GFR

Question 1

Renal failure leads to?

Answer 1

Edema, increase in workload of heart, heart failure, death

Question 2

Functional unit of the kidney

Answer 2

Nephron (1million in each kidney)

Question 3

What is the most unique thing about the glomerular capillary system?

Answer 3

Pressure drop occures in two steps so as to keep high hydrostatic pressure within the glomerular capillary.

Question 4

Where are the two pressure drops?

Answer 4

Afferent areteriole, Efferent arteriole

Question 5

Concentration of glomerular filtrate?

Answer 5

Similar to plasma but without large proteins

Question 6

GFR in ml/min?

Answer 6

130

Question 7

GFR in L/day

Answer 7

180

Question 8

Three barriers to glomerular filtration. What the hell are they

Answer 8

1. ) Capillary enothelium- very leaky comparede to the capillary system of other organs.
2. ) Basement Membrane- Collagen and proteoglycan
3. ) Epithelium or podocyte monolayer- foot processes forming slit pores

Question 9

GFR=

Answer 9

Kf x net filtration pressure

Question 10

WHat is Kf

Answer 10

Filtration coefficeint, relates to the hydraulic conductivity x the surface area of the glomerular capillary

Question 11

What is net filtration pressure?

Answer 11

(Glomerular hydrostatic pressure (high) + bowmans space oncotic pressure (low)) - (glomerular oncotic + bowmans hydrostatic)

Question 12

How would Bowmans space hydrostatic pressure go up?

Answer 12

Aome sort of blockage of the lower urinary tract would cause a back up of fluid and therefore an increase in pressure in the bowmans space. This makes filtration harder and lowers GFR

Question 13

How is net filtration pressure reduced?

Answer 13

Increase capillary oncotic pressure

Question 14

What is Oncotic pressure

Answer 14

The pressure created by large proteins which draws fluid in.

Question 15

What is auto-regulation of GFR

Answer 15

The kidneys ability to maintain constant GFR in the face of changes in blood pressure, vascular pressure, obstructions.

Question 16

How does the body change glomerular filtration rate?

Answer 16

By changing the resistance in the afferent arterioles

Question 17

How is the afferent arteriole resistance changed?

Answer 17

1.) Myogenic mechanism- contraction of arteriolar smooth muscles.
2.) Tubuloglomerular feedback mechanism- involves the juxtaglomerular complex (macula densa, juxta cells) The theory is that when there is higher NaCl at the MD, afferent resistance goes up and GFR down.
The opposite is true as well.
Important to realize that it is an increase or decrease in GFR that starts this. It somehow causes the NaCl to change conc. Not vice versa

Question 18

When and how is Renin Angiotensin system activated>

Answer 18

When there is a decrease in arterial pressure or EC volume. The decrease in BP causes a decrease in GFR which leads to a decrease in chloride at teh Macula densa. Signals are sent to Juxta cells to release renin. THis activates angiotensin which activates aldosterone and you get sodium and water retention

Question 19

Adrenaline does what to GFR?

Answer 19

decreases it

Question 20

Endothelin 1 does what to GFR

Answer 20

decreases it

Question 21

NO and Prostaglandin does what to GFR?

Answer 21

decreses it