Chap 20- The Kidney Flashcards
1
Q
where is the kidney located?
A
- either side of vertebrae in retroperitoneal space
- positioning protects it from trauma and has a cushion of fat arround it
2
Q
what are the layers of the kidney?
A
- capsule- covering
- cortex- outer layer, contains glomeruli and portions of tubules, gets the most BF -> reabsorbing function
- medulla- inner later
3
Q
what is the nephron?
A
- functional unit of kidney
- cortical nephron
- juxtamedullary nephron
4
Q
what is the cortical nephron?
A
- located mostly in cortex
- 85% of all nephrons in kidney
- mostly help in excretory and secretory functions
5
Q
what is the juxtamedullary nephron?
A
- boarder between cortex and medulla
- parts go deep into the medulla
- helps with urine concentration
6
Q
what is the renal hilum
A
- opening in the kidney
- where the renal artery and nerves enter
- renal vein and ureter exit
7
Q
what is the renal sinus
A
- cavity within the kidney which is occupied by the renal pelvis
- where all the different parts of the kidney are located
8
Q
what are calyces (calyx)
A
tubes through which urine drains into the renal pelvis
9
Q
parts of the nephron
A
- glomerulus
- proximal convoluted tubule
- descending and ascending loops of henle
- distal convulted tubule
- collecting duct
10
Q
what is the glomerulus?
A
- cluster of capillaries
- plasma filtered from capillaries bowman’s capsule
11
Q
what is the bowman’s capsule?
A
- double layered, cup shaped membrane that receives plasma from glomerulus
- filters plasma except proteins and cells
12
Q
what is the main job of the proximal convoluted tubule?
A
- reabsorb most of the filtered load
13
Q
what is the main job of the loop of henle?
A
concentrate urine
14
Q
what is the main job of the distal convoluted tubule?
A
reabsorb sodium and water
15
Q
what is the main job of the collecting duct?
A
collect urine for excretion
16
Q
ureter
A
transports urine from calyces to bladder
17
Q
bladder
A
muscular structure that serves as reservoir for urine until it can be excreted
18
Q
urethra
A
transports urine from bladder to urinary meatus
19
Q
what is the difference in the urethra in men and women?
A
- men have much longer urethra
- shorter length in women is why they are more likely to get UTI
- also more likely to get UTI due to seated position during urination
20
Q
functions of the kindey
A
- Excretion of metabolic wast products
- excretion of foreign chemicals
- hormone synthesis, metabolism and excretion
- regulate pH
- regulate arterial pressure
- regulate water and electroyle imbalance
- gluconeogenesis
21
Q
what is gluconeogenesis?
A
new production of glucose from alternate sources like AA
22
Q
how is urine formed?
A
- glomerular filtration
- tubular reabsorption
- tubular secretion
23
Q
what is the equation for urinary excretion rate?
A
filtration rate - reabsorption rate + secretion rate
24
Q
filtration of urine
A
- non selective process, filters everything except proteins and blood cells
- helps immediately remove toxins
- about 20% of renal plasma flow
25
reabsorption of urine
- highly variable and selective
- depends on the body's needs
- most electrolytes and nutritional substances are almost completely reabsorbed
26
secretion of urine
- highly variable
| - important for rapidly excreting some waste products, foreign substances, and toxins
27
what is normal GFR?
~ 125 mL/min
- rate at which plasma is filtered
- is directly related to perfusion pressure of glomerular capillaries maintained between 80-180 mmHg
28
where does urine formation begin?
large amounts of fluid flowing through glomerular capillaries into Bowman's capsule
29
glomerular filtration barriers
- endothelium of the capillary
- basement membrane
- layer of epithelial cells (podocytes)
- all layers have negative charges and provide barrier to filtration of plasma proteins (proteins also neg charge)
30
endothelium of capillary
- have multiple holes called fenestrae
| - allows passage of fluid through them
31
basement membrane
- type of ECM
- made of collagen and proteoglycan that have large spaces through which large amounts of water and small solutes can filter
32
podocytes
- epithelial cells with foot-like processes
| - foot processes separated by caps called slit pores through which glomerular filtrate moves
33
determinants of GFR
- glomerular hydrostatic pressure
| - glomerular capillary colloid osmotic pressure
34
vasoconstrictors that control GFR
- NE
- E
- endothelin
- call cause a reduction in GFR
35
vasodilators that control GFR
- endothelial- derived NO
- prostaglandins
- all cause increase in GFR
36
how does angiotensin II effect GFR?
- prevents GFR from reducing
- selectively constricts outgoing arteriole
- constriction prevents GFR from falling
37
autoregulation of GFR
- feedback mechanisms intrinsic to kidneys
- normally keep renal BF and GFR constant despite changes in arterial blood pressure
- types- myogenic and tubuloglomerular feedback
38
myogenic feedback
- resistance to increase in arterial pressure
- increase in arterial pressure will stretch vessel
- stretch is opposed by contraction of vascular smooth muscle cells due to Ca
- stretch neutralized by vascular SMC contraction
39
what is the macula densa?
- specialized group of endothelial cells in distal tubule
- sodium sensor
- secrete renin
40
what is the juxtaglomerular complex?
macula densa and juxtaglomerular cells
41
how do you calculate GFR?
GFR= Cinsulin = (Uin X V)/ Pin
| - Cinsulin- clearance of insulin
42
how to use Cinulin to determine GFR
- if Cx < Cin indicates reabsorption of molecule x
| - if Cx > Cin indicates secretion of molecule x
43
reabsorption of different solutes
- glucose and AA- completely reabsorbed
- Ions like Na, Cl, HCO2- variable reabsorption depending on needs
- waste products like urea and creatinine- poorly reabsorbed
44
how are water and solutes transported through cell membranes?
- through transceulluar route
- through spaces between cell junctions called paracellular route
- once moved into interstitial fluid, transported into blood
- some substances secreted into tubules by secondary active transport with couter-transport
45
what is counter tranposrt
- energy greated from downhill movement of one substance enables uphill movement of second substance in opposite direction
- i.e. hydrogen ion secretion coupled with Na reabsorption in luminal membrane
46
clearance
- rate at which substances are removed/ cleared from plasma
47
renal clearance
- volume of plasma completely cleared of substance per minute of kidneys
- if clearance = GFR then cleared at same rate
48
formation of dilute urine
- continue electrolyte reabsorption
- decrease water reabsorption
- mechanism: decreased ADH release and reduced water permeability in distal and collecting tubules
49
formation of concentrated urine
- continue electrolyte reabsorption
- increase water reabsorption
- mechanism- increase ADH release -> increases water permeability, high osmolarity of renal medulla, countercurrent flow of tubular fluid
50
what is not in normal urine?
- no protein
- no RBC
- no heme
- no cellular casts
- no fat
- no sugar
51
Azotemia
- biochemical manifestation of acute or chronic kidney injury
- elevated BUN
- elevated SCr
- reduced GFR
52
nephrotic syndrome
- injury to glomerulus that causes abnormal filtration
- excessively permeable to proteins
- heavy proteinuria
- hypoalbuminemia
- edema
- hyperlipidemia and lipiduria
53
nephritic syndrome
- inflammation of nephron
- hematuria
- azotemia
- HTN
- sub-nephrotic proteinuria
54
what does asymptomatic hematuria or proteinuria indicate?
- mild glomerular abnormablities
| - can be reversible
55
acute kidney injury
- rapid drop in GFR
- dysregulation of fluid and electrolyte balance
- oligouria or anuria
56
chronic kidney disease
- GFR persistently <60 mL/min for at least 3 months
- can be from any cause
- and/or persistent albuminuria
57
renal tubular defects
- problem with proximal or distal tubules
| - lead to nocturia, polyuria and electrolyte imbalances
58
urinary tract obstruction
- bateriuria
| - pyuria- pus in urine
59
nephrolithiasis
- kidney stones
- spasms of severe pain that spreads to inner thigh
- often have recurrent stone formation
60
what is the GFR in renal insufficiency?
- 20-30% of normal GFR
| - ~ 37.5 mL/min
61
what is the GFR in renal failure?
- 10-25% of normal GFR
| - less than 37 mL/min
62
what is the pathogenesis of most glomerular injury?
- usually immune related
- injury can be from antibodies in situ or deposited antigen-antibody complexes
- other causes are viruses, drugs, toxins, systemic/ vascular diseases
63
why does edema occur in nephrotic syndrome?
- low serum albumin -> low oncotic pressure
| - increased Na retention
64
complications of nephrotic syndrome
- infection and sepsis due to excessive loss of anitbodies
- thrombosis
- AKI
- end state renal disease if proteinuria not controlled
65
symptoms of nephrotic syndrome
- fatigue
- frothy urine
- anorexia
- N/V
- abdominal pain
- weight gain due to fluid retention
- SOB from pleural effusion
- signs and sx of DVT/ PE
66
glomerular diseases that present as nephrotic syndrome
- minimal change disease
- focal segmental glomerulosclerosis
- membranous nephropathy
67
minimal change disease
- under normal light microscope see no change
- under electron microscope see thinning of podocytes
- main cause of nephrotic syndrome in kids <10
- very responsive to steroids
- primary cause idiopathic
68
focal segmental glomerulosclerosis
- common cause of nephrotic syndrome in adults
- only effects some glomeruli
- only some of the affected glomeruli undergo sclerosis
- primary cause is idiopathic
69
membranous nephropathy
- most common cause of nephrotic syndrome in elderly
- slowly dev sx
- basement membrane becomes thick due to immune complex deposition
- high incidence of renal vein thrombosis, PE, and DVT
- primary cause is idiopathic
70
other causes of nephrotic syndrome
- diabetes mellitus
- amyloidosis
- IgA nephropathy
71
targets of nephritic syndrome
- glomerular endothelium
- glomerular basement membrane
- glomerular mesangium
72
post streptococcal glomerulonephritis (PSGN)
- occurs a few weeks after strep infection
- hematuria
- serum has anti-streptolysin (ASO) titer
- low C3
- due to deposition of antigen-antibody complex with proteins from infection
73
IgA nephropathy (berger disease)
- most common primary glomerular nephritis in dev countries
- present with dark urine 1-3 days after URT infection
- can progress to end stage renal disease if untreated
- dx- abnormal deposition of IgA in glomeruli that cause inflammation
74
chronic glomerulonephritis
- end stage glomerular disease
- irreversible damage
- glomerular and tubulointerstitial fibrosis
- reduced GFR
- uremia
75
diabetic nephropathy
- 2nd cause of death from diabetes
- characterized by glomerular lesions, renal vascular lesions, and pyelophritis
- basement membrane thickening
- atherosclerosis
- earliest manifestation is microalbuminuria
76
acute tubular injury/necrosis (ATI/ ATN)
- most common cause of AKI
- cause- ischemia
- can be due to endogenous or exogenous substances
77
pathogenesis of ATI/ ATN
- tubular injury
- cells lining tubules die
- release cytokines -> inflammation
- dead cells are excreted or block lumen
- blocked tubule will cause back flow of urine
- causes reduced GFR
78
Ischemic type ATI/ ATN
- tubular necrosis is patchy
| - lumen of DCT and CD contain casts
79
toxic acute tubular injury
- extensive necrosis is continuous
| - lumens of DCT and CD contain casts
80
pyelonephritis and UTI
- valve between ureter and urinary bladder fails
| - infectious agent colonizes in urethra, then bladder, then kidney
81
why are females more likely to develope UTI?
- shorter urethra
- seated position = increased chance of urine stagnation
- urethra can be damaged during sexual intercourse
- don't have prostatic secretions as protective agents
82
risk factors for UTI
- female sex
- immunosuppression
- indwelling catheters
- diabetes mellitus
- urinary tract obstruction
83
clinical features of pyelonephritis
- sudden onset of pain
- systemic evidence of infection
- dysuria, frequency, and urgency
- pyuria
84
complications of pyelonephritis
- renal abscess
- recurent infection -> chronic pyelonephritis
- papillary necrosis
85
chronic pyelonephritis
- chronic tubulointerstital inflammation
- scarring of calyces and pelvis
- one of only diseases that involves renal calyx
- most common cause- congenital lower urinary tract abnormalities
86
renal artery stenosis
- narrowing of renal artery
- important cause of secondary HTN
- HTN is due to increased production of renin from the ischemic kidney
- clinical course similar to essential HTN
87
autosomal dominant polycystic kidney disease
- adult onset
- multiple cysts in kidneys that cause destruction of parenchyma and eventual renal failure
- due to mutation on PKD1 or PKD2 genes
88
clinical course of autosomal dominant polycystic kidney disease
- asymptomatic for years
- tubular epithelial cells grow excessively and have differentiation problems
- cysts form which can cause glomerular damage, vascular damage, inflammation and pain
- kidneys become enlarged
89
autosomal recessive polycystic kidney disease
- childhood onset
- can be either perinatal, neonatal, infantile, or juvenile
- due to mutation in PKHD1 gene which encodes for fibrocystin
- manifestation is same as adults
- likely will also have congenital hepatic fibrosis
90
urolithiasis
- aka kidney stones
| - caused by increased urinary concentration of stone constituents
91
influencing factors for kidney stone formation
- increased concentration of stone constituents
- change in urinary pH
- decreased urine volume
- presence of bacteria
92
types of kidney stones
- Calcium
- triple stones made of magnesium ammonium phosphate
- uric acid stones
- cysteine stones
93
renal cell carinoma
- most common malignant tumor of kidney
| - very strongly associated with smoking, elderly, obesity
94
clinical course of renal cell carcinoma
- costovertebral pain
- palpable mass
- hematuria
- abnormal hormone production
- widely metastasize- lungs and bones first
