PRELIM-renal function Flashcards

1
Q

how many percent of blood that is pumped by the heart are being filtered by the kidney?

A

25%

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2
Q

Plasma filtrate must pass through three glomerular filtration
barrier cellular layers: the ___, the ___, and the ___

A

capillary wall membrane,
basement membrane (basal lamina)
visceral epithelium of
Bowman’s capsule.

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3
Q

The endothelial cells of the capillary wall differ from those in other capillaries by containing pores and
are referred to as ___.

A

fenestrated

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4
Q

In addition to the structure of the glomerular filtration bar
rier that prohibits the filtration of large molecules, the barrier
contains a ____ positive charge even though they are small enough to pass
through the three layers of the barrier

A

shield of negativity that repels molecules with a

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5
Q

example of a component being repelled by a shield of negativity

A

albumin

albumin (the primary protein associated with
renal disease) has a positive charge and would easily pass
through the barrier

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6
Q

what are the Factors influence the actual filtration process

A
  • Cellular structure of the capillary walls and bowman’s capsule
  • Hydrostatic and oncotic pressures
  • Feedback mechanisms of the renin angiotensin-aldosterone system
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7
Q

a part of glomerulus that is

o Containing pores and are referred to as fenestrated
o Pores increase capillary permeability but do not allow the passage of large molecules and blood cells

A
  • Capillary wall membrane
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8
Q

a part of glomerulus that is

o Restriction of large molecules occurs as the filtrate passes

A
  • Basement membrane
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9
Q

a part of glomerulus that is

o Thin membranes covering the filtration slits formed by the intertwining processes of the podocytes of the inner layer of bowman’s capsules

A
  • Visceral epithelium of bowman’s capsule
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10
Q
  • Prevent a marked decrease in blood flowing through the kidney, thus preventing an increase in the blood level of toxic waste products
A

Dilation of the afferent arterioles and constriction of the efferent arterioles

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11
Q

a mechanism of the arterioles managed by the juxtaglomerular apparatus
to prevent over-filtration or damage to the glomerulus

A

constriction of the afferent arterioles and the dilation of the efferent

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12
Q

regulates the flow
of blood to and within the glomerulus. The system responds
to changes in blood pressure and plasma sodium content that
are monitored by the juxtaglomerular apparatus

A

The renin-angiotensin-aldosterone system

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13
Q

what are the function of angiotensin II

A

: causing vasodilation of the afferent arterioles and constriction of the efferent arterioles
: stimulating reabsorption of sodium and water in the proximal convoluted tubules,
: triggering the release of the
sodium-retaining hormone aldosterone by the adrenal cortex
: Release of antidiuretic hormone from hypothalamus.

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14
Q

the action of ___ is to produce a constant pressure within the
nephron

A

angiotensin II

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15
Q

only difference between the compositions of the filtrate and the plasma is the __

A

absence of plasma protein, any protein-bound substances, and cells.

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16
Q

the specific gravity of a fluid leaving the glomerulus and stating that it is really an ultrafiltrate of the plasma is __

A

specific gravity of 1.010

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17
Q

what are the two/2 cellular mechanisms involved in tubular reabsorption

A

active transport and passive transport.

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18
Q

a cellular mechanism involved in reabsorption that needs a carrier protein contained in the membrane of the renal tubular epithelial cells

A

active transport

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19
Q

active transport is responsible in reabsorption of ____ in ____

A

glucose, amino acids, and salts in the proximal convoluted tubule,

chloride in the ascending loop of Henle,

sodium in the distal convoluted tubule.

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20
Q

passive transport is responsible in reabsorption of ____ in ____

A

WATER in Proximal convoluted tubule
Descending loop of Henle
Collecting duct

urea in Proximal convoluted tubule
Ascending loop of Henle

sodium in Ascending loop of Henle

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21
Q

the movement of molecules across a
membrane as a result of differences in their concentration or
electrical potential on opposite sides of the membrane

A

passive transport

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22
Q

what is it called to a physical differences in the concentration or electric potential on opposite sides of the membrane; related to passive transport

A

gradient

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23
Q

which part of the nephron is impermeable to water?

A

ascending loop of henle

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24
Q

if the concentration of the substances needed to be reabsorved reached the ___ the substances will appear on the urin

A

maximal reabsorptive capacity

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25
Q

The plasma concentration at
which active transport stops is termed the ___.

A

renal threshold

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26
Q

renal threshold for glucose

A

160-180 mg/dl

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27
Q

Glucose appearing in the urine of a
person with a normal blood glucose level is the result of
tubular damage and not diabetes mellitus.

true or false

A

true

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28
Q

A non fasting
patient with high glucose intake would not have a normal
blood glucose.

true or false

A

true

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29
Q

Renal concentration begins in the ___, where the filtrate is exposed to the high
osmotic gradient of the renal medulla

A

descending and ascending
loops of Henle

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30
Q

Water is removed by
osmosis in the descending loop of Henle, and sodium and
chloride are reabsorbed in the ascending loop. Excessive reab
sorption of water as the filtrate passes through the highly con
centrated medulla is prevented by the water-impermeable walls
of the ascending loop. This selective reabsorption process is
called the ___ and serves to maintain
the osmotic gradient of the medulla

A

countercurrent mechanism

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31
Q

The final concentration of the filtrate through the reabsorption
of water begins in the ___ and -__

A

late distal convoluted tubule and continues in the collecting duct

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32
Q

in collecting duct, A high level of ADH
will what the permeability and what will happen to the urine concentration

A

A high level of ADH
increases permeability, resulting in increased reabsorption of
water, and a low-volume concentrated urine

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33
Q

what is the actual final determinant of urine volume and concentration?

A

chemical balance in the body

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34
Q

2 purpose of tubular secretion

A

eliminating waste products not filtered by the glomerulus

regulating the acid–base balance in the body through the secretion of hydrogen ions.

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35
Q

The major site for removal of these nonfiltered substances/ or for the secretion is
the ___

A

proximal convoluted tubule

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36
Q

ammonia is
produced from the breakdown of the __

A

amino acid glutamine.

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37
Q

explain how bicarbonate ions are kept in the plasma and prevented from getting ecreted by the hydrogen ions

A

the secretion
of hydrogen ions (H+) by the renal tubular cells into the filtrate
prevents the filtered bicarbonate from being excreted in the
urine and causes the return of a bicarbonate ion to the plasma.

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38
Q

where does the hydrogen ions are secreted?

A

in the proximal convoluted tubule

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39
Q

aside from the distal convoluted tubule, which part of the nephron is able to secret ammonium ion as well?

A

collecting duct

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40
Q

A disruption
in these secretory functions can result in ___, the inability to produce an acid urine.

A

metabolic acidosis or
renal tubular acidosis

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41
Q

The standard tests used to measure the filtering capacity of
the glomeruli are termed ___

A

clearance tests

42
Q

In clearance test, A test that requires an infused substance is termed an ___ and is seldom the method of choice if a
suitable test substance is already present in the body (____).

A

exogenous procedure; endogenous procedure

43
Q
  • Standard method for Glomerular Filtration Rate
A

Urea Clearance test

44
Q

The earliest glomerular filtration tests measured urea
because of its presence in all urine specimens and the
existence of routinely used methods of chemical analysis.

A

urea clearance test

45
Q

urea clearance test has how many percent of urea as its indication?

A

40%

46
Q

was the original refer
ence method for clearance tests,

A

inulin clearance test

47
Q

a polymer of fructose, is an extremely stable sub
stance that is not reabsorbed or secreted by the tubules. It
is not a normal body constituent, however, and must be
infused by IV at a constant rate throughout the testing
period.

A

inulin cleareance test

48
Q

2 types of infusion for inulin clearance test

A

priming dose and continuous infusion

49
Q

give the concentration of each type of infusion for inulin clearance test

A

o Priming Dose: 25 mL of 10% Inulin Solution
o Continuous Infusion: 500 mL of 1.5% Inulin Solution

50
Q

reference values for inulin clearance test

A

 127 mL/min → Male
 118 mL/min → Female

51
Q

is a waste product of muscle metabolism that is pro
duced enzymatically by creatine phosphokinase from creatine,

A

creatinine

52
Q

Because creatinine is normally found at a relatively constant level in the
blood,, it provides the laboratory with an endogenous procedure for evaluating glomerular function.

A

creatinine clearance test

53
Q

Some creatinine is secreted by the tubules, and secretion
increases as blood levels ___.

increase or decrease

A

increase / rise

54
Q

true or false

. Bacteria will break down urinary creatinine if specimens
are kept at room temperature for extended periods

A

true

55
Q

Medications, including gentamicin, cephalosporins, and
cimetidine (Tagamet), inhibit tubular secretion of creati
nine, thus causing falsely low serum levels.

true or false

A

true

56
Q

Measurement of creatinine clearance is not a reliable
indicator in patients suffering from MUSCLE-WASTING DISEASES or persons involved in heavy exercise or athletes SUPPLEMENTING with creatine.

true or false

A

true

57
Q

for creatine clearance test, Accurate results depend on the accurate completeness
of __

A

a 24-hour collection.

58
Q

GFR is reported in what units?

A

milliliters per minute (ml/mn)

59
Q

whatis the most frequently used formula for ESTIMATED GLOMERULAR FILTRATION RATE or eGFR

A

Modification of Diet in Renal Disease (MDRD) study

60
Q

significance of creatinine clearance test or cct

A

o Determines the functional Capacity of Nephrons

o Determines the extent of nephron damage in known cases of renal disease

o Monitor the effectiveness of treatment

o Determine the feasibility of administering medications

61
Q

reference values for creatinine clearance test

A

 107-139 mL/min → Male
 87-107 mL/min → Female

  • Normal reference of plasma creatinine is 0.5-1.5 mg/dL
62
Q

Measurement of serum ___ has been shown to provide
a good procedure for screening and monitoring GFR

A

cystatin C

63
Q

is a small protein (molecular weight 13,359) produced at a
constant rate by all nucleated cells.

A

cystatin C

64
Q

An advantage of cystatin C is that it is independent of muscle mass.

true or false

A

true

65
Q

Recent studies also have shown that measuring both
serum or plasma ____ and __– can provide even
more accurate information on a patient’s GFR.6

A

cystatin C and creatinine

66
Q

do we need fasting for the cystatin?

A

nope

67
Q

diseases we can identfy elevated cystatin C?

A

Acute & Chronic Renal Failure, Diabetic Nephropathy

68
Q
  • Indirect estimate of GFR
A

cystatin C

69
Q
  • Dissociates from human leukocyte antigens at constant rate and is rapidly removed from plasma by glomerular filtration
A

beta 2 microglobulin

70
Q
  • A rise has been to be more sensitive indicator of decrease in GFR than creatinine clearance
A

beta microgolobulin

71
Q
  • Not reliable in patient who have history of immunologic disorder or malignancy
A

beta 2 microglobulin

72
Q

a methos for beta - 2 microglobulin

A

enzyme immunoassay

73
Q

It would monitor the high risk for renal disease such as patients with uncontrolled hypertension, patients who are diabetic; the most common complication of DM is Kidney Failure

A

estimated glomerular filtration rate or the eGFR

74
Q

the ___ is often the first function affected in renal disease.

A

loss of tubular reabsorption capability

75
Q

Tests to determine the ability of the tubules to reabsorb the essential salts and water that have been nonselectively filtered by the glomerulus are called ___

A

concentration tests

76
Q

the ultrafiltrate that enters the tubules has a specific
gravity of 1.010; therefore, after reabsorption one would expect
the final urine product to be more CONCENTRATED

true or false

A

true

77
Q

___ measures only
the number of particles in a solution,

A

osmolality

78
Q

specific gravity
is influenced by the number and ___ of the particles.

A

density (molecular weight)

79
Q

___ is performed for a more accurate evaluation of renal
concentrating ability

A

osmolality

80
Q

stage 1 of GFR rate

A

kidney damage with normal or elevated GFR > or – to 90

81
Q

stage 2 of GFR rate

A

kidney damage with mild decrease of GFR 60-89

82
Q

stage 3 of GFR

A

moderate decrease of GFR 30-59

83
Q

stage 4 of GFR rate

A

severe decrease of GFR 15-29

84
Q

stage 5 of decrease GFR

A

kidney failure lower than 15
<15 or dialysis

85
Q

2 test we can conduct for the specific gravty

A

fishberg test and mosenthal test

86
Q

a test in SG in which the patients are deprived of fluids for 24 hours prior to measuring SG

A

fishberg test

87
Q

a test for SG in which it Compares volume and specific gravity of urine of day and night urine samples

A

mosenthal test

88
Q

o Renal concentration is concerned with small particles, primarily ___

A

sodium and chloride molecules

89
Q
  • Large molecular-weight molecules such as __- and - do not contribute to the evaluation of renal concentration
A

glucose and urea

90
Q

Principle: Measurement of Dew point

A

VAPOR PRESSURE OSMOMETERS

91
Q
  • Temperature at which water vapor condenses to a liquid
  • Standard reference: NaCl
A

VAPOR PRESSURE OSMOMETERS

92
Q

Temperature at which water and ice are in equilibrium and is related to solute concentration Standard Reference: NaCl

A

FREEZING POINT OSMOMETERS

93
Q

_____ are used
primarily to analyze serum and sweat microsamples for
disorders NOT RELATED to renal function, such as cystic fibro
sis. They are used primarily in the chemistry department.

A

Vapor pressure osmometers

94
Q

disease we can use vapor pressure osmometer

A

cystic fibrosis

95
Q

total renal blood flow through the nephron must be measured by a
substance that is ___ rather than filtered through the
glomerulus

A

secreted

96
Q

The test most commonly associated with tubular secretion
and renal blood flow is the ____

A

p-aminohippuric acid (PAH) test.

97
Q

To measure the exact amount of blood flowing through the
kidney, it is necessary to use a substance that is completely removed from the blood (plasma) each time it comes in contact
with functional renal tissue

A

PAH Test

98
Q

if the PAH wasn’t able to be in ocntact with the fnctional renal tissue, it will be secreted in the ___

A

proximal convoluted tube

99
Q

The inability to produce an acid urine in the presence of
metabolic acidosis is called _____

A

renal tubular acidosis.

100
Q

__are the measurements can be used to determine the defective function of tubular secretion primarily the proximal or distal convoluted tube

A

Urine pH, titratable acidity, and urinary ammonia

101
Q
A