Lecture 11/11: Renal Physiology Flashcards

Final

1
Q

What is plasma oncotic pressure at the AA?

A

28 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is plasma oncotic pressure at the middle of the GC?

A

32 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is plasma oncotic pressure at the end of the GC?

A

36 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why does oncotic pressure increase as you cross the GC?

A

Fluids are reabsorbed and not colloids therefore increasing the CONCENTRATION of colloids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is hydrostatic pressure of bowman’s capsule?

A

Ptubule = 18 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

_______ is used to manipulate auto regulation. ______ is used to fine tune GFR.

A

AA

EA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

EA =

A

Efferent Artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

T/F: Autoregulation in the kidneys is a flat line

A

F

Slanted line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe autoregulation in the kidneys

A

Imperfect autoregulation that maintain a constant GFR and helps regulate BP long term

The line is slant and represents how the kidney is able to get rid of fluid when pressure is high and retain when low.

LL = 50
UL = 150

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens to the things that stay in the nephron?

A

Get excreted in urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the plasma oncotic pressure in bowman’s capsule?

A

0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

_____% of filtrate in nephron gets reabsorbed

A

99

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the normal rate of reaborption in the nephron?

A

124 ml/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the name of the beginning of the nephron?

A

Bowman’s capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

There are some proteins in the nephron. Describe their use. Do they contribute to oncotic pressure?

A

These proteins are strictly used for cell functioning in the nephron

They are tethered to the cell wall and are not floating around freely

They do not contribute to oncotic pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the NFP at the GC?

A

10 mmHg

Use formula and calculate
Need to memorize formula baby
Need to memorize normal values

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Equation: Filtration Rate (GFR)

A

GFR = Kf x NFP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the Renal interstitium? What is its importance?

A

Matrix outside of nephron

Contains: proteins, ions, energy compounds, & filaments

** things reabsorbed into the PT cap/vasa recta have to go through here** <– very important for creating a gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

PT cap =

A

Peritubular capillary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What type of blood is filtered through the kidneys?

A

Plasma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

VR =

A

Vasa Recta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is ∆P from upstream of the AA to the GC?

A

40 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is ∆P from the GC to downstream of the EA?

A

42 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which artery in the kidney is used to fine tune GFR?

A

EA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Which artery in the kidney has the highest vascular resistance?

A

EA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a hydrostatic pressure at the end of the EA?

A

18 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the second set of capillary beds in the kidney?

A

Peritubular capillaries/Vasa recta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What happens when you constrict/dilate the EA?

A

Constrict –> Increase GC pressure –> increase GFR

Dilate –> decrease GC pressure –> decrease GFR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Where does reabsorption occur?

A

All segments of the tubule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the hydrostatic pressure in the PT cap?

A

13 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the PT cap oncotic pressure?

A

Beginning: 36 mmHg

Middle: 32 mmHg

End: 28 mmHg

99% of fluids being reabsorbed here dilutes the colloids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the Renal ISF hydrostatic pressure?

A

6 mmHg

33
Q

What is Renal ISF oncotic pressure?

A

15 mmHg

34
Q

What happens to everything that was reabsorbed back into the PT cap?

A

Goes back into CVS via renal vein

35
Q

What is the NFP in the PT cap?

A

-10 mmHg

36
Q

What is the NRP in the PT cap?

A

10 mmHg

37
Q

Define excretion

A

Removed in urine

38
Q

The more we filter, the more we _______

A

Excrete

39
Q

What happens if the reabsorption rate equals filtration rate?

A

There’s no excretion

40
Q

Define secretion

A

Pumping things back into the the nephron from PT cap and Renal ISF

41
Q

What ions do we commonly see secreted?

A

K+
Organic cations/anions
Protons
NH4
Creatinine
Phosphate

42
Q

Equation: Excretion

A

Excretion = Filtration + secretion - reabsorbed

43
Q

What is normal urine excretion rate?

A

1ml/min

44
Q

What happens to colloids in the GC if you constrict the EA?

A

colloids become even more concentrated bc GFR is increased

Colloid pressure increases –> Increasing reabsorption downstream

45
Q

What happens to colloids in the GC if you dilate the EA?

A

colloids become more dilute bc GFR is decreased

Colloid pressure decreases –> Decreasing reabsorption downstream

46
Q

What is filtration fraction looking at?

A

How much fluid is being filtered and how much plasma has made it through the kidney

47
Q

Approximately _____% of blood that goes through the kidney is filtered

A

10%

48
Q

Equation: Filtration Fraction

A

FF = GFR / RPF

49
Q

What is normal renal plasma flow? How do we find it?

A

660 ml/min

1100ml/min x 0.6

50
Q

What is the percent of Hct in the blood?

A

40%

0.40

51
Q

What is a normal FF?

A

0.19 = 19%

About 20% Per Dr. S

52
Q

Constricting the AA or EA will ________ RBF

A

decrease

53
Q

Relaxing the AA or EA will ______ RBF

A

increase

54
Q

How does dilating the AA affect RBF & GFR?

A

RBF: increase
GFR: increase

55
Q

How does dilating the EA affect RBF & GFR?

A

RBF: Increase
GFR: Decrease

56
Q

_____ is good at autoregulation at a higher MAP; _______ is good at autoregulation at a lower MAP. Explain this.

A

GFR
-GFR autoregulation starts dropping off well before the lower limit of 50 mmHg.
-But even above a MAP of 150 it doesn’t go straight up.

RBF
- RBF autoregulation doesnt drop off until MAP of 50
-At MAP of 150 the autoregulation line starts to go up rapidly.

57
Q

What does autoregulation in the kidneys depend on?

A

The ability of the AA being able to constrict/dilate

58
Q

If you’re sick, what happens to your autoregulation in the kidneys?

A

AA wont be able to dilate normally –> YOU NEED A HIGHER MAP THAN 50 TO PERFUSE THE KIDNEYS!!!!!

Do not let your kidneys hang around a MAP of 50

59
Q

What would happen in the kidneys if we didn’t have autoregulation?

A

High filtration and urine dumping as blood pressure goes up to try to bring down BP

This would damage the kidneys by causing severe damge to the GC dt the high pressure from high RBF.

60
Q

As BP increases, UO ______ to _______ BP

A

Increases

Decrease

61
Q

As BP decreases, UO ________ to try to ________ BP

A

decreases

Increase

This is to conserve fluid

62
Q

What are the 4 paths for compounds in the kidney?

A
  1. Filtration only
  2. Filtration, partial reabsorption
  3. Filtration, complete reabsorption
  4. Filtration, secretion
63
Q

Name a compound that follows the path of filtration only

A

Inulin/creatinine

64
Q

Name a compound that follows the path of filtration, partial reabsorption

A

Na+

This is bc we eat way more than we need so more is filtered than reabsorbed

65
Q

Name a compound that follow the path of filtration, complete reabsorption

A

Glucose, in a non diabetic person (or sugar WNL)

66
Q

Name a compound that follows the path of filtration, secretion

A

PAH

67
Q

PAH =

A

Para Amino Hippuric Acid

68
Q

What is PAH?

A

Dx compound used to measure Clearance & RBF

69
Q

Removal of PAH is dependent on _____

A

RBF

70
Q

The more PAH that missing the _____ the RBF

A

higher

71
Q

THe lower the PAH clearance = ______ RBF

A

lower

72
Q

What are the structures that allows things to get filtered through the GC? What are they?

A

-Fenestrations: specialize openings in the endothelium of GC

-Slit pores: gaps between foot processes of podocytes in GC
Crucial part of filtration barrier
-allows small molecules & blocks large ones

73
Q

Describe the layers of the GC

A
  1. Endothelium: inner layer
    Neg charge
  2. Basement Membrane: Neg charge
  3. Epithelium: outer layer: specialized layer made of podocytes to provide structural support to GC (Esp at high pressures)
74
Q

How are proteins kept from being filtered at the GC?

A

Proteins are negatively charged

The basement membrane and Endothelium of the GC are both neg charged which repel proteins

75
Q

What are the cells in the epithelium of the GC? Describe them

A

Podocytes

Highly specialized cells that provide structural support to the GC to help prevent its surface area from expanding and falling apart dt high pressure

76
Q

What is a dextran?

A

synthetic sugar that scientist can make larger/smaller

77
Q

In relation to size and charge, what makes something easier to filter at the GC? Harder?

A

Easier: Smaller; Adding positive charges

Harder: Larger; adding negative charges

Ex) A neutral sugar that is large is not able to be filtered
– We added a positive charge on to that same exact sugar & now its able to be filtered

78
Q

What are 4 things that have a filterability of 1.0?

A

Water
Na
Glucose
Inulin

79
Q

T/F: You cant filter myoglobin

A

F

You can; its filterability if 0.75 but we really shouldnt even have myoglobun present in the blood under healthy conditions

Myoglobin is released in the blood when muscle tissue is damaged.