Renal Histology: Kidney and Urinary Tract Flashcards

1
Q

kidney function

A

regulate volume and composition of body fluids

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2
Q

stroma

A

thin capsule of collagen fibers
interstitial connective tissue
reticular fibers

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3
Q

parenchyma

A

epithelial cells in tubules

drain to renal pelvis

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4
Q

renal pelvis

A

expansion of proximal ureter
supported in bed of fat
lie within renal sinus

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5
Q

renal sinus

A
aka hilum
central cavity opening medially
passing through:
-renal pelvis
-nerves
-vessels
-lymphatics
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6
Q

minor calyx

A

renal papilla empty to minor calyx
become major calyx when join with other minor calyx

empty into renal pelvis

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7
Q

renal columns of bertin

A

cortex that extends down to medulla between pyramids

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8
Q

renal lobe

A

consists of one medullary pyramid and its overlying cortex

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9
Q

corpuscle = ?

A

body

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10
Q

nephron

A

functional unit of kidney
subdivides to:
-renal corpuscle w/ bowmans capsule
-secretory tubule

nephron empties to collecting duct

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11
Q

bowmans capsule

A

double walled epithelium

  • parietal epithelium (outer)
  • visceral epithelium (on top of capillary)
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12
Q

parietal epithelium of bowmans capsule

A

squamous outer wall

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13
Q

visceral epithelium of bowmans capsule

A

reflected tubular epithelium (podocytes)

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14
Q

podocytes

A

modified epithelium cells

visceral epithelium

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15
Q

bowmans space

A

urinary space
between parietal and visceral layers
-receives the glomerular filtrate

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16
Q

glomerulus

A

tuft of capillaries that indent bowmans capsule

-vascular and urinary poles

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17
Q

cells of renal corpuscle

A
endothleial cells of capillaries
mesangial cells (and matrix)
podocytes
squamous cells of parietal epithelium
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18
Q

arterioles

A

arterioles have smooth muscle

  • within corpuscle we have capillary
  • no smooth muscle in corpuscle
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19
Q

glomerular filtration barrier

A

endothelial cell and epithelial cell (podocyte)

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20
Q

endothelial cell of GFB

A

produce sialic acid-rich glycocalyx

-fenestrated that lack diaphragms

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21
Q

epithelial cell of GFB

A

aka podocytes
produce sialic acid-rich glycocalyx
-trabeculae and foot processes (pedicels) interdigitate with one another to form filtration slits (closed by diaphragms)

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22
Q

structure of GFB?

A

trilaminar
lamina rara externa - produced by podocytes
lamina densa - central layer
lamina rara interna - produced by capillaries

primary barrier to filtration

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23
Q

what is GFB made of

A

rich in heparin-sulfate, chondroitin-sulfate, hyaluronic acid, and dermatain sulfate

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24
Q

lamina densa

A

lots of collagen type IV (globular)

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25
Q

GFB function?

A

barrier to both size and charge

type IV collagen in lamina densa size barrier
proteoglycans (heparine sulfate) is barrier to charge

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26
Q

LRI and LRE

A

composed of:
laminin - connect to basement membrane
heparan sulfate and hyaluronic acid - polyanionic charge barrier

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27
Q

reptation

A

snakelike motion of large protein through barrier

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28
Q

most filtered molecules restricted at?

A

LRI
69000 MW don’t pass

larger - albumin and other plasma proteins
-shouldn’t see albumin in urine

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29
Q

charge filtration?

A

strongly anionic filtration barrier
-due to heparin sulfate proteoglycan in LRI and LRE

cations pass more readily

net electrical charge determines
-degree of hydration, rigidity, electrophysical interactions

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30
Q

uriniferous tubules

A

stellate lumen
fuzzy microvilli border
acidophilic (mitochondria)

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31
Q

PCT?

A

proximal convoluted tubule
-in cortex forms at urinary pole
reabsorption** 70-80% of ultrafiltrate
-water, salt, amino acids, glucose, proteins

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32
Q

cells in PCT?

A

cuboidal cells
dense microvillus border
numerous basolateral interdigitations
abundant mitochondria

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33
Q

staining?

A

PCT dark

DCT paler

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34
Q

PST

A

proximal straight tubule
in cortex and medulla

reabsorbs glomerular filtrate

shorter cells
microvilli less developed
fewer infoldings
run in medullary ray from cortex to medulla

narrow into loop of henle

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35
Q

loop of henle

A

in medulla
-establishes hypertonic medullary interstitium

ascending limb - pumps NaCl

site of countercurrent multiplier

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36
Q

morphology of loop of henle

A

thin limbs

  • simple squamous epithelium
  • narrow lumen
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37
Q

descending loop of henle?

A

water and ions diffuse freely

-water out, urea in

38
Q

ascending loop of henle?

A

impermeable to water (lack of aquaporin)

NaCl pumped actively to medulla

-creates osmotic pressure drawing water into medullary space

39
Q

countercurrent multiplier

A

in loop of henle

40
Q

distal straight tubule

A

continuous with ascending loop of henle

  • impermeable to water
  • transports ions from lumen to interstitium
  • gradient kept by slow flow of vasa recta
41
Q

morphology of DST

A

cuboidal epithelium
-basolateral interdigitations

round smooth lumen
apically placed nuclei

numerous mitochondria

paler than PCT

42
Q

DCT

A

only in cortex**

  • returns to renal corpuscle of origin
  • shorter than PCT

under influence of aldosterone

43
Q

DCT function

A

under influence of aldosterone

  • reabsorb Na
  • secrete K
  • reabsorb bicarbonate (secrete H)
  • secrete ammonia
44
Q

morphology of DCT

A

simple cuboidal epithelium with basolateral interdigitations

round smooth lumen
paler stain than PCT
numerous mitochondria

45
Q

juxtaglomerular apparatus

A

regulates body salt and water balance
-distal tubule plus afferent arteriole

distal tubule - monitors salt levels
afferent arteriole - monitors blood pressure

releases renin when levels are low

46
Q

cell types of juxtaglomerular appartus

A

afferent arteriole
macula densa of distal tubule
extraglomerular mesangial cells

47
Q

juxtaglomerular cells

A

modified smooth muscle of afferent arteriole

-secrete enzyme renin

48
Q

macula densa of distal tubule

A

closely packed cells of DCT adjacent to afferent arteriole
-monitor Na+ concentration in tubule and regulate filtration rate

stimulate renin release from JG cells
stimulate contraction of afferent arteriole smooth muscle

49
Q

renin

A

angiotensinogase

secreted by JG celIs

50
Q

extraglomerular mesangial cells

A

aka cells of lacis or cells of polkisson

fusiform/flat cells that provide support

other functions unclear

51
Q

collecting duct

A

receive urine from several nephrons
duct runs in center of medullary ray toward medulla

initially cuboidal, then columnar

lumen increases in width distally

52
Q

medullary portion of collecting duct

A

site of concentration of urine

H2O lost to increasingly hypertonic medullary interstitium

ADH makes duct more permeable to water

53
Q

action of ADH

A

makes collecting duct more permeability to water

54
Q

medullary tissue

A

no glomeruli

-only in cortex

55
Q

ducts of bellini?

A

combination of collecting ducts in medulla

open at area cribosa of papilla

56
Q

cells of collecting duct?

A

light cells - principle cells

dark cells - intercalated cells

57
Q

light cells

A

principle cells
in collecting duct
-involved in releasing water from tubule (through aquaporin channels)

58
Q

dark cells

A

intercalated cells
in collecting duct
-alpha and beta

involved in controlling acid/base balance of urine

59
Q

alpha dark cells?

A

secrete H+

60
Q

beta dark cells?

A

secrete HCO3-

61
Q

renal interstitium cells?

A

surrounding collecting duct:

  • principal type I - produce vasodilators
  • type II - phagocytic
  • type III - function unknown
62
Q

leukotriene

A

arachidonic acid derivative

vasoconstrictor made in glomerulus

63
Q

prostaglandins

A

arachidonic acid derivative

vasodilator made in type I cells of collecting duct

64
Q

what controls glomerular blood flow?

A

leukotrienes and prostaglandins

65
Q

renal columns of bertin

A

cortex that extends into medulla between adjacent pyraminds

66
Q

medullary rays

A

areas of medulla that go out to cortex

-loop of henle, PSTs, DSTs, central collecting duct

67
Q

extension of cortex into medulla

A
renal corpuscles
PCTs, DCTs
loops of henle
associated PSTs, DSTs
central collecting duct
68
Q

renal lobule

A

found only in cortex
-surround collecting duct and medullary ray

include:

  • medullary ray
  • labyrinth surrounding ray
  • renal corpuscles
  • PCT and DCT

bordered by interlobar arteries

69
Q

interlobar arteries

A

supply renal corpuscle of renal lobule

70
Q

renal vasculature?

A
aorta
renal artery
segmental artery
interlobar artery
arcuate artery
interlobular artery
afferent arteriole
glomerulus
efferent arteriole
vasa recta OR peritubular capillaries
71
Q

interlobar artery

A

between pyramids

72
Q

arcuate artery

A

arches over base of pyramid

73
Q

interlobular artery

A

from arcuate branches to capsule

74
Q

vasa recta

A

in renal columns of medulla

descend into medulla and parallel loops of henle
loop and return to corticomedullary boundary
bypass interlobular veins

drain directly into arcuate veins**

75
Q

peritubular capillary

A

in renal cortex

drain into interlobular veins**
then into arcuate veins

76
Q

arcuate veins

A

drain to segmental veins

77
Q

venous drainage of renal?

A
arcuate vein
interlobar vein
segmental vein
renal vein
inferior vena cava
78
Q

outflow tract of urinary drainage

A

renal pelvis (minor and major calyx)
ureters
urinary bladder
urethra

79
Q

layers of outflow tract?

A

mucosa - transitional epithelium and lamina propria

muscularis - inner long / outer circular

adventitia - attaches organs to surrounding structure

80
Q

transitional epithelium

A

stratified epithelium

  • surface umbrella cells
  • bulge to lumen in relaxed state
  • stretch and flatten
  • joined by tight barrier
81
Q

cells of calyx?

A

lined with transitional epithelium (2 or 3 thick)

also have lamina propria and some muscle fibers
-compress papilla to eject urine

82
Q

ureter

A

stellatee, flattened lumen

mucosa - transitional epithlieum, dense lamina propria

muscularis - inner long / outer circular, thick and organized

adventitia - serosa is peritonealized (on ventrla surface)**

83
Q

vesico-ureteric junction

A

ureter pierces bladder wall obliquely

  • filling of bladder with urine compresses ureter within bladder wall
  • creates pseudovalve
  • prevents backflow
84
Q

cells of urinary bladder

A

mucosa - transitional epithelium (6-8 thick)

muscularis - very thick (detrusor muscle)

connective tissue septa - nerve and vessels (PS ganglia)

85
Q

detrusor muscle

A

muscularis in urinary bladder

interlace bundles of smooth muscle spiral around intramural ureter at micturition

86
Q

internal sphincter of smooth muscle

A

opens when detrusor contracts

87
Q

bladder

A

covered by peritoneum

-other surfaces adventitia attaches to pelvic wall via pelvic ligaments

88
Q

urethra

A

stellate lumen, highly folded, high in elastin

-transitional epithlium that changes to pseudostratified and then to stratified squamous epithelium at external orifice

89
Q

female urethra

A

also surrounded by venous plexus

90
Q

male urethra

A

prostatic - passes through prostate gland

membranous - surrounde by skeletal muscle
-urogenital diaphragm

penile - runs through corpus sponginosum

  • cylindrical body of vascular lacunae
  • venous plexus enclosed by CT capsule