test 2: questions

Question 1

Final regulation of water excertion occurs where?

a) Glomerulus
b. Proximal tubule
c) Collecting ducts
d. Loop of Henle

Answer 1

collecting ducts

Question 2

The major force of filtration is:

a. the oncotic pressure of the plasma
b. the hydrostatic pressure of the blood
c. the oncotic pressure of the glomerular filtrate
d. the hydrostatic pressure of the glomerular filtrate
e. the ultrafiltration coefficient

Answer 2

b. the hydrostatic pressure of the blood

Question 3

Selectivity of filtration is determined by

a. the properties of glomerular capillary wall
b. the oncotic pressure of the glomerular filtrate
c. the properties of filtered molecules
d. the hydrostatic pressure in the glomerulus
e. A and C
f. B and D

Answer 3

A and C

Question 4

The following statement about renin is false:

a. Renin is a steroid hormone which regulates blood pressure and renal perfusion
b. Renin is produced and released by juxtaglomerular cells in response to decrease in renal perfusion

C.Renin promotes conversion of angiotensinogen into angiotensin

d. Release of renin is suppressed by increase in the state of renal perfusion and highconcentration of angiotensin Il in the plasma

Answer 4

a. Renin is a steroid hormone which regulates blood pressure and renal perfusion

renin is a polypeptide

Question 5

The following statement is false:

a. K is a major intracellular cation
b. insulin inhibits the activity of Na’, K’-ATPase
c. Herbivores’ food intake of K* is larger than carnivores
d. Less than 2% of total body K* is in the extracellular fluid
c. Na’, K’-ATPase moves K* into the cells and Na’ out.

Answer 5

b insulin inhibits the activity of Na’, K’-ATPase

insulin activates Na K pumps

Question 6

17. Aldosterone increases secretion of K’ through the following mechanisms:
    a. Increase in the number of apical Na* channels which stimulate Na* K*-ATPase
    b. Increase in the number of Na’.K’-ATPase pumps
    c. Increased in the number of apical K* channels
    d. Decreasing the extent of K’ backleak through basolateral K’ channels
    e. All of the above

Answer 6

e all of the above

Question 7

Osmotic diuresis can be described as

a. A decrease in the renal excretion of water and the urine flow
b. A decrease in urine osmolality
c. A result of insufficient secretion of vasopressin (ADH)
d. )A result of the presence of high levels of non-reabsorbed solute in the tubular lumen

Answer 7

d. A result of the presence of high levels of non-reabsorbed solute in the tubular lumen

Question 8

The loop of Henle plays a central role in urine concentration because:

a. Water is actively transported to interstitial fluid from tubular fluid through the thin descending limb of the loop of Henle
b. Water is passively transported to interstitial fluid from tubular fluid through the thin ascending limb of the loop of Henle
c. The two limbs of the loop of Henle work to generate an osmotic gradient within the medullary region of the kidney
d. Water is passively transported to interstitial fluid from tubular fluid through the thick ascending limb of the loop of Henle

Answer 8

c. The two limbs of the loop of Henle work to generate an osmotic gradient within the medullary region of the kidney

Question 9

The net result of countercurrent exchange mechanism in vasa recta is:

a. A removal of fluid from medullary tissue to cortical region without disturbing the osmotic gradient
b. A decrease in osmolality of blood plasma
c. An increase in osmolality of interstitial fluid
d. A formation of osmotic gradient in medullary tissue
e. All of the above

Answer 9

a. A removal of fluid from medullary tissue to cortical region without disturbing the osmotic gradient

Question 10

The key functions of kidney include

a. maintenance of volume and composition of extracellular fluid
b. regulation of the acid-base balance
c. synthesis and release of hormones
d. excretion of metabolic waste
e. all of the above

Answer 10

e all of the above

Question 11

Micturition describes a process of

a. emptying the bladder
b. glomerular filtration
c. re-absorbtion of the solutes and urine formation
d. passage of urine to the urinal bladder

Answer 11

a. emptying the bladder

Question 12

3. Most of filtration occurs in
   a. Macula densa
   b Glomerulus
   c. Loop of Henle
   d. Collecting duct
   c. All of the above

Answer 12

b Glomerulus

Question 13

Most of re-absorption of solutes occurs in

q. Loop of Henle
b. Collecting duct
c. Proximal tubule
d. Glomerulus
e. All of the above

Answer 13

c. Proximal tubule

Question 14

Selectivity of filtration is determined by
a. the properties of glomerular capillary wall
b. the properties of filtered molecules
C. the hydrostatic pressure in the glomerulus
the oncotic pressure of the glomerular filtrate
d. A and B
f. C and D

Answer 14

d. A and B

a. the properties of glomerular capillary wall
b. the properties of filtered molecules

Question 15

The following statement about regulation of glomerular filtration rate is true:

a. correction of renal blood flow triggered by myogenic reflex through changes of tension in arteriolar wall is a slow-acting mechanism, which requires function of central nervous system
b. aldosterone directly constricts afferent arterioles
c. tubulo-glomerular feedback mechanism relies on sensitivity of the cells of macula densa to the rate of tubular flow rate
d. Glomerular filtration rate is increased by a low protein meal
e. vasopressin is released from the adrenal gland in response to rennin stimulation

Answer 15

c. tubulo-glomerular feedback mechanism relies on sensitivity of the cells of macula densa to the rate of tubular flow rate

Question 16

10. Functions of angiotensin II include:

a. vasoconstrictive effect
b. stimulation of the release of aldosterone by the adrenal gland
c. stimulation of the release of vasopressin by the pituitary gland
d. suppression of release of renin
e. production of vasodilative renal prostaglandins
f. all of the above

Answer 16

f. all of the above

Question 17

11. Glomerular filtration rate can be determined by calculating renal clearance of

a. ammonia
b. inulin
c. para-aminohippuric acid
d. urea

Answer 17

b. inulin

Question 18

The following statement is false:

a. K’ is a major intracellular cation
b. Insulin inhibits the activity of Na*, K’-ATPase
c. Herbivores’ food intake of K* is larger than carnivores
d. Less than 2% of total body K* is in the extracellular fluid
e. Na”, K’-ATPase moves K* into the cells and Na” out.

Answer 18

b. Insulin inhibits the activity of Na*, K’-ATPase

insulin activates

1.Insulin – stimulates - increases the entry of K⁺ into the cell

Question 19

Aldosterone increases secretion of K* through the following mechanisms:

a. Increase in the number of apical Nat channels which stimulate NatK+-ATPase
b. Increase in the number of Na*K’-ATPase pumps
c. Increased in the number of apical K channels
d. Decreasing the extent of K backleak through basolateral K* channels
e. All of the above

Answer 19

e. All of the above

Question 20

The net result of countercurrent exchange mechanism in vasa recta is:

a. A removal of fluid from medullary tissue to cortical region without disturbing the osmotic gradient
b. decrease in osmolality of blood plasma

c. An increase in osmolality of interstitial fluid
d. A formation of osmotic gradient in medullary tissue
e. All of the above

Answer 20

a. A removal of fluid from medullary tissue to cortical region without disturbing the osmotic gradient

Question 21

The following statements about vasopressin (ADH) are true (indicate 2):

a. Vasopressin is a steroid hormone secreted by adrenal cortex
b. Vasopressin is produced by JG cells in afferent arteriole
c. Vasopressin blocks the water channels in proximal tubule
d. Vasopressin is synthesized by supraoptic nucleus of the hypothalamus and is secreted by the posterior pituitary gland
e. Vasopressin promotes localization of water channels (aquaporins) at the luminal membrane

Answer 21

d. Vasopressin is synthesized by supraoptic nucleus of the hypothalamus and is secreted by the posterior pituitary gland
e. Vasopressin promotes localization of water channels (aquaporins) at the luminal membrane

not a= vasopression is a peptide hormone

JG cells make renin

vaspression starts water channels in collecting duct

Question 22

22. In the absence of vasopressin (ADH), the final urine becomes hypoosmotic because:
    a. The osmotic gradient cannot be formed by the loop of Henle
    b. The osmotic gradient is disturbed due to the lack of Na’ reabsorption
    c. Cells of the distal tubule and medullary collecting ducts are impermeable to water
    d. Kidney filtration rates are increased

Answer 22

c. Cells of the distal tubule and medullary collecting ducts are impermeable to water

need ADH to make aquaporins

Question 23

The following statement about Ca?* excretion is false:

a. Filtration of Ca?* in glomeruli depends on its binding to plasma proteins
b. More than 30% of filtered Ca,2+ is excreted in the final urine
c. A large fraction of filtered Ca?+ is reabsorbed in the proximal tubule
d. Reabsorbtion of filtered Ca?* is regulated by hormones

Answer 23

b. More than 30% of filtered Ca,2+ is excreted in the final urine

. Only 1-5% of filtered Ca²⁺ is found in the final urine.

Question 24

The following statement about Mg?* excretion is true:
a Filtration of Mg?* in glomeruli depends on its binding to plasma proteins
b. A larger fraction of Mg? is reabsorbed in the thick ascending limb of the loop of Henle than in proximal tubule
c. Reabsorbtion of filtered Mg?* is regulated by hormones

d. all of the above

Answer 24

all of the above

•in the proximal tubule:•60% of filtered Ca²⁺•20% of filtered Mg²⁺

loop of henle: Up to 60% of filtered Mg²⁺ is reabsorbed here,

Mg reabsorption by PTH

filtration : 80% free, 20 % protein (Whereas free solutes are readily filtered in glomeruli, protein bound Ca²⁺, Mg²⁺ and PO4 cannot undergo filtration.)

Question 25

The following statement about parathyroid hormone (PTH) is false:
a, PTH is released in response to decrease in plasma [Ca?*]
b. Receptors for PTH are found in the proximal tubule, thick ascending limb of the loop of Henle and collecting ducts.

c. PTH regulates renal excretion of Ca?*, Mg?* and PO4
d. PTH is a steroid hormone synthesized in the thyroid gland
e. PTH stimulates enzymatic conversion of vitamin D into its active form

Answer 25

d. PTH is a steroid hormone synthesized in the thyroid gland

made in the parathyroid

Question 26

The following statements about vasopressin (ADH) are true (indicate 3):

a. Vasopressin is a steroid hormone secreted by adrenal cortex
b. Vasopressin is secrete in greater concentrations in response to increased blood volume
c. Vasopressin is produced by Juxtaglomerular cells in afferent arteriole
d. Vasopressin blocks the water channels in proximal tubule
e. Vasopressin is not secreted in great enough amounts in individuals with diabetes insipidus
f. Vasopressin promotes localization of water channels (aquaporins) at the luminal membrane

Answer 26

d. Vasopressin blocks the water channels in proximal tubule
e. Vasopressin is not secreted in great enough amounts in individuals with diabetes insipidus
f. Vasopressin promotes localization of water channels (aquaporins) at the luminal membrane

not a: vasopression= peptide hormone

not b. vasopressin released in response to low BP

not c. vasopressin (ADH) from the pituitary gland.

Question 27

In the absence of vasopressin (ADED). the final urine becomes hypoosmotic because.

a. The osmotic gradient cannot be formed by the loop of Henle
b. The osmotic gradient is disturbed due to the lack of Na” reabsorption
c. Cells of the distal tubule and medullary collecting ducts are impermeable to water
d. Kidney filtration rates are increased

Answer 27

c. Cells of the distal tubule and medullary collecting ducts are impermeable to water

vasopressin needed to make aquaporin

Question 28

The following statement about parathyroid hormone (P’TH) is false:

a. PTH is released in response to decrease in plasma Ca
b. Receptors for PTH are found in the proximal tubule, thick ascending limb of the loop of Henle and collecting ducts.
c. PTH regulates renal excretion of Ca?*, Mg?* and PO4 *
d. PTH is a steroid hormone synthesized in the thyroid gland
e. PTH stimulates enzymatic conversion of vitamin D into its active form

Answer 28

d. PTH is a steroid hormone synthesized in the thyroid gland

PTH is made by parathyroid

Question 29

Bicarbonate buffer is effective at maintaining the blood plasma at pH 7.4 because:

a. Its pK is within 1 pH unit from the 7.4 value
b. One of its components is volatile
c. It operates in an open system
d. Both A and B are correct
e. Both B and C are correct

Answer 29

e. Both B and C are correct

b. One of its components is volatile
c. It operates in an open system

Question 30

Functions of angiotensin II include:

a. vasoconstrictive effect
b. stimulation of the release of aldosterone by the adrenal gland
c. stimulation of the release of vasopressin by the pituitary gland
d. suppression of release of renin
e. production of vasodilative renal prostaglandins
f. all of the above

Answer 30

f. all of the above

• 1 directly - constricts arterial blood vessels to increase systemic blood pressure and renal perfusion pressure; and
• 2 indirectly - stimulates the release of:•2a - the mineralocorticoid steroid hormone aldosterone from the adrenal gland•2b - polypeptide hormone vasopressin (a.k.a. ADH, anti-diuretic hormone) from the pituitary gland.
• Both these hormones retain electrolytes and water from excretion, thus increasing overall intravascular circulating volume and elevating systemic blood pressure and renal perfusion.

Question 31

Factors that determine clearance of a substance from the plasma include

a. Glomerular filtration rate
b. rate of synthesis and degradation of this substance in the kidney
c. rate of tubular reabsorption of this substance
d. rate of tubular secretion of this substance
e. all of the above
f. none of the above

Answer 31

e. all of the above

Question 32

6) Which two of the following statements are false?
a. renal cortex contains mostly glomeruli of the nephrons
b) glomerulus is responsible for the secretion of solutes and water into the tubular fluid in a manner that depends on arterial pressure and renal perfusion
c. Once leaving the glomerulus, the fluid moves consequently through proximal tubule, thin descending limb of the loop of Henle, thin ascending limb of the loop of Henle, distal convoluted tubule, cortical collecting duct, outer medullary collecting duct, inner medullary collecting duct, renal pelvis.
d) tubular fluids moves along the tubule because of the hydrostatic pressure of blood in renal artery
e. renal medulla contains mostly tubular parts of the nephrons
f. Macula densa is formed bv the neuroendocrine cells that surround the afferent and efferent arteriols
8) macula dens and juxtaglomerular cells along with the afferent and efferent arteriols form the juxtaglomerular apparatus

Answer 32

b) glomerulus is responsible for the secretion of solutes and water into the tubular fluid in a manner that depends on arterial pressure and renal perfusion
f. Macula densa is formed by the neuroendocrine cells that surround the afferent and efferent arteriols

these are JC cells

Question 33

Selectivity of filtration is determined by (indicate all):

a. the hydrostatic pressure of blood in the glomerulus
b. the radius, charge and shape of the filtered molecule
c. the magnitude of the osmotic gradient
d. the properties of glomerular capillary wall
e. the hydrostatic pressure in the Bowman’s capsule
f. the oncotic pressure of plasma

Answer 33

b. the radius, charge and shape of the filtered molecule
d. the properties of glomerular capillary wall

Question 34

Calculate the renal plasma flow and filtration fraction
in a beagle that is under a normal state of hydration when the kidneys receive 20% of all cardiac output given the following parameters measured in this animal: hematocrit 40%, GFR
48 ml/min, and the overall cardiac output is 1.6 liter/min.

Answer 34

RPF= cardiac output in ml/min (% to kidney) (% to plasma)

1600 (20/100)(60/100)= 192 ml/min

FF=GFR/RPF = 48/192= 0.25

Question 35

Factors that determine clearance of a substance from the plasma include:

a) glomerular filtration rate
b) rate of synthesis and degradation of this substance in the kidney
c) rate of tubular reabsorption of this substance
d) rate of tubular secretion of this substance
e) all of the above

Answer 35

all of the above

Question 36

Match the following parameters and conditions:
(A) pH > 7.42, Pac02 <38 mM
(B) pH > 7.42, HCO3 > 26 mM
(C) pH < 7.38, Paco2 > 42 mM
(D) pH < 7.38, HC0} < 22 mM

1. Respiratory alkalosis
2. Metabolic acidosis
3. Metabolic alkalosis
4. Respiratory acidosis

Answer 36

pH > 7.42, Pac02 <38 mM → respiratory alkalosis

(B) pH > 7.42, HCO3 > 26 mM → Metabolic alkalosis

(C) pH < 7.38, Paco2 > 42 mM → 4. Respiratory acidosis

pH < 7.38, HC03 < 22 mM → 2. Metabolic acidosis

Question 37

The following statements about excretion of Mg2+, CaZ+ and phosphate are true except one (indicate this one)

3) Filtration of these solutes depends on their interaction with serum albumins
b) Bulk reabsorption of these solutes occurs in proximal tubule mostly by solvent drag
c) Regulated reabsorption of these solutes in distal tubule and thick ascending limb of the loop of Henle occurs passively along the electro-chemical gradient
d) Major regulators of renal excretion of these solutes are calcitriol (produced by activation of vitamin D3 in many tissues including the skin) and thyroid hormone produced in the thyroid glands
c) Thyroid hormone is a steroid hormone and requires the intracellar receptor for its function

Answer 37

d) Major regulators of renal excretion of these solutes are calcitriol (produced by activation of vitamin D3 in many tissues including the skin) and thyroid hormone produced in the thyroid glands

Mg and Ca PO4 by PTH made by parathyroid

Question 38

Which of the following buffer systems are most effective in compensating the pH changes caused by diabetic ketoacetodosis?

a) Bicarbonate
b) Intracellular and extracellular protein
c) Inorganic phosphate.
d) Band C

Answer 38

a) Bicarbonate

In spite of its pK = 6.1, the HCO3-/CO2 system functions as an
effective buffer in maintaining the normal arterial blood plasma pH at 7.4 in response to acid addition because one of its component is volatile and the system is open.

Bicarbonate buffer is efficient against metabolic
acids (e.g. problems with acid excretion due to kidney
pathology), when capacities of other buffers are
overwhelmed

Question 39

Which of the following mechanisms contribute to the regulation of the acid-base
balance by kidneys:
a) reabsorption of bicarbonate
b) filtration of aminoacids and small peptides
c) excretion of titratable acid
d) delivery of CO, from lungs to the peritubular capillaries
e) excretion of ammonia
f. A, B, and E
g. A, Cand E
h. B, C and D

Answer 39

g. A, Cand E
a) reabsorption of bicarbonate
c) excretion of titratable acid
e) excretion of ammonia

Question 40

26. When a solution contains more than one buffer:
    a. All buffer pairs (HA and A) are in equilibrium with the same pH
    b. Buffering capacity depends on the buffer concentrations
    c. Buffering capacity depends on pK of the buffers present in the solution
    d All of the above

Answer 40

d All of the above

Question 41

Bicarbonate buffer is effective at maintaining the blood plasma at pH 7.4 because:
a. Its pK is within 1 pH unit from the 7.4 value
b. One of its components is volatile
c. It operates in an open system
d. Both A and B are correct
e Both B and C are correct

Answer 41

e Both B and C are correct

both volatile and open

Question 42

Fractional excretion rate is the net result of:

a. rates of tubular flow and micturition
b. tubular re-absorption and secretion
c. glomerular filtration and the rate of water reabsorption
d. all of the above

Answer 42

b. tubular re-absorption and secretion

FER= the percentage of a filtered substance that is ultimately
excreted in the urine.

FERx = (Ux/Px)/(Ucreatinine/Pcreatinine) x 100%

Question 43

The following statements about vasopressin (ADH) are true (indicate all):

a. Vasopressin is a steroid hormone secreted by adrenal cortex
b. Vasopressin is secreted in greater concentrations in response to decreased blood volume
c) Vasopressin is produced by JG cells in afferent arteriole
d) Vasopressin blocks the water channels in proximal tubule
e) Vasopressin is not secreted in great enough amounts in individuals with diabetes insipidus
f. Vasopressin promotes localization of water channels (aquaporins) at the luminal membrane

Answer 43

b. Vasopressin is secreted in greater concentrations in response to decreased blood volume
e) Vasopressin is not secreted in great enough amounts in individuals with diabetes insipidus
f. Vasopressin promotes localization of water channels (aquaporins) at the luminal membrane

Question 44

match the segments to its function

1. Glomerulus
2. Proximal tubule
3. Loop of Henle
4. Distal tubule and collecting ducts

Formation of osmotic gradient

Bulk reabsorption

Filtration

Regulated reabsorption and secretion

Answer 44

Glomerulus → filtration

2. Proximal tubule → bulk reabsorption
3. Loop of Henle → formation of osmotic gradient
4. Distal tubule and collecting ducts → regulated reab and sec

Question 45

Which of the following buffer systems are most effective in compensating the pH changes caused by bronchial obstruction?

a. Bicarbonate
b. Intracellular and extracellular protein
c. Inorganic phosphate.
d. B and C

Answer 45

b. Intracellular and extracellular protein
c. Inorganic phosphate.
d. B and C

Bicarbonate buffer is NOT much a factor in buffering
increased concentrations of CO2

Question 46

Which three of the following statements are false?

a) Renin is a hormone produced by the juxtaglomerular cells in response to a decreased renal perfusion
b) Renin enters its target cells, interacts with the steroid hormones receptor leading to stimulation of the conversion of angiotensinogen to angiotensin I
c) Angiotensin I is then converted to angiotensin Il by ACE
d) Angiotensin I results in systemic vasoconstriction of arterioles in all tissues including liver and kidney
e) Angiotensin II stimulates the release of aldosterone leading to retention of Na+ and water
f) Angiotensin Il stimulates the release of vasopressin leading to an increased diuresis
g. Summary results of renin action are the increase in the volume of extracellular fluids, increase in systemic blood pressure and restoration of renal perfusion.

Answer 46

b) Renin enters its target cells, interacts with the steroid hormones receptor leading to stimulation of the conversion of angiotensinogen to angiotensin (renin= polypeptide)
d) Angiotensin I results in systemic vasoconstriction of arterioles in all tissues including liver and kidney (does not include kidneys → vasodilation in the kidneys)
f) Angiotensin Il stimulates the release of vasopressin leading to an increased diuresis (decrease in diressis ADH)

Question 47

The mechanisms of solute transport through transcellular and paracellular
pathways in the proximal tublule include:
a) passive diffusion
b) solvent drag
c) primary active transport

d. all of the above

Answer 47

d. all of the above

Question 48

Which two of the following statements about intrinsic factors that regulate GFR are true?

a. Intrinsic factors function within the kidney to directly control the glomerular capillary perfusion
b) These factors include myogenic reflex, tubulo-glomerular feedback and secretion of renin
c) Regulation of GFR by the myogenic reflex is augmented by the activity of the parasympathetic nervous system via the vagus nerve and attenuated by the actions of the sympathetic nervous system
d. Tubulo-glomerular feedback is mediated by the cells of macula densa
e) These macula densa cells are sensing an increase in the rate of blood flow in the efferent arteriole and, accordingly, they act to decrease the GFR

Answer 48

a. Intrinsic factors function within the kidney to directly control the glomerular capillary perfusion (Intrinsic factors (control of renal blood flow, P_GC, and K_f)
d. Tubulo-glomerular feedback is mediated by the cells of macula densa

Question 49

Renal clearance of which of the following substances can be used to determine glomerular filtration rate?

a) ammonia
b) inulin
c) para-aminohippuric acid
d) urea
e) creatinine

Answer 49

b) inulin
e) creatinine

GFR= (Ux x V)/(Px)

Question 50

Calculate the GFR

in a very well hydrated and apparently healthy golden retriever that weights 15 kg. This dog was brought to have his teeth cleaned and the blood test revealed a marginal increase in the plasma creatinine level of 2.1 mg/dL., A proactive owner agreed with a veterinarian to proceed with a subsequent urinalysis in the urine collected for 2hr (total volume of 1200 ml) that showed the concentration of urinal creatinine at 4.2 mg/dI

Answer 50

GFR= (U x V)/P

V= 1200 ml/2 hr = 10ml/min

(4.2 x 10)/(2.1) = 20

20/15 kg= 1.3 ml/min/kg

Question 51

Which of the following statements are false?

a) Bulk reabsorption in the proximal tubule is helped by anatomo-histologic characteristics of the epithelium (brush border) and of blood supply (peritubular plexus)
b) Active transcellular transport of Na+ underlies all other mechanisms of reabsorption in the proximal tubule
c) Numerous mitochondria provide the ATP required for active exchange of Na+ and K+ in proximal tubule and thin descending limb of the loop of Henle
d) Glucose and aminoacids are co-transported from the lumen into the tubular cells along with Na+
e) Endocytosis plays a major role in reabsorption of small biologically active peptides
f) Chloride ions are reabsorbed along the gradient via the paracellular pathway- this movement creates a solvent drag that moves many other solutes
g) High hydrostatic pressure and low protein concentration in the blood of peritubular plexus are conducive for removing the reabsorbed water and solutes from interstitial tissues into the blood stream along the Starling forces

Answer 51

c) Numerous mitochondria provide the ATP required for active exchange of Na+ and K+ in proximal tubule and thin descending limb of the loop of Henle (ATP in collecting duct)
g) High hydrostatic pressure and low protein concentration in the blood of peritubular plexus are conducive for removing the reabsorbed water and solutes from interstitial tissues into the blood stream along the Starling forces

Starling Blood in these capillaries has high oncotic pressure (due to loss of volume to filtrate and concurrent increase in protein concentration) and low hydrostatic pressure (due to low resistance of their walls). Both of these conditions are conducive to the movement of fluid and solutes from the interstitium into the bloodstream

Question 52

The following facts about the reabsorption of solutes in the thick ascending limb of the loop of Henle are true (indicate all applicable):

a. it is a highly regulated process that consumes energy and works against the concentration gradient
b. it is not isoosmotic and proceeds in the absence of water movement
c. it decreases the osmolality of the tubular fluid to ensure the concentration of the final urine
d. it is the primary target of clinically important diuretics

Answer 52

all of the above

Question 53

The ultimate rate of excretion of K+ in the urine is mainly determined by regulation
of two of the following rates (indicate both)
a) the efficiency of K* reabsorption by intercalated cells of the collecting ducts
(b) the efficiency of K* secretion by the principal cells of the collecting ducts
c) the efficiency of the glomerular filtration of K*
d) the efficiency of K* reabsorption in the proximal tubule
e) the efficiency of K secretion in the thick ascending limb of the loop of Henle

Answer 53

a) the efficiency of K* reabsorption by intercalated cells of the collecting ducts
(b) the efficiency of K* secretion by the principal cells of the collecting ducts

Question 54

The following statement about proximal tubular reabsorption is false:

a. This transport of Na* is mediated by Na* K* ATPase pump located in the basolateral plasma membrane
b. Operation of this pump results in cell polarization and creates a gradient
c. This pump extrudes three H’ ions from the cell into the interstitial fluid and takes up two molecules of glucose into the cell per one molecule of utilized ATP
d. Movement of Na” is coupled to the movement of other solutes in the same direction
c. Low molecular weight proteins are reabsorbed via endocytosis

Answer 54

c. This pump extrudes three H’ ions from the cell into the interstitial fluid and takes up two molecules of glucose into the cell per one molecule of utilized ATP

Question 55

The following statement about renal excretion of water is false:

a. The rate of renal excretion of water is regulated by efficiency of its filtration in glomerulus
b. More than 60% of filtered water is reabsorbed in proximal tubule
c. Reabsorption of water is a passive process
d. Reabsorption of water from the collecting ducts is dependent on vasopressin (ADHI)

Answer 55

a. The rate of renal excretion of water is regulated by efficiency of its filtration in glomerulus

Question 56

GFR

Answer 56

(U x V)/P

in animals divide by kg

to get ml/min/kg

Question 57

FF

Answer 57

filtration fraction

fraction of renal plasma flow that is actually filtered by golmeruli

FF = GFR/RPF

renal plasma flow = cardiac output (20%)(60%) = ___ ml/min

Question 58

FE

Answer 58

fractional excretion

rate of urinary excertion of X by its rate of filtration

FE= (Ux x V)/(Px x GFR)

???

If FE > 1, there is net secretion of the indicator substance by the tubule

If FE < 1, there is net re-absorption of the indicator substance by the tubule

Question 59

FER

Answer 59

fraction excretion rate

FER= (Ux/Px)/(Ucreat/Pcreat) x 100%

Question 60

FAR

Answer 60

fractional reabsorption rate

% of filtered substance that is reabsorbed

FAR= 100-FER

FER= (Ux/Px)/ (Ucreat/Pcreat) x 100 %