Glomerular Filtration Flashcards Preview

Block 2 Week 4 > Glomerular Filtration > Flashcards

Flashcards in Glomerular Filtration Deck (25)
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1
Q

What is the equation for filtration?

A

K [(Pc (hydrostatic) +Pit (oncotic))-((Pt(hydrostatic) +Pic (oncotic))]
C=glomerulus
t= bowmen’s space
Pit is always zero!!

2
Q

What factors favor filtation from glomerulus to bowmens space?
What factors oppose it?

A

Favor=glomerular hydrostatic pressure, oncotic pressure due to proteins in the bowman’s space
Oppose= oncotic pressure in the glomerulus, hydrostatic pressure in the bowman’s space

3
Q

Describe how a glomerular capillary differs from skeletal capillaries?

A

As you move along the length of the capillary, you maintain a net filtration and Never have net reabsorption

4
Q

Why does plasma oncotic pressure increase along the length of the capillary?
What is the significance of this?

A
  • Because you are decreasing the amount of water in the capillary so your proteins are becoming more concentrated
  • limits filtration
5
Q

The k filtration constant is dependent upon what 2 things?

A

capillary surface area ad permeability of this surface

6
Q

When you have a urinary tract obstruction what happens?

A

you increase hydrostatic pressure in the capsule space therefore you reduce net filtration

7
Q

When you have hypoalbumineria what happens?

A

you have decrease in oncotic pressure in the capillary therefore you increase the net filtration

8
Q

When you have diabetic nephropathy what happens?

A

you have increase in K filtration due to permeability of the glomerulus to albmumin which results in increase in oncotic pressure of capsule space and an increase in net filtration

9
Q

When you go from the affarent arteriole to the efferent arteriole what happens to your oncotic pressure in them?

A

increases towards the efferent

10
Q

What happens to your oncotic pressure as move from the efferent capillary to the peritubular capillary?
What happens to your hydrostatic pressure?

A
  • the oncotic pressure stays the same until the very end of the peritubular capillary where it decreases.
  • You have a decrease in hydrostatic pressure
11
Q

The drop of hydrostatic pressure in the efferent arteriole and in the peritubular capillary favors what?

A

reabsorption

12
Q

What happens to reabsorption with a decrease in peritubular hydrostatic pressure?

A

increased reabsorption

13
Q

What happens to reabsorption with a decrease in peritubular colloid osmotic pressure?

A

decreased reabsorption

14
Q

as particles get larger and their charges become more negative their ability to be (blank) decreases.

A

filtered

15
Q

Why do negatively charges particles have a hard time crossing the barrier to become filtered?

A

the barrier also has a negative charge

16
Q

What is the volume of plasma per minute from which all of a substance is removed?

A

clearance

17
Q

Is clearance a volume or a concentration?

A

a volume

18
Q

What are the three reasons why you can you Cleareance of inulin to determine GFR?

A

1 )freely filtered

2) not reabsorbed
3) not secreted

19
Q

What is the clearance equation?

A

Cleareance rate= (concenrtaion of substane in urine times urine flow rate)/ (concentration of substance in the plasma)
Cx=(Ux * V)/ Px

20
Q

If you dont want to inject inulin then what can you use instead to determine GFR?

A

Creatinine clearance

21
Q

What is the filtered load?

A

gives you information about the rate at which a substance is filtered. So if a substance is freely filtered than u know, that there is an equal concentration in both compartments. If you multiply it with the GFR you get the filtered load.

22
Q

What is the equation for filtered load?

A

GFR X concentration in plasam

23
Q

How much sodium do we excrete per day?

A

2.4 g Na

24
Q

What is the equation for fractional excretion?

A

excretion rate/filtered load

25
Q

What is the equation for fractional reabsorption?

A

reabsorption rate/ filtered load