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Vet Year 1 > Renal Physiology > Flashcards

Renal Physiology Flashcards

1
Q

Which of the following is NOT a process important for renal function and formation of urine?
A. Filtration via glomeruli
B. Reabsorption via tubules
C. Secretion via tubules
D. Filtration via the ureter

A

D

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2
Q

Which method are sodium ions most likely to be excreted by?
1. filtration only
2. filtration and partial reabsorption
3. filtration and complete reabsorption
4. filtration and secretion

A

2

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3
Q
  1. What capillary networks in the nephron are involved with filtration versus reabsorption?
A

A: Glomerular capillaries are for filtration; Peritubular capillaries are for reabsorption

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4
Q
  1. True or False: All 3 layers of the filtration barrier has a positive charge.
A

False

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5
Q
  1. What molecules are not freely filtered into the glomerular filtrate?
A

Answer: Proteins, calcium, and fatty acids (calcium and fatty acids that are bond to proteins are not filtered)

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6
Q

. True or false: Endothelin acts as a vasodilator when released by damaged renal endothelial cells

A

Answer: False - endothelin acts as a vasoconstrictor

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7
Q
  1. Which Na reabsorption in renal tubules is incorrect?
    A) Na is actively transported against the electrochemical gradient out of cells on the basolateral membrane through ATPase
    B) Na diffuses into cells due to electrochemical gradient on the luminal membrane
    C) Na is involved in secondary active transport of glucose and amino acids on the luminal membrane
    D) Na diffuses into cells due to electrochemical gradient on the basolateral membrane
A

D

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8
Q
  1. Which is reached first in solute reabsorption, the transport maximum or threshold? What occurs when the first is surpassed and why?
A

A: The threshold is reached before the transport maximum. If the threshold is surpassed, solutes (eg. Glucose) will begin to be excreted in the urine due to nephrons having different transport maximum capacities, where the overall transport maximum represents the point at which transport through all nephrons has been sufficiently maximized.

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9
Q
  1. Which of the following best describes renal clearance?
    a) the volume of plasma for which a substance is completely removed by the kidneys per unit of time
    b) the rate at which urine is produced by the kidneys
    c) the amount of waste products excreted from the kidneys over 24hours
    d) the efficiency of the kidneys to filter and excrete waste products
A

A

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10
Q
  1. What are the gradient transport rules for passive renal reabsorption? select all that apply:
    A) Time
    B) permeability of the membrane
    C) ATP available for transport
    D) electrochemical gradient force
A

A,B, and D

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11
Q
  1. True or false: The leakiness of glomerular capillaries means they do not contribute much to renal vascular resistance. True or False?
A

True

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12
Q

What is in the proximal tubules that are adapted for high reabsorption capacity?
a epithelial cells
bamino acids
c glucose
d proteins

A

a

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13
Q

Select the correct order of substances based on the % that is filtered and reabsorbed back into the blood (least to greatest):
1. Urea
2. Waste products
3. Sodium
4. Glucose/amino acids
5. Water
6. Bicarbonate

  1. 1 > 3 > 2 > 6 > 4 > 5
  2. 2 > 1 > 5 > 3 > 6 > 4
  3. 2 > 1 > 4 > 3 > 5 > 6
  4. 1 > 2 > 6 > 3 > 5 > 4
A

2

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14
Q

The reabsorption of proteins happens by
1. Passive transport from lumen of tubule to the peritubular capillary
2. active transport via pinocytosis which traps the proteins in vesicles and move them to the peritubular capillary
3. active transport using Na+/K+ ATPase
4. diffuse across membranes

A

2

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15
Q
  1. As hydrostatic pressure of the arterioles (peritubular capillaries) rises, what happens to the hydrostatic pressure of the interstitial fluid?
    a. it rises
    b. it stays the same
    c. it decreases
A

a

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16
Q
  1. True or false: the transport maximums are the same for each nephron.
A

False

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17
Q
  1. True or false: under normal conditions the net reabsorption force is negative
A

False

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18
Q

Which cells are responsible for the day-to-day adjustments of [K+]?
1. intercalated cells in the late distal and collecting tubules
2. endothelial cells in the proximal tubules
3. endothelial cells in the thick ascending section in the loop of Henle
4. principal cells in the late distal and collecting tubules

A

4

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19
Q
  1. Which is faster when adjusting K+ plasma levels?
    a. Transport between extra- and intracellular stores
    b. Using renal excretion
A

a

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20
Q
  1. True or false: calcium is secreted by the kidneys?
A

false

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21
Q
  1. Which of the following is false regarding aldosterone?
    a. increased extracellular potassium stimulates it release
    b. it increases sodium reabsorption and potassium secretion
    c. if the adrenal gland function was reduced, sodium concentration would increase
    d. it is released from adrenal cortex
A

c

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22
Q
  1. The NHE transporters on the apical surface of the tubule epithelial cells move Na+ ____ and H+ _____ of the cell. This is important for _______________.
A

Into, Out, acid base balance

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23
Q

If an animal is in a state of water excess in the urine, what hormone is low?
1. Insulin
2. ADH
3. PAH
4. Serotonin

A

2

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24
Q
  1. True or False: ADH and the hyperosmolarity of the renal medullary interstitium are the two main factors affecting the urine concentrating process.
A

true

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25
Q

What are the two main mechanisms involved in the regulation of extracellular fluid osmolarity?
1. thirst mechanism, pressure natriuresis and diuresis
2. pressure natriuresis and diuresis, tubuloglomerular feedback
3. thirst mechanism, osmoreceptor-ADH system
4. tubuloglomerular feedback, glomerulotubular balance mechanism

A

3

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26
Q
  1. Name the 2 components required for the bicarbonate buffer system
A

Answer: The bicarbonate buffer system requires carbonic acid (H2CO3) and a bicarbonate salt (e.g. NaHCO3).

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27
Q

Glucose is actively transported by different transporters on the apical vs. basolateral membranes of the proximal tubules. At the apical membranes, glucose is transported primarily (90%) by:
1. SGLT1
2. SGLT2
3. GLUT1
4. GLUT2

A

2

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28
Q
  1. Which of the following is INCORRECT regarding the main causes/forms of postrenal acute renal failure?
    a. Ureter obstruction
    b. Tubular obstruction
    c. Bladder obstruction
    d. Urethra obstruction
A

b

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29
Q

With metabolic acidosis, what is the primary issue and what is the renal compensatory response?
1. Decreased HCO3-, increased H+ excretion
2. Increased HCO3-, increased H+ excretion
3. Decreased PCO2, decreased H+ excretion
4. Increased PCO2, decreased H+ excretion

A

1

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30
Q

Which molecule is an example of a substance that is freely filtered and entirely reabsorbed?
1. H+ ion
2. Glucose
3. Chloride
4. Sodium

A

2

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31
Q

Nephrons with a loop of Henle that can concentrate urine are unique to which species?
1. dogs
2. horses
3. chickens
4. all of the above

A

4

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32
Q
  1. Most diuretics work by primarily:
          a. Reducing water reabsorption
          b. Decreasing urine output
          c. Interfering with Na+ reabsorption
          d. Excretion of K+, Cl-, Mg2+, and Ca2+
A

c

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33
Q
  1. What transport mechanism is utilized to absorb proteins in proximal tubules?
A

Answer: pinocytosis

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34
Q
  1. What are the two main mechanisms involved for regulating extracellular fluid osmolarity?
A

osmoreceptor-ADH system and the thirst mechanism

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35
Q

Explain the difference between cortical and juxtaglomerular nephrons.

A

A: cortical nephrons have their glomerulus in the outer cortex, they have a short loop of
Henle, and an extensive peritubular capillary network. Juxtamedullary nephrons have a
glomerulus close to the renal medulla (but still in the cortex), a long loop of Henle, and a
less extensive peritubular capillary network that has a vasa recta.

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36
Q

What are the 4 different methods that substances may be excreted from the body?
Provide an example of one substance that may be primarily secreted using each
method.

A
  1. filtration only (waste products)
  2. filtration and partial reabsorption (electrolytes)
  3. filtration and complete reabsorption (nutrients)
  4. filtration and secretion (organic acids/bases)
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37
Q

If the efferent arteriolar resistance increases, what is the effect on pressure? What is
a characteristic of this increased resistance?

A

A: The pressure will increase. Unique characteristic of this type of resistance is that it is
biphasic. The increased resistance is short lived and is followed by a decrease.

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38
Q

Which of the following is true about kidney?
A. Renal pyramid refers to the shape of the kidney.
B. Kidneys are located inside of the peritoneal cavity.
C. Collecting duct is located in renal pelvis
D. Ascending loop of Henle of nephron has thin and thick segments
E. Vasa recta vessels branch off the efferent artrioles of cortical nephron

A

D

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39
Q

What molecules are not freely filtered out of the glomerular capsule and why?

A

Proteins are not able to be filtered because they are large and negatively charged.
Calcium cannot be filtered freely because half is bound to proteins and fatty acids cannot
be filtered because they are also bound to proteins.

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40
Q

What type of molecules has the best filterability in the glomerulus in a healthy
animal?
a) small negative charged molecules
b) large negative charged molecules
c) small neutral molecules
d) small positive charged molecules

A

D

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41
Q

Albumin is a protein abundant in the blood and is relatively smaller than other
proteins. Why doesn’t albumin get filtered from the glomerular capillaries into the
Bowman’s capsule?

A

The three filtration membranes all have negative charge, and proteins carry a negative
charge, therefore they electrically repulse each other. Even though albumin is a relatively
small protein, it is still larger than other substances that pass freely through the filter.

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42
Q

There are 4 main processes by which substances are excreted in the renal system.
Which of these pairs of substances most commonly undergo the process of filtration
and complete reabsorption?
(a) urea and sodium
(b) glucose and amino acids
(c) glucose and organic acids
(d) creatinine and amino acids

A

B

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43
Q

What are the 5 ways the kidneys regulate body fluids?

A

A: Regulation of plasma volume, inorganic solutes, osmotic balance, pH, & waste
removal

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44
Q

Which of the following do not make up the filtration barrier?
a. Endothelium of glomerular capillaries
b. Podocytes
c. Basement membrane of capillaries
d. Epithelial cells of Bowman’s capsule
e. None of the above

A

d

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45
Q

. Determine if the following determinants↑or↓GFR
Norepinephrine
Epinephrine
Endothelin
NO
Prostaglandins
Bradykinin
Glomerular hydrostatic pressure
Hydrostatic pressure of bowman’s capsule
Glomerular colloid osmotic pressure
Colloid osmotic pressure of bowman’s capsule

A

(↓) Norepinephrine
(↓) Epinephrine
(↓) Endothelin
(↑) NO
(↑) Prostaglandins
(↑) Bradykinin
(↑) Glomerular hydrostatic pressure
(↓) Hydrostatic pressure of bowman’s capsule
(↓) Glomerular colloid osmotic pressure
(↑) Colloid osmotic pressure of bowman’s capsule

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46
Q

How do kidney stones affect GFR and why?

A

Kidney stones decrease GFR because they increase the hydrostatic pressure in Bowman’s
capsule and oppose filtration.

47
Q

The three processes involved in urine formation at the level of the nephron are
_______, ___________, and __________.:

A

Filtration, reabsorption, secretion.

48
Q

What are the three processes of urine formation?
a) filtration, reabsorption and secretion
b) refiltration, secretion and absorption
c) re-secretion, reabsorption and filtration
d) none of the above

A

a

49
Q

Which region of the kidney is the cortical nephron located?

A

The glomeruli is located in the outer cortex of the kidney.

50
Q

Which vasculature is NOT a main determinant of renal vascular resistance
A. Efferent arterioles
B. Glomerular capillaries
C. Afferent arterioles
D. Interlobular arterioles

A

b

51
Q

Which statements below are true?
a. As glomerular capillary pressure increases, GFR increases.
b. Macula dense cells send signals to granular cells to release renin.
c. Juxtaglomerular apparatus consists of the glomerulus and the proximal tubule.
d. If there is no auto regulation of renal blood flow, a small change in arterial blood pressure
results in only a small increase in excretion by kidneys.

A

A, B

52
Q

What are the specialized cells on the distal tubule that contribute to autoregulation
of renal blood flow and GFR?
a. Granular cells
b. Endothelial cells
c. Podocytes
d. Macula densa

A

d

53
Q

Which statement about the four forces in the glomerular capillaries and bowman’s
capsule is correct?
A. Glomerular hydrostatic pressure and bowman’s capsule hydrostatic pressure both promote
filtration
B. Bowman’s capsule hydrostatic pressure and colloid osmotic pressure of glomerular
capillaries both oppose filtration
C. Colloid osmotic pressure of bowman’s capsule and colloid osmotic pressure of glomerular
capillaries both promote filtration
D. Glomerular hydrostatic pressure and colloid osmotic pressure of bowman’s capsule both
oppose filtration

A

B

54
Q

What would be the result to the electrical change within the tubular epithelial cell
and the resulting movement of Na+ if the Na+/K+ ATPase was non-functional?

A

The electrical charge within the cell would be higher (less negative) and there would be
less movement of Na+ out of the lumen of the tubule into the tubular epithelial cell (less
reabsorption).

55
Q

Name and explain the mechanism by which solutes are reabsorbed from the
interstitial fluid into the capillaries.

A

Reabsorbtion of solutes from the lumen of the tubules results in a high concentration of each
solute in the interstial fluid (between the tubular cells and the peritubular capillaries). This
high concentration establishes a concentration gradient which is used to drive the solutes into
the lumen of the capillaries via BULK FLOW.

56
Q

What is the main reason the kidneys require so much blood flow?

A

active reabsorption of sodium

57
Q

In sodium reabsorption, where is active transport against the electrochemical
gradient necessary?
A. At the luminal membrane
B. At the basolateral membrane
C. At the peritubular capillaries
D. All of the above

A

B

58
Q

Which of the following substances is filtered but NOT normally excreted in the
urine?
a) water
b) sodium
c) glucose
d) urea

A

c

59
Q

What are the 3 rules that affect passive reabsorption?

A
  1. Electrochemical gradient force
  2. Permeability of the membrane
  3. Time
60
Q

How do Macula densa cells increase GFR? (2 mechanisms)”

A
  1. Signal afferent arterioles to relax/dilate
  2. Signal juxtaglomerular cells to release renin -> more angiotensin I / II -> Constricts
    efferent arterioles
61
Q

Explain why the sodium and chloride concentrations stay the same in the proximal
tubules.

A

The sodium and chloride in the proximal tubules are reabsorbed but since water follows the
movement of sodium water is reabsorbed into the plasma in the same ratio so the actual
concentration of sodium and chloride does not change, but the amount present in the tubule is
actually decreased.

62
Q

Which hormones will increase BOTH sodium and water reabsorption into the
peritubular capillaries:
a) ADH and Atrial natriuretic peptide hormone
b) ADH and parathyroid hormone
c) Aldosterone and Angiotension II
d) Atrial Natriuretic peptide and parathyroid hormone

A

c

63
Q

Which of the following substances should not be present in the renal tubules beyond
the proximal tubule under normal physiological conditions?
a. Calcium
b. Water
c. Glucose
d. Organic acids

A

c

64
Q

How does impairing the functioning of the adrenal glands (reduced aldosterone)
affect the body?
a) accumulation of Na2+; loss of K+
b) accumulation K+ and Na2+
c) accumulation of K+; loss of Na2+
d) loss of K+ and Na2+

A

c

65
Q

How is K+ excreted when aldosterone activates principal cells.
A) Potassium is actively transported into the lumen
b) Increased Na/K Atpase creates a higher concentration K+ in the cell. K+ leaves through
leaky channels on the luminal side
c) Increased Na/K Atpase creates a higher concentration K+ in the cell. K+ leaves through
leaky channels on the basal lateral side
D) Increased intracellular potassium due to Na/K Atpase has no effect on K+ leaving
through leaky channels

A

b

66
Q

List the 3 mechanisms by which Angiotensin II increases sodium and water
reabsorption

A

A: 1) Stimulates aldosterone secretion
2) Constricts efferent arterioles
3) Directly stimulates sodium reabsorption in all segments of the tubules

67
Q

what is the main mechanism responsible for day-to-day adjustments of K+
excretion?

A

day-to-day adjustments of K+ excretion are mainly accomplished through K+ secretion by
principal cells in the late distal and collecting tubules.

68
Q

A disease causes damage to the adrenal glands, which reduces their ability to secrete
aldosterone. Which of the following is the most likely consequence at the nephron?
a. Loss of Na+ and retention of K+
b. Retention of Na+ and loss of K+
c. Loss of Na+ and K+
d. Retention of Na+ and K+

A

a

69
Q

Which two substances rely on sodium for renal reabsorption and what is this type of
transport called?

A

Glucose and amino acids; secondary active transport

70
Q

Which hormone is released due to low blood pressure and low extracellular fluid
volume?
a. Antidiuretic hormone
b. Angiotensin II
c. Aldosterone
d. Atrial natriuretic peptide

A

b

71
Q

increased extracellular potassium levels…
a) Stimulate Na+/K+ pumps on the basolateral side of principal cells
b) Reduce leakage of intracellular K+ to the interstitium
c) stimulate aldosterone secretion and K+ secretion
d) all of the above

A

d

72
Q

What substance can be used to accurately measure GFR? Why can it be used? Is
there any other substance that can be used?

A

Inulin is an accurate measure of GFR. This is because inulin is freely filtered by the
glomerulus and is not reabsorbed or secreted in the tubules. Therefore, its clearance rate is
equal to the glomerular filtration rate. Creatinine which is produced by the body is another
substance that can be used since it has the same properties as inulin.

73
Q

Which of the following does not increase magnesium excretion?
a.) increased extracellular magnesium
b.) increased extracellular phosphate
c.) increased extracellular calcium
d.) increased extracellular volume

A

b

74
Q

What initial action does the body take to ensure the plasma potassium levels do not
become too elevated after potassium is ingested? How does the body get rid of that
potassium?

A

Answer: Initial response is to take potassium up into the cells to add it to the intracellular
stores of potassium, so the plasma concentration of potassium stays low. After that, the
kidneys gradually excrete the excess potassium from our system.

75
Q

In what part(s) of the nephron does most of the daily adjustment of potassium
secretion occur and which cells are involved?
a. late distal tubule and collecting tubule; intercalated cells
b. late distal tubule and collecting tubule; principal cells
c. early distal tubules; macula densa cells
d. none of the above

A

b

76
Q

Choose the most incorrect answer
a) water is reabsorbed due to high intercellular concentrations
b) Antidiuretic hormone can change water permeability in tubules
c) water is not reabsorbed through tight junctions of cells
d) water is involved in the mechanism called “solvent drag”

A

c

77
Q

In the descending limb of the loop of Henle, why is more water reabsorbed out of
the tubule lumen than solutes?

A

A: More water is reabsorbed into the renal medulla tissue because (1) the descending limb of
the loop of Henle is permeable to water and (2) because the renal medulla interstitium is
hyperosmotic compared to the filtrate passing through the descending limb. This increased
interstitial osmolarity pulls more water than solutes out of tubule filtrate and into the renal
medullary interstitium.

78
Q

How do kidneys regulate water excretion?
a) change the volume of urine and alter rate of solute excretion
b) maintain volume of urine and alter rate of solute excretion
c) change volume of urine and maintain rate of solute excretion
d) regulate water channels

A

c

79
Q

How does urine specific gravity differ from osmolarity?

A

Answer: Osmolarity is only concerned with the number of molecules present, while specific
gravity includes that as well as the molecular weight of the solutes.

80
Q

Which of the following is true about glomerulotubular balance?
A) The mechanisms are fully known.
B) It is the ability to adjust tubular reabsorption in response to increased tubular inflow.
C) It can only occur by hormone feedback
D) It is completed by tiny kidney goblins fueled by urea.

A

b

81
Q

What will occur with hypercalcemia?
A. Reduced nerve and muscle excitability
B. Cardiac arrhythmia
C. Cardiac arrest
D. Nothing

A

b

82
Q

When concentrating urine, the osmolarity of the descending limb and the renal
medullary interstitium reach equilibrium due to the movement of?
a) sodium ions
b) chloride ions
c) sodium and chloride ions
d) water

A

d

83
Q

Which parts of the renal tubule are not permeable to urea?

A

Answer: the thick segment of ascending loop of Henle, the distal tubule, and the collecting
tubule.

84
Q

The medulla-cortex ratios of a cat, dog, pig and beaver are 11, 8, 3.3 and 2,
respectively. What animal would you expect to have the greatest max medulla
osmolarity (mosm/L) ?
a) cat
b) beaver
c) dog
d) pig

A

a

85
Q

Which of the following cannot remove H+ but instead hold onto it until another
system can remove the H+.
a. Kidney
b. Acid base system
c. Respiratory system
d. All of the above
e. None of the above

A

b

86
Q

What buffer systems are important for buffering intracellular fluid?
a.Bicarbonate and phosphate
b.Bicarbonate and proteins
c.Bicarbonate, phosphate, and proteins
d.Phosphate and proteins

A

d

87
Q

What does the glomerular capillary filtration coefficient represent and what can it
be used to determine?

A

Kf is an indicator of membrane permeability and surface area; used to calculate GFR.

88
Q

Which of the following is true about permeability?
A. Descending loop of henle is permeable to water
B. Ascending loop of henle is impermeable to water
C. Collecting duct is permeable to water under the influence of ADH
D. All of the above

A

d

89
Q

Which of the following statements is correct regarding water permeability?
a) The thin descending loop of Henle is impermeable to water but the thin ascending is
permeable to water.
b) Both the proximal tubule and the thin descending loop of Henle are permeable to water.
c) The thin descending and thin ascending loops of Henle are impermeable to water.
d) None of the above.

A

b

90
Q

Which mechanism adjusts tubular reabsorption in response to increased tubular
inflow?
a. Tubuloglomerular feedback
b. Glomerulotubular balance
c. Myogenic autoregulation
d. Pressure natriuresis

A

b

91
Q

describe the concept of renal clearance and explain why a substrate like inulin may
be used as an accurate way calculate renal clearance rate

A

Renal clearance is the rate at which a substance is completely removed from plasma per
unit time. Inulin can be used to calculate renal clearance rate because it is a substance that is
freely filtered and none of it is reabsorbed back into circulation. This means that any plasma
that is filtered through the kidneys per unit of time will be completely cleared of inulin. The
inulin will remain in the filtrate and be excreted in the urine.

92
Q

Which of the following are true about phosphate reabsorption and excretion?
A) Mainly absorbed at the Loop of Henle, and PTH increases the transport maximum
B) Mainly absorbed at the proximal tubules, and PTH decreases the transport maximum of
phosphate
C) Mainly absorbed at the proximal tubules and PTH increases the transport maximum
D) None of the above

A

b

93
Q

Why do hydrogen ions need to be carefully regulated?

A

Answer: When hydrogen ions are too high in the body fluids, it can cause acidosis. When
they are too low, it can cause alkalosis. These conditions will affect cellular functions in the
body.

94
Q

Which one of the following is false?
1. The two mechanisms that are involved in the regulation of extracellular fluid osmolarity
are the osmoreceptor-ADH system and the thirst mechanism.
2. When the concentration of sodium in ECF increases, the osmoreceptors expands to fire
signals to supraoptic and paraventricular neurons for releasing ADH
3. Decreased arterial pressure and decreased blood volume sensed by the barorecptors will
affect ADH release from shrinkage of the osmorecptors
4. Sequence of osmoreceptor-ADH feedback mechanism is 1) Increased plasma Na+ 2)
Osmoreceptors stimulation 3) ADH release 4) Increased water permeability in renal tubules

A

2

95
Q

What are the 3 defence mechanisms against H+ concentration? How fast does each
one react? And what is the mechanism of maintaining H+?

A
  1. Acid-base buffer systems of body fluids; within seconds; ties up H+ till it can be removed
  2. Respiratory system; within minutes; removes acid by CO2
  3. Kidneys; within hours and days; secretes hydrogen ions and bicarbonate to adjust acid-
    base
96
Q

True or false: During urination, the detrusor muscle and external sphincter
contracts, and urine is released from the bladder.

A

False- during urination, the detrusor muscle contracts, and the external sphincter relaxes

97
Q

Which of the following statements is correct about Uric Acid?
A. It has the formula CH4N2O
B. It requires 50-100 times less water to excrete the same amount of nitrogen compared to
ammonia
C. Unlike ammonia and urea, it is excreted in urine
D. It is both insoluble and antioxidant

A

d

98
Q

Which factor does not cause an increase in H+ secretion at the kidneys?
a) Increased partial pressure of CO2 in the extracellular fluid;
b) Increased H+ concentration in the extracellular fluid;
c) Decreased aldosterone release;
d) Increased reabsorption of Na+ at tubular epithelial cells;
e) Decreased extracellular volume of fluid.

A

c

99
Q

What are the two main ways kidneys regulate water excretion?

A
  1. Producing urine with a wide range of osmolarity
  2. Changing the volume of urine without altering rate of solute excretion
100
Q

How do the kidneys compensate for metabolic acidosis?

A

A: The kidneys secrete more H+ into tubular lumen and hyperventilation is induced to
remove more CO2 from circulation.

101
Q

Which compensation mechanism is false?
A) Metabolic Alkalosis compensation: increased HCO3- excretion and hypoventilation
B) Respiratory Acidosis compensation: increased H+ secretion and increased HCO3-
reabsorption
C) Respiratory Alkalosis compensation: increased HCO3- excretion and hypoventilation
D) Metabolic Acidosis compensation: increased H+ excretion and hyperventilation

A

c

102
Q

How will sympathetic stimulation affect the renal vascular resistance?
a) Increase renal vascular resistance by causing vasodilation?
b) Increase renal vascular resistance by causing vasoconstriction?
c) Decrease renal vascular resistance by causing vasodilation?
d) Decrease renal vascular resistance by causing vasoconstriction?

A

b

103
Q

When might the specific gravity of urine be greater than the osmolarity of the same
sample?

A

answer: When there are larger molecules present in the urine.

104
Q

In what conditions are Intrarenal (local) adjustments made? What 2 processes are
being adjusted?

A

A: adjustments made during normal variations of Na+ intake (regulate normal fluctuations in
Na+ intake)
The GFR and reabsorption is being adjusted.

105
Q

Name two places in the nephron where the fluid in the tubule and in the tissue
surrounding the tubule are isosmotic.

A

1) Proximal Tubule (300mOsm/L)
2) Bottom of Loop of Henle (600mOsm/L) BT: it can go up to 1200 mOsm/L

106
Q
  1. If the action of certain diuretic drugs (eg Furosemide) is to inhibit the Na/2Cl/K
    transporters in the thick ascending segment of the loop of Henle, how does doing so
    reduce water reabsorption in the subsequent segments?
A

A: I think it has to do with the amount of solutes kept in the lumen of the tubule- if more
solutes are kept in the tubule more water would continue to stay in the tubule beyond the
thick ascending segment (even in areas with water permeable membranes such as in the
collecting ducts). So these diuretic drugs cause reduced water reabsorption downstream in
the nephron by creating a situation in which excess water is left in the tubule, which would
overwhelm the water reabsorption capacities of the collecting ducts.

107
Q

What is characteristic of a carbonic anhydrase inhibitor diuretic?
a) K+ sparing, action in the distal tubule
b) Reduce Na+/Cl- absorption, action in the Loop of Henle
c) Enhance osmotic pressure, action along entire tubule
d) Reduce Na+/HCO3- reabsorption, action in the proximal tubule
e) K+ sparing, action in the proximal tubule

A

d

108
Q

Which buffer system is most important for buffering the extracellular fluid?
A) Proteins
B) Phosphate buffer system
C) Bicarbonate buffer system
D) All of the above

A

c

109
Q

What would happen if the medullary interstitium was not hyperosmotic- describe
how this would affect the renal concentration/dilution of urine.

A

A: Without the hyperosmolarity of the medullary interstitium, no water would flow out in the
descending loop of Henle, nor would there be any transport (active or otherwise) in the
ascending loop. So without these, the osmolarity inside the tube would not change from the
distal loop, but would solely be affected by ADH’s control over the water permeability of the
distal tubules and collecting duct.

110
Q

What are the 3 possible fates of a substance after being filtered into the tubule and
give an example of each substance (BT: there is also a forth scenario,,,)

A

Freely filtered with no reabsorption
Ie: inulin/creatinine
* Freely filtered and all reabsorbed
Ie: glucose
* Freely filtered with no reabsorption and additional secretion into the tubule
ie: H ions or para-aminohippuric acid

111
Q

What is the correct arrangement of animals when ordering their nitrogenous
waste process from least to most energetically expensive? (Least being on the left,
most being on the right)
a. Fish < dog < bird = snake
b. Cat < seal < lizard
c. Goldfish = whale < bird < llama
d. Fish = bird < whale

A

a

112
Q

Which diuretic does not match the site of action?
A. Sodium channel blockers, cortical collecting tubule
B. Carbonic anhydrase inhibitors, loop of henle
C. Thiazide diuretics, distal tubule
D. Loop diuretics, thick ascending loop of Henle

A

b

113
Q

What is the clinical relevance of diuretics?

A

Answer: to reduce volume of ECF (like in cases of edema)

Vet Year 1 (4 decks)

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