Question | Answer |
What part of the nephron allows for water resorption while blocking sodium. | The thin descending limb |
What part of the nephron allows for sodium resorption while blocking water. | The thick ascending limb |
Name the 3 major parts of the Juxtaglomerular apparatus. | 1. Renin-producing granular cells
2. Macula densa
3. Extraglomerular mesangial cells |
Do the extraglomerular mesangial cells effect eh afferent or efferent arteriole? | As the cells contract they change the tone of the afferent arterioles. |
What are the 4 possibilities a fluid has traveling in the nephron? | 1. Filtered
2. Reabsorbed
3. Secreted
4. Excreted |
What id glomerular filtration rate (GFR)? | Volume/Time
Normal = 180 L/day or 125 mL/min |
What determines the rate of filtration? | Rate = Kf X NFP
Kf = hydraulic permeability X surface area |
What is included in the net filtration pressure (NFP)? | NFP = Pgc - Pcb - πgc
So
GFR = Kf (Pgc - Pbc - πgc) |
How will increasing Kf effect GFR? | Increases GFR |
How will increasing Pgc effect GFR? | Increases GFR |
How will increasing Pbc effect GFR? | Decreases GFR |
How will increasing πbc effect GFR? | Decreases GFR |
Increase in afferent arteriolar resistance will effect Pgc, GFR, and RBF in what ways? | Decreases Pgc
Decreases GFR
Decreases RBF |
Increase in efferent arteriolar resistance will effect Pgc, GFR, and RBF in what ways? | Increase Pgc
increases GFR
Decrease RCF |
What about equal increase in afferent and effecent resistance | Can cause decrease in RBF while the Pgc stays about the same |
Explain filtration factor a little bit. | FF = GFR/RPF
FF is greater at low plasma flow |
What will SNS stimulation and angiotension II do in regards to the kidney? | It will increase afferent and efferent resistances and decrease RBF. |
Where does angiotension II work most? | Efferent arterioles |
What effect will an ACE/ARB have on GFR? | CAE/ARB will cause vasodilation of the efferent arterioles thus decreasing GFR |
How are changes in GFR sensed? | As increases or decreases in NaCl sensed by the Macula Dense |
Paracrines from the Macula Dense work where? | In the afferent arteriole or vasoconstrict/dilate |
What is the over all effect of the SNS and RAAS system in regards to GFR? | decrease in RPF with only a little or no change in GFR |
How does ADH (vasopressin) work? | Vasoconstricts but normally RBF and GFR remain constant |
What about ANP? | Afferent dilation, causing increases in both GFR and RBF.
Also inhibits the secretion of Renin |
What is the role of prostaglandins? | Generally protective against excessive vasoconstriction like that seen with SNS and ANG II |