GFR and filtration

Question 1

Label

Answer 1

Question 2

where does the afferent arteriole come from?

Answer 2

interlobular

Question 3

what does the efferent arteriole drain into?

describe order of blood flow from Aorta ending at IVC

Answer 3

peritubular capillaries

Question 4

label

Answer 4

Question 5

what r the 2 types of nephrons we have and how do they differ?

which one is more abundant?

Answer 5

Question 6

difference btw peritubular capillaries and vasa recta?

Answer 6

efferent A in CORTICOL NEPHRON>> Goes to form peritubular capillary

efferent A in Juxtameduallry NEPHRON>> Goes to form vasa recta

Question 7

what is Renal plasma flow

what is filtration fraction,

Answer 7

600ml

Question 8

which part of the kidney is the glomerulus found?

what is filtration fraction

Answer 8

cortex only!

Question 9

_______% blood arriving exits via efferent arteriole (unfiltered)

Answer 9

80

Question 10

how much GFR?

Answer 10

120-125 ml/min

Question 11

what is the Renal corpuscle ?

Answer 11

Question 12

what 2 things makes up the filtration barrier?

Describe the 3 layers

Answer 12

capillary endothelium and visceral layer of Bowman’s capsule

all these 3 have a negative charge! & protein have a fixed - charge, causing them to repel!

Question 13

in some kidney diseases, this negative charge on the filtration barrier is lost!

how can this be a problamo?

Answer 13

proteins are more readily filtered - a condition called proteinuria

Question 14

describe the effeect of charge

Answer 14

graph in lecture!

Question 15

name the Physical forces involved in the filtering of plasma to form ultra filtrate

Answer 15

oncotic pressure in the glomerulus is telling the hydrostic p. in the capsule>>> please dont leave me, i’ve got all the proteins come to meee pleaseee

(so it opposing filtration)

Question 16

describe the hydtostatic oressure of the glomerulus, why does it remain high across the entire capillar bed?

Answer 16

bc the glomerular capillaries r drained by a high-resistance efferent arteriole who resistence is smaller than the afferent that feeds them

Question 17

describe Renal Autoregulation what is its purpose

Answer 17

the relative consistency of GFR and renal BF

to maintain a reletevly constant GFR!

total plamsa is only about 3 liters! any change in renal excretion can quikcly deplete it!

Question 18

how is Renal autoregulation mediated?

Answer 18

2 mechanisms:

faster myogenic response

slower tubuloglomerular (TG) feedback system.

Question 19

describe the myogenic mechanism

to what vessels does this apply to?

how quick is it?

Answer 19

ability of blood vessels to resist stretching during increased BP

super quick! (3-10s)

It is a property predominantly of the preglomerular resistance vessels

– accurate

– interlobular

– Afferent arteriole

Question 20

thinking about afferent and efferent…

how can we decrease GFR (2 ways)

how can we increase GFR (2 ways)

Answer 20

Question 21

BUT BE AWARE… effect of EFFERENT arterioles depends on the severity of the constriction…explain

Answer 21

if we increase the efferent resistence slightly> the hydosta. p will increase & GFR increase

BUTT

if they r severly constrcited! this can block renal BF! casuing proetin concentration to increase, and opppsoing forces increase, GFR decrease!

Question 22

Autoregulation is able to maintain GFR when blood pressure is within physiological limits (80-180 mmHg)

Question 23

describe the mechanism of tubular Glomerular Feedback!

Answer 23

This mechanism links Na⁺ and Cl^- concentration at the macula densa with control of renal arteriolar resistance

It has 2 components

1. 􏰃 Afferent arteriole mechaniam
2. 􏰃 Efferent arteriolar mechanism

these depend on the anaotmical arrangments of the juxtamedullary cells

Question 24

what is the juxtameduallry complex

Answer 24

consists of:

• Macular Densa on distal tubule
• jusxtamedullary cells in walls of aff and eff arterioles.

Macula densa contains golgo since its needs to send scretery organlles towards the arterioles!

Question 25

what do the macula densa sense? what recpeter do they work by?

Answer 25

changes in blood volume!

it works via the Na/k/2Cl cotransporter in the apical membrane

and its via this transporter where it can detect a change in Cl^-

Question 26

what sorts of chemicals does the jusxtameduallry apparatus release?

to increase GFR

reducd GFR

Answer 26

To increase GFR >> Prostaglandins >>vasodilator of AA

Reduce GFR>> Adenosine >>

mainlyyyy works through A1 recepter on affer>> causes constriction

and A2 on efferent >> dilation

Question 27

how does NSAIDS have an effect on the the bp?

Answer 27

NSAIDS inhbit prostaglandins

no dilation of afferent

decreased GFR

Decrease Bp

Question 28

BUT THESE R ALL ACUTE MECHANISM!

Question 29

Neural regulation of GFR

Answer 29

• Sympathetic nerve fibres innervate AE and EA
• Fight or Flight Or ischaemia Or haemorrhage (sever) can stimulate renal vessels
• Vasoconstriction occurs as a result which conserves BV (haemorrhage) and can cause a fall in GFR

Question 30

if Na CL was _____at macula densa, this causes _____of afferent Arterioles!

Question 31

whic areteriole is highly sensitive to ANg 2

Answer 31

EFFERENT

Question 32

1st line of defence Myogenic and TG feedback

what comes next?

Answer 32

2nd line of defence

Glomerulotubular Balance blunts sodium excretion response to any GFR changes which do occur despite 1st line reposnses