Renal Histology: Kidney and Urinary Tract Flashcards Preview

MSS - Renal Exam 1 > Renal Histology: Kidney and Urinary Tract > Flashcards

Flashcards in Renal Histology: Kidney and Urinary Tract Deck (90):
1

kidney function

regulate volume and composition of body fluids

2

stroma

thin capsule of collagen fibers
interstitial connective tissue
reticular fibers

3

parenchyma

epithelial cells in tubules
drain to renal pelvis

4

renal pelvis

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

5

renal sinus

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

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minor calyx

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

empty into renal pelvis

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renal columns of bertin

cortex that extends down to medulla between pyramids

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renal lobe

consists of one medullary pyramid and its overlying cortex

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corpuscle = ?

body

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nephron

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

nephron empties to collecting duct

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bowmans capsule

double walled epithelium
-parietal epithelium (outer)
-visceral epithelium (on top of capillary)

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parietal epithelium of bowmans capsule

squamous outer wall

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visceral epithelium of bowmans capsule

reflected tubular epithelium (podocytes)

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podocytes

modified epithelium cells

visceral epithelium

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bowmans space

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

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glomerulus

tuft of capillaries that indent bowmans capsule
-vascular and urinary poles

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cells of renal corpuscle

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

18

arterioles

arterioles have smooth muscle
-within corpuscle we have capillary
-no smooth muscle in corpuscle

19

glomerular filtration barrier

endothelial cell and epithelial cell (podocyte)

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endothelial cell of GFB

produce sialic acid-rich glycocalyx
-fenestrated that lack diaphragms

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epithelial cell of GFB

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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structure of GFB?

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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what is GFB made of

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

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lamina densa

lots of collagen type IV (globular)

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GFB function?

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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LRI and LRE

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

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reptation

snakelike motion of large protein through barrier

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most filtered molecules restricted at?

LRI
69000 MW don't pass

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

29

charge filtration?

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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uriniferous tubules

stellate lumen
fuzzy microvilli border
acidophilic (mitochondria)

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PCT?

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

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cells in PCT?

cuboidal cells
dense microvillus border
numerous basolateral interdigitations
abundant mitochondria

33

staining?

PCT dark
DCT paler

34

PST

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

35

loop of henle

in medulla
-establishes hypertonic medullary interstitium

ascending limb - pumps NaCl

site of countercurrent multiplier

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morphology of loop of henle

thin limbs
-simple squamous epithelium
-narrow lumen

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descending loop of henle?

water and ions diffuse freely
-water out, urea in

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ascending loop of henle?

impermeable to water (lack of aquaporin)

NaCl pumped actively to medulla

-creates osmotic pressure drawing water into medullary space

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countercurrent multiplier

in loop of henle

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distal straight tubule

continuous with ascending loop of henle
-impermeable to water
-transports ions from lumen to interstitium
-gradient kept by slow flow of vasa recta

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morphology of DST

cuboidal epithelium
-basolateral interdigitations

round smooth lumen
apically placed nuclei

numerous mitochondria

paler than PCT

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DCT

only in cortex**
-returns to renal corpuscle of origin
-shorter than PCT

under influence of aldosterone

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DCT function

under influence of aldosterone
-reabsorb Na
-secrete K
-reabsorb bicarbonate (secrete H)
-secrete ammonia

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morphology of DCT

simple cuboidal epithelium with basolateral interdigitations

round smooth lumen
paler stain than PCT
numerous mitochondria

45

juxtaglomerular apparatus

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

cell types of juxtaglomerular appartus

afferent arteriole
macula densa of distal tubule
extraglomerular mesangial cells

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juxtaglomerular cells

modified smooth muscle of afferent arteriole
-secrete enzyme renin

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macula densa of distal tubule

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

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renin

angiotensinogase

secreted by JG celIs

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extraglomerular mesangial cells

aka cells of lacis or cells of polkisson

fusiform/flat cells that provide support

other functions unclear

51

collecting duct

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

initially cuboidal, then columnar

lumen increases in width distally

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medullary portion of collecting duct

site of concentration of urine

H2O lost to increasingly hypertonic medullary interstitium

ADH makes duct more permeable to water

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action of ADH

makes collecting duct more permeability to water

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medullary tissue

no glomeruli
-only in cortex

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ducts of bellini?

combination of collecting ducts in medulla

open at area cribosa of papilla

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cells of collecting duct?

light cells - principle cells
dark cells - intercalated cells

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light cells

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

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dark cells

intercalated cells
in collecting duct
-alpha and beta

involved in controlling acid/base balance of urine

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alpha dark cells?

secrete H+

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beta dark cells?

secrete HCO3-

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renal interstitium cells?

surrounding collecting duct:
-principal type I - produce vasodilators
-type II - phagocytic
-type III - function unknown

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leukotriene

arachidonic acid derivative
vasoconstrictor made in glomerulus

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prostaglandins

arachidonic acid derivative
vasodilator made in type I cells of collecting duct

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what controls glomerular blood flow?

leukotrienes and prostaglandins

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renal columns of bertin

cortex that extends into medulla between adjacent pyraminds

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medullary rays

areas of medulla that go out to cortex
-loop of henle, PSTs, DSTs, central collecting duct

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extension of cortex into medulla

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

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renal lobule

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

interlobar arteries

supply renal corpuscle of renal lobule

70

renal vasculature?

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

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interlobar artery

between pyramids

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arcuate artery

arches over base of pyramid

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interlobular artery

from arcuate branches to capsule

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vasa recta

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

peritubular capillary

in renal cortex

drain into interlobular veins**
then into arcuate veins

76

arcuate veins

drain to segmental veins

77

venous drainage of renal?

arcuate vein
interlobar vein
segmental vein
renal vein
inferior vena cava

78

outflow tract of urinary drainage

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

79

layers of outflow tract?

mucosa - transitional epithelium and lamina propria

muscularis - inner long / outer circular

adventitia - attaches organs to surrounding structure

80

transitional epithelium

stratified epithelium
-surface umbrella cells
-bulge to lumen in relaxed state
-stretch and flatten
-joined by tight barrier

81

cells of calyx?

lined with transitional epithelium (2 or 3 thick)

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

82

ureter

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

vesico-ureteric junction

ureter pierces bladder wall obliquely
-filling of bladder with urine compresses ureter within bladder wall
-creates pseudovalve
-prevents backflow

84

cells of urinary bladder

mucosa - transitional epithelium (6-8 thick)

muscularis - very thick (detrusor muscle)

connective tissue septa - nerve and vessels (PS ganglia)

85

detrusor muscle

muscularis in urinary bladder

interlace bundles of smooth muscle spiral around intramural ureter at micturition

86

internal sphincter of smooth muscle

opens when detrusor contracts

87

bladder

covered by peritoneum
-other surfaces adventitia attaches to pelvic wall via pelvic ligaments

88

urethra

stellate lumen, highly folded, high in elastin
-transitional epithlium that changes to pseudostratified and then to stratified squamous epithelium at external orifice

89

female urethra

also surrounded by venous plexus

90

male urethra

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