Renal Physiology

Front 1

"Dirtier" blood travels in through the (a) ____________________ and "Cleaner" blood travels out through the (b) _______________________. The waste leaves through the (c) _____________________ from the kidneys in the (d) _____________________.

Back 1

(a) Renal Artery

(b) Renal Vein

(c) Ureter

(d) Urine

Front 2

Kidneys are (a) _____% of our body weight. Kidneys also take (b) _____% in O2 consumption. The cardiac output of the kidneys is (c) _____-_____%.

Back 2

(a) 0.5

(b) 6

(c) 20-25

Front 3

What does the structure of the Nephron consist of?

Back 3

Bowman's capsule and Glomerulus

Front 4

___________________ is a network of porous capillaries having large pores in endothelial cells and large gaps between endothelial cells.

Back 4

Glomerulus

Front 5

_______________________________ is the beginning of the renal tubular system, consisting of epithelial cells with foot-like processes (podocytes) separated by large gaps.

Back 5

Bowman's capsule

Front 6

_____________________________ in the glomerular capillaries drives rapid filtration of protein-free fluid from glomerular capillary into the Bowman's capsule.

Back 6

Blood pressure

Front 7

A juxtamedullary nephron has a long loop of Henle that extends into the (a) ______________________, whereas a cortical nephron has a short loop of Henle that is situated mostly in the (b) ________________________.

Back 7

(a) renal medulla

(b) renal cortex

Front 8

The primary function of the loop of Henle is:

Back 8

production of an osmotic gradient in the renal interstitium from approximately 300 mOsM in the renal cortex to approximately 1,200 mOsM in the renal medulla.

Front 9

Known as the major diluting segment of the nephron because they are capable of lowering tubular fluid osmolarity to lower than 100 mOsM by reabsorbing Na+ from the tubular fluid to peritubular capillaries.

Back 9

Distal convoluted tubule

Front 10

The last segment of the nephron; it is important for producing concentrated urine during dehydration by allowing fluid in the collecting duct to equilibrate with the high osmolarity in renal medulla.

Back 10

Medullary collecting duct

Front 11

Name the two capillary networks and their functions.

Back 11

Glomerular Capillary for Glomerular Filtration.

Peritubular Capillary for Reabsorption and Secretion.

Front 12

Name the three fundamental processes in a Nephron.

Back 12

Glomerular filtration, tubular reabsorption, and tubular secretion.

Front 13

What is the equation for Net Hydrostatic Pressure for Glomerular Filtration?

Back 13

Net Hydrostatic Pressure for Glomerular Filtration = PGC - PBC

PGC = Glomerular capillary blood pressure

PBC = Bowman's capsule fluid pressure

Front 14

What is the equation for Net Protein Osmotic Pressure Against Glomerular Filtration?

Back 14

Net Protein Osmotic Pressure Against Glomerular Filtration = πGC - πBC

πGC = Protein osmotic pressure in glomerular capillary blood

πBC = Bowman's capsule fluid

Front 15

What is/What is the equation for Glomerular filtration pressure?

Back 15

Glomerular filtration pressure = PGC - PBC - πGC + πBC

PGC = Glomerular capillary blood pressure

PBC = Bowman's capsule fluid pressure

πGC = Protein osmotic pressure in glomerular capillary blood

πBC = Bowman's capsule fluid

Front 16

What are glomerular capillary blood pressure and glomerular filtration rate dependent on and why?

Back 16

Glomerular capillary blood pressure and glomerular filtration rate are dependent upon vascular resistances of afferent and efferent arterioles, because glomerular capillary is situated between afferent and efferent arterioles.

Front 17

____________________________ controls the blood pressure drop from the renal artery to the glomerular capillary.

Back 17

Afferent arteriole

Front 18

_____________________________ controls the blood pressure drop from the glomerular capillary to the peritubular capillaries.

Back 18

Efferent arteriole

Front 19

Afferent arteriolar vasoconstriction (a) __________________ glomerular filtration pressure and glomerular filtration rate. A(n) (b) __________________ in afferent arteriolar resistance (c) ________________ the blood pressure drop from the renal artery to the glomerular capillary.

Back 19

(a) decreases

(b) increase

(c) increase

Front 20

Efferent arteriolar vasoconstriction (a) ____________________ glomerular filtration pressure and glomerular filtration rate, because a(n) (b) __________________ in efferent arteriolar resistance (c) ___________________ the pressure drop from the glomerular capillary to the peritubular capillary.

Back 20

(a) increases

(b) increase

(c) decreases

Front 21

Renal blood flow ____________________ in response to an increase in renal vascular resistance, regardless of the vessel of vasoconstriction.

Back 21

decreases

Front 22

______________________________ is the process of transporting a molecule by renal tubular cells from glomerular filtrate in the renal tubular system to peritubular capillaries, thereby decreasing the excretion of a molecule.

Back 22

Renal reabsorption

Front 23

______________________________ is the process of transporting a molecule by renal tubular cells from peritubular capillaries into the renal tubular system, thereby increasing the excretion of a molecule.

Back 23

Renal secretion

Front 24

What is the equation for excretion?

Back 24

Excretion = Filtration - Reabsorption + Secretion

Front 25

The ___________________ Tubule is isoosmotic reabsorption and has high H2O permeability.

Back 25

Proximal

Front 26

The (a) _______________________ Limb of Henle and (b) ____________________ Tubule is used for diluting segments of the nephron and uses Na+-pumping activity.

Back 26

(a) Ascending

(b) Distal

Front 27

It is a major site of renal reabsorption and more than 60% of glomerular filtrate is reabsorbed by it.

Back 27

Proximal convolute tubule

Front 28

Transporters on the luminal side of proximal tubular cells are _________________________________________________ for driving reabsorption of molecules against their concentration gradient.

Back 28

Na+-coupled transporters

Front 29

Renal tubular reabsorption of (a) ___________________ and (b) ___________________ by distinct transporters occurs in the luminal and basolateral membranes of a proximal tubular cell.

Back 29

(a) Phosphate

(b) Glucose

Front 30

__________________________________________ is an important criterion for classification of kidney disease.

Back 30

Glomerular filtration rate

Front 31

When GFR * [Glucose]plasma < Tmax, glucose is __________________________________ and [Glucose]urine = 0.

Back 31

completely reabsorbed

Front 32

When GFR * [Glucose]plasma = Tmax and [Glucose]plasma = Renal threshold, glucose is __________________________________________. [Glucose]urine = 0

Back 32

completely reabsorbed

Front 33

Renal threshold for complete glucose reabsorption is about _______ mM.

Back 33

11

Front 34

When GFR * [Glucose]plasma > Tmax, glucose is __________________________________ and [Glucose]urine > 0.

Back 34

not completely reabsorbed

Front 35

What is the equation for urinary glucose excretion?

Back 35

Urinary Glucose Excretion = GFR * [Glucose]plasma - Tmax

Front 36

Label this graph of Renal Handling of Glucose.

Back 36

A. Rate of Glucose Filtration or Glucose Excretion

B. Transport Maximum (Tmax)

C. Glucose Excretion = GFR * [Glucose]plasma - Tmax

D. [Glucose]plasma

E. Complete Glucose Reabsorption

F. Renal Threshold

G. Glucose Filtration = GFR * [Glucose]plasma

Front 37

Label the arrows in this graph of Regulation of Extracellular Fluid Osmolarity by Regulating Urine Osmolarity.

Back 37

A. Concentrated Urine Osmolarity

B. Plasma Osmolarity (280 mOsM)

C. Dilute Urine Osmolarity

Front 38

___________________ increases water permeability of collecting duct to enhance the diffusion of water from collecting duct to the renal interstitium.

Back 38

ADH

Front 39

Fluid reabsorption by the proximal tubule is known as ___________________________________.

Back 39

Isoosmotic reabsorption

Front 40

What is a major function of the loop of Henle?

Back 40

A major function of the loop of Henle is the generation of an osmotic gradient in the renal interstitium by countercurrent multiplication.

Front 41

What does "countercurrent" refer to?

Back 41

"Countercurrent" refers to the opposite direction of fluid flow in the descending and ascending limbs of the loop of Henel.

Front 42

What does "multiplication" refer to?

Back 42

"Multiplication" refers to amplification of the Na+ pumping effect of each segment of the loop to generate a large overall osmotic gradient in the renal interstitium.

Front 43

The overall osmotic gradient in the renal interstitium ranges from (a) ______ mOsM in the renal cortex to (b) _______ mOsM in the renal medulla.

Back 43

(a) 300

(b) 1,200

Front 44

(a)______________________ in the hypothalamus detect the increase in the plasma osmolarity and in response stimulate the release of (b) __________ from posterior pituitary.

Back 44

(a) Osmoreceptors

(b) ADH/VP

Front 45

An increase in plasma concentration of ADH/VP causes the (a) ___________________ in renal water reabsorption and (b) ___________________ in urine osmolarity.

Back 45

(a) increase

(b) increase

Front 46

__________ increases water reabsorption by increasing water permeability of collecting duct for the production of concentrated urine.

Back 46

ADH

Front 47

ADH increases water permeability of cells of (a) _____________________________________ and (b) _____________________________________ by inserting (c) __________________ channels onto the cell membrane.

Back 47

(a) collecting tubule

(b) collecting duct

(c) aquaporin

Front 48

In presence of _______________________, water channels (aquaporin channels) insert onto collecting duct membrane and permit osmotic equilibrium between collecting duct fluid and medullary interstitial fluid, thereby producing concentrated urine.

Back 48

vasopressin

Front 49

Draw the effect of antidiuretic hormone (vasopressin, VP) on urine osmolarity.

Back 49

Front 50

__________________________________ can be caused by genetic deficiencies in vasopressin receptor and aquaporin.

Back 50

Diabetes insipidus

Front 51

In absence of (a) ____________________________, water channels (aquaporin channels) are (b) _________________ from collecting duct membrane, causing tubular fluid to remain (c) _________________ as it passes through collecting duct.

Back 51

(a) vasopressin

(b) removed

(c) hypoosmotic

Front 52

Regulation of extracellular fluid volume by renin-angiotensin-aldosterone system causes these three things.

Back 52

(a) Sympathetic activity

(b) Tubular Na+ & Cl- reabsorption, K+ excretion, H2O retention

(c) Aldosterone secretion

Front 53

High ECF Osmolarity -->

______ Plasma ADH/VP -->

______ Renal Reabsorption of Water

Back 53

Increases

Increases

Front 54

_________________________________________ are sensors of Na+ delivery through distal tubule. In response to low Na+ delivery through the distal tubule, these signal juxtaglomerular cells to release renin.

Back 54

Macula densa cells

Front 55

Macula densa signal (a) __________________________ cells to release (b) ________________ when they sense low Na+ delivery through distal tubule.

Back 55

(a) juxtaglomerular

(b) renin

Front 56

Angiotensin II stimulates ________________________ secretion by adrenal cortex.

Back 56

Aldosterone

Front 57

Aldosterone (a) ________________________ Na+ reabsorption in the (b) _______________________ limb of Henle, (c) _____________________ tubule, and (d) ____________________ tubule.

Back 57

(a) increases

(b) ascending

(c) distal

(d) collecting

Front 58

Aldosterone increases __________________________________________________ by increasing Na+ reabsorption.

Back 58

extracellular fluid volume

Front 59

How is the kidney involved in hypertension?

Back 59

From the kidney, angiotensin II-induced vasoconstriction and aldosterone-induced Na+ and water retention causes high blood pressure (hypertension).

Front 60

How is the sympathetic nervous system involved in hypertension?

Back 60

The sympathetic nervous system causes sympathetic stimulation of vasoconstriction, which causes high blood pressure (hypertension).

Front 61

What interactions between the sympathetic nervous system and kidney cause hypertension?

Back 61

The sympathetic nervous system causes the sympathetic nerves to stimulate renin release by the kidney. The kidney produces angiotensin II, which stimulates activity of the sympathetic nervous system. These result in vasoconstriction and the increase in blood pressure (hypertension).

Front 62

Vitamin D is hydroxylated in the _________________ and ____________________.

Back 62

Liver and kidney

Front 63

Vitamin D is _______________________ in the liver and kidney.

Back 63

hydroxylated

Front 64

________________________________ and ________________________________ enhance renal Ca2+-reabsorption by stimulating protein expression of Ca2+ transporters in renal tubular epithelial cells.

Back 64

Parathyroid hormone and vitamin D

Front 65

Parathyroid hormone and vitamin D enhance (a) __________________________________________________ by stimulating protein expression of (b) _________________________________ in renal tubular epithelial cells.

Back 65

(a) renal Ca2+-reabsorption

(b) Ca2+ transporters

Front 66

Ca2+ enters the (a) _____________________ side of a tubular cell through (b) _____________________ channels, and leaves the (c) _____________________ side through (d) ____________________________ and (e) ___________________________.

Back 66

(a) luminal

(b) calcium

(c) basolateral

(d) Na+/Ca2+ exchange

(e) Ca2+-ATPase

Front 67

What is the CO2/bicarbonate buffer system?

Back 67

CO2 + H2O <--> H2CO3 <--> H+ + HCO3-

Front 68

What is the equation of the chemical equilibrium of the CO2/bicarbonate buffer system?

Back 68

K = [H+] * [HCO3-] / [H2CO3]

Front 69

What is the Henderson-Hasselbalch equation?

Back 69

pH = pK + log{[HCO3-]/αPCO2}

Front 70

Extracellular pH is dependent on the ___________________ ratio.

Back 70

[HCO3-]/PCO2

Front 71

What causes an increase and decrease in CO2?

Back 71

Increase: (Hypoventilation) Respiratory acidosis

Decrease: (Hyperventilation) Respiratory Alkalosis

Front 72

What causes the increase and decrease in HCO3-?

Back 72

Increase: (acid production) Metabolic acidosis

Decrease: (bicarbonate production) Metabolic alkalosis

Front 73

If there is an increase in CO2, there is a(n) __________________________ in HCO3-.

Back 73

decrease

Front 74

If there is a decrease in CO2, there is a(n) __________________________ in HCO3-.

Back 74

increase

Front 75

List the three ways the kidneys regulate acid-base.

Back 75

1. Tubular reabsorption of HCO3-

2. Tubular secretion of H+ as titratable acid

3. Tubular excretion of NH4+

Front 76

Bicarbonate is filtered from the plasma into the renal tubular system by glomerular filtration but is completely reabsorbed back to the circulation by _______________________________________.

Back 76

renal tubular cells

Front 77

Inside a tubular cell, ____________________________ catalyzes the conversion of CO2 to H2O to H2CO3.

Back 77

carbonic anhydrase

Front 78

H2CO3 dissociates into _______ and _______.

Back 78

H+ and HCO-.

Front 79

H+ is transported from a tubular cell into tubular lumen by (a) _____________ exchange and (b) __________________ at the luminal membrane for neutralization of (c) ___________ to form (d) ___________.

Back 79

(a) Na+/H+

(b) H+-ATPase

(c) luminal HCO3-

(d) H2CO3

Front 80

Carbonic anhydrase converts H2CO3 to ___________ and __________.

Back 80

CO2 and H2O

Front 81

K+ is reabsorbed in the nephron through (a) ___________ exchange channels and (b) ___________ channels.

Back 81

(a) Na+/K+

(b) Na+/Cl-/K+

Front 82

In the CNT or principal cell of the nephron, K+ is secreted through ___________ channels and ____________.

Back 82

K+

K+-ATPase

Front 83

In the intercalated cell (α) in the nephron, K+ is secreted through (a) _________ channels and (b) _____________. (c) ______________ exchange channels and (d) ____________ channels are used in the secretion of K+ as well.

Back 83

(a) Na+/K+

(b) K+-ATPase

(c) HCO3-/Cl-

(d) Cl--ATPase

Front 84

During tubular secretion, H+ is transported actively from a (a) _______________________ into (b) _______________________ by H+-ATPase at the (c) ______________________________ and HCO3- is transported to the circulation via (d) ______________________________ at the (e) ______________________________.

Back 84

(a) tubular cell

(b) luminal fluid

(c) luminal membrane

(d) HCO3-/Cl- exchange

(e) basolateral membrane

Front 85

During tubular secretion, H+ in tubular fluid is buffered mostly by (a) __________________ resulting in a modest (b) ___________________ in pH.

Back 85

(a) phosphate

(b) decrease

Front 86

What is a "titratable acid" and why?

Back 86

The amount of H+ captured by buffer in the urine is known as "titratable acid," because it can be determined by titrating the pH of urine back to 7.4.

Front 87

During renal excretion of ammonium, renal tubular cells produce __________ and ___________ from glutamine.

Back 87

HCO3- and NH4+

Front 88

During renal excretion of ammonium, renal tubular cells produce HCO3- and NH4+ from _____________________.

Back 88

glutamine

Front 89

How is HCO3- transported from a tubular cell to the circulation and where does it occur during renal excretion of ammonium?

Back 89

HCO3- is transported from a tubular cell to the circulation via Na+/NH4+ exchange at the luminal membrane.

Front 90

Name the modes of transport in tubular excretion of ammonium.

Back 90

Na+/H+ exchange, NH3/NH4+ channels, Na+/HCO3- cotransport

Front 91

What is a measure of the kidney's rate of clearing plasma of a given molecule X by urinary excretion?

Back 91

Renal clearance

Front 92

What is renal clearance?

Back 92

Renal clearance is a measure of the kidney's rate of clearing plasma of a given molecule X by urinary excretion

Front 93

Quantitatively, renal clearance is the flow of clean plasma cleared of X by what equation?

Back 93

Clearance of X = [X]urine * Urine Flow / [X]plasma

or Clearance of X = Rate of Urinary Excretion of X / [X]plasma

or C = UV/P

C = clearance of X

U = conc. of X

V = urine flow

P = plasma conc. of X

Front 94

Label this chart.

Back 94

Front 95

What is the equation for Rate of Creatinine Excretion?

Back 95

Rate of Creatinine Excretion =

[Creatinine]urine * Urine Flow =

[Creatinine]plasma * GFR

Front 96

What is the equation for Clearance of Creatinine?

Back 96

Clearance of Creatinine =

[Creatinine]plasma * GFR / [Creatinine]plasma =

GFR

Front 97

Creatinine is handled by _____________________________________ only.

Back 97

Glomerular filtration

Clearance of Creatinine = Glomerular Filtration Rate

Front 98

When Clearance = GFR, how is the substance handled by the kidney?

Back 98

Filtration only

Front 99

When Clearance < GFR, how is the substance handled by the kidney?

Back 99

Filtration + Reabsorption

Front 100

When Clearance > GFR, how is the substance handled by the kidney?

Back 100

Filtration + Secretion

Front 101

In clearance values, when maximum clearance is reached, what is it equal to and how is it handled by the kidneys? Give an example.

Back 101

Maximum clearance = Renal plasma flow

It is handled by the kidneys through Glomerular filtration + complete secretion.

An examples is Para-aminohippuric acid (PAH)

Front 102

What is an indicator os kidney failure and why?

Back 102

High [Creatinine] in plasma

[Creatinine]plasma * GFR = Rate of Creatinine Excretion

[Creatinine]plasma = Rate of Creatinine Excretion/GFR

At constant rate of creatinine excretion,

Inc. [Creatinine]plasma reflects Dec. GFR

Front 103

Detrusor muscle of bladder wall (smooth muscle) is stimulated by the (a) ___________________________________ of the (b) ______________________ Nervous System.

Back 103

(a) pelvic nerve

(b) parasympathetic

Front 104

The __________________________________________________ (smooth muscle) is stimulated by the hypogastric nerve of the sympathetic nervous system.

Back 104

Internal Urethral Sphincter

Front 105

The __________________________________________________ (skeletal muscle) is stimulated by pudendal nerve of the somatic nervous system.

Back 105

External urethral sphincter

Front 106

The micturition center in the brain stem regulates (a) _________________________ and (b) _____________________________ of the lower urinary tract by regulating (c) ___________________________, (d) __________________________, and (e) ____________________________ in response to mechanosensory input from the urinary bladder wall.

Back 106

(a) urine storage (continence)

(b) urination (micturition)

(c) parasympathetic

(d) sympathetic

(e) somatic output

Front 107

During the continence phase, when the urinary bladder is (a) ______________________ filled, mechanosensory input to the micturition center is (b) ________________________, because mechanical stretch of the urinary bladder wall is (c) _________________________.

Back 107

(a) not fully

(b) low

(c) low

Front 108

During the continence phase, the micturition center (a) ______________________ parasympathetic output and (b) _____________________ sympathetic and somatic outputs to the lower urinary tract.

Back 108

(a) inhibits

(b) stimulates

Front 109

During the continence phase, the inhibition of parasympathetic output to the detrusor smooth muscle cells causes __________________________ of the bladder wall for accommodating continued filling of the urinary bladder with urine.

Back 109

relaxation

Front 110

The stimulation of sympathetic output to smooth muscle cells of the internal urethral sphincter and somatic output to skeletal muscle cells of the external urethral sphincter causes (a) ____________________________ of these two sphincters for (b) __________________________________________________ of urine during the continence phase.

Back 110

(a) contraction

(b) preventing leakage

Front 111

During the micturition phase, when the urinary bladder is (a) ___________________ filled, mechanosensory input to the micturition center is (b) ___________________, because mechanical stretch of the urinary bladder wall is (c) ___________________.

Back 111

(a) fully

(b) high

(c) high

Front 112

During the micturition phase, the micturition center (a) __________________ parasympathetic output and (b) ___________________ sympathetic and somatic outputs to the lower urinary tract.

Back 112

(a) inhibits

(b) stimulates

Front 113

During the micturition phase, the stimulation of the parasympathetic output to detrusor smooth muscle cells causes (a) _____________________ of the bladder wall and (b) ____________________ of pressure inside the urinary bladder.

Back 113

(a) contraction

(b) buildup/increase

Front 114

The inhibition of sympathetic output to smooth muscle cells of the internal urethral sphincter and somatic output to skeletal muscle cells of the external urethral sphincter causes ____________________________ of these two sphincters for urinary flow during the micturition phase.

Back 114

relaxation

Front 115

Diuretics (a) ___________________ plasma volume by (b) ______________________ Na+ reabsorption.

Back 115

(a) lower

(b) inhibiting

Front 116

What is chronic kidney failure characterized by?

Back 116

Chronic kidney failure is characterized by a diminished glomerular filtration rate, increased urinary excretion of protein, or both.

Front 117

What does kidney failure lead to?

Back 117

Kidney failure leads to the accumulation of waste products and excess volume in the extracellular fluid, which can lead to failures in multiple organs.

Front 118

What are the dialysis systems used for?

Back 118

Dialysis systems are used for removing waste products from the extracellular fluid in patients having kidney failure.

Front 119

During hypoxic stress, what happens to the erythropoietin production levels? Where is erythropoietin produced?

Back 119

In hypoxic stress, erythropoietin production may increase a 1000-fold, reaching 10,000 mU/ml of blood. Erythropoietin is produced mainly by peritubular capillary lining cells of the renal cortex, which are highly specialized, epithelial-like cells. It is synthesized by renal peritubular cells in adults, with a small amount being produced in the liver.

Front 120

What is the basic principle of dialysis?

Back 120

The basic principle of dialysis is a diffusional exchange of waste products between extracellular fluid and dialysate through a membrane system that is selectively permeable to small molecules but impermeable to proteins and cells.

Front 121

What is the difference between peritoneal dialysis and hemodialysis?

Back 121

During peritoneal dialysis, clean dialysate is infused into the abdominal cavity via a catheter. Can be performed at home.

During hemodialysis, blood is pumped out of the patient's circulation via an artery into a membrane dialyzer for diffusional exchange with dialysate. Cleansed blood leaving the membrane dialyzer is pumped back into the patient's circulation via a vein. Usually performed at a clinical center.

Front 122

How is kidney transplantation performed?

Back 122

The donor's kidney's renal artery and renal vein are typically connected to the recipient's artery and vein in the abdominal cavity. The donor's kidney's ureter is typically connected to the recipient's urinary bladder. The recipient's failed kidneys are usually left in place, unless they cause infection or hypertension in the patient.