(DSA) Introduction to Renal Blood Flow and GFR | (Pierce) Flashcards

1
Q

What is this structure?

A

Glomerulus

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2
Q

In order for filtration to occur, what three layers must the particulate cross through?

A
  1. Capillary Endothelium
  2. Glomerular basement membrane
  3. Podocyte epithelium
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3
Q

Describe the movement of fluid from the capillary lumen…

A

Capillary lumen –>

Capillary endothelium –>

Glomerular basement membrane –>

Podocyte epithelium –>

BOWMANS CAPSULE

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4
Q

What is shown in this image?

A

View seen from the capillary side

Holes = fenestrea of the endothelial cells

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5
Q

What are the arrows pointing at?

A

*fuzzy border = Biogel

Glomerular endothelium glycocalyx forms a biogel in the endothelial lumen

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6
Q

What is the major cell adhesion molecule that specifically functions in the glomerulus?

Function?

A

NEPHRIN

Nephrin blocks Larger proteins from entering bowmans space

*frequently absent in diseased renal states

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7
Q

Any molecule less than _____ angstroms are freely filtered

A

20

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8
Q

Any molecule greater than _____ angstroms are not filtered

A

42

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9
Q

What are podocytes?

A

Cells in bowmans capsule that wrap around capillaries of the glomerulus

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10
Q

What passes through the filtration barrier?

Freely filtered?

A

Water

Small solutes (glucose, amino acids, electrolytes)

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11
Q

What is not freely filtered through the filtration barrier?

A
  • Large molecules (proteins)
  • Formed elements (cells)
  • Miniscule amounts of protein are filtered

*Tamm-Horsfall protein

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12
Q

What molecules are more freely filtered,

Cations or Anions?

A

CATIONS!!! ++++++++++

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13
Q

What does the cortex contain?

How are they organized?

A

Renal corpuscles, coiled blood vessles, coiled tubules

Intertwined randomly like plate of spaghetti

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14
Q

What does the medulla contain?

How are they organized?

A

Straight blood vessels and Straight tubules

Organized in parallel array like bundles of pencils

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15
Q

RBF is regulated…

A

Minute-by-minute oversight

*For example: during intense exercise, the renal fraction of blood flow decreases because blood is shunted to the musculature

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16
Q

What is filtered load?

A

The amount of a substance that is filtered into the bowman’s space per unit time (mg/min)

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17
Q

How do you calculate filtered load?

A

FL = GFR x Px

18
Q

Equation for urinary excretion?

A

Amount filtered - Amount reabsorbed + amount secreted = Urinary Excretion

19
Q

Equation for tubular reabsorption?

A

Glomerular filtration - Urinary excretion + Amount secreted

20
Q

If excretion > filtration then…

A

Tubular secretion must have occured!!!

21
Q

Equation for urine exretion rate?

A

Urine excretion rate of x = Ux x V

Ux= the concentration of that substance in the urine in a given volume

V=Urine flow rate, rate at which urine is produced

22
Q

How do you calculate Ux?

A

Ux= concentration of X (Ux) = the concentration of that substance in the urine in a given volume

23
Q

How do you calculate V?

A

V= Urine flow rate, the rate at which urine is produced

24
Q

What is renal clearance?

A

Renal Clearance (C) is the rate at which substances are removed (cleared) from plasma)

IT’S A FLOW RATE

25
What are the units for **renal clearance (C)?**
Volumer per unit time (mL/min, L/hour, L/day)
26
What is the equation for **renal clearance?**
27
What is the **glomerular filtrate?**
_Volume of plasma filtered_ into combined nephrons of both kidneys per unit time (mL/min)
28
What is the equation for **filtration fraction?**
FF = GFR / RPF GFR= glomerular filtration rate RPF = renal plasma flow \*FF is typically 20% of RPF
29
Describe the relationship between **filtration fraction** and **glomerular oncotic pressure**
30
What is **filtered load?**
A rate in mg/min
31
What is **filtration fraction (FF)?**
A ratio of GFR to RBF
32
What percentage of the filtered load of sodium is reabsorbed per day?
33
GFR is directly proportional to renal clearance under these conditions:
1. Substance must be **freely filterable** in the glomeruli 2. Substance must be **neither reabsorbed** nor **secreted** by the renal tubules 3. Substance must **not be synthesized, broken down,** or **accumulated** by the kidney 4. Substance must be **physiologically inert**
34
What is an example of a substance that has the GFR = C?
Inulin Creatinine
35
In clinical situations, the GFR of a patient is usually determined by measuring the \_\_\_\_\_\_\_\_\_\_
Clearance of **creatinine**
36
Sympathetic stimulation causes:
Vasoconstriction Renin release + RAAS Na-K ATPase activity; Increased Na+ reabsorption **INCREASED BLOOD PRESSURE**
37
What are the receptor subtypes for:
38
Plasma creatinine concentration and GFR are _________ proportional
Inversely
39
What is BUN?
Blood urine nitrogen
40
What can PAH (Para-aminohippuric acid) be used for?
Estimating renal plasma flow \*We can assume that all the PAH presented to the kidney appears in the urine
41