Kidney Flashcards
What does cortex of kidney do?
Forms urine and where nephron is located
Function of kidney
- Filter 180 l blood/daily to rid toxin
- Regulate blood vol & BP
- maintain salt water balance
- maintain acid back balance
- regulate erythrocyte production
What is purpose of medulla and pyramids?
Dilute/condensate urine
Calyces, pelvis, ureter does?
Transport urine and has smooth muscle in walls
Blood flow through kidney
Arcuate artery, cortical radiate artery, afferent arteriole, glomerulus, efferent arteriole, peritubular capillaries and vasa recta, cortical radiate vein, arcuate vein
What is the nephron?
structural and functional unit of kidney and consists of renal tubules and glomerulus
Difference between cortical nephron and juxtamedullary nephron
Cortical-make up 85% of nephrons and go from efferent arterioles to peritubular capillaries
Juxtamedullary-make up 15% and go from efferent to vasa recta so they are longer
What are the 3 nephron functions
Filtration-blood to renal tubule
Reabsorption-renal tubule to blood
Secretion-blood to renal tubule
How much urine on average is produced?
2l/day
What cells secretes renin? What cells secrete ATP?
Afferent arteriole JG cells and modified mechanoreceptors -renin
DCT cells macula densa cells osmoreceptors - ATP
What is the purpose of the juxtaglomerular apparatus?
Helps regulate filtration and BP
Where does filtration occur? Reabsorption?
Bowman’s capsule-filtration
Everywhere else -Reabsorption
How is salt sensor in kidney?
DCT cells macula densa cells and osmoreceptors ( look for osmolarity)
What is filtrate?
What enters bowman’s capsule (like plasma w/o protein)
What is glomerular filtration rate (GFR)?
- Amount of filtrate formed per min
- sum of both Kinsey’s and all nephrons
- a good rate in average ~125 ml/min
- GFR directly proportional to NFP
Explain glomerular filtration
~From glomerulus to Bowman’s capsule
~passive process driven by pressure difference
~much filtrate formed
~high pressure through permeable membrane
Net filtration pressure (NFP) is?
10 mmHg
Reaction of a change in NFP
GFR change therefore increase BP increase in GFR and vis versa of decrease
If GFR too high?
Filtration flow rate too fast not enough filtrate reabsorbed
If GFR too low?
Filtrate flow rate too slow too much filtrate reabsorbed
What does does the intrinsic control do?
Controls GFR by altering afferent arteriole diameter
Vasodilation= increase NFP & GFR
Vasoconstriction=decrease NFP &GFR
What does extrinsic control do?
Contributes to control of GFR influence is outside kidney via sympathetic NS to control BP (diameter of afferent arteriole) and Renin angiotensin system constrict efferent arteriole
What is myogenic mechanism?
Part of the intrinsic control of GFR contract when stretched
⬆️ BP raise NFP & GFR arteriole constrict prevent ⬆️ GFR
⬇️BP ⬇️NFP& GFR arteriole dilate prevent decrease in GFR
Explain tubuloglomerular feedback
If NFP hi > GFR hi > rate of filtration flow hi > osmolarity hi at DCT > more ATP ( macula densa cells) > more vacoconstrict of afferent arteriole > less NFP
vice versa if NFP too low
Effects of angiotensin II
- strong vasoconstrictor
- induces adrenal cortex to secrete aldosterone
PCT “job” in Reabsorption
Reclaim all nutritive substances
Loop of Henle “job” in Reabsorption
Set up the medullary, interstitial osmotic gradient
DCT/collecting duct “job” I’m reabsorbtion
Reclaim H2O and salt if you are dehydrated hormones required here
Reabsorption occurs between what to epithelial cells?
Paracellular and transepethelial
Explain paracellular reabsorption
Minor role right junctions between epithelial cells allows movement of water and some ions Mg++ Ca++ K+ and some Na+
Reabsorption occurs across across what three membranes
- Luminal
- Basolateral
- Peritubular capillary endothelium
