Renal Histology: Kidney and Urinary Tract Flashcards
1
Q
kidney function
A
regulate volume and composition of body fluids
2
Q
stroma
A
thin capsule of collagen fibers
interstitial connective tissue
reticular fibers
3
Q
parenchyma
A
epithelial cells in tubules
drain to renal pelvis
4
Q
renal pelvis
A
expansion of proximal ureter
supported in bed of fat
lie within renal sinus
5
Q
renal sinus
A
aka hilum central cavity opening medially passing through: -renal pelvis -nerves -vessels -lymphatics
6
Q
minor calyx
A
renal papilla empty to minor calyx
become major calyx when join with other minor calyx
empty into renal pelvis
7
Q
renal columns of bertin
A
cortex that extends down to medulla between pyramids
8
Q
renal lobe
A
consists of one medullary pyramid and its overlying cortex
9
Q
corpuscle = ?
A
body
10
Q
nephron
A
functional unit of kidney
subdivides to:
-renal corpuscle w/ bowmans capsule
-secretory tubule
nephron empties to collecting duct
11
Q
bowmans capsule
A
double walled epithelium
- parietal epithelium (outer)
- visceral epithelium (on top of capillary)
12
Q
parietal epithelium of bowmans capsule
A
squamous outer wall
13
Q
visceral epithelium of bowmans capsule
A
reflected tubular epithelium (podocytes)
14
Q
podocytes
A
modified epithelium cells
visceral epithelium
15
Q
bowmans space
A
urinary space
between parietal and visceral layers
-receives the glomerular filtrate
16
Q
glomerulus
A
tuft of capillaries that indent bowmans capsule
-vascular and urinary poles
17
Q
cells of renal corpuscle
A
endothleial cells of capillaries mesangial cells (and matrix) podocytes squamous cells of parietal epithelium
18
Q
arterioles
A
arterioles have smooth muscle
- within corpuscle we have capillary
- no smooth muscle in corpuscle
19
Q
glomerular filtration barrier
A
endothelial cell and epithelial cell (podocyte)
20
Q
endothelial cell of GFB
A
produce sialic acid-rich glycocalyx
-fenestrated that lack diaphragms
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)
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
23
Q
what is GFB made of
A
rich in heparin-sulfate, chondroitin-sulfate, hyaluronic acid, and dermatain sulfate
24
Q
lamina densa
A
lots of collagen type IV (globular)
25
GFB function?
barrier to both size and charge
type IV collagen in lamina densa size barrier
proteoglycans (heparine sulfate) is barrier to charge
26
LRI and LRE
composed of:
laminin - connect to basement membrane
heparan sulfate and hyaluronic acid - polyanionic charge barrier
27
reptation
snakelike motion of large protein through barrier
28
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
30
uriniferous tubules
stellate lumen
fuzzy microvilli border
acidophilic (mitochondria)
31
PCT?
proximal convoluted tubule
-in cortex forms at urinary pole
reabsorption** 70-80% of ultrafiltrate
-water, salt, amino acids, glucose, proteins
32
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
36
morphology of loop of henle
thin limbs
- simple squamous epithelium
- narrow lumen
37
descending loop of henle?
water and ions diffuse freely
| -water out, urea in
38
ascending loop of henle?
impermeable to water (lack of aquaporin)
NaCl pumped actively to medulla
-creates osmotic pressure drawing water into medullary space
39
countercurrent multiplier
in loop of henle
40
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
41
morphology of DST
cuboidal epithelium
-basolateral interdigitations
round smooth lumen
apically placed nuclei
numerous mitochondria
paler than PCT
42
DCT
only in cortex**
- returns to renal corpuscle of origin
- shorter than PCT
under influence of aldosterone
43
DCT function
under influence of aldosterone
- reabsorb Na
- secrete K
- reabsorb bicarbonate (secrete H)
- secrete ammonia
44
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
47
juxtaglomerular cells
modified smooth muscle of afferent arteriole
| -secrete enzyme renin
48
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
49
renin
angiotensinogase
secreted by JG celIs
50
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
52
medullary portion of collecting duct
site of concentration of urine
H2O lost to increasingly hypertonic medullary interstitium
ADH makes duct more permeable to water
53
action of ADH
makes collecting duct more permeability to water
54
medullary tissue
no glomeruli
| -only in cortex
55
ducts of bellini?
combination of collecting ducts in medulla
open at area cribosa of papilla
56
cells of collecting duct?
light cells - principle cells
| dark cells - intercalated cells
57
light cells
principle cells
in collecting duct
-involved in releasing water from tubule (through aquaporin channels)
58
dark cells
intercalated cells
in collecting duct
-alpha and beta
involved in controlling acid/base balance of urine
59
alpha dark cells?
secrete H+
60
beta dark cells?
secrete HCO3-
61
renal interstitium cells?
surrounding collecting duct:
- principal type I - produce vasodilators
- type II - phagocytic
- type III - function unknown
62
leukotriene
arachidonic acid derivative
| vasoconstrictor made in glomerulus
63
prostaglandins
arachidonic acid derivative
| vasodilator made in type I cells of collecting duct
64
what controls glomerular blood flow?
leukotrienes and prostaglandins
65
renal columns of bertin
cortex that extends into medulla between adjacent pyraminds
66
medullary rays
areas of medulla that go out to cortex
| -loop of henle, PSTs, DSTs, central collecting duct
67
extension of cortex into medulla
```
renal corpuscles
PCTs, DCTs
loops of henle
associated PSTs, DSTs
central collecting duct
```
68
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
```
71
interlobar artery
between pyramids
72
arcuate artery
arches over base of pyramid
73
interlobular artery
from arcuate branches to capsule
74
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
