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Structure and Function of
the Renal and Urologic
Systems
Chapter 35
1
Structures of the Kidney

Kidneys
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Retroperitoneal
Renal capsule
Renal fascia
Hilum
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Structures of the Kidney
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Structures of the Kidney
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Renal cortex
Renal medulla
Renal pyramids
Renal columns
Minor calyx
Major calyx
Renal pelvis
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Structures of the Kidney
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Nephron
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
1.2 million nephrons per kidney
Functional unit of the kidney
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Superficial cortical nephrons
Midcortical nephrons
Juxtamedullary nephrons
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Nephron

Renal corpuscle
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Glomerulus
Bowman capsule
Mesangial cells
Bowman space
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Nephron

Glomerular filtration membrane
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Glomerular endothelium
Basement membrane
Capillary epithelium
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Also referred to as podocytes or visceral epithelium
Filtration slits
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Nephron

Juxtaglomerular apparatus
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
Juxtaglomerular cells
Macula densa
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Juxtaglomerular Apparatus
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Nephron
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Renal tubules
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Proximal tubule
Loop of Henle
Distal tubule
Collecting duct
Principal cells
Intercalated cells
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Structures of the Kidney
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Structures of the Kidney
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Blood Vessels
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Renal arteries
Interlobar arteries
Arcuate arteries
Interlobular arteries
Afferent arterioles
Glomerular capillaries
Efferent arterioles
Peritubular capillaries and vasa recta
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Structures of the Kidney
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Structures of the Kidney
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Ureters
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30 cm long
Long, intertwining muscle bundles
Pass obliquely though posterior aspect of bladder
Peristaltic activity
Micturition compresses the lower end of the
ureter to avoid urine reflux
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Structures of the Kidney
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Bladder
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Detrusor muscle
Transitional epithelium
Trigone
Micturition reflex
Urethra
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Internal and external sphincters
3 to 4 cm in females
18 to 20 cm in males
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Bladder and Urethra
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Renal Blood Flow
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Receive 1000 to 1200 mL of blood per minute
Glomerular filtration rate (GFR)
Autoregulation
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Myogenic mechanism
Tubuloglomerular feedback
Neural regulation
Hormones
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Renin-angiotensin system
Natriuretic peptides
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Renal Blood Flow
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Nephron Function

Glomerular filtration

Net filtration pressure
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Glomerular hydrostatic pressure
Capsular hydrostatic pressure
Blood oncotic pressure
Filtration rate
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Glomerular Filtration
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Nephron Function
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Tubular reabsorption
Tubular secretion
Excretion
Tubular transport
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Proximal tubule
Loop of Henle and distal tubule
Glomerulotubular balance
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Nephron Function
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Nephron Function
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Nephron Function
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Concentration and Dilution of
Urine
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Countercurrent exchange system
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Contributes to production of concentrated urine
Fluid flows in opposite direction through parallel
tubes
Fluid moves up and down the parallel limbs of
the loop of Henle
The longer the loop, the greater the concentration
gradient
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Countercurrent Exchange System
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Concentration and Dilution of
Urine
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Urea
Catecholamines
Antidiuretic hormone (ADH)
Urodilantin
Natriuretic peptide
Diuretics
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Renal Hormones
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Vitamin D
Erythropoietin
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Tests of Renal Function
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Clearance and glomerular filtration rate
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Inulin
Creatinine
Clearance and renal blood flow
Blood tests
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Plasma creatinine concentration
Plasma cystatin C concentration
Blood urea nitrogen (BUN)
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Tests of Renal Function
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Urinalysis
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Urine color
Urine pH
Specific gravity
Urine sediment
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RBCs
Casts
Crystals
WBCs
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Tests of Renal Function
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Urinalysis
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Reagent strips (dipsticks)
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Glucose
Bilirubin
Urobilinogen
Leukocyte esterase
Nitrates
Ketones
Proteins
RBCs, hemoglobin, and myoglobin
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Aging and Renal Function
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Decrease in kidney size
Decrease in renal blood flow and GFR
Number of nephrons decrease due to renal
vascular and perfusion changes
Glomerular capillaries atrophy
Tubular transport response decreases
Increased bladder symptoms
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Urgency, frequency, and nocturia
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