 1. pinocytosis
• 2. active ion transport
• 3. Osmosis
• 4. exocytosis

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IV. Proximal Convoluted Tubule

• C. Function 19.16
• 4. reabsorption
• a. all glucose
• b. amino acids
• c. 85 NaCl H20
• d. PO4, Ca
• e. protein
• 5. secretion/excretion

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V. Loop of Henle

• A. Components (19.16)
• 1. thick descending limb
• 2. thin descending limb
• 3. thin ascending limb
• 4. thick ascending limb

cortex
medulla
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V. Loop of Henle

• B. Cell structure
• 1. thick descending PCT
• 2. thick ascending DCT
• 3. thin limbs (19.18,19.19)

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V. Loop of Henle

• C. Function 19-16
• 1. capability of forming hypertonic urine
• a. water retention
• 2. thin descending limb
• a. permeable to water
• 3. ascending limb
• a. impermeable to water

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VI. Distal Convoluted Tubule

• A. Location (19.16)
• 1. continuation of thick ascending limb
• 2. cortex
• 3. vascular pole of renal corpuscle
• a. juxtaglomerular region

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VI. Distal Convoluted Tubule

• B. Cell structure (19.16,19.19)
• 1. simple cuboidal epithelium
• 2. cells smaller than PCT
• a. more nuclei visible/XS
• 3. lack brush border

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VI. Distal Convoluted Tubule

• B. Cell structure (19.19)
• 4. less acidophilic than PCT
• 5. larger lumen than PCT
• 6. similar basal infoldings

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VI. Distal Convoluted Tubule

• C. Function 19.16
• 1. under influence of aldosterone
• 2. absorb Na (and H2O)
• 3. secretes K, H, NH4

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VI. Distal Convoluted Tubule

• D. Juxtaglomerular region
• 1. macula densa of DCT (19.21)
• a. DCT cells columnar
• b. able to sense flow and ionic conc.
• c. influences afferent arteriole
  constriction, glomerular filtration, renin
  secretion

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VI. Distal Convoluted Tubule

• D. Juxtaglomerular region
• 2. JG apparatus (19.25)
• a. modified smooth muscle of afferent
  arteriole
• b. secretory granules
• c. protein synthesizing organelles
• d. synthesize renin
• e. effect increase Na and Cl- absorption
  distal tubules

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VII. Collecting Tubules Ducts

• A. Cell structure
• 1. cuboidal to columnar (19.22)
• 2. weakly staining
• 3. few organelles

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VII. Collecting Tubules Ducts

• A. Cell structure
• 4. no basal striations (19.23)
• 5. clear intercellular borders
• 6. empty into minor calyx at renal papilla

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VII. Collecting Tubules Ducts

• B. Function 19-16
• 1. ADH (vasopressin)
• a. causes epithelium to be permeable to H2O
• b. reabsorption of H2O

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VIII. Blood Flow

• A. Renal artery (19.26)
• B. Interlobar arteries
• C. Arcuate arteries
• D. Interlobular arteries

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VIII. Blood Flow

• E. Afferent arterioles (19.26)
• F. Efferent arterioles
• G. Peritubular capillary network
• G. Vasa recta

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IX. Ureter Bladder

• A. Ureter 19-28
• 1. mucosa
• a. transitional epithelium
• b. lamina propria
• 2. muscularis
• a. inner longitudinal
• b. outer circular
• 3. adventitia

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IX. Ureter Bladder

• B. Urinary bladder
• 1. mucosa (19.27)
• a. transitional epithelium
• b. lamina propria
• 2. muscularis
• a. fibers run in all directions
• b. no layers
• 3. adventitia / serosa

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X. Urethra

• A. Male urethra (22.1)
• 1. prostatic urethra
• 2. membranous urethra
• 3. pendulous urethra
• a. pseudostratified / columnar epithelium
• b. corpus spongiosum
• 4. bulbous urethra

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X. Urethra

• B. Female urethra
• 1. pseudostratified columnar, 4-5 cm long
• 2. stratified squamous

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