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Histo Final Exam Extravaganza! > Renal Physiology > Flashcards

Renal Physiology Flashcards

1
Q

concentration

A

the amount of a specified solute in a unit amount of solvent

Can be expressed as percentage, molarity, molality, or electrochemical equivalence

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2
Q

What can’t cross the lipid bilayer by diffusion?

A

charged particles and polar molecules

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3
Q

What can diffuse through the lipid bilayer?

A

lipid soluble molecules and small polar molecules

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4
Q

diffusion

A

movement of particles between two regions from an area of high concentration to an area of low concentration.
Passive: requires no energy

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5
Q

determinants of rate of diffussion

A

size of gradient and permeability of membrane

Sometimes temperature. Faster at higher temperatures

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6
Q

facilitated diffusion

A

Similar to diffusion as it is passive and requires no energy, but it is for particles that can’t normally cross membrane (like charged or polar molecules) and require pores, channels, or carrier proteins

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7
Q

electrochemical gradient

A

concentration gradient and electrical gradient

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8
Q

Which is true about potassium transport by facilitated diffusion?

a. K moves against electrochemical gradient
b. This K transport requires energy
c. Cell membranes in kidney are freely permeable to K
d. This K is transported via transmembrane protein

A

d. This K is transported via transmembrane protein

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9
Q

Active transport

A

movement of particles between two regions from area of low concentration against electrochemical gradient
Requires energy: transporter molecule hydrolyses ATP to ADP

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10
Q

co-transport

A

secondary active transport, movement of molecules across biological membrane against gradient
Requires energy acquired not be direct ATP hydrolysis, but uses potential energy created by active transport elsewhere

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11
Q

symport via symporter

A

co-transport in same direction. ie. sodium glucose symporter

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12
Q

antiport via antiporter

A

co-transport in opposite directions. ie sodium proton exchanger

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13
Q

Sodium potassium ATPase moves sodium by active transport. Which of these is correct?

a. Na K ATPase required hydrolysis of ATP to move Na
b. Na K ATPase moves Na down its concentration gradient
c. Na transport continues until equilibrium is met
d. Na K ATPase is located in the cytosol

A

a. Na K ATPase required hydrolysis of ATP to move Na

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14
Q

Osmosis

A

movement of water across a selectively permeable membrane from a dilute to a concentrated solution
Diffusion of water

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15
Q

effective osmole

A

molecule that can’t cross a membrane and generates osmosis

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16
Q

ineffective osmole

A

when membrane is permeable to a molecule and moves by diffusion down its concentration gradient

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17
Q

osmolarity/osmolality

A

concentration of osmotically active atoms (osmoles/L or osmoles/kg)

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18
Q

How does osmolarity impact osmosis?

A

During osmosis, water moves from low osmolarity to high osmolarity.

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19
Q

A neuron in the brain of a healthy dog has an osmolarity of 300 mOsm/L. The dog becomes sick and acute vomit/diarrhea causes significant water loss from extracellular space, increasing extracellular osmolarity to 350 mOsm/L. What will happen to the nerve cell?

A

Shrink

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20
Q

Tonicity

A

the overall concentration of effective osmoles in a solution

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21
Q

hypotonic

A

a solution with a lower effective osmolarity than another

Cell swells

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22
Q

hypertonic

A

a solution with a higher effective osmolarity than another, cell shrinks

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23
Q

isotonic

A

a solution with the same effective osmolarity as another

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24
Q

Function of renal system

A
  1. cleans the blood
  2. Regulates important extracellular fluid components
  3. endocrine tissue
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25
Q

How does the kidney “clean” the blood?

A

removes waste products by filtering blood then selectively reabsorbing desirable components and passing undesirable components in urine

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26
Q

What percentage of the cardiac output do the kidneys receive?

A

25%

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27
Q

What hormones does the kidney produce?

A

renin to regulate blood pressure and erythropoietin for red blood cell production

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28
Q

location of kidneys

A

just posterior to 13 rib, left kidney is more ventral and caudal
This is conserved across all mammals

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29
Q

capsule

A

layer of mostly collagen with some smooth muscle surrounding the kidney

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30
Q

hilum

A

cleft where ureter and vein leave and artery enters

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31
Q

cortex

A

darker because more organelles in the cytoplasm and more vasculature

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32
Q

medulla

A

lighter portion, fluid has higher osmolarity

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33
Q

renal papilla

A

apex of renal pyramid, fuse to become renal crest

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34
Q

renal pelvis

A

extension of ureter. Sits in the renal sinus, contacts renal papilla. Collects urine and funnels it to ureter.
Made of transitional epithelium

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35
Q

Which is correct?

a. Cleft in kidney where ureter and vasculature enter/leave is called the capsule
b. paired kidneys are located anteriorly in the body cavity
c. gross external morphology is high conserved across species
d. in most species, the right kidney is more cranial than the left

A

d. in most species, the right kidney is more cranial than the left

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36
Q

renal corpuscle

A

site of filtration, includes glomerulus and Bowman’s capsule. Glomerulus is capillary tuft enveloped by Bowman’s capsule

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37
Q

proximal tubule

A

place for majority of reabsorption

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38
Q

loop of Henle

A

used reabsorption of Na, Cl, and water

Longer in desert animals and shorter in aquatic animals

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39
Q

collecting tubule/duct

A

to fine tune fluid constituents. Place for final reabsorption/ secretion
Derived from uriniferous tubule

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40
Q

Structures in the cortex

A

renal corpuscles, cortical labyrinth and medullary rays

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41
Q

components in cortical labyrinth

A

Proximal convoluted tubules and distal convoluted tubules

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42
Q

structures in medullary rays

A

proximal straight tubules, distal straight tubules, collecting ducts

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43
Q

Is the proximal or distal convoluted tubule longer?

A

proximal

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44
Q

structures in outer medulla

A

loops of Henle, distal straight tubules, collecting ducts

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45
Q

structures in inner medula

A

collecting ducts

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46
Q

Which of these is only in the cortex?

a. collecting duct
b. loop of Henle
c. renal corpuscle
d. distal straight tubule
e. renal pelvis

A

c. renal corpuscle

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47
Q

What determines capillary pressure in the glomerulus?

A

afferent/efferent arteriole structure

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48
Q

afferent vs efferent arterioles

A

Blood leaves through efferent arteriole and enters through afferent arteriole.
Efferent has slightly smaller lumen and is less stretchy than afferent. Builds pressure in glomerulus

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49
Q

What percentage of blood enters the bowman’s capsule from the glomerulus?

A

20%

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50
Q

macula densa

A

specialized cells in wall of distal straight tubule touching the glomerulus.
Regulates glomerular filtration. Located at vascular pole of renal corpuscle. Cells are tall and tightly packed. Lack a basement membrane

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51
Q

visceral layer of Bowman’s space

A

includes podocytes and pedicels

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52
Q

filters in glomerulus

A

basal lamina and slit diaphragm

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53
Q

layers of basal lamina

A

lamina rara externa, lamina densa, lamina rara interna

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54
Q

Which of these is only in the medulla?

a. Proximal tubule
b. Loop of Henle
c. collecting duct
d. distal tubule
e. renal corpuscle

A

b. Loop of Henle

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55
Q

Proximal tubule

A

found in cortical labyrinth and medullary rays
Luminal membrane has long microvilli (brush border).
Lots of mitochondria for active processes like active transport.
Nucleus is large and centrally located or toward basolateral membrane.

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56
Q

Which is most accurate regarding proximal tubule?

a. They lack mitochondria
b. Nuclei are located apically
c. they are inefficient at absorption
d. they have simple squamous epithelium
e. they have an extensive brush border

A

e. they have an extensive brush border

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57
Q

Loop of Henle

A

starts at corticomedullary boundary. Ascending limb is slightly shorter than descending limb. Used for passive absorption. Descending limb is permeable to water but not solutes. Ascending limb is permeable to solutes and not water.
Consists of simple squamous epithelium and clear lumen

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58
Q

Distal tubule

A

low cuboidal epithelium. oval shaped apical nuclei, few microvilli, fewer mitochondria, not permeable to water
Used for reabsorption but not as much as proximal tubule.
Distal straight has more mitochondria than distal convoluted tubule.
Later distal tubule can be permeable to water with antidiuretic hormone.

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59
Q

Juxtaglomerular cells

A

Specialized muscle cells in the afferent arteriole, trigger renin-angiotensin system

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60
Q

Juxtaglomerular apparatus

A

includes macula densa, extraglomerular mesangial cells, and juxtaglomerular cells
stretch receptors in afferent arterioles, initiates renin-angiotensin system to increase a low ECF volume in a process separate to renal autoregulation that regulates GFR and control of Na reabsorption

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61
Q

collecting tubules

A

located all the way from the outer cortex to the renal crest.
Clear lumen with clear halo around cell nuclei

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62
Q

principal cells

A

found in cortical collecting tubules, for reabsorption. Cuboidal epithelium. Nuclei oval shaped and centrally located or toward the lumen. Lightly staining, no brush border

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63
Q

intercalated cells

A

in the cortical collecting tubules. Used for secretion, protrude past the principal cells, fewer going deep into medulla

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64
Q

ureter

A

conveys urine from kidney to bladder.
Mucosa: transitional epithelium overlying lamina propria (loose connective tissue, protective and immune functions)
Tunica muscularis: 2/3 layers of smooth muscle
Outer coat (adventitia): connective tissue

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65
Q

Bladder

A

Mucosa: transitional epithelium overlying 2 layers of lamina propria
Tunica muscularis: 3 layers of smooth muscle (detrusor muscle)
Outer coat (adventitia): connective tissue

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66
Q

internal sphincter muscle of urinary bladder

A

involuntary control of urination. Opens with bladder is full

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67
Q

external sphincter muscle of urinary bladder

A

voluntary control of voiding the bladder

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68
Q

micturition

A

filling and voiding of bladder

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69
Q

urethra

A

Mucosa; transitional epithelium overlying large porous lamina propria
Tunica muscularis: 2 irregular layers of smooth muscle
Outer coat (adventitia): connective tissue
Dominant layer is circular muscle with deeper longitudinal layer.

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70
Q

Which epithelial type is in the Loop of Henle?

a. cuboidal
b. simple squamous
c. transitional
d. low cuboidal

A

b. simple squamous`

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71
Q

fenestrated epithelium of glomerulus

A

large pores filter cells, antibodies and large proteins

Polyanionic glycoprotein glycocalyx with heparin sulfate repels negative charges

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72
Q

Filtration by lamina rara interna and externa

A

in glomerulus, has polyanionic non-collagenous proteins

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73
Q

filtration by lamina rara densa

A

in glomerulus, collagenous proteins form a mesh that filters based on size

74
Q

filtration by slit diaphragm

A

in glomerulus, perforated with small pores, not an effective filter
podocytes with polyanionic glycoprotein glycocalyx repels negative charges and neighboring podocytes

75
Q

equation for glomerular filtration rate

A

Kf((Pc-Pbs)-(pi c - pi bs))

76
Q

Kf

A

= permeability of capillary multiplied by filtration surface area

77
Q

Do diseases increase or decrease filtration surface area?

A

decrease

78
Q

How does capillary hydrostatic pressure (Pc) change when the efferent arteriole contracts?

A

it increases

79
Q

How does liver failure impact GFR?

A

Hypoproteinemia, pi c decreases and GFR increases

80
Q

How can blockage in urethra or ureter impact GFR?

A

increases Bowman’s space oncotic pressure and GFR decreases

81
Q

Which is correct?

a. Normal afferent arteriole and constricted afferent arteriole decreases GFR
b. constricted afferent arteriole and normal efferent arteriole increases GFR
c. normal afferent arteriole and dilated efferent arteriole increases GFR
d. dilated afferent arteriole and normal efferent arteriole increases GFR

A

d. dilated afferent arteriole and normal efferent arteriole increases GFR

82
Q

Goals of renal autoregulation

A
  1. Prevent damage to glomeruli caused by spiking blood pressure (maintain flow)
  2. prevent fluctuations in blood pressure from changing delivery of filtrate to tubules (maintain GFR)
83
Q

myogenic mechanism of renal autoregulation

A

triggered by fluctuations blood pressure in afferent arteriole
Increased BP causes vasoconstriction. Decreased BP causes vasodilation.
Rapid changes in 1-2 seconds

84
Q

Which is true about the myogenic mechanism?

a. it helps to protect the glomerulus
b. it is triggered in the efferent arteriole wall
c. it will reduce GFR in response to low blood pressure
d. it is a slow acting response
e. the main effect is to constrict the efferent arteriole

A

a. it helps to protect the glomerulus

85
Q

Tubuloglomerular feedback mechanism of autoregulation.

A

triggered by fluctuation in BP changing GFR and composition of distal tubule fluid.
Low/high ion concentration is sensed by macula densa and juxtaglomerular apparatus changes arteriole resistance.
Slower changes in 10-12 seconds.

86
Q

extraglomerular mesangial cells

A

part of JGA, promote information transfer between macula densa and juxtaglomerular cells

87
Q

production of angiotensin II

A

liver produces angiotensinogen that is converted to angiotensin I by renin which is converted to angiotensin II by angiotensin converting enzyme (ACE) produced in the lungs

88
Q

angiotensin II

A

systemic arteriolar vasoconstriction to increase blood pressure
Increases aldosterone secretion by adrenal cortex.
Promotes ADH secretion in pituitary and thirst
Increases tubular NaCl uptake.

89
Q

Which is correct when high GFR is lowered by tubular glomerular feedback?

a. JG cells release renin
b. macula densa releases PGE2
c. The trigger is low Na, K, and Cl sensed by the macula densa
d. a key intermediate step is decreased intracellular Ca in extraglomerular mesangial cells.
e. afferent arteriole smooth muscle contracts

A

e. afferent arteriole smooth muscle contracts

90
Q

How do NSAIDs cause acute renal failure?

A

prevent production of PGE2

91
Q

Captopril is an ACE inhibitor. Which is correct?

a. Captopril increases Angiotensin II and decreases GFR
b. Captopril reduces Angiotensin II and increases GFR
c. Captopril reduces Angiotensin II and decreases GFR
d. Captopril increases Angiotensin II and increases GFR

A

c. Captopril reduces Angiotensin II and decreases GFR

92
Q

luminal membrane

A

separates tubular cell from tubular fluid

93
Q

basolateral membrane

A

separates cell from peritubular interstitium

94
Q

Transepithelial potential difference

A

the potential difference between tubular lumen and peritubular interstitium
Changes between tubular sections and contributes to electrochemical gradient

95
Q

Transcellular reabsorption or secretion

A

Reabsorption or secretion through cytoplasm of tubular.

Both passive and active transport can be transcellular but all active transport must be transcullar

96
Q

paracellular reabsorption or secretion

A

not crossing the membrane, simple diffusion.
Reabsorption between tubular cells across tight junctions.
Allows reabsorption of ions and nonpolar solutes by passive transport only.

97
Q

Which membrane has Na K ATPase? Which tubular sections?

A

basolateral membrane of all sections

98
Q

Which is correct regarding Na K ATPase?

a. It transports Na and K at the luminal membrane of nephron epithelia
b. It moves 3 Na into the cells in exchange for 2 K out of the cell
c. Na movement is by facilitated diffusion
d. It requires energy in the form of ATP
e. It moves K paracellularly

A

d. It requires energy in the form of ATP

99
Q

Reabsorption in 1st half of proximal tubule

A
  1. Na K ATPase generates Na gradient
  2. Na enters down electrochemical gradient via passive transport by Na H antiporter and secondary active transport by Na glucose symporter
  3. Water follows Na down osmotic gradient
100
Q

How would diabetes impact reabsorption in the proximal tubule?

A

more glucose in the lumen acts as an osmole sink preventing water reabsorption, Animal become polyureic

101
Q

Reabsorption in 2ns half of proximal tubule

A
  1. Na K ATPase generates Na gradient
  2. Na enters down electrochemical gradient via Na H antiporter
  3. Cl enters down electrochemical gradient via Cl anion antiporter and pia paracellular route.
  4. Lumen +ve PD drives Na down paracellular route. Water follows by osmosis
102
Q

anions used by Cl anion antiporter

A

hydroxyl, formate, etc

103
Q

protein reabsorption in proximal tubule

A

some small proteins filtered by glomerulus
These are partially degraded by enzymes in luminal membrane and reabsorbed by endocytosis
Further degraded by enzymes in lysozyme into amino acids and leave via basolateral membrane
Process can be easily saturated because Tmax is low so proteins can appear in the urine (proteinuria)

104
Q

Reabsorption in Loop of Henle

A

water reabsorption occurs in descending limb only

NaCl reabsorption si passive and occurs in ascending limb only

105
Q

Which is correct about tubular reabsorption?

a. Na is reabsorbed actively at the luminal membrane in the proximal tubule
b. Glucose is reabsorbed via facilitated diffusion
c. Cl reabsorption is both transcellular and paracellular
d. Most water is reabsorbed in the descending loop of Henle

A

c. Cl reabsorption is both transcellular and paracellular

106
Q

Reabsorption in initial distal tuble

A
  1. Na K ATPase generates Na gradient
  2. Na enters cell via NKCC1 symporter and Na H antiporter.
  3. +ve TPD means cations move down electrochemical gradient via paracellular route. Water does not follow because it is not permeable here.
107
Q

What is the mechanism of loop diuretics?

A

Loop diuretics like furosemide inhibit NKCC1 symporter

108
Q

ion movement by NKCC1 symporter

A

2 cl and 1 Na moves inside cell down electrochemical gradient, 1 K moves inside cell against electrochemical gradient

109
Q

reabsorption in later distal tubule

A

Still impermeable to water

  1. Na K ATPase generates Na gradient
  2. Na enters cell via Na Cl symporter
110
Q

What is the mechanism of Thiazide diuretics

A

inhibit Na Cl symporter in later distal tubule

111
Q

reabsorption by principal cells

A

in collecting ducts

  1. Na K ATPase generates Na gradient
  2. Na enters cell via amiloride sensitive Na channels. Water follows via aquaporin when ADH is present
  3. K leaves through K channels down K gradient (important for K homeostasis)
  4. Na reabsorption generates negative PD so Cl are reabsorbed via paracellular route
112
Q

Reabsorption by intercalated cells

A

in papillary collecting ducts
Can secrete H or HCO3-, which is important for maintaining acid-base balance (maybe, proton could be secreted just to balance the Na absorbed by principal cells)

113
Q

Which of these is in order from most Na reabsorption to least Na reabsorption?

a. distal tubule, proximal tubule, loop of Henle
b. Distal tubule, loop of Henle, proximal tubule
c. proximal tubule, loop of Henle, distal tubule
d. proximal tubule, distal tubule, loop of Henle
e. loop of Henle, Proximal tubule, distal tubule

A

c. proximal tubule, loop of Henle, distal tubule

114
Q

Countercurrent Multiplication in Loop of Henle

A

Most water is reabsorbed in proximal tubule since it follows the concentration of ions.
Loop of Henle dissociates water reabsorption from the absorption of glucose, phosphates, and amino acid molecules,
Fluid is moving in two directions, action in ascending limb amplifies water absorption descending limb and vice versa

115
Q

How does interstitial osmolarity change between cortex and medulla?

A

the deeper into the medulla, the higher the interstitial osmolarity

116
Q

What is the tonicity of fluid entering the distal tubule?

A

Hypotonic

117
Q

Which is true about the loop of Henle?

a. Distal tubule fluid is hypertonic compared to interstitium
b. Na is reabsorbed passively at the descending limb
c. Water is reabsorbed down an osmolarity gradient (low to high osmolarity)
d. interstitial osmolarity decreases towards papilla

A

c. Water is reabsorbed down an osmolarity gradient (low to high osmolarity)

118
Q

What are the monitoring locations for release of ADH hormone?

A

osmoreceptors in hypothalamus shrink and swell to detect changes in body fluid osmolality
Baroreceptors in circulatory system detect changes in plasma volume or arterial pressure. Suppresses ADH production when blood pressure and fluid volume increases.

119
Q

Other names for Antidiuretic hormone?

A

abbreviated ADH, vasopressin and arginine vasopressin

120
Q

Mechanisms of ADH

A
  1. Changes collecting duct permeability to water by increasing expression of aquaporins
  2. Changes MEDULLARY collecting duct permeability to urea by increasing expression of urea transporters
121
Q

diuresis

A

production of a large volume of dilute urine

Occurs when ADH levels are low and the animal is trying to excrete water

122
Q

Antidiuresis

A

when ADH levels are high, Low volume of concentrated urine is produce because collecting duct is able to reabsorb water

123
Q

reabsorption of urea

A

excreted into blood stream by liver, a little is reabsorbed in proximal tubule. Loop of Henle is not very permeable to urea. As water leaves the descending limb, concentration of urea increases in tubules. When ADH is present, urea can exit the medullary collecting duct into the medullary interstitial fluid. Here urea is an ineffective osmole, but it is an effective osmole at the loop of Henle and helps to reabsorb more water than normal in the descending limb

124
Q

Which is true during diuresis?

a. Medullary urea concentration is relatively low
b. collecting duct permeability to water is high
c. water reabsorption in the descending limb of the loop is increased
d. fluid in the collecting duct is hypertonic to interstitium

A

a. Medullary urea concentration is relatively low

125
Q

vasa recta

A

network of blood vessels that acts as a countercurrent multiplier to remove the reabsorbed water and solutes in the interstitium surrounding the loop of Henle to maintain the right concentrations.
Sodium moves into the lumen of the descending limb and water moves into the lumen of the ascending limb

126
Q

Mannitol can be used as an osmotic diuretic. It is freely filtered and acts as an effective osmole within the collecting duct, increasing the osmolarity of the tubular fluid in the collecting. What would happen to urine volume?

A

it will increase

127
Q

How does the kidney regulate ECF osmolarity?

Volume?

A

Kidney regulates ECF osmolarity by changing ECF Na concentration. Kidneys regulate ECF volume by changing ECF Na amount.

128
Q

What is the only organ in the animal that can regulate Na concentration and amount in the ECF and therefore the only organ that can regulate ECF osmolarity and volume?

A

the kidney

129
Q

What molecule/ion is the primary determinant of ECF osmolarity?

A

sodium

130
Q

consequences of hypernatremia

A

high ECF Na concentration:

rupture of cerebral vessels/ hemorrhage, muscle weakness, behavioral changes/ ataxia, coma leading to death

131
Q

consequences of hyponatremia

A

low ECF Na concentration: cerebral/ pulmonary edema, muscle weakness, incoordination and seizures

132
Q

Defense against changes in ECF Osmolarity

A

osmoreceptors swell or shrink and can create thirst response in pituitary to produce ADH

133
Q

Which is true about hyponatremia?

a. There will likely be translocation of fluid from ECF to ICF
b. Osmoreceptors in hypothalamus will shrink
c. ADH release will be increased
d. The animal will feel thirsty
e. A hyponatremic animal will have high ECF Na concentration

A

a. There will likely be translocation of fluid from ECF to ICF

134
Q

consequences of high ECF volume

A

hypervolemia, high blood pressure, ascites, pulmonary edema

Must increase Na excretion

135
Q

consequences of low ECF volume

A

hypovolemia, hypovolemic shock, organ damage, low blood pressure

136
Q

potential causes of changes to ECF fluid volume

A

Changes to ECF sodium amount, blood loss, vomiting, liver failure

137
Q

ascites

A

fluid accumulation in the abdomen

due to high ECF volume

138
Q

hypovolemic shock

A

due to low ECF volume, increases heart contraction, tachycardic, dizziness

139
Q

diseases impacting sodium reabsorption in the kidney

A

Addison’s and Cushing’s disease

140
Q

How does liver failure impact ECF volume?

A

less protein, decreased capillary oncotic pressure, decreased ECF volume in bloodstream

141
Q

Baroreceptors

A

stretch receptors, in heart, aorta, carotid sinus, causes sympathetic nervous system to increase low ECF volume, causes natriuretic peptide release to decrease a high ECF volume

142
Q

How does sympathetic flow regulate ECF volume?

A

Baroreceptors detect decreased ECF volume to increase sympathetic flow which increases Na and water reabsorption which increases ECF volume.
1. Norepinephrine is a vasoconstrictor.
Efferent arteriole constricts more than afferent= increased GFR. Alters Starling’s forces to increase Na reabsorption
2. Stimulates Na reabsorption from proximal tubule
3. Stimulates renin release from JGA to activate RAS

143
Q

Decreased ECF volume and the RAAS

A

Stimulation of RAS increases Na and water reabsorption, increasing ECF volume

  1. angiotensin II constricts efferent arterioles to increase GFR and change starling’s forces to increase Na and water uptake
  2. Angiotensin II stimulates Na H antiporter to increase Na uptake
  3. Angiotensin II stimulates ADH release to increase water uptake
  4. Angiotensin II stimulates aldosterone release to increase Na uptake
144
Q

Aldosterone

A
  1. increases NKCC1 transporter
  2. increases sodium channels in luminal membrane of collecting duct
  3. increases number and activity of Na K ATPase
145
Q

natriuretic peptides

A

Increased natriuretic peptide decreases Na reabsorption which reduces water reabsorption and decreases ECF volume

  1. Constricts efferent arterioles and dilates afferent arterioles. This increases GFR to increase Na and water load entering tubules
  2. Inhibits renin release from JGA to inhibit RAS
  3. Inhibits ADH release by inhibiting RAS
  4. Inhibits aldosterone release by inhibiting RAS and acting directly on adrenal cortex
  5. Inhibits NaCl reabsorption in collecting duct by inhibiting Na channels
146
Q

Which is correct about hypovolemia?

a. The animal will respond by increasing sympathetic flow to the kidneys
b. To correct it, the Renin-Angiotensin system will be inhibited
c. The animal will respond by increased release of natriuretic peptides
d. It is defined as high ECF volume
e. It is caused by low ECF Na concentration

A

a. The animal will respond by increasing sympathetic flow to the kidneys

Want to increase Na reabsorption

147
Q

Low ECF volume is returned to normal by:

a. stimulation of RAAS
b. increased natriuretic peptide release
c. increased sympathetic flow to kidneys
d. A and C only
e. all of the above

A

d. A and C only

148
Q

potassium

A

main intracellular cation
Major determinant of resting membrane potential, therefore determines behavior of all excitable cells
concentration

149
Q

Hypokalemia

A

decreased serum potassium concentration
action potential harder to initiate
Presents with muscle weakness, respiratory problems, cardiac arrhythmia, renal dysfunction

150
Q

Hyperkalemia

A

increased serum potassium
action potential harder to repeat
Presents with muscle weakness, cardiac dysfunction

151
Q

regulators of K balance

A

Insulin: promotes movement of K into cells by stimulating Na K ATPase
Epinephrine: promotes movement of K into cells (beta stimulation of Na K ATPase) and out of cells (alpha)

152
Q

impacts of acidosis/alkalosis on K balance

A

High H+ (acidosis) promotes movement of K out of cells (to maintain electroneutrality)
low H+ (alkalosis) moves K into cells

153
Q

What is the only regulated site of potassium excretion?

A

the kidney

balances excretion with K consumption

154
Q

Which is true about extracellular fluid K concentration?

a. Oliguria (low urine output) may increase ECF K concentration
b. ECF K concentration is higher than that of ICF
c. Insulin will increase ECF K concentration
d. Acidemia (decreasing ECF K concentration)
e. Increased dietary K will decrease ECF K concentration

A

a. Oliguria (low urine output) may increase ECF K concentration

155
Q

Reabsorption of K in proximal tubule

A

67% of K reabsorption, through channels in basolateral membrane and Lumen +ve PD moves K via paracellular route

156
Q

K secretion

A

principal cells in collecting duct

  1. Na K ATPase generates Na gradient
  2. Na enters cell via amiloride sensitive Na channels
  3. K leaves through K channels down K gradient
157
Q

amiloride like diuretics

A

a.k.a K sparing diuretics don’t let potassium leak out and be secreted

158
Q

K reabsorption in distal tubule and collecting duct

A

alpha intercalated cells in distal tubule and collecting duct: H+ leaves through H K ATPase and K enters

159
Q

Which section of the nephron is able to both absorb and secrete K?

A

distal tubule

160
Q

Bartter’s syndrome is a genetic disorder that causes a dysfunctional, impaired NKCC1. What can be a result?

A

hypokalemia

161
Q

How does increased plasma K concentration impact K excretion?

A 
Aldosterone:
1. Increases Na K ATPase
2. Increases Na channels
3. Increases K channels
These processes are less active when plasma K is decreased
162
Q

Kon’s disorder

A

hyperaldosteronism and hypokalemia

163
Q

Addison’s disese

A

Hypoaldosteronism and hyperkalemia

164
Q

How does tubular flow rate impact K excretion?

A

Decreased tubular flow rate decreases K secretion.
Increased tubular flow rate increases K secretion.
Exception: normal everyday diuresis and antidiuresis

165
Q

How does lumen electronegativity impact K excretion?

A

Increased lumen electronegativity increases K secretion.
Decreased lumen electronegativity decreases K secretion.
(Acidosis promotes K secretion at basolateral membrane causing hyperkalemia)

166
Q

Which of the following could lead to hypokalemia?

a. Decreased lumen electronegative (less, negative, more positive)
b. Low tubular flow rate
c. increase aldosterone release
d. amiloride-like diuretics

A

c. increase aldosterone release

167
Q

normal blood pH

A

7.35 to 7.45

168
Q

acidosis

A

processes by which acidemia occurs (pH<7.35

Protons bind to proteins denaturing them

169
Q

alkalosis

A

the processes by which alkalemia occurs (pH>7.45 protons dissociate from proteins, netaturing them

170
Q

3 things that determine pH

A
  1. partial pressure of carbon dioxide
  2. strong ion difference (SID)
  3. Weak acid buffers (Atot)
171
Q

respiratory acidosis

A

decreased ventilation rate causes increase ECF CO2 and more protons

172
Q

respiratory alkalosis

A

increased ventilation rate causes decreased ECF CO2 and less protons

173
Q

T/F Increasing ventilation rate will decrease ECF pH

A

False, respiratory alkalosis, increased pH

174
Q

strong ion difference

A

SID, difference between the greater amount of positive ions and lesser amount of negative ions
Changing SID changes ionic strength of ECF. SID drives dissociation of water to maintain electroneutrality with more cations than anions.

175
Q

How do vomiting and diarrhea impact SID?

A

vomiting causes loss of chloride ions, diarrhea causes excessive loss of sodium ions.

176
Q

What are the effects on SID and acid base balance by diarrhea? (excessive loss of sodium)

A

SID will decrease and cause metabolic acidosis by increasing H+ relative to OH-

177
Q

How do proteins impact pH?

A

they are negatively charged and weak acids so if Atot increases, pH will decrease

178
Q

Which statement about Atot is correct?

a. It is primarily determined by ECF phosphate concentration
b. it will increase if animal is hypoproteinemic
c. It is decreased by proteinuria

A

c. It is decreased by proteinuria

179
Q

How do the three determinants of pH interact?

A

Disturbance in one factor is compensated by the other two so respiratory acidosis is compensated by metabolic alkalosis

180
Q

How is renal NH4+ synthesis and secretion impacted by acidosis or alkalosis?

A

Acidosis stimulates renal NH4+ synthesis and secretion to maintain electroneutrality. In alkalosis, renal NH4+ is suppressed

Histo Final Exam Extravaganza! (9 decks)

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