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ABSC (pt. 2) > Kidney (K1-K9) > Flashcards

Kidney (K1-K9) Flashcards

1
Q

these are firm, reddish brown glands, located close to the dorsal body wall high in the abdomen at the level of the thoracolumbar junction

A

kidneys

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2
Q

this kidney is usually more cranial (except the pig)

A

right

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3
Q

the right kidney is embedded in this of the liver, which secures its position

A

renal fossa

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4
Q

this is tough and fibrous covering of the kidneys that restricts their ability to expand

A

capsule

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5
Q

within the kidney, the parenchyma can be visually divided into these two sections

A

outer cortex and inner medulla

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6
Q

this part of the kidneys contains the renal corpuscles and convoluted parts of renal tubules; it is light in color and granular in appearance

A

cortex

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7
Q

this part of the kidney is characterized by its striated appearance and contains collecting ducts and nephric loops

A

inner medulla

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8
Q

these are the functional units of the kidney, the structures that are apparent within the cortex and medulla

A

nephrons (corpuscle, tubules, loops, and ducts)

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9
Q

these are paired tubes that form as the internal ducts within the kidneys join to form a common expansion (renal pelvis); exit the kidney at the hilus and follow a saggital course towards the pelvis

A

ureters

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10
Q

the ureter bends medially to enter this in the male

A

genital fold

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11
Q

the ureter bends medially to enter this in the female

A

broad ligament

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12
Q

what are the three regions of the bladder

A

apex, the neck, body

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13
Q

this region of the bladder is a cranial blind end

A

apex

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14
Q

this region of the bladder is a funnel-shaped region between ureter openings and urethra

A

the neck

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15
Q

this region of the bladder is situated between the neck and apex

A

the body

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16
Q

this is the duct through which urine is discharged from the bladder

A

urethra

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17
Q

the male urethra consists of these two components

A

pelvic and penile

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18
Q

each kidney is supplied by this artery arising from the abdominal aorta

A

renal artery

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19
Q

veins that correspond with the arteries of the kidney join to form this single vein that enters the vena cava

A

renal vein

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20
Q

efferent arterioles arising from juxtamedullary nephrons descend into the medulla and give rise to this, which descend and re-ascend close to the Loops of Henle

A

vasa recta

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21
Q

this is the functional unit of the kidney and consists of the renal corpuscles and renal tubules

A

nephron

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22
Q

what are the two major parts of the nephron

A

renal corpuscles and renal tubules

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23
Q

these are responsible for the filtration of blood and are made up of Bowman’s capsule and the glomerulus

A

renal corpuscles

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24
Q

this part of the renal corpuscles consists of a single layer of flattened cells resting on a basement membrane

A

Bowman’s capsule

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25
Q

this is a network of capillaries that arise from the afferent arteriole, and invaginate Bowman’s capsule

A

glomerulus

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26
Q

the renal cortex is easily identified at low magnification due to the presence of these, which are not found in the renal medulla

A

renal corpuscles

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27
Q

the capillary loops of the glomerulus are supported by specialized connective tissue called this

A

glomerular mesangium

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28
Q

these cells are contractile and can modify the diameter of glomerular capillaries (secrete vasoactive substances and other factors)

A

mesangial

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29
Q

this is the first part of the renal tubule which drains Bowman’s capsule and is made up of a coiled section and a shorter straight segment

A

proximal tubule

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30
Q

this is the coiled section of the proximal tubule; it is lined by simple, cuboidal epithelium with a prominent brush border which increases surface area for absorption; it is the longest and most convoluted part of the nephron

A

proximal convoluted tubule (PCT)

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31
Q

this is the shorter straight segment of the proximal tubule; it is lined by low cuboidal epithelium with no brush border and leads onto the loop of Henle

A

proximal straight tubule (PST)

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32
Q

name the three parts of the loop of Henle

A

descending thin limb, ascending thin limb, thick ascending limb

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33
Q

the cells in th thick ascending limb of loop of Henle that lie closest to Bowman’s capsule are specialized cells known as this; they mark the end of the thick ascending limb and start of distal convoluted tubule

A

macula densa

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34
Q

this is a group of specialized cells that regulate renal blood blow comprised of 3 cell types

A

juxtaglomerular apparatus

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35
Q

what are the 3 cell type that comprise the juxtaglomerular apparatus?

A
  1. extraglomerular mesangial cells
  2. granular cells
  3. macula densa cells
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36
Q

once the fluid has been deposited into the calyx it is known as this and no longer changes

A

urine

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37
Q

this is an area of the urinary bladder and is a dorsal triangular area connecting the ureteral openings and urethral exit; has a smooth mucosa and originates from mesoderm

A

trigone

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38
Q

the male urethra is lined by this type of epithelium

A

stratified or psuedostratified columnar epithelium

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39
Q

the female urethra is predominately lined by this type of epithelium (but changes to stratified squamous epithelium near the external urethral orifice)

A

urinary epithelium

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40
Q

this species kidney has obvious external demarcation of the cortex and separation of the medulla into lobes/pyramids

A

bovine

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41
Q

what is the classification of the bovine kidney

A

multilobar or multipyramidal

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42
Q

this species kidney is multilobar, however has a single cortex with a smooth outer surface and has a flattened appearance

A

pig

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43
Q

these species (5) kidney is unilobar, the cortex and medulla fuse into a single unit and the linearly fused papillae form a renal crest

A

cat, dog, horse, rodent, and sheep

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44
Q

these 2 species have the standard smooth, bean-shaped kidneys that are reddish brown and cannot be distinguished from each other

A

dog and sheep

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45
Q

this species has a unilobular kidney with a fused cortex and is heart-shaped/triangle-shaped

A

horse

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46
Q

approximately 2/3 of total body water (40% total body weight) is located within cells and known as this

A

intracellular fluid (ICF)

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47
Q

one third (20% total body weight) is located outside of cells and known as this

A

extracellular fluid (ECF)

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48
Q

what are the two subcategories of extracellular fluid

A

interstitial or intravascular

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49
Q

what percent of total lean bodyweight is made up of water

A

60%

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50
Q

what is the ratio of fluid percentages in the body? (total lean bodyweight made of water:intracellular fluid:extracellular fluid)

A

60:40:20

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51
Q

the intracellular and extracellular fluid compartments are separated by this

A

cell membrane

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52
Q

the interstitial and intravascular fluid compartments are divided by this

A

vascular endothelium

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53
Q

what are the three main colloid particles within plasma?
vascular endothelium is not permeable to them

A

albumin, globulins, and fibrinogen

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54
Q

the particles within a particular fluid compartment exert this meaning they can cause fluid to move by osmosis to one or other side of the membrane, towards the area of higher solute concentration (higher osmolarity)

A

osmotic pressure (tonicity)

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55
Q

this is a measure of all particles dissolved within a fluid compartment , whether or not they can cross the semi-permeable membrane

A

total fluid osmolarity

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56
Q

particles that can cross the semi-permeable membrane contribute to this but not to this

A

osmolarity but not osmotic pressure

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57
Q

what is the average plasma osmolarity in a dog

A

300 mOsm/kg

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58
Q

this pressure is the contribution of colloid particles and their associated electrolytes towards plasma oncotic pressure

A

oncotic pressure (aka colloid osmotic pressure, COP)

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59
Q

this is the only difference between intravascular and interstitial fluid

A

the concentration of proteins

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60
Q

standard biochemical tests measure solutes within this fluid and may not reflect changes in total body solute levels

A

extracellular fluid

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61
Q

fluid flux across the capillary endothelium is described by this equation

A

Starling’s equation

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62
Q

what are the Starling forces in Starling’s equation

A

the oncotic and hydrostatic pressure gradient’s between the capillary and interstitium

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63
Q

along the length of the capillary, this pressure increases and this pressure decreases

A

oncotic pressure increases, hydrostatic pressure decreases

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64
Q

fluid moves (into or out of?) the capillary at the arteriolar end/beginning

A

out of (into the interstitium)

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65
Q

fluid moves (into or out of?) the capillary at the end ?

A

into the capillary

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66
Q

why is plasma COP essential to prevent excessive fluid efflux into the the interstitium?

A

intravascular and interstitial osmolality would be identical and fluid would move freely out of capillaries causing oedema and potential loss of blood volume

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67
Q

this is a gel-like matrix on the luminal surface of endothelial cells now thought to determine transcapillary fluid flux

A

glycocalyx

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68
Q

these are fluids containing electrolytes and other solutes that can freely cross the capillary endothelium to pass between the intravascular and interstitial space

A

crystalloids

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69
Q

crystalloids are classified according to this

A

their osmolarity relative to that of plasma

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70
Q

fluids with osmolarity greater than plasma (300 mOsm/kg) are termed this
ex: 7.2% NaCl

A

hypertonic

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71
Q

fluids with osmolarity lower than plasma (300 mOsm/kg) are termed this
ex: 0.45% NaCl

A

hypotonic

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72
Q

fluids with osmolarity similar to plasma (300 mOsm/kg) are termed this
ex: 0.9% NaCl

A

isotonic

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73
Q

this type of saline is very effective for resuscitating patients in severe shock because water is pulled rapidly out of the intracellular space and redistributes between the interstitial and intravascular spaces

A

hypertonic saline

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74
Q

these losses of water are easy to measure, i.e. urine

A

sensible losses

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75
Q

these losses of water are difficult to measure, i.e. feces, saliva, evaporation from respiratory tract, skin

A

insensible losses

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76
Q

this component of urinary water loss is the amount of water required for the kidney to excrete solutes such as urea

A

obligatory loss

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77
Q

this component of urinary water loss is the removal of any water excess to body requirements

A

free loss

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78
Q

healthy dogs drink about this much water per day

A

50-60 mL/day

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79
Q

if a dog drinks more than 100 mL of water per day it is defined as this

A

polydipsia

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80
Q

what is the normal urine output of a healthy dog?

A

1-2 mL/kg/hour

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81
Q

name some causes of abnormal fluid loss

A

vomiting, diarrhea, polyuria, high body temp, excessive panting, hemorrhage, exudation/transudation into a body category, ongoing physiological losses due to reduced water intake

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82
Q

fluid is often lost first from here

A

extracellular fluid

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83
Q

a loss of hypotonic fluid will have this effect on ECF tonicity resulting in this shift of fluid

A

hypertonic, water moves out of ICF

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84
Q

a loss of hypertonic fluid will have this effect on ECF tonicity resulting in this shift of fluid

A

hypotonic, water moves into ICF

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85
Q

this type of fluid loss is loss of water in excess of solute

A

hypotonic

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86
Q

this type of fluid loss is loss of water and solute in equal proportions

A

isotonic

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87
Q

this type of fluid loss is loss of solute in excess of water

A

hypertonic

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88
Q

perfusion of tissue with blood depends on this fluid compartment

A

intravascular fluid compartment

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89
Q

hydration depends on these 2 fluid compartments

A

interstitial and intracellular fluid compartments

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90
Q

this is the process by which water and solutes leave the vascular system through the filtration barrier of the glomerular capillaries and enter the Bowman’s space

A

glomerular filtration

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91
Q

the volume of filtrate formed per unit of time by glomerular filtration is known as this

A

Glomerular Filtration Rate (GFR)

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92
Q

this is a network of capillaries between the afferent and efferent arterioles, encased within the Bowman’s capsule

A

glomerular filter

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93
Q

what are the three major layers of the glomerular capillary membrane which make up the filtration barrier

A
  1. glomerular endothelium
  2. basement membrane
  3. podocytes
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94
Q

this layer of the glomerular capillary membrane prevents filtration of plasma proteins because of the strong negative electrical charges associated with the proteoglycan molecules

A

basement membrane

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95
Q

what 3 layers is the basement membrane of the glomerular capillary membrane made up of

A
  1. lamina rara interna: fused to endothelium
  2. lamina densa: middle
  3. lamina rara externa: fused to epithelium
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96
Q

which is the most significant filtration barrier of the glomerular capillary?

A

basement membrane

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97
Q

this is a layer of intricate interlocking cells that make up the visceral epithelium of the glomerular capillary membrane

A

podocytes

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98
Q

this is the resulting product of glomerular filtration

A

an ultrafiltrate of plasma

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99
Q

solutes pass through the 3 layers of glomerular capillary membrane to form an ultra filtrate which enters this

A

proximal tubule

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100
Q

the glomerular filtration barrier restricts the filtration of molecules on the basis of these 3 things

A

size, weight, and electrical charge

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101
Q

all surfaces of the glomerular filtration barrier contained fixed polyanions, which repel macromolecules with this charge (prevents protein loss with urine since many proteins in the blood have this charge)

A

negative

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102
Q

which Starling’s forces favor glomerular capillary filtration

A

hydrostatic pressure in glomerular capillary (oncotic pressure in Bowman’s capsule is near zero so doesn’t really favor filtration)

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103
Q

which Starling’s forces oppose glomerular capillary filtration

A

oncotic pressure in glomerular capillary bed and hydrostatic pressure in Bowman’s space

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104
Q

for glomerular capillaries, the net ultrafiltration pressure always (favors or opposes?) filtration
so, the direction of fluid movement is always (into or out of?) capillaries

A

favors filtration, out of capillaries

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105
Q

GFR is regulated by changes in the hydrostatic pressure within the glomerular capillary which is mediated by changes in this

A

resistance of the afferent and efferent arteriole

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106
Q

afferent arteriolar resistance is (positively or negatively?) correlated with the hydrostatic pressure in the glomerular capillary and therefore GFR?

A

negatively (decrease in resistance increases hydrostatic pressure and GFR)

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107
Q

efferent arteriolar resistance is (positively or negatively?) correlated with the hydrostatic pressure in the glomerular capillary and therefore GFR?

A

positively (decrease in resistance decreases hydrostatic pressure and GFR)

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108
Q

what is the equation for renal blood flow (RBF)?

A

RBF = (renal artery pressure - renal vein pressure) / total renal vascular resistance

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109
Q

the blood flow through the kidneys serves these 5 important functions

A
  1. indirectly determines GFR
  2. modifies rate of solute & water reabsorption by proximal tubule
  3. participates in concentration & dilution of urine
  4. delivers O2, nutrients, and hormones to cells of nephron and returns CO2 and reabsorbed fluid and solutes to general circulation
  5. delivers substrates for urinary excretion
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110
Q

what are the 3 major sites for renal resistance

A
  1. interlobular arteries
  2. afferent arterioles
  3. efferent arterioles
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111
Q

Vasodilation of the afferent arteriole (decreased resistance) will have this effect on RBF and GFR

A

increase both RBF and GFR

112
Q

Vasoconstriction of the afferent arteriole (increased resistance) will have this effect on RBF and GFR

A

decrease both RBF and GFR

113
Q

Vasodilation of the efferent arteriole (decreased resistance) will have this effect on RBF and GFR

A

increase RBF and decrease GFR

114
Q

Vasoconstriction of the efferent arteriole (increased resistance) will have this effect on RBF and GFR

A

decrease RBF and increase GFR

115
Q

what are the 2 autoregulation mechanisms that maintain constant RBF and GFR when the systemic blood pressure is between 80-200 mmHg

A

myogenic reflex and tubuloglomerular feedback

116
Q

this reflex responds to changes in arterial blood pressure by constricting or dilating the afferent arteriole to maintain RBF and GFR at a constant level

A

myogenic

117
Q

this reflex responds to changes in the NaCl concentration of tubular fluid and has a predominant effect on the afferent arteriole to regulate RBF and GFR

A

tubuloglomerular feedback

118
Q

the NaCl concentration of tubular fluid is sensed by this part of the juxtaglomerular apparatus (JGA)

A

macula densa

119
Q

what are the 3 components of the juxtaglomerular apparatus (JGA)?

A
  1. macula densa
  2. extraglomerular mesangial cells
  3. juxtaglomerular cells
120
Q

this component of the juxtaglomerular apparatus (JGA) is the thick ascending limb of Loop of Henle

A

macula densa

121
Q

this component of the juxtaglomerular apparatus (JGA) surround the capillary loop

A

extraglomerular mesagnial cells

122
Q

this component of the juxtaglomerular apparatus (JGA) are specialized smooth muscle cells and make up the afferent and efferent arterioles

A

juxtaglomerular cells

123
Q

when increased tubular fluid NaCl concentration is sensed by the macula densa, ATP and adenosine are released by the macula densa cells which has this effect on the afferent arteriole

A

vasoconstrictive effect (decreases RBF & GFR)

124
Q

when decreased tubular fluid NaCl concentration is sensed by the macula densa, signals are initiated with these 2 effects

A

vasodilation of afferent arteriole and increased renin release from JGA cells

125
Q

the ideal glomerular biomarker for measuring GFR must have these 3 characteristics

A
  1. be readily filtered across the glomerular capillaries, with no size or charge restrictions
  2. be secreted unchanged
  3. cannot effect GFR
126
Q

this is the most tradition biomarker used for determining glomerular filtration; fructose polymer with 5000 Da molecular weight

A

inulin

127
Q

this is an end-product of muscle catabolism and is an example of an endogenously produced biomarker for GFR
-it is freely filtered by the glomerulus at a constant rate but is a poor sensitive marker for GFR as blood serum levels do not increase until GFR decreases > 75%

A

creatinine

128
Q

this is defined as the amount of substance filtered by the glomerulus into the Bowman’s space per unit time

A

filtered load

129
Q

this is the movement of filtered solutes and water from tubular lumen back into the peritubular capillary

A

reabsorption

130
Q

what are the 4 general mechanisms for reabsorption within the nephron

A

diffusion, facilitated diffusion, coupled transport, and active transport

131
Q

this is when solutes dissolved in water are also carried along with the water when it is reabsorbed across tubule segments

A

solvent drag

132
Q

if both solutes are transported via coupled transport in the same direction, the carrier protein is known as this

A

symporter

133
Q

name 2 examples of symporters (one in the proximal tubule and one in the thick ascending limb of the loop of Henle)

A
  1. Na-glucose transporter
  2. Na-K-2Cl transporter
134
Q

if each solute is transported via coupled transport in opposite directions, the carrier protein is known as this

A

antiporter

135
Q

name an example of an antiporter in the proximal tubule

A

Na-H transporter (Na into cell, H+ out of the cell into the lumen)

136
Q

what is the most prevalent example of active transport within the kidney (within the basolateral membrane)

A

Na-K-ATPase pump

137
Q

this is when solutes cross the tubular epithelium by passing BETWEEN the cells (through tight junctions)

A

paracellular transport

138
Q

this is when solutes cross the tubular epithelium by passing THROUGH cells

A

transcellular transport

138
Q

this type of junction in tubular epithelium promotes the reabsorption of a large concentration of solutes and water; commonly seen within the proximal tubule

A

leaky junction

139
Q

this type of junction in tubular epithelium have a low basal water permeability and effectively bar paracellular flow of water and solutes; typically found within the distal tubule

A

tight junctions

140
Q

most reabsorption of water and solutes that have been filtered by the glomerulus occurs here

A

proximal convoluted tubule (PCT)

141
Q

this is the longest and most convoluted part of nephron with a rich capillary network of peritubular capillaries surrounding it

A

proximal convoluted tubule (PCT)

142
Q

in mammals, the peritubular capillary originates at this and subdivides, wrapping closely around the proximal tubule, allowing for the return of reabsorbed molecules back into the bloodstream

A

efferent arteriole

143
Q

what are 4 reasons the proximal convoluted tubule has such a high efficacy for solute reabsorption

A
  1. rich peritubular capillary network
  2. brush border of microvilli
  3. lateral cellular interdigitations of basolateral cell membrane
  4. large numbers of mitochondria and protein carrier molecules
144
Q

this accounts for almost half of the total solutes in the tubular fluid entering the PCT and most of the rest are anions that must accompany it to maintain electroneutrality

A

sodium

145
Q

this is the first step in the process of solute reabsorption in the PCT
-achieved by the Na-K-ATPase pump

A

active transport of sodium out of tubular epithelial cell into interstitium

146
Q

how is glucose reabsorbed across the tubular epithelium in the PCT?

A

glucose transporters (not paracellular transport)

147
Q

why is glucose able to be almost completely reabsorbed in the PCT?

A

it is impermeable to the tight junctions

148
Q

how are many of the solutes (including urea, potassium, calcium and magnesium) reabsorbed in the PCT?

A

paracellular transport via leaky tight junctions

149
Q

this is responsible for concentrating or diluting the tubular fluid using concurrent multiplication

A

loop of Henle

150
Q

this limb of the loop of Henle has low, simple squamous epithelium with few mitochondria so there is relatively little active transport of solutes here; however it is highly permeable to water with aquaporin 1 receptors and is responsible for 20% of water resorption

A

thin descending limb

151
Q

the descending limb of the loop of Henle does not reabsorb solutes, so the tubular fluid tonicity (increases or decreases?) along its length and becomes this

A

increases, hypertonic

152
Q

solutes are reabsorbed within this limb of the loop of Henle (impermeable to water)

A

ascending limb

153
Q

the epithelial cells within this segment of the loop of Henle are relatively tall with many mitochondria and membrane in-foldings to allow for high capacity active solute transport

A

thick ascending limb

154
Q

these segments of the renal tubule are commonly referred to as the ‘diluting segment’ of the nephron because there is resorption of solutes without water which dilutes the tubular fluid

A

ascending limb of the loop of Henle & distal tubule

155
Q

this is known as the connecting segment and has properties of both the distal tubule and the collecting duct

A

late distal tubule

156
Q

this is the site for final urine processing by regulated tubular resorption and secretion largely by the actions of aldosterone and vasopressin

A

late distal tubule and collecting ducts

157
Q

what are the two distinct epithelial cells found in the late distal tubule and collecting ducts

A

principal cells and intercalated cells

158
Q

these cells in the late distal tubule/collecting ducts act to resorb both water and sodium & secrete potassium

A

principal cells

159
Q

this hormone acts to amplify the process of principal cells by up regulating and activating the basolateral Na-K-ATPase pumps, up regulating the apical sodium channels, and stimulating potassium secretion into the tubular lumen

A

aldosterone

160
Q

the water permeability of principal cells is directly controlled by this hormone which binds to specific receptors on the basolateral membrane, resulting in the insertion of water specific channels into the luminal membrane

A

vasopressin

161
Q

these cells found in the late distal tubule/collecting ducts are largely involved with regulation of acid base balance

A

intercalated cells

162
Q

name the 2 types of intercalated cells

A

alpha and beta

163
Q

this type of intercalated cells are the most important and function to secrete H+ ions and reabsorb HCO3 ions (key role in acid-base regulation)
-also resorb potassium into tubular fluid

A

alpha intercalated cells

164
Q

this type of intercalated cell functions to secrete HCO3 and reabsorb H+

A

beta intercalated cells

165
Q

where is the majority of sodium (65%) reabsorbed?

A

PCT (proximal convoluted tubule)

166
Q

these are channels for the transfer of water which are expressed in the luminal cell membranes in the descending limb of the loop of Henle

A

Aquaporins (AQP)

167
Q

most of the nephrons in the kidney are short-loop nephrons, so they don’t have this section

A

ascending thin limbs of Henle’s loop

168
Q

by what mechanism does the distal convoluted tubule reabsorb salt without water

A

Na-Cl symporter

169
Q

what 3 types of baroreceptors are important in regulating sodium excretion

A
  1. arterial baroreceptors
  2. cardiopulmonary baroreceptors
  3. intrarenal baroreceptors
170
Q

these stretch receptors detect low perfusion pressure, usually when intravascular volume is too low

A

high-pressure arterial stretch receptors

171
Q

these stretch receptors detect whether intravascular volume is too high

A

low-pressure venous stretch receptors

172
Q

these cells in the brain have sensory sodium channels that detect and respond to extracellular sodium concentrations and respond by modulating the activity of nearby neurons involved in the control of body sodium

A

glial cells

173
Q

this is the most important controller of sodium excretion and volume sensing

A

RAAS

174
Q

this is the most important peptide produced by the RAAS,

A

angiotensin II

175
Q

this is produced in the kidneys by the juxtaglomerular apparatus and converts angiotensinogen to angiotensin I

A

renin

176
Q

this is the rate limiting step of the formation of angiotensin II

A

amount of renin available to convert angiotensinogen to AI

177
Q

these are the 3 key regulators of renin production

A
  1. sympathetic input
  2. aferent arteriole pressure
  3. macula densa response
178
Q

this is released from postganglionic sympathetic nerve cells and activates the release of renin from the juxtaglomerular granular cells

A

norepinephrine

179
Q

the granular cells respond directly to pressure in the afferent arteriole; when pressure decreases, renin production (increases or decreases?)

A

increases

180
Q

what are the 4 key actions of angiotensin II via the RAAS?

A
  1. stimulates behavioral actions
  2. promotes sodium reabsorption
  3. controls the secretion of aldosterone
  4. vasoconstrictor
181
Q

this is a key hormone secreted mainly by the heart; it inhibits the release of renin (and the actions of AII that promote sodium reabsorption), acts on the medullary collecting duct to inhibit sodium reabsorption, and relaxes the afferent arteriole promoting increased glomerular filtration

A

atrial natriuretic peptide (ANP)

182
Q

these are agents that increase urine flow; their goal is to reduce ECF volume to correct or prevent edema and they work by increasing sodium excretion

A

diuretics

183
Q

the most powerful diuretics act by blocking this in the thick ascending limb of the loop of Henle (called loop diuretics)

A

Na-K-Cl symporter

184
Q

this group of diuretics block the Na-Cl symporter in the DCT

A

thiazide diuretics

185
Q

what is the most dangerous unwanted side effect of many diuretics

A

increased secretion of potassium (hypokalemia)

186
Q

the vast majority of body potassium is (intracellular or extracellular?)

A

intracellular

187
Q

a patient with hypokalemia has a more (negative or positive?) resting potential than normal; this makes the cell (more or less?) excitable

A

negative (potassium ions diffuse faster out of cell); less excitable

188
Q

this is the rapid homeostatic mechanism that prevents large post prandial swings in serum potassium

A

intracellular sequestration (extrarenal potassium homeostasis)

189
Q

what are the two major factors that stimulate the Na-K-ATPase pump for potassium uptake?

A

insulin and adrenaline

190
Q

what happens to potassium when extracellular hydrogen levels are high (acidosis) so H+ moves into the cells

A

potassium moves out of the cell to maintain electroneutrality

191
Q

potassium can be both secreted and reabsorbed in this part of the kidney (reabsorption always but secretion only when the body needs to get rid of potassium)

A

distal nephron

192
Q

Reabsorption of potassium always occurs at these 3 parts in the kidney

A
  1. proximal convoluted tubule (paracellular route)
  2. thick ascending limb of loop of Henle (Na-K-2Cl cotransporter)
  3. Collecting ducts (intercalated cells)
193
Q

Secretion of potassium only occurs when the body needs to get rid of potassium in this location in the kidneys

A

collecting ducts (principal cells)

194
Q

these cells in the collecting ducts reabsorb sodium and secrete potassium

A

principal cells

195
Q

this is the dominant stimulus for renal potassium excretion; it is secreted by the adrenal glands in response to angiotensin II and by increased plasma potassium concentration
it acts on the principal cells to enhance sodium reabsorption and potassium secretion

A

aldosterone

196
Q

which one inhibits the Na-K-ATPase pumps and which stimulates them: acidosis and alkalosis?

A

acidosis inhibits, alkalosis stimulates

197
Q

this is the most commonly used K+ wasting diuretic; it acts on the thick ascending limb of loop of Henle where it inhibits the luminal Na-K-Cl cotransporter, exacerbating potassium loss

A

furosemide

198
Q

what are the 2 classes of potassium-sparing diuretics

A
  1. aldosterone receptor antagonists
  2. aldosterone independent mechanisms
199
Q

this is an aldosterone receptor antagonist diuretic which blocks the aldosterone receptor located on basolateral side of the cortical collecting duct principal cells (causing lack of potassium excretion)

A

spironolactone

200
Q

the production of either concentrated or dilute urine by the kidney is regulated via these 3 main mechanisms

A
  1. dilution of tubule fluid by TAL and DCT
  2. generation of hypertonic medullary interstitium
  3. variability of water permeability of collecting duct in response to vasopressin
201
Q

a change in this is the major determinant of the volume of water lost by the kidney

A

change in plasma osmolality

202
Q

this is defined as 1 mole of any fully dissociated substance dissolved in water

A

osmole

203
Q

this is defined as the concentration of osmoles in a mass of solvent (kg)

A

osmolality

204
Q

this is defined as the concentration of osmoles in a volume of solvent (L)

A

osmolarity

205
Q

this is the major determinant of plasma osmolality

A

serum sodium concentration

206
Q

these are located within the hypothalamus and sense changes in plasma osmolality

A

osmoreceptors

207
Q

an increase in plasma osmolality sensed by osmoreceptors in the hypothalamus results in increased production and release of this into circulation

A

vasopressin

208
Q

name 3 effects of vasopressin that have a direct effect on both the volume of urine produced and the urine concentration/osmolality

A
  1. net absorption of water from tubule lumen
  2. stimulates reabsorption of urea
  3. enhances reabsorption of NaCl
209
Q

the formation of a dilute or concentrated urine is achieved via a countercurrent mechanism within the nephron including these 3 structures

A
  1. loop of Henle
  2. cortical and medullary collecting ducts
  3. blood supply to these segments
210
Q

what are the 2 countercurrent systems present within the nephron?

A
  1. loop of Henle
  2. vasa recta
211
Q

this limb of the loop of Henle is permeable to water and impermeable to solutes

A

descending limb

212
Q

this limb of the loop of Henle is permeable to solute and impermeable to water

A

ascending limb

213
Q

at any point along the loop of Henle, the fluid in the ascending limb has (higher or lower?) osmolality than the fluid in the descending limb

A

lower

214
Q

osmolality of the tubular fluid and interstitium at the tip of the hairpin turn of the loop of Henle is much (greater or lesser?) compared to those at the corticomedullary junction

A

greater

215
Q

these are the most abundant solutes within the interstitial medulla

A

NaCl and urea

216
Q

this is generated by the liver as a product of protein metabolism and is freely filtered by the glomerulus

A

urea

217
Q

what are the 2 basic steps for the formation of dilute urine

A
  1. NaCl reabsorption w/o water in the thick ascending limb of loop of Henle
  2. absence of vasopressin causing no water reabsorption in collecting tubules
218
Q

what are the two major steps for the excretion of a concentrated urine

A
  1. medullary interstitium is made hyperosmotic by reabsorption of NaCl without water in ascending limb of loop of Henle
  2. vasopressin increases permeability of collecting duct to water to be reabsorbed passively
219
Q

this is a capillary network derived from efferent arterioles that form a parallel set of hairpin loops with the loop of Henle within the medulla;
highly permeable to solute and water & return NaCl and H2O back into systemic circulation; plays integral role in maintenance of medullary osmotic gradient

A

vasa recta

220
Q

what percent of the total body calcium is distributed in the extracellular and intracellular fluid?

A

1%

221
Q

what are the 3 forms of calcium present in the total extracellular calcium?

A
  1. free (55%)
  2. Protein bound (35%)
  3. complexed to other anions (10%)
222
Q

this is the biologically active form of calcium and is the most important for physiological control of calcium concentrations

A

ionized form

223
Q

what form of extracellular Ca is favored with acidemia (increased acid w/in the blood)?

A

ionized Ca (free)

224
Q

what form of extracellular Ca is favored with alkalemia (acid deficit w/in the blood)?

A

protein bound (albumin-bound)

225
Q

what happens to the total calcium concentration when there is decreased albumin concentration?

A

decreases (decr. protein bound fraction of Ca)

226
Q

what is the distribution of phosphorus in the body? (3 locations)

A
  1. bone (80-85%)
  2. soft tissues (15%)
  3. extracellular space (1%)
227
Q

where is the majority of filtered calcium reabsorbed?

A

proximal tubule

228
Q

what percent of phosphorous is excreted with the urine

A

20% (bc it only reabsorbed in proximal tubule)

229
Q

where is PTH synthesized?

A

parathyroid gland (by chief cells)

230
Q

what is the major and principal stimulus for PTH release?

A

decreased plasma calcium concentration

231
Q

what is responsible for the minut-to-minute control of serum [iCa]?

A

PTH

232
Q

what effect does PTH have on serum [Ca] and serum [phosphorous] ?

A

increases serum [Ca], decreases serum [phosphorus]

233
Q

what are the 3 mechanisms by which PTH increases serum [Ca] and decreases serum [phosphorus]

A
  1. effect on nephron (incr. Ca reabsorption and Phosphorus excretion in urine)
  2. effect on bone (activates osteoclasts to release Ca and phosphorous into circulation)
  3. stimulates formation of active form of vitamin D (calcitriol)
234
Q

this initial form of vitamin D is synthesized in the skin with the help of UV light

A

vitamin D3

235
Q

this initial form of vitamin D is ingested in the diet

A

vitamin D2

236
Q

the liver converts vitamin D2 and D3 to this (due to presence of 25-hydroxylase)

A

calcidiol

237
Q

this is found within the proximal tubular cells of the nephron and acts on calcidiol to form calcitriol (the active form of vitamin D)

A

1⍺-hydroxylase

238
Q

what affect does PTH have on the synthesis of 1⍺-hydroxylase (and therefore the formation of calcitriol)?

A

increases it

239
Q

this is responsible for the day-to-day control of serum [iCa]

A

calcitriol

240
Q

what effect does calcitriol have on the serum [Ca] and serum [phosphorus]

A

increases both

241
Q

what is the major site of action for calcitriol

A

intestinal tract

242
Q

what effect does calcitriol have on the intestinal tract?

A

increases calcium and phosphate absorption

243
Q

what effect does calcitriol have on the kidney?

A

stimulates reabsorption of both calcium and phosphate w/in distal tubule

244
Q

what effect does calcitriol have on the bones?

A

bone resorption (increases circulating Ca and phosphorous)

245
Q

what effect does PTH have on the kidney?

A

stimulates Ca reabsorption by thick limb of LoH and inhibits phosphate reabsorption in proximal tubule

246
Q

what effect does PTH have on bones

A

activates osteoclasts (bone breakdown so more Ca and Phosphorous into circulation)

247
Q

name 4 factors that stimulates PTH release

A
  1. hypocalcemia
  2. hyperphosphatemia
  3. decr. PTH
  4. decr. calcitriol
248
Q

name 4 factors that stimulates calcitriol release

A
  1. hypophosphatemia
  2. hypocalcemia
  3. incr. PTH
  4. decr. calcitriol
249
Q

name 4 factors that inhibit PTH

A
  1. hypophosphatemia
  2. hypercalcemia
  3. incr. PTH
  4. incr. calcitriol
250
Q

name 4 factors that inhibit calcitriol

A
  1. incr. calcitriol
  2. hypercalcemia
  3. hyperphosphatemia
  4. decr. PTH
251
Q

name the effect hypercalcemia has on PTH, calcitriol, and calcitonin

A

decr. PTH, decr. calcitriol, incr. calcitonin

252
Q

name the effect hypocalcemia has on PTH, calcitriol and calcitonin

A

incr. PTH, incr. calcitriol, decr. calcitonin

253
Q

this is a hormone synthesized and released from the thyroid gland in response to increased calcium concentration

A

calcitonin

254
Q

which hormone essentially has the opposite effects to PTH

A

calcitonin

255
Q

this is a protein secreted mainly by osteocytes with the overall effect to decrease plasma concentration of ionized phosphorous

A

fibroblast growth factor 23 (FGF-23)

256
Q

what is the equation for pH?

A

pH = -log[H+]

257
Q

under this pH, the patient will be dead

A

< 6.8

258
Q

above this pH, the patient will be dead

A

> 8

259
Q

is considered normal pH

A

7.4

260
Q

this is the main extracellular buffer

A

bicarbonate (HCO3-)

261
Q

these are weak acids or bases which can either bind to or release H+ (H+ titration) to prevent large changes in pH

A

buffers

262
Q

what is the equation for bicarbonate buffering with H+

A

HCO3- + H+ <-> H2CO3

263
Q

when bicarbonate titrates H+, the extra CO2 produced stimulates this in order to eliminate it from the lungs

A

hyperventilation

264
Q

what is the kidneys’ role in maintaining acid-base balance (metabolic component)

A

reabsorption of filtered bicarbonate and generation of new bicarbonate

265
Q

what is the lungs’ role in maintaining acid-bace balance (respiratory component)

A

eliminate or retain CO2 based on H+ concentration

266
Q

this acts as a urinary buffer to allow excretion of H+

A

ammonium (NH4)

267
Q

Describe the process of renal ammoniagenesis in the proximal tubule and fate of the ammonium

A
  1. glutamine is taken up by the proximal tubular cells and converted to bicarbonate and ammonium
  2. ammonium is secreted into tubular lumen
  3. ammonium is reabsorbed into medullary interstitium at LoH
  4. ammonium is secreted again into the collecting duct
268
Q

this is the enzyme which catalyzes H2O + CO2 <-> HCO3- + H+ reaction; it is present in large quantities in the proximal tubule brush border and cytosol of cells

A

carbonic anhydrase

269
Q

what happens to H+ secreted from the proximal tubule into the tubular lumen?

A

recombine with filtered HCO3- (prevents loss of bicarbonate)

270
Q

this is where 80%of bicarbonate is reabsorbed

A

proximal tubule

271
Q

this part of the nephron secretes a quantity of H+ equal to that generated by the animal’s metabolism; secrete H+ combines with a urinary buffer to be excreted in the urine

A

collecting duct (distal nephron)

272
Q

this type of cell in the collecting duct secretes H+

A

type A intercalated cells

273
Q

this type of cell in the collecting duct secretes HCO3-

A

type B intercalated cells

274
Q

urine leaving the collecting duct of carnivores has this pH

A

5.5-7.5

275
Q

urine leaving the collecting duct of ruminants has this pH

A

6-9

ABSC (pt. 2) (4 decks)

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