kidney Flashcards

1
Q

what does urinary system consist of

A

kidneys
ureters
urinary bladder
urethra

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2
Q

describe what urinary system contributes to

A

excretion- elimination of waste products of metabolism - such as urea
regulation of total body water
regulation of electrolyte balance
endocrine secretion of renin (enzyme) and epo (hormone)- both released in blood stream = endocrine secretion

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3
Q

describe features of kidney

A

shape - bean shape
concave border - hilum, convex surface = see renal pelvis
renal pelvis = expanded portion of ureter
human kidney is divided in lobes and lobules

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4
Q

describe capsule of kidney

A

tough ct capsule

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5
Q

describe cortex of kidney

A

presence of small renal corpuscles and some tubules gives grainy appearance

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6
Q

describe medulla of kidney

A

striated due to presence of ducts

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7
Q

describe cortico-medullary junction of kidney

A

limit between cortex and medulla

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8
Q

describe medullary pyramids of kidney

A

base faces junction and tip = renal papilla

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9
Q

describe medullary rays of kidney

A

center of renal lobules

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10
Q

describe columns of bertin of kidney

A

interlobar cortical tissue and ct
between lobes, can find renal corpuscles

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11
Q

describe renal papilla and area cribrosa area of kidney

A

tip of pyramid = renal papilla and area cribrosa = means they are perforated, ~25 orifices - openings opens into
ma = major calyx and opens into mi = minor calyx - opens into renal pelvis

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12
Q

name 2 parts of uriniferous tubule

A

nephron
collecting system

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13
Q

describe nephron

A

each kidney has 1-4 mil
if less than 1 mil = renal insufficiency, need dialysis

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14
Q

name parts of uriniferous tubule

A

renal corpuscle
pct
loop of henle
dct

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15
Q

describe renal corpuscle (uriniferous tubule)

A

dilated portion of nephron which contains glomerular tuft of capillaries - in between 2 arterioles, afferent - thicker and efferent - drains all blood from corpuscle - glomerulus
double wall of epithelial cells enclosing glomerular tuft of capillaries

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16
Q

describe pct (uriniferous tubule)

A

proximal convoluted tubule
acidophilic
then becomes straight
thin then thick again - ascends in medulla

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17
Q

describe loop of henle (uriniferous tubule)

A

sd = thick descending limn - in medullary ray
tl = thin limb - in medulla
sa = thick ascending limb - in medulla and medullary ray
becomes dct

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18
Q

describe DCT (uriniferous tubule)

A

distal convoluted tubule
connected to collecting tubules in cortex
becomes collecting duct after junction - changes name
as approach area cribrosa = huge, called papillary ducts of Bellini - lower end, opens at level of area cribrosa

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19
Q

describe bowmans capsule (renal corpuscle)

A

2 layers =
Parietal = external, squamous cells, reticular fibers, BM
visceral = podocytes, processes interdigitating surrounding capillaries
visceral layer continous with parietal layer at vascular pole
capsular space= between layers

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20
Q

describe vascular pole (renal corpuscle)

A

entrance of arterioles - macula densa here
AA enters and divides into 5+ capillaries and EA leaves structure

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21
Q

describe macula densa (renal corpuscle)

A

appears in section, surrounded by cuboidal cells but near afferent = becomes columnar tight joined together

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22
Q

describe urinary pole (renal corpuscle)

A

part of dct
ultrafiltrate drained through pct

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23
Q

describe hydrostatic pressure (renal corpuscle)

A

Pressure of liquid agasint wall so high = plasma is filtered betwen processes of podocytes = ultrafiltrate in capsular space

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24
Q

describe afferent arteriole (renal corpuscle)

A

branches into 5-6 glomerular capillaries - joins or merges into efferent arteriole
1 layer sm cells seen near entrance, looks cuboidal near entrance
Specialized in secreting renin into blood stream - enzymes

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25
Q

describe capillaries (renal corpuscle)

A

highly fenestrated
rest on bm

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26
Q

describe podocyte

A

big nucleus, loose delicate chromatin
big primary processes
thin secondary processes = pedicels surrounds capillaries

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27
Q

describe BM (renal corpuscle)

A

bm shared by pedicels of podocytes and endothelial cells -similar to lung

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28
Q

describe mesangial cells

A

between adjacent capillaries (glomerular) and under bm
dark nucleus - can confused with endothelial cell

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29
Q

where are some of mesangial cells located

A

present between afferent and efferent arteriole and are outside renal corpuscle
called extraglomerular mesangial cells
have intra and extra glomerular mesangial cells

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30
Q

name 2 functions of mesangial cells

A

implicated in phagocytosis of particles, germs and bm
also implicated in structural support of capillaries
produce cytokines
complex cell with many functions

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31
Q

define mesangial cell

A

mesos = middle and angeion = vessel
located between blood vessels, intra and extra glomerular and under bm

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32
Q

describe what mesangial cells are believed to do

A

remove pieces of bm that are already clogged with stuff = sends small processes and removes areas where bm has already filtered and then endothelial cells and pedicles make new bm
for efficient filtration

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33
Q

what is plasma filtered through

A

openings - slits

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34
Q

describe filtration slits

A

25nm - extremely small gap
note presence of diaphragms = between 2 adjacent pedicels, closed by small diaphragm
negatively charged proteins and proteins greater than albumin, 70,000mw do not pass these pores
if see many proteins = proteineuria = bad

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35
Q

describe medullary ray

A

straight thick ascending and descending limbs and collecting tubules

36
Q

describe PCT in detail

A

60um - cortex
brushborder microvilli - absorption of 85% of proteins, glucose, na, cl,ca and fluids - reabsorbed from ultrafiltrate
apical layer has microvilii - increases absorptive surface
called microvilli in em and brush/striated border in lm

brushborder = can see actin filaments cut in cross section

37
Q

what does pct secrete

A

creatinine into lumen

38
Q

describe PM of pct

A

central nuclei
cells columnar
rest on bm
acidophilic
folded pm resting on bm = inside folds = mitochondria - cells very active

39
Q

describe filtrate of pct

A

ultrafiltrate is isotonic anyways = wont change osmolarity since passive movement of water and ions across apical membrance
folloed by active resabsorption across basolateral membrane via na/k/atpase pump
pump creates gradient
solutes reabsorbed isotonically = osmotic potential of fluid leaving pct is same of initial glomerular filtrate

40
Q

what does pct have

A

prominent endocytic apparatus
for endocytosis

41
Q

desribe thin limb

A

12um - medulla
easy to confused with capillaries
empty lumen
flat/squamous cells, rest on bm
permits free diffusion of water
thin descending limb permeable to water but entire ascending limb is not - impermeable to water

42
Q

describe dct - specifics

A

60um - cortex
cuboidal cell
apical nuclei - almost kissing
larger lumen than pct
infoldings of pm with many mitochondria
na/k atpase = creates gradient out, water out= active pump
basal laterla pm has pump

43
Q

describe dct - secretions

A

few microvilli
absorbs na and secretes k
also secrets protons into lumen - H+ and absorb bicarb or vice versa
site of aldosterone action - regulates absorption of sodium by pump - secreted by adrenals and stimulates incorporation of na and cl

44
Q

what is also expressed in dct

A

a arginine vasopressin receptor 2

45
Q

describe uniporter, symporter and antiporter

A

uni = one molecule one dir
symporter = 2 molecules, same dir
anti = 2 molecules, opp dir

46
Q

describe loop of henle SD

A

thick descending limb
found in medullary rays and upper part of medulla - similar to pct
terminal part of pct but structure will be straight

47
Q

describe loop of henle TL

A

found in medulla

48
Q

describe loop of henle SA

A

found in medulla and medullary rays
similar to dct
ascending limb
longitudinal section in medullary rays

49
Q

describe permeability of loop of henle

A

descending = permeable to water
ascending= impermeable to water

upper cortex/medulla = less concentrated in sodium
near area cribrosa = highly concentrated in sodium
ions actively penetrate into inner tissue of medulla

50
Q

describe permeability of loop of henle - to solutes

A

Permeable to solutes but na, cl, k are actively transported into medullary space, making filtrate hypotonic and medulla hypertonic

51
Q

describe collecting tubule

A

40-50um diameter
found in cortex and medullary rays
cells cuboidal
pale stain
cells bulge into lumen
similar to dct but nuclei are more central
sometimes see lateral pm since membrane thick - visible with lm

52
Q

describe collecting duct

A

aka collecting duct of Bellini
200um
large
closer to area cribrosa
papillary
impermeable to water
site of adh action

53
Q

describe ADH

A

antidiuretic hormone
vasopressin
makes collecting ducts permeable to water and water is retained
produced by pituitary gland

54
Q

describe ADH effect when exercise

A

hot and sweat a lot, urine concentrated, adh secreted, water retained

55
Q

describe ADH effect when hypertonic tissue of kidney

A

adh will make it permeable and water will escape from collecting tubule and urine more concentrated

56
Q

name parts of juxtaglomerular apparatus

A

juxtaglomerular cells
macula densa
extraglomerular mesangial cells - not shown

57
Q

describe juxtaglomerular cells of juxtaglomerular apparatus

A

secretes renin - enzyme
Modified smooth muscle cell of afferent arteriole = become kinda cuboidal cell, epithelial cell and are called juxtaglomerular cells

58
Q

what do juxtaglomerular cells do

A

secrete renin - produced by juxtaglomerular cells in kidney
enzyme acts on plasma angiotensin - liver protein

59
Q

describe conversion of angiotensin

A

angiotensin –> (10aa) angiotensin 1 –> angiotensin 2 (8aa)

first arrow = enzyme that removes some aa’s and converts
second arrow= endothelial cell, removes 2 aa’s = octapeptide

60
Q

describe macula dense - production of factors

A

composed of specialized epithelial cells in the DCT that detects sodium concentration of fluid in tubule
these cells are also involved in production of nitric oxide (NO) & other factors

61
Q

describe angiotensin 2

A

stimulates contraction of arterioles and increases blood pressure and stimulates production of aldosterone - by adrenal glands, acts on dct, water & sodium retained= more fluid in blood = higher bp

62
Q

describe pathway of blood supply - 1

A

renal artery and vein
hilum = entrance of renal artery (branches) and exit of renal vein
renal artery branches around renal pyramids - small cones

63
Q

describe pathway of blood supply - 2

A

interlobular artery and vein (vein - in opposite direction)
interlobular space
forms elbow

64
Q

describe pathway of blood supply - 3

A

arcuate artery and vein - located in corticomedullary junctions

65
Q

describe pathway of blood supply - 4

A

lobular artery and vein
straight artery then afferent arteriole going to renal corpuscle

66
Q

where are arcuate arteries and veins located

A

corticomedullar junction

67
Q

what merges into efferent arteriole

A

afferent then glomerular capillaries and then will merge into efferent arteriole=forms capillaries

68
Q

describe pathway of blood supply - 5

A

afferent arteriole

69
Q

describe pathway of blood supply - 6

A

efferent arteriole - forms peritubular capillaries

70
Q

describe pathway of blood supply - 7

A

peritubular capillaries
provides blood and oxygen and nutrients to pct and dct
capillary network in cortex
drains into venules and then lobular veins

71
Q

describe pathway of blood supply - 8

A

under capsule there is also a capillary network that together with peritubular capillaries drain into stellate veins
Lobular arteriole will form network under capsule = subcapsular capillary network at end of lobular arteriole = drain into veins = stellate veins
stellate also drains into lobular arteries

72
Q

what does stellate mean

A

looks like stars

73
Q

describe pathway of blood supply - 9

A

lobular veins
then arcuate vein then interlobar then renal vein
opposite way

74
Q

describe erythropoietin

A

produced by peritubular capillaries - cells of cortex and outer medulla, most likely endothelial
glycoprotein that promotes proliferation and differentiation of erythrocyte precursors
major site epo production = kidney while liver is main extra renal site of epo production
if high altitudes = more epo so more rbcs
recombinant epo = bad in sports

75
Q

what is close to cm junction and medulla and renal corpuscles

A

juxtamedullary renal corpuscles - close to medulla

76
Q

describe vasa recta

A

capillaries that emerge from efferent arterioles of juxtamedullary renal corpuscles and drain into arcuate veins

forms long capillary that will turn = called vasa recta - seen near collecting ducts of bellini
also forms loops and goes parallel to vasa recta of nephrons

77
Q

where are vasa recta seen

A

in cross section of medulla

78
Q

describe concentration of sodium in medulla

A

high concentration

79
Q

describe permeability of CD - collecting duct

A

Normally the cd are impermeable to water

80
Q

lots of hypertonic material

A

vasopressin makes the cd permeable to water

81
Q

name layers of urinary bladder

A

mucosa
submucosa
tunica muscularis

82
Q

describe mucosa of urinary bladder

A

transitional epithelium
lp is loose ct - small

83
Q

describe submucosa of urinary bladder

A

denser with collagen and elastic fibers

84
Q

describe tunica muscularis of urinary bladder

A

at entrance of ureter has =
inner longitudinal
middle circular
outer longitudinal
cannot see but must know

85
Q

describe transitional epithelium

A

basal columnar cells
middle polygonal cells
superficial facet cells = bulging and apical, prominent apical pm and granulations
similar to strat squa non kera but this gas dome cells
when distended = number of layers decrease = stretched out