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pathophysiology ii exam 2 renal > Renal Module I > Flashcards

Renal Module I Flashcards

1
Q

What space are the kidneys located?

A

Retroperitoneal

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2
Q

Which kidney is slightly lower?

A

right kidney (due to liver)

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3
Q

What are the kidneys protected by?

A

Posterior wall muscles and ribs

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4
Q

Approximately what are the measurements of the kidneys?

A

4-5 inches long, 2 inches tall

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5
Q

What arteries supply kidneys?

A

R/L renal arteries

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6
Q

How many liters of blood do the kidneys receive per minute? This accounts for how much of the cardiac input?

A

~1-1.25 L/min (20-25% cardiac output)

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7
Q

What is the dense connective tissue that surrounds the kidneys?

A

Renal capsule (fibrous capsule)

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8
Q

What is the layer of fat that provides shock absorption in the kidneys?

A

Renal fat pad

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9
Q

What is the connective tissue layer that surrounds the renal pad?

A

Renal fascia

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10
Q

What is a common symptom of many urinary tract diseases?

A

Flank pain/CVA tenderness

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11
Q

What causes flank pain?

A

Distention of the renal capsule, renal pelvis, and ureter

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12
Q

What causes “higher” flank patterns when compared to ureter pathology?

A

Kidney pathology

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13
Q

Severity of flank pain is directly related to what? What is it nor directly related to?

A

Directly related to speed of onset (but not degree of distention)

Ex. small kidney stone lodged in the ureter causes more pain than a slow growing, large tumor that distends the ureter

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14
Q

What is the outer region of the kidney that contains the nephrons?

A

Renal cortex

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15
Q

What is the inner region of the kidney that consists of renal columns and pyramids?

A

Renal medulla

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16
Q

What are the spaces located between each renal pyramid that contain nephrons?

A

Renal columns

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17
Q

What are the triangular shaped spaces that contain nephritic tubules (loop of Henle) and collecting ducts?

A

Renal pyramids

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18
Q

Where do the renal pyramids descend to?

A

The renal papilla (apex of the pyramids)

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19
Q

What is the urine pathway?

A

Flows from: Collecting ducts in the renal papilla (apex) -> minor calyce-> major calyce -> renal pelvis -> ureter
-> bladder

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20
Q

What do the calyces, renal pelvis, and ureters contain to facilitate the flow of urine into the bladder?

A

Smooth muscle

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21
Q

What is a ureteral stent (ureteric stent)?

A

Thin tube inserted into ureter to prevent or treat urine obstruction

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22
Q

Indications for a ureteral stent?

A

-Bilateral ureteral obstruction
-Obstruction of solitary functioning kidney
-Ureteric injury
-Post treatment of urolithiasis in pts w/ solitary kidney

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23
Q

When is pre-surgical ureteral stenting used?

A

Prophylactically in case of injury to ureter during surgery

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24
Q

What is considered the functional unit of the kidney?

A

Nephrons

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25
Q

How many nephrons per kidney?

A

1.2 million

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26
Q

What is the role of nephrons?

A

Formation of urine

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27
Q

Structures of nephrons?

A

-Renal corpuscle
-Glomerulus
-Bowman’s capsule/space
-Proximal convoluted tubule
-Loop of Henle
-Distal convoluted tubule
-Collecting duct

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28
Q

What are the two types of nephrons?

A

Cortical and juxtamedullary

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29
Q

What percentage of nephrons are cortical?

A

85%

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30
Q

Cortical nephrons extend partially into what structure?

A

Medulla

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31
Q

What are cortical nephrons responsible for?

A

Filtration, absorption, secretion, and excretion

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32
Q

What percentage of nephrons are juxtamedullary?

A

15%

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33
Q

Juxtamedullary nephrons extend deep into what structure?

A

Medulla

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34
Q

What structures make up the renal corpuscle?

A

Glomerulus, Bowman’s capsule

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35
Q

What are juxtamedullary nephrons responsible for?

A

Urine concentration, filtration, absorption, secretion, and excretion

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36
Q

“Capillaries from renal circulation that extend into Bowman’s capsule/space” describes what structure?

A

Glomerulus

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36
Q

What structures make up the renal corpuscle?

A

Glomerulus, Bowman’s capsule

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37
Q

What is Bowman’s capsule?

A

The first section of the nephron (entrance point)

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38
Q

The renal corpuscle is the site of what?

A

Filtration

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39
Q

Blood enters the glomerulus through what?

A

Afferent arteriole

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40
Q

Blood is filtered where?

A

Glomerulus

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41
Q

Plasma is filtered through what structure before entering Bowman’s capsule? What is blood known as when it reaches Bowman’s capsule?

A

Passes through glomerular filtration membrane,
Blood is known as filtrate

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42
Q

What happens to blood that is not filtered by the renal corpuscle?

A

Exits glomerulus through efferent arteriole

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43
Q

What serves as the “filter for the nephron”?

A

Glomerular filtration membrane

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44
Q

What is the glomerular filtration membrane formed by?

A

Walls of both the glomerular capillary and Bowman’s capsule

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45
Q

What are the three layers of the glomerular filtration membrane?

A

-Fenestrated endothelium of the capillary
-Glomerular basement membrane (GBM) of the capillary
-Podocytes formed by the epithelium of Bowman’s capsule

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46
Q

What does the term mesangium (in the context of glomerular mesangial cells) refer to?

A

Space between the glomerular capillaries

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47
Q

Where are the glomerular mesangial cells located?

A

Centrally in space between glomerular capillaries

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47
Q

What structures make up the renal corpuscle?

A

Glomerulus, Bowman’s capsule

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48
Q

What do glomerular mesangial cells consist of?

A

Matrix of smooth muscle cells and phagocytic cells

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49
Q

Function of glomerular mesangial cells?

A

Contraction/relaxation to regulate filtration by altering surface area of glomerular filtration membrane & phagocytic removal of macromolecules

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50
Q

What is the proximal convoluted tubule (PCT) a continuation of?

A

Bowman’s capsule

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51
Q

What is the PCT?

A

Single layer of simple cuboidal cells w/ microvilli that line the lumen wall

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52
Q

What do the microvilli of the PCT provide?

A

Large surface area for reabsorption/secretion (form a brush border similar to small intestine)

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53
Q

Function of the PCT?

A

Reabsorb most of the filtrate (60-95%) & secrete some drugs and meds (antibiotics, ACE-I, many other metabolic byproducts)

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54
Q

What is the loop of Henle formed by?

A

Descending limb and ascending limb-and its sub region known as the thick ascending limb (TAL)

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55
Q

Where is the juxtaglomerular apparatus (JGA) located?

A

Where the distal convoluted tubule passes by the glomerular arterioles

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56
Q

What is the role of the juxtaglomerular apparatus (JGA)?

A

Regulation of renal blood flow, glomerular filtration, and renin secretion

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57
Q

What kind of cells are in the juxtaglomerular apparatus (JGA)?

A

juxtaglomerular cells, mesangial cells, macula densa

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58
Q

What are juxtaglomerular cells in the JGA?

A

granular cells located adjacent to the afferent glomerular arteriole

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59
Q

What are mesangial cells in the JGA?

A

Continuation of mesangial cells from glomerulus

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60
Q

What are the macula densa of the JGA?

A

Specialized receptor cells located in the distal convoluted tubule that monitor sodium-chloride concentration of filtrate flowing through the nephron

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61
Q

What structures make up the renal corpuscle?

A

Glomerulus, Bowman’s capsule

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61
Q

What are the borders of the distal convoluted tubule?

A

Begin at macula densa, end at connection to collecting duct

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62
Q

What makes up the epithelium of the distal convoluted tubule?

A

Simple cuboidal cells w/ fewer microvilli than PCT cells

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63
Q

How is the distal convoluted tubule divided?

A

Functionally- into early DCT and late DCT

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64
Q

What is the function of the early DCT?

A

Continues to dilute filtrate, reabsorbs sodium

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65
Q

What is the function of the late DCT?

A

Begins to concentrate fluid as it enters the collecting duct

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66
Q

Numerous collecting ducts are found where?

A

In each renal pyramid

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67
Q

Each collecting duct will descend to the _____ and drain into the _____?

A

descend to renal papilla, drain into minor callyces

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68
Q

How many nephrons drain into each collecting duct?

A

Several

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69
Q

As the collecting ducts descend they merge to form about 30 ducts that open where?

A

Renal papilla

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70
Q

Epithelium of the collecting duct? What is the epithelium’s important role?

A

Simple squamous epithelium line the collecting ducts
Role: final fine tuning of urine concentration/water reabsorption, and urine dilution

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71
Q

Which filtration layer is a capillary wall with microscopic openings?

A

Fenestrated endothelium of the capillary

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72
Q

Openings in the fenestrated endothelium of the capillary are about how big?

A

60-80 nm

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73
Q

How large is a RBC?

A

8,000 nm

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74
Q

How large is a WBC?

A

8,000-15,000 nm

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75
Q

How large are most plasma proteins?

A

> or = 60 nm

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76
Q

The fenestrated endothelium layer of the capillary blocks what from passing?

A

Blood cells and some proteins (too large to fit through openings), but allows all other material to pass (small enough to fit through openings)

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77
Q

The fenestrated endothelium of the capillary has what charge? What lipoprotein lines the endothelium?

A

negative
lipoprotein glycocalyx is negatively charged- small molecules that can fit through the openings may be repelled/prevented from passing (charge acts as a push back to acid in filtration)

78
Q

Which filtration layer is a thin gel layer of collagen and other proteins (proteogycans, glycoproteins) that sits between the glomerular capillary wall and podocytes?

A

Glomerular basement membrane (GBM)

79
Q

What are the three sub-layers of the GBM?

A

-inner/outer layers with negative charge
-middle layer made of collagen matrix
-spaces between collagen matrix creates ~10nm “pores”

79
Q

What structures make up the renal corpuscle?

A

Glomerulus, Bowman’s capsule

80
Q

How does the GBM potentially filter molecules?

A

Pore size (blocks molecules >7-10nm)
Polarity (negative layer charge repels smaller molecules that are negatively charged)

81
Q

Epithelium of bowman’s capsule?

A

Podocytes w/ “foot-like” projections (that are negatively charged)

82
Q

The foot like projections of podocytes wrap around what structure? What does this create?

A

Wrap around capillaries, creates matrix of ~40nm filtration slits/openings (also contain slit diaphragm/SD)

83
Q

What is a slit diaphragm?

A

A layer formed by complex arrangement of micro-proteins (critical role in final ultrafiltration of plasma)

84
Q

What structures make up the renal corpuscle?

A

Glomerulus, Bowman’s capsule

84
Q

What is proteinuria?

A

Damage to the podocytes/slit diaphragms allowing for excess albumin & other plasma proteins to flow into the nephron

85
Q

How do plasma proteins circulate?

A

In negatively charged lipoprotein packages

86
Q

Plasma proteins?

A

Bilirubin, hemoglobin, albumin, immunoglobulins, fibrinogen

87
Q

Can most plasma proteins and lipoprotein molecules pass through fenestrated openings (60-80nm) and the GBM (~10nm)?

A

No, most are too large to pass

88
Q

Which plasma proteins are able to pass through openings/filtration?

A

Albumin (due to shape), and some other smaller proteins

89
Q

Some albumin passes through the filtration membranes to the nephron while the rest is repelled by what?

A

Negative polarity

90
Q

Why cant unconjugated bilirubin pass through the kidney if it is 1nm in size/able to fit?

A

Unconjugated bilirubin is not soluble in water, and cannot be renally excreted (needs to be bound to albumin to be soluble)

91
Q

How do fats circulate?

A

Attached to protein carrier as negatively charged protein packages

92
Q

Lipoprotein sizes?

A

HDL ~ 8-13 nm
LDL ~ 18-23 nm
VLDL ~ 30-80 nm
chylomicrons ~ 75-1200 nm

93
Q

Why are smaller lipoproteins repelled by the GBM & filtration slits?

A

negative charge

94
Q

Pathology of what kidney structures will result in blood cells, proteins, or other substances to pass into urine?

A

-Glomerular capillary
-GBM
-Podocytes

95
Q

Clinical meaning of proteinuria?

A

Excess level of proteins in urine, “foamy pee”
(damage to podocytes lets excess albumin pass into nephron)

96
Q

Clinical meaning of hematuria? What leads to hematuria?

A

Any condition where blood is found in the urine
–> inflammatory pathology/damage to capillary wall or GBM will lead to hematuria

97
Q

Are nephrotic and nephritic syndromes a specific pathology/disease?

A

No, generally represent lab findings associated with different renal pathologies/diseases

98
Q

What structures make up the renal corpuscle?

A

Glomerulus, Bowman’s capsule

98
Q

What does nephritic syndrome refer to?

A

Renal pathology that leads to hematuria as the primary finding
*inflammation/damage to GBM/capillary wall

99
Q

What does nephrotic syndrome refer to?

A

Renal pathology that leads to proteinuria (albumin) as the primary finding
*damage to podocytes

100
Q

Clinical findings with nephrotic syndrome?

A

-Proteinuria >3 g/d (protein/albumin in urine is diagnostic)
-Hypoalbuminemia (low plasma albumin due to renal loss), edema as a result of altered albumin levels in the blood
-Lipiduria: hyperlipidemia leads to lipids in the urine

101
Q

Clinical findings with nephritic syndrome?

A

-Hematuria (microscopic or gross)
-Red blood cell casts (tiny particles of RBCs found w/ microscope)
-Proteinuria (mild to moderate: 1-3 g/d)
-Oliguria: reduced urine production

102
Q

What is minimal change disease (MCD)?

A

Damage to podocytes/foot projections by “effacement” or “fusion” that is difficult to see on light microscopy due to minimal changes

*aka podocyte foot processes disease

can be primary/idiopathic or have secondary causes

103
Q

Minimal change disease (MCD) is associated with what?

A

Nephrotic syndrome

104
Q

What is focal segmental glomerulosclerosis (FSGS)?

A

Segments of sclerosis in the glomeruli that can display alterations to the mesangial cells and/or loss (“effacement”) of podocyte foot processes

Can have primary or secondary causes

105
Q

Segmental glomerulosclerosis (FSGS) is associated with what?

A

Nephrotic syndrome

106
Q

What is Mesangiocapillary glomerulonephritis (MCGN) aka membranoproliferative GN (MPGN)?

A

Thickening of the mesangial matrix and glomerular capillary walls due to immune complex deposits and/or compliment factors —> all leading to abnormal GBM formation

107
Q

Mesangiocapillary glomerulonephritis (MCGN) is related to what?

A

Both nephrotic and nephritic syndrome

108
Q

What is anti-GBM disease (Goodpasture’s disease)?

A

Rare autoimmune disorder that affects kidneys and lungs
–> attacks glomeruli capillaries (&alveolar capillaries), damaging GBM

**Can be fatal if not treated

109
Q

Anti-GBM (Goodpasture’s disease) is associated with what?

A

Nephritic syndrome

110
Q

Blood flows from the descending aorta to which structures of the kidneys?

A

R/L renal arteries

111
Q

What structures make up the renal corpuscle?

A

Glomerulus, Bowman’s capsule

111
Q

From the R/L renal arteries, multiple branches eventually bring the blood into what?

A

Afferent glomerular arterioles of the nephrons

112
Q

Blood is filtered where in the nephrons?

A

Glomerular capillary beds

113
Q

After being filtered in the glomerular capillary beds, blood flows out via what?

A

The efferent glomerular arteriole and enters the peritubular capillaries & vasa recta

114
Q

From the peritubular capillaries and vasa recta, blood flows where?

A

Into venous return

115
Q

What is the role of the afferent arteriole?

A

Regulates blood entering glomerular capillary bed: constriction or dilation alters filtration

116
Q

What is the role of the efferent arteriole?

A

Regulates blood leaving glomerular capillary bed: constriction or dilation alters filtration

117
Q

Renal circulation pressure of the glomerular capillaries?

A

Relatively high to encourage filtration, ideally ~ 55 mmHg

*afferent&efferent arterioles regulate ideal glomerular capillary pressure

118
Q

Renal circulation pressure of peritubular capillaries?

A

~8 mmHg to allow reabsorption & secretion along tubules of the nephron

119
Q

Renal circulation pressure of vasa recta? What does vasa recta surround?

A

~8 mmHg to allow reabsorption & secretion
-Surround loop of Henle in the juxtamedullary nephrons

120
Q

Renal circulation pressure of venous return?

A

As blood leaves kidney: ~4 mmHg (typical of IVC pressures)

121
Q

What is renal blood flow (RBF)?

A

Volume of blood that flows through the glomerular capillaries of both kidneys per minute

122
Q

Average RBF?

A

1.0-1.2 L/min

123
Q

At rest, what percentage of cardiac output flows into the kidney?

A

20-25%

124
Q

What is renal plasma flow (RPF)?

A

Volume of plasma that flows through glomerular capillaries of both kidneys per minute

125
Q

Average RPF?

A

600-700 mL/min

126
Q

How to calculate RPF?

A

RPF = RBF (1- hematocrit)

127
Q

What is glomerular filtration rate (GFR)?

A

Volume of plasma filtered into Bowman’s capsule per minute

128
Q

What determines GFR?

A

Net filtration pressure in the glomerulus

129
Q

What is net filtration pressure (NFP)?

A

Net sum of 3 types of pressures acting between the glomerular capillary and Bowman’s space

130
Q

NFP of healthy adult?

A

~10 mmHg “pushing into” Bowman’s capsule

131
Q

Which three pressures form NFP?

A

-Hydrostatic pressure of glomerular capillary (~55 mmHg pushing into Bowman’s capsule)
-Hydrostatic pressure of glomerular capillary (~15 mmHg pushing into Bowman’s capsule)
-Osmotic pressure of glomerular blood (~30 mmHg pulling back into glomerular capillary)

132
Q

What is filtration fraction (FF)?

A

% of renal plasma flow that filters into Bowman’s capsule

133
Q

Average FF?

A

20-25%

134
Q

How to calculate filtration fraction (FF)?

A

GFR/renal plasma flow

135
Q

Average GFR? What may cause average GFR to vary?

A

120 mL/min
Varies w? age, sex, size

136
Q

What is the gold standard test for measuring GFR? Is it ideal for clinical practice?

A

Insulin clearance,
not ideal for clinical practice

137
Q

What is insulin clearance testing?

A

Infusion of insulin and measure amount of insulin in urine

138
Q

Why is insulin an ideal marker for GFR?

A

It is freely filtered by glomerulus and not secreted or reabsorbed in the tubules

139
Q

Is creatinine easily filtered by the glomerulus?

A

Yes

140
Q

How does the urine creatinine test overestimate actual GFR?

A

Creatinine is also secreted into the proximal tubule, which overestimates amount filtered by the glomerulus

141
Q

What is a creatinine clearance (CrCl) test?

A

24 hour urine sample to measure amount of creatinine in urine, blood draw to measure amount of creatinine in the blood

142
Q

How does CrCl estimate GFR?

A

Comparing amount of creatinine in urine w/ amount of creatinine in serum

143
Q

Why is CrCl not routinely used in clinical practice?

A

Challenge of 24 hour collection

144
Q

What is estimated cretinine clearance rate (eCCR) testing?

A

Blood draw to meaure amount of creatinine in blood

145
Q

How does eCCR estimate GFR?

A

By calculating creatinine clearance using serum creatinine levels & other factors (age, sex, size)

146
Q

What needs to be maintained in order to maintain GFR?

A

Net filtration pressure (NFP)

147
Q

GFR is maintained by autoregulation if MAP is ______?

A

Between 80-180 mmHg

148
Q

What GFR rate is used as an overall threshold for inadequate kidney function?

A

< 60 mL/min

149
Q

MAP needed for autoregulation/maintenance of adequate GFR in a healthy individual?

A

“In theory” if MAP > or = 60 mmHg
**Higher MAP values are used for clinical thresholds

150
Q

What occurs when MAP drops too low to maintain NFP and GFR?

A

Acute renal insufficiency

151
Q

What structures make up the renal corpuscle?

A

Glomerulus, Bowman’s capsule

151
Q

What is the universal recommendation to avoid/minimize progression of acute renal insufficiency?

A

Maintain MAP > or = 65 mmHg

152
Q

Evidence suggests that maintaining a MAP within 72-82 mmHg or more could be necessary to avoid acute renal insufficiency in patients with which conditions?

A

Acute septic shock and initial renal function impairment

153
Q

What is chronic kidney disease (CKD)?

A

Abnormal kidney structure and/or dysfunction for >3 months that impacts health

154
Q

Diagnostic criteria for CKD?

A

At least one of the following for at least 3 months:
-GFR < 60 mL/min
-objective measure of kidney damage/dysfunction: proteinuria, hematuria, abnormal electrolyte balance d/t renal cause, renal abnormalities detected by histology/imaging, kidney transplant

155
Q

Stage 1 CKD values?

A

GFR >/= 90 mL/min, objective markers present

156
Q

Stage 2 CKD values?

A

GFR = 60-90 mL/min, objective markers present

157
Q

Stage 3 CKD values?

A

GFR = 30-59 mL/min, objective markers present or absent

158
Q

Stage 4 CKD values?

A

GFR = 15-29 mL/min, objective markers present or absent

159
Q

Stage 5 CKD values?

A

GFR = < 15 mL/min, objective markers present or absent

160
Q

Ongoing evidence based guidelines are being developed to create other staging models for GFR that predict what?

A

Outcome risks

161
Q

Intrinsic signaling of the kidney?

A

Renal autoregulation by two mechanisms: myogenic feedback and tubuloglomerular feedback

*concerned with trying to maintain ideal GFR

162
Q

Kidney is very effective at autoregulation if MAP remains between what values?

A

80-180 mmHg

163
Q

Extrinsic signaling of the kidney?

A

SNS and RAAS signaling influence GFR
*concerned with trying to maintain BP (influences GFR to maintain BP)

164
Q

Autoregulation principles of glomerular arterioles?

A

-Afferent arteriole/blood entering glomerular capillary
-Efferent arteriole/blood leaving glomerular capillary
*will contract or dilate to alter filtration

165
Q

What happens to filtration if the afferent arteriole constricts and/or the efferent arteriole dilates?

A

Filtration decreases

166
Q

What happens to filtration if the afferent arteriole dilates and/or the efferent arteriole constricts?

A

Filtration increases

167
Q

What is the myogenic feedback mechanism of intrinsic signaling?

A

Mechanical increase/decrease in pressure on arteriole wall SM stimulates contraction or relaxation reflex

–> if systemic BP increases: myogenic feedback will relax or constrict afferent arteriole to adjust GFR and NFP

168
Q

What happens during myogenic feedback if there is an increase in systemic BP?

A

Stimulates vasoconstriction of afferent arteriole (decreases excess GFR created by high systemic BP)

169
Q

What happens during myogenic feedback if there is a decrease in systemic BP?

A

Stimulates vasodilation of afferent arteriole (increases low GFR created by low systemic BP)

170
Q

What is the tubuloglomerular feedback mechanism of intrinsic signaling?

A

Macula dena monitors amount of NaCl flowing in the DCT

–> if too much/too little NaCl flow, signals JGA to adjust GFR/restore optimal NaCl flow in the DCT

171
Q

What happens during tubuloglomerular feedback if GFR is elevated?

A

Elevated GFR –> increases NaCl flowing through DCT
Macula densa detects increased NaCl and signals juxtaglomerular (JG) cells to release ATP and adenosine
–> ATP and adenosine stimulate mesangial cells of afferent arteriole to constrict, decreasing GFR (restoring optimal NaCl flow through DCT)

172
Q

What happens during tubuloglomerular feedback if GFR is low?

A

Decreased GFR –> decreases NaCl flowing through DCT
Macula densa detects decreased NaCl and signals juxtaglomerular (JG) cells to release nitric oxide and prostaglandins
–> NO and prostaglandins stimulate mesangial cells of afferent arteriole to relax, increasing GFR (restoring optimal NaCl flow through DCT)

173
Q

What effect do NSAIDS have on GFR/tubuloglomerular feedback?

A

Excess NSAID use can inhibit prostaglandin synthesis and signaling & may gradually decrease GFR

**Chronic use can induce kidney injury

174
Q

What is the role of SNS in extrinsic signaling of the kidneys?

A

Stimulates afferent arteriole vasoconstriction, decreasing GFR and NFP

175
Q

During times of stress, exertion, or hypovolemic shock, the SNS will do what?

A

-Vasoconstrict most BV –> increases systemic BP
-Directly decreases GFR by constriction of the afferent arteriole/rediraction of blood flow to other regions with increased need and/or to keep the body alive

176
Q

What is the role of the RAAS (renin angiotensin aldosterone system) in extrinsic signaling of the kidneys?

A

Low systemic BP and SNS signal JGA cells in kidney to release renin –> renin converts angiotensinogen to angiotensin I –> ACE1 found in BV of lungs/glomerulus/other organs converts angiotensin I to angiotensin II
*angiotensin II stimulates the adrenal gland to release aldosterone (stimulates nephron to retain sodium while ADH allows water to follow)

177
Q

What is the effect of angiotensin II on GFR?

A

Vasoconstricts afferent and efferent glomerular arterioles

*acts primarily on the efferent arteriole, has very small vasoconstrictive effect on afferent arteriole

Net effect: vasoconstriction of efferent arteriole–> increases GFR

178
Q

ACE-I/ARBs effect on RAAS/GFR?

A

Relax efferent arteriole –> decreases GFR
ACE-I: block conversion of angio I –> agio II (less angio II)
ARBs: block antio II R’s (angio II can’t constrict BV)

179
Q

What structures make up the renal corpuscle?

A

Glomerulus, Bowman’s capsule

179
Q

Why are ACE-I and ARB effects a non-issue in kidneys with normal renal bloodflow?

A

ACE-I/ARBs may decrease GFR, but kidney is able to autoregulate/maintain GFR

180
Q

Why are ACE-I and ARB effects a potential issue in kidneys with poor renal bloodflow (renal artery stenosis, etc.)?

A

ACE-I/ARBs may decrease GFR, and kidney may not be able to autoregulate/maintain GFR d/t poor renal bloodflow

181
Q

Effect of natriuretic peptides (extrinsic signaling) on RAAS and GFR?

A

Counteracts RAAS, influence GFR

182
Q

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are produced and secreted from what?

A

The heart and brain

183
Q

How to ANP and BNP increase GFR?

A

Vasodilate glomerular afferent arteriole, stimulates diuresis and natriuresis
Inhibit aldosterone, renin (RAAS) and sympathetic influence on kidney

184
Q

What is renal natriuretic peptide secreted by and what is its role on the kidneys?

A

Urodilation- stimulates natriuresis and diuresis
Secreted by: DCT/collecting ducts

185
Q

What is C-type natriuretic peptide (CNP) produced/secreted by and what is its role on the kidneys?

A

Decreases systemic BP (vasodilates), may increase GFR
Produced/secreted by: vascular endothelium

186
Q

Renal artery stenosis (RAS) can cause what form of HTN?

A

Renovascular HTN

187
Q

Renal artery stenosis (RAS) decreases bloodflow to the kidneys and causes what?

A

Decreased GFR, Decreased NaCl flow through DCT
Dec. NaCl flow stimulates renin release–>stimulates RAS causing HTN

188
Q

Why is renal artery stenosis (RAS) considered the silent killer?

A

Often does not cause signs/sx until RAS becomes severe

189
Q

When should you suspect renal artery stenosis (RAS)?

A

Abnormal onset of HTN: HTN onset at young age, HTN worsens abruptly, kidney signs/sx, atherosclerosis in other arteries

pathophysiology ii exam 2 renal (5 decks)

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