RBF/GFR (DSA + Lecture) Flashcards

1
Q

What is the Tamm-Horsefall protein? Why is it seen in urine?

A

Protein produced by thick ascending loop of henle

Surpasses filtration of proteins in PCT, so ends up in urine

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2
Q

What two molecules are responsible for the negative charge of biogel? Where is biogel found?

A

Found over the fenestrations of capillary endothelium (in lumen)

Heparin Sulfates and Hyaluronin

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3
Q

What are three molecular fillers found in the filtration diaphragm?

Which one is specific to renal?

A

Cadherin, actin, and Nephrin

Nephrin is specific to renal

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4
Q

Role of molecular fillers?

A

Provide a physical barrier against larger molecules

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5
Q

What are 3 characteristics indicate a damaged filtration barrier?

A

Hypercellularity

Thickened Basement membrane (increases distance for filtration)

Glomerulosclerosis (increased extracellular tissue, so decreased SA for filtration)

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6
Q

Which part of the kidney has coiled blood vessels/ intertwined tubules?

A

Cortex

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7
Q

What 5 criteria is are necessary for a substance to be able to measure GFR?

A
  1. Can’t be broken down or metabolized by kidney
  2. Shouldn’t be reabsorbed or secreted
  3. Shouldn’t alter GFR
  4. Should have a stable plasma concentration
  5. Should be able to freely diffuse across the glomerulus
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8
Q

What happens to oncotic pressure of the efferent arteriole when GFR Increases?

A

It increases

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9
Q

What receptors lead to vasoconstriction of afferent arterioles?

A

Sympathetic stimulation of a1 receptors

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10
Q

What receptors lead to increased RAAS activation by the JGA cells?

A

Sympathetic stimulation of B1 receptors

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11
Q

What receptors lead to increased N/K ATPase functioning

A

Sympathetic stimulation of a1 receptors

(Results in more reabsorption of Na) –> more retention of water and increased blood volume

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12
Q

Immediate effects of sympathetic stimulation

A
  • Vasoconstriction of afferent arterioles
  • RAAS stimulation
  • Decreased GFR
  • Decreased RBF
  • Increased Thirst
  • Increased BP
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13
Q

Long term effects of sympathetic stimulation

A
  • Decreased urine output
  • Increased water intake
  • Decreased Na secretion
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14
Q

What is a normal BUN:Creatine Ratio?

A

10:1

Post renal problem

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15
Q

What is a High BUN:Creatine Ratio?

A

20:1

Pre-renal problem

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16
Q

What is a Low BUN:Creatine Ratio?

A

10:1

Intrarenal problem

17
Q

Dilation of afferent arteriole

A

IN GFR

IN RBF

18
Q

General rule with GFR/ RBF/ arterioles?

A

With Afferent: Both RBF and GFR will move in same direction

With Efferent: GFR and RBF move in opposite directions

Hydrostatic pressure moves in same direction as RBF
Oncotic pressure of efferent arteriole moves in same direction as GFR

19
Q

Constriction of afferent arteriole

A

DEC GFR

DEC RBF

20
Q

Constriction of efferent arteriole

A

INC GFR

DEC RBF

21
Q

Dilation of efferent arteriole

A

DEC GFR

INC RBF

22
Q

What causes constriction of efferent arterioles?

A

RAAS system

AGT 2

23
Q

What causes constriction of afferent arterioles?

A

Sympathetic Nervous system

24
Q

What causes vasodilation of afferent arterioles?

A
NO
Prostaglandins
Dopamine
ANP
Bradykinin
25
Q

Glomerulartubular Balance

A

GFR impacts tubule conditions

Increase in GFR = Increase in reabsorption in tubules

26
Q

What are the 3 mechanisms of GT Balance?

A
  1. Change in pressure
  2. Change in flow rate
  3. GFR and flow rate impact microvilli sheer stress
27
Q

What is autoregulation?

A

Allows for RBF and GFR to be maintained within narrow limits

28
Q

What is the myogenic response of autoregulation?

A

Increased pressure results in contractions (local reflex) (since blood vessels resist stretch)

Results in a decreased GFR

29
Q

What is TG Feedback?

A

Tubule impacts GFR!
Feedback loop between:
1. Macula densa cells= detect Na+ changes
2. JGA cells = Renin secretion
3. Mesangial cells= Transduction of signal

30
Q

Steps of TG Feedback with Increased Perfusion Pressure

A
  1. Increased Na+ = stimulation of macula densa
  2. Influx of Na triggers ATP/Adenosine to be released
  3. ATP binds to its receptor (PX2) and Adenosine binds to A1 receptor on VSM cells.
  4. This binding will allow calcium signaling —> decrease in GFR: afferent will constrict
31
Q

Steps of TG Feedback with Decreased Perfusion Pressure

A
  1. Decreased NA+
  2. Macula Densa signals to JGA Cells
  3. JGA Cells secrete renin
  4. Activation of RAAS pathway
  5. Efferent arterioles constrict due to AGT2
  6. Increase in GFR